Part 10 - cd3wd410.zip - Offline

Part 10 - cd3wd410.zip - Offline
AT,
MICROFICHE
;3lTs?l;;cE
A project of Volunteers in Asia
I
J&&# Technoloav l-&&&
By: VITA
Published by: Volunteers in Technical Assistance
1815 North Lynn Street
Arlington, VA 22209
Available from: Volunteers in Technical Assistance
1815 North Lynn Street
Arlington, VA 22209
Reproduced with permission.
Reproduction of this microfiche document in any form is subject to the same
restrictions as those of the original document.
Volunteers in Te.chical Assistance
18l5 Nor& Lynn Street
Arhgto~vii22musA
Cqyright @ !98R Vohmtccrs in Technical Assistant
rights reserved. Na part of this publi,at.ion may be reproduced or transmilted
in any form or by any means, electronic or mechanical, including photocopy,
recording, or any information storage and retrieval system, without the written
permission of the publisher.
All
(This is the third edition of a manual first published in 1’263, with the support of
the U. S. Agency for International Dcvelopmcnt, and revised in 1970, which has
gqnc through eight ma,ior printings.)
anufactured in the United States of America.
Set in Times Ron~u~r type on an LBM personal computer, a gift to VITA from
lntcrnational Business Machines Corporation, using WordPerfect software donated
by WordPerfect Corporation.
Puhlishcd by: Volunteers in Technical Assistance
1815 North Lynn Street, Suite XXI
Arlington, Virginia 22209 USA
10987654321
Library of Congress Cat
i~-~~~t~ Data
Village technology handbaok.
Etihliography: p. 413
I. Building--Amateurs’ manuals. 2. Do-it-yourself work. 3. Home economics,
Rural--Handbooks, manuals, etc. 1. Volunteers in Technical Assistance.
88-L ;.i!
TH148.V64 1088
620’.41734
ISBN O-S&519-275-1
I
...
nn
WATER RESSURCES
Deve
WaterSources . . . . . .
Getting Ground Water from Wells and Springs
Ground Water . . . . . . . .
FlowofWatertoWells
. . . . .
WhereToDigaWell . . . . . .
Well Casing and Seal . . . . . .
Wel! Development . . . . . . .
Tubewells . . . . . . . . . . .
Well Casing and Platforms . . . .
Hand-Operated Drilling Equipment . .
Dry Bucket Well Drilling . . . . .
Driven Wells . . . . . . . . .
DugWells . . . . . . . . . . .
Sealed Dug Well. . . . . . . .
Deep Dug Well . . . . . . . .
Reconstructing Dug Wells . . . . .
Spring Development . . . . . . . .
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3
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5
6
10
11
12
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18
47
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53
54
57
60
63
Water
andTransport . . . . . . . . . . . . 67
Overview . . . . . . . . . . . . . . . _ . . 67
Moving Water . . . . . . . . . . . . . . . . 67
Lifting Water . . . . . . . . . . . . . . . . 67
Water Transport . . . . . . . . . . . . . . . . 69
Estimating Small Stream Water Flow . . . . . . . . . 69
Measuring Water Flow in Partially Filled Pipes
. . . . . 72
Determining Probable Flow with Known Reservior Height and
SiieandLengthofPipe . . . . . . . . . . . . 74
EstimatingWater Flow from Horizontal Pipes . . . . . . 76
Determining Pipe Size or Velocity of Water in Pipes
. . . 78
Estimating Flow Resistance of Pipe Fittings
. . . . . .80
Bamboo Piping. . . . . . . . . . . . . . . . 82
Water
Lifting . . . . . . . . . . I . . . . . . 88
Pump Spccitications: Choosing or Evaluating a Pnmp . . . . 88
Determining Pump Capacity and Horsepower Requirements . . 92
Determining
Lit Pump Capability . . . . . . . . . . 95
Simple Pumps . . . . . . . . . . . . . . . . %
Chain Pump for Irrigation . . . . . . . . . . . %
Inertia
Haud Pump. . . . . . . . . . . . . . . 101
Handle Mechanism for Hand Pumps . . . . . . . . . 105
Hydraulic Ram . . . _ . . . . . . . . . . . . 108
Reciprocating Wire Power Transmission for Water Pumps. . . . 111
W’ind Energy for Water Pumping . . . . . . . . . . . 117
Overview . . . . . . . . . . . . . . . . . 117
Decision Making Process . . . . . . . . . . . . . 117
WaterSorqeandTreafment
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Cisterns . . . . . . . . . . . . . . . . . .
Cistern Tank . . . . . . . . . . . . . . .
Catchment
Ares . . . . . . . . . . . .
Cistern Filter . . . . . . . . . . . . . .
Selecting a Dam Site . I . . . . . . _ . ~ . . .
Catchment Area . . . . . . . . . . . . . .
Rainfail . . . . . . . . . . . _ . . . . .
Location. . . . . . . . . . . . . . . . .
Water Purification . . . . . . . . . . . . .
Boiler for Drinking Water . . . . . . . . . . .
. . . . . .
Chlorinating Wells, Springs, and Cisterns
Water Purification Plant . . . . . . . . . . .
Sand Filter . . . . . . . . . . . . . . . .
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129
129
131
132
135
136
136
136
138
140
142
147
149
HEALTH AND SANITATION
SanilaryLatrines..
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.x55
Overview. . . . . . . . . . . . . . . . . 157
Privy Location . . . . . . . . _ . . . . . . 157
Privy Shelters . . . . . . . . . . . . . . . 1.59
Privy Types . . . . . . . . . . . . . . . . . . 161
Pit Privy. . . . . . . . . . . . . . . . 161
Water Privy . . . . . . . . . . . . . . . . . 164
Philippine Water-Seal Latrine . . . _ L . : . . . . 169
Thailand Water-Seal Privy Slab . . . . . . . . . . 174
Bii . . . . . _
The Parasites . . . . .
Symptoms and Diagnosis
Treatment . . . . . .
Prevention . . . . . .
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.185
185
187
187
187
Ridding an Area of Biiarziasis
. . . . . . . . . . . 189
MalarZaCcmtroi
.... - ........... l!U
C-mmunity Preventive Measures . . . . . . . . . . . 1%
Personal Preventive Meiusures . . . . . . . . . . . 192
Treatment . . . . . . . . . . . . . . . . . . 192
Oral RehydratiouTherapy . . . . . . . . . . . . . W
Dehydration-A Life-Ttueateuing Condition . . . . . . . .195
Treating or Preventing Dehydration . . . . . . . . . . 195
~~~~~f~
Drag Grader. . . . . .
Fresno Scraper . . . . .
Barrel Fresno Scraper
. .
Construction . . . .
Operation . . . . .
Repairing theBarrel Fresno
Adapting for Heavy Duty .
Float with Adjustable Blade
Buck Scraper . . . . .
V-Drag . . . . . . .
Multiple Hitches . . . .
andRoadBl&Iilrg
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Scraper . . . . .
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Irrigatiolb . . . . . . . . .
Siphon Tubes . . . . . . . .
Using Tile for Irrigation and Dr&age
Making a ConcreteTide Machine
Making the Tie . . . . . .
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Sceds,WeedqandPests. . .
Seed Cleaner . . , . . .
Seed Cleaning Sieves
. . .
Drying Grain with Wooden Blocks
PreTaringthe Blocks . . .
Using the Blocks . I . .
Buck% Sprayer I . . . . .
Backpack Crop Duster. . . .
How the Duster Operates. .
Adjusting the Duster . . .
Filling the Duster
. . .
Making Springs for the Duster
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vii
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* 201
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. 199
. 203
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209
210
213
214
214
214
217
219
221
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239
240
241
242
243
243
245
250
250
251
251
. . . . . . . . . . .
Po&ryRai&g
. . . . .
Brooder with Corral for 280 Chicks
. .
KeroseneLampBrooder for75 to 10OChicks
Brooder for 300 Chicks . . . . . . . . .
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. .253
. . 253
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. . 255
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. . 257
. .257
. .2.58
. . 258
. .259
. . 260
irIg . .
The Soil . . . . . .
The Growing Beds. . .
. .
Fertilizing the Soil
. .
Selection of Crops
Mulch. . . . . . .
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Bamboo Poultry House
House. . . . .
Roof . . . . .
Feeders . . . .
Nests. . . . .
Poultry Feed Formulas
~~~0~~~
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261
261
261
262
263
264
-265
D PROCESSfNG AND PRESERVATION
~~~~atHome. . . . . .
How to Care for Various Kinds of Food
DairyFoods. . . . . . . .
. . .
Fresh Meat, Fish, Poultry
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Eggs.
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Fresh Fruits and Vegetables
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Fats and Oils
Baked Goods . . . . . . .
Dried Foods. . . . . . . .
CannedGoods . . . . . . .
Leftover Cooked Foods . . . .
FoodSpoilage . . . . . . . .
WbeuisFoodSpoiled? . . . .
Why Sod Spoils . . . . . .
Containers for Food . . . . . .
Types of Containers . . . . .
Care of Food Containers . . . .
The Storage Area . . . . . . .
GoodVentilation . . . . . .
Keep the Storage Area Cool and Dry
Keep the Storage Area Clean . .
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.273
. 273
.273
. 274
.275
. 275
. 276
. 276
. 277
. 277
. 277
. 278
. 278
. 278
. 281
. 281
. ‘282
. 283
. 284
. 284
. 284
. .
Evaporative Food Cooler .
Iceless Cooler . . . .
Window Box. . . . .
Other Ways To Keep Foods
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-285:
. 286
. 288
. 288
. 290
andFruit.sforW~erUse
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.295
.295
. 2%
.297
. 2%
.298
. 299
. 300
KeepingFoodsCool
StoihlgV
Post Plank Cellar
CabbagePits .
Storage Cones .
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Cool
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SaltingFiih
. . . . . . .
Preparing the Fish
Salting . . . . . . . . . . .
Washing and Drying To Remove Excess Salt
AirDrying. . . . . . . . . .
Using Salted Fish . . . . . . . .
Smoking Fisn . . . . . . . . . .
FiiPreseNation
a3
291
292
293
293
WCTION
.eteConatruction = . . . . . .
Overview. . . . . . . . . . .
ImportanceofaGoodMixture . . . .
Ee;gates: Gravel and Sand . . . .
. . . . . . . . . . . .
Calculating Amounts of Materials for Concrete
Using the “Concrete Catculator”
. . .
Using the Water Displacement Method .
Using “Rule of Thumb” Proportions . .
Mixing Concrete . . . . . . . . .
Making a Mixing Boat or Floor . . . .
Slump Tests . . . . . . . . .
Making Forms for Concrete . . . . . .
Placing Concrete in Forms . . . . . .
Curing Concrete . . . . . . . . .
Quick-Setting Concrete . . . . . . .
ElalIlboo-.
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303
. 303
. 304
. 305
. 305
. 306
.39
. 311
. 311
. 311
. 313
. 314
. 316
. 316
. 317
. . . . . . . .
. . . . . . . .
........
........
. . . . . . . .
. . . . . . . .
. . . . . . . .
.
Preparing Bamboo. . . . . . .
Splitting Bamboo . . . . . .
Bamboo Preservation . . . . .
Bamboo
Joints
e . . . . . . .
Bamboo Boards. . . . . . .
Bamboo Wags, Partitions, and Ceilings
ix
319
320
220
322
323
326
328
Walls. . . . . . . . . . . . . . . . . . .32S
Partitions . . . . . . . . . . . . . . . . . 328
ceilings. . . . . . . . . . . . . . . . . .330
Ekrth-on . . . .
Overview. . . . . . . . . . .
Soil Characteristics . . . . . . .
. . . . . . . .
Testing the Soil
Composition Test . . . . . . .
Compaction Test . . . . . . .
Shrinkage lest . . . . . . . .
Making Adobe Blocks. . . . . . .
Making Compressed Earth Blocks and Tiles
Building with Stabilized Earth Blocks
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-331
. 331
. 331
. 332
. 332
. 333
. 333
. 334
. 336
. 337
Glues . .
ue. . . . .
Making Casein Powdec
Mixing Casein Glue .
Using Casein Glue . .
Liquid Fish Glue . . .
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.xf9
.339
. 339
. 340
. 341
. 342
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Simple W~~a~n~ . _ .
Plunger Type Clothes Washer . .
Making the Washer. . . . .
Using the Washer . . . . .
Hand-Operated Washing Machine .
Making the Washing Machine
Usiig the Washing Machine . .
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ChkersandStowa . . . . . .
Fireless Cooker
. . . . . . .
Making the Fireless Cooker . . .
Using the Fireless Cooker . . .
Charcoal Oven . . . . . . . .
How To Build the Oven . . . .
HowToUsetheOven. . . . .
Portable Metal Cookstoves . . . .
Principles of Energy-Efficient Stoves
Cookstove Desigu . . . . . .
Producing the Cookstoves . . .
Outdoor Oven . . . . . . . .
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. 345
. 345
. 34s
.346
.346
. 350
351
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.
.
.
.353
. 353
. 3.54
. 354
. 355
. 355
. 357
. 357
. 357
. 359
. 361
. 363
Home Snap M
. . . . . . . . . . . . . ..M
Two Basic Methods . . . . . . . . . . . . . . 365
Iogredients for Soap . . . . . . . . . . . . . . . 36.5
Fat.s and Oii . . . . . . . . . . . . . . . 365
Lye.. . . . . . . . . . . . . . . . . .366
Borax. . . . . . . . . . . . . . . . . . .366
Perfume. . . . . . . . . . . . . . . . . .366
Water. . . . . . . . . . . . . . . . . . .36G
Soap Makmg with Commercial Lye. . . . . . . . . . . 367
Recipes . . . . . . . . . . . . . . . . . . 367
HowToMaketheSoap . . . . . . . . . . . . . 368
HowToKnowGoodSoap . . . . . . . . . . . . 369
Reclaimmg Unsatisfactory Soap . . . . . . . . . , 369
Soft Soap with Lye Leached from Ashes . . . . . . . . . 370
Leaching the Lye . . . . . . . . . . . . . . . 370
Making the Soap . . . . . . . . . . . . . . . 372
Larger-Scale Soap Making . . . . . . . . . . . . . 373
. 375
. 375
. 377
. 377
, 378
. . . . . . . . _.........
A West of Low-Cost Beds. . . . . . . . . . . . .
How To Make a Mattress. . . . . . . . . . . . .
Making the Mattress . . . . . . . . . . . .
Making a Rolled Edge. . . . . . . . . . . . .
AND?4LfAGEINDUSTRY
Pottery . . . . . . . . . . . . . . . . . . .381
Waste-Oil Fired Kiln . . . . . . . . . . . . . . . 381
Cost Advantages of Waste Oil . . . . . . . . . . 381
DesignofKilnandFireBox . . . . . . . . . . . 381
Operating the Kiln . . . . . . . . . . . . 383
Small
Rectangular
Kiln . . . . . . . . . . . . . . 383
Construction . . . . . . . . . . . . . . . . 383
Firing . . . . . . . . . . . . . . . . .388
Salt Glaze for Pottery . . . ? . . . . . . . . . . 390
Considerations . . . . . . . . . . . . . . 390
How To Fiie the Pottery . . . . . . . . . . . . . 390
~~~P~~~.
.
.
.
Papermakmg Processes . .
Pre-processing . . . .
Pulpin& . . . . . .
Lifting, Couch@, Stacking
Pressing and Drying .
Sizing . . . . . .
Calendering . . . . .
.
.
.
.
.
.
. . . . . . . . .
. . . . . . . . .
. . _ . . . .
. . . ) . . . _ ”
. . . . . . . .
. . . . . . . .
. . . . . . . .
.
.
.
.
.
.
.
xi
.
.
.
.
.
.391
. . 391
. . 391
. . 391
. 392
. . 392
. .392
. . 393
Sorting and Cutting . . . . .
Making Paper iu the Small Workshop .
Pulping . . . . . . . f .
Making the Sheets . . . . . .
Pressing
and Drying . . . . .
Sizing and Coating . . . . .
Making Paper in the Micro-Factcry .
CandIeMakiag.... . -.
Making the Jigs . . 1
Preparing the Wax . . . . .
Dipping the Candles . . . .
cm
.
.
.
.
.
.
.
. .
. . .
. .
. .
.
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.
. _.
. . . .
. . . .
. . . .
.
~ .
.
.
.
.
.
.
393
393
393
394
39.5
395
396
. . -397
. . ~
397
. _ . 398
. . . 398
CATIONS
BamImorRcedwrittPeas
. . . . . . . . . . . .4m
s~k~~n~ . . . . . . .
Building the Silk Screen Printer . .
Printing . . . . . . . . . . .
Preparing A Paper Stencil . . .
Making Silk Screen Paint . . . .
lmxpc&RubberGmeti.
ItEmsENcEs..
. . . .
. . . . .
. . . .
. _ . . .
. . . .
.405
. 405
. 406
. 408
. 409
. . . . . . . . . . .
-411
. . . . . .
. .
. .
. .
. .
. .
*.
.
.
.
.
.
. . . . . .
*4I3
CONVERSION TABLES . . . . . . . . . . . . 1 423
xii
The Village Technology Handbook has been an important tool for development
workers and do-it-yourselfers for 25 years. First published in 1%3 under the
auspices of the U.S. Agency for International Development, the Handbook has
gone through eight major printings. Versions in French and Spanish, as well as
English, are on shelves in bookstores, on desks in government ofhcts and local
organizations, in school libr-iries and technical centers, and in the field kits of
village workers around the world. The technologies it contains, like the chain and
washer pump, the evaporative food cooler, and the hay box cooker, have been
built for technology fairs and demonstration centers throughout the developing
world-and more importantly, have been adopted and adapted by people everywhere.
Because !he Handbook has been a faithful friend for so long, this revision was
approached with care. As even the best of friendships needs an occasional
reassessment, our question was how to update the book without damaging its
fundamental utility-to avoid throwing !he baby out with the bath water.
We began by circulating sections of the book to VITA Volunteers with expertise
in the various technical areas. We asked them to take a good hard look at what
was presented and let us know what should be revised, updated, discarded,
replaced. The volunteers’ replies affirmed what tens of thousands of users aroued
the world have recognized over the years, that the basic material was sound.
Where they suggested changes, additions, and deletions, we have done our best to
oblige.
I
Concurrently, we reviewed the comments that many of those users have sent to
us over the years. Comments on what worked, what caused trouble, and what
would be nice to have included. With so much going on in the development of
small-scale, village technologies, the latter category was extensive. But because so
much of the original book is still very applicable today, we opted to make the
additions and changes selectively. We made the decision to add to this volume
where it seemed most feasible, and to begin to compile a companion volume that
will cover a selection of those other technologies.
Since the Hundbrwk is primarily intended for “do-it-yourselfers” in villages and
rural regions, most space still is allocated to the development of water resources
and to agriculture. And rather than simply replacing everything and starting over,
this new edition reorganizes some sections, updates several of the original
articles, and includes a number of new ones on frequently requested topics. The
new articles cover energy efficient stoves, the use of wind power to pump water,
stabilized earth construction, a novel ceramics kiln, small-scale candle and paper
production, high yield gardening, oral rehydration therapy, and malaria control. An
all-new reference section is also provided.
VlTA is committed to asisting sustainable growth: that is, to progress, based on
expressed needs, that increases self reliance. Access to clearly presented technical
information is a key to such growth. VITA searches out, develops, and disseminates techniques and devices that contribute to self suffrency. The ViNrrgr?
Technolop Handbook is one such VITA effort to support sustainable growth with
easy to read technical information for the communities of the world.
VITA Volunteers are similarly committed to helping VITA help others, and many
of them were involved in this project, reviewing material in their technical fields.
VITA wishes to thank Robert M. Ross and David C. Neubert for reviewing the
sections on agriculture; Phil D. Weinert, Charles G. Bumey, Walter Lawrence, and
Steven Schaefer, water resources and purification; Malcolm C. Bourne and Norman
M. Spain, food processing and preservation; Dwight R. Brown and Witliam Perenchio, construction; Charles D. Spangler, sanitation; Jeff Wartluft, Mark Hadley,
Marietta Ellis, Gerald Kinsman, and Peter Zweig, home improvement; Dwight
Brown aqd Victor Palmeri, crafts and village industries; and Grant Rykken,
communications.
Most especially* we would like to thank VITA Volunteer engineer and literacy
specialist Len Doak, who was coaxed out of retirement and away from the fishing
docks to coordinate the revision, sort out the comments, and pull the new pieces
together.
VITA staff who were involved included Suzanne Brooks, administrative support and
graphics; Julie Berman, administrative support; Margaret Crouch, editorial; and
Maria Garth, typesetting.
And finally, this effort has given all of us a new respect for Dan Johnson, one of
VITA’s “founding fathers” and currently a member of the Board of Directors, who
devoted a year of his life to putting the original Handbook together a quarter of
a century ago. That so much of that work has stood the test of time is due in no
small measure to the care with which he and the other VITA Volunteers who
worked with him approached their task.
-VITA Ptkhations
January 1988
xiv
The village Technology Hundbook contains eight major subject sections, each containing several articles. The articles cover both the broad topic areas such as
agriculture, as well as specific agricultural projects such as building a scraper.
If you are planning an entirely new project you would benetlt by reading the entire section through. If you are planning a specific project (such as building a
wind-driven water pump) only that article need be read.
The skills needed for each of the projects described vary considerably, but none
of the projects requires more than the usual construction and trade skills such as
carpentry, welding, or farming that are generally found in most modest sized viilages.
When the materials suggested in the Handbook are not available, it may be possible to substitute other materials. Be careful tc make any changes in dimensions
made necessary by such substitutions.
If you need translations of articles from the Handbook, we ask that you let us
know. The book itself has been translated intn English, French, and Spanish, and
some individual articles may be available in other languages.
The articles in the Handbook came from many sources. Your comments and suggestions for changes, difficulties with any of the projects described, or ideas for
new articles are welcome. Those kinds of comments were a very important element in preparing this revised edition, and we expect to rely on them in the
future as well. Please send your comments so that we may continue to share.
~ su
I
BY SECTP
Section 1. Water
Water resources are so vital that extensive coverage is provided. Much of this
material is from the original, but it has been reorganized and updated. The
sequence of articles begins with principles of hydrology that explain wheie
underground water is likely to be found. This is followed by articles on types of
wells and how to make well drilling tools and how to drill or dig the wells.
Next come articles on practical methods to lift water from wells and to transport
it. Articles on several pumps and water piping occur here. A new article on winddriven pumps is in this section. A number of charts and tables help in the
calculation af pipe size and water flow.
Water storage and puriticatiorr are the topics of the next series of articles. This
section is unchanged from the earlier edition, but several new references are
listed.
section 2.
ealth and $anitati~n
Next to pure water, sanitation is one of the most critical health needs of any
society. This section begins with two brief articles on the principles for disposal
of human waste. These are followed by details of how to build various types of
latrines. Also included is an article on bilharziasis (schistosomiasis) and a new
articles on malaria control and oral rehydration therapy.
stool 3. Agriculture
Seven topics are covered, beginning with earth moving devices to level fields and
build irrigation ditches. This is followed by directions for an irrigation system
based on concrete tile, including how to make the tile in the field. A variety of
material on raising poultry is included, and a new article on small, high yield
gardens has been added.
Section 4. Food Processing and Prese~ation
The articles in this section describe storage and handling of different types of
food, evaporative coolers and other cold storage technologies, and a variety of
other storage and processing systems and devices. The section has been revised
and updated and new references have been added.
Section 5. Construction
Much of this section deals with construction of buildings and walls using concrete
or bamboo. A new article on stabilized earth construction has been added, and
instructions for making glues to use in construction are also included.
Section 6. Home Improvements
Washing clothes, cooking, making soap, and making bedding are covered here. An
important new addition is an article on the construction of an energy efficient
cookstove developed in West Africa. The stove has shown more than double the
fuel efficiency of the traditional open fire.
Section 7. Crafts and Village Industry
Traditionai crafts that lend themselves to development as small businesses are
discussed in this section--pottery, hand papermaking, and candle making. Ceramic
kilns described include an alternative kiln design fueled by waste motor oil.
Section 8. Communications
T&s section remains Iunchanged from the original on the premise that while
changes in communications could actually fill volumes on their own, there are
many places in developing areas where the simple technologies presented here are
still quite useful. Simple writing instruments and silk screen printing are discussed. The skills and materials described should be available in most rural
villages.
CES @BARD
ONAL INFO
TIQN
Each article in the Hundbwk concludes with one or more source references. These
and other sources of information have been compiled into the new expanded
Reference section at the back of the book. VfTA publications that are fisted may
be ordered directly from VITA Publications, Post Of&e Box 12028, Arlington,
Virginia 22204 USA.
You may also request technical assistance from VITA Volunteer experts by writing
to VITA, 1815 North Lynn Street, Suite 200, Arlington, Virginia 22209 USA.
xvii
Volunteers in Technical Assistance (VITA) is a private, nonprofit, international
development organization. It makes available to individuals and groups in developing countries a variety of information and technical resources aimed at fostering
self suffLziency-needs assessment and program development support; by-mail and
on-site consulting services; information systems training; and management of longterm field projects.
Throughout its history, VITA has concentrated on practical and workable technologies for development. It has collected, organized, tested, synthesized, and
disseminated information on these technologies to more than 70,000 requesters and
hundreds of organizations in the developing countries. As the information revolution dawned, VITA found itself in a leadership position in the effort to bring the
benefits of that revolution to those in the Third World who are traditionally
passed over in the development process.
Perhaps of greatest significance is VITA’s emphasis on technologies that are
commercially viable. These have the potential of creating new wealth through
adding value to local materials, thereby creating jobs and increasing income as
well as strengthening the private sector. We have increasingly translated our
experiences in information management to the implementation of projects in the
field. This evolution from information to implementation to create jobs, businesses, and new wealth is what VITA is really about. It provides missing links
without creating dependency.
VITA places speciai emphasis on the areas of agriculture and food processing,
renewable energy applications, water supply and sanitation, housing and construction, and small business development. VITA’s activities are facilitated by the
active involvement of thousands of VITA Volunteer technical experts from around
the world, and by its documentation center containing specialized technical
material of interest to people in developing countries.
VITA currently publishes over 150 technical manuals, papers, and bulletins, many
available in French and Spanish as well as English. Manuals deal with construction
or implementation details for such specific topics as windmills, reforestation,
water wheels, and rabbit raising. In addition, VITA Technical Bulletins present
plans and case studies of specific technologies to encourage further expcrimcntation and testing. The technical papers-“Understanding Technology”-offer general
introductions to the applications and necessary resources for technologies or
technical systems, Included in the series are topics that range from composting to
Stirling engines, from sanitation at the community level to tropical root crops.
Publications catalogues are available upon request.
KTA News is a quarterly magazine that provides an important communications
link among far-flung organirations involved in technology transfer and adaptation.
The News contains articles about projects, issues, and organirations around the
world, reviews of new books, technical abstracts, and a resources bulletin board.
WTA derives its income from government, foundation, and corporate grants, fees
for setices; contracts; and individual contributions.
For fur!her information write to VITA, 1815 North Lynn Street, Suite 200,
Arlington, Virginia 22209 USA.
@.
* .
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1
at
inch
foot
degrees Celsius (Centigrade)
cubic centimeter
centimeter
centimeters per second
diameter
degrees ‘Fahrenheit
gram
gallons per minute
horsepower
kilogram
kilometer
liter
liters per minute
liters per second
meter
milliiters
millimeters
m’eters per minute
meters per second
parts per million
radius
There are three main sources of water for small water-supply systems: ground
water, surface water, and rainwater. The choice of the source of water depends
on local circumstances and the availability of resources to develop the water
source.
study of the local area should be made to determiue which source is best for
providing water that is (1) safe and wholesome, (2) easily available, and (3)
sufficient in quantity. The entries that follow describe the methods for tapping
ground water:
A
0
Tubewells
- Well Casings and Platforms
- Hand-Operated Drilling Equipment
- Driven Wells
0
Dug Wells
Spring Development
0
Ouce the water is made available, it must be brought from where it is to where it
is needed and steps must be taken to be sure that it is pure. These subjects are
covered in the major sections that follow:
0
-0
Water Lifting and Transport
Water Storage and Treatment
This section de&res ground water, discusses its occurrence, and explains its
movement. It desc:ibes how to decide on the best site for a well, taking into
consideration the nearness to surface water, topography, sediment type, and
nearness to pollutants. It also discusses briefly the process of capping and sealing
the well and developing the well to assure maximum flow of water.
Ground water is subsurface water, which tills small openings (pores) of loose
sediments (such as sand and gravel) or rocks. For example, if we took a clear
glass bowl, filled it with sand, and then poured in some water, we would notice
4
the water “disappear” into the sand (see Figure 1). However, if we looked through
the sidr of the bowl, we would see water in thz sand, but below the top of the
sand. The sand containing the
water is said to be saturated. The
top of the saturated sand is called
t h e wafer ruble; it is the level o f
the water in the sand.
F/&UPS *
The water beneath the water table
is true ground water available (by
pumping) for human use. There is
water in the soil above the water table, bnt it does not fIow into a well and is
not avaitahle for use by pumping.
If we inserted a straw inio the saturated sand in the bowl in Figure I and sucked
on tht- straw, we would obtain some w’ater (initially, we would get some sand too).
If WC socked long enough, the water table or water level would drop toward the
bottom of the bowl. This is exactly what happens when water is pumped from a
well drilled below the waler table.
The IWO basic factors in the oc~currence of ground water are: (1) the presence of
water, and (2) a medium to “house” the water. In nature, water is provided by
precipitation (rain and snow) and surface water features (rivers and lakes). The
medium is porous rock or loose sediments.
The most abundant ground water reservoir occurs in the loose sands and gravcis
in ri?cr valleys. Hcrc the water table roughly par&Is the iand surface, lhai is,
the dcplh to the water table is gcncraily coolant. Disregarding any drastic
ch:tnges in climate, natural ground water conditions are fairly uniform or baianccd. In Figure 2, the water poured into the bowl (analogous to precipitation) is
balanced by the water discharging out of the bowl at the lower elevation (analo-gous to discharge into a stream)
This movement of ground water is
slow, genera!ly just ccntimcters or
inches per day.
F/GOAT-E 2
When the waler table intersects the
land surface, springs or swamps are
formed (see Figure 3). During a
particularly wet season, the water
table will come much closer to the
land surface than it normally does
and many new springs or swampy
areas wil! appear. On the other hand, during a particularly dry season, the watel
table will be lower than normal and many springs will “dry up” Many shallow
wells may also “go dry.”
5
A newly dug well fills with water a meter or so (a few feet) deep, but after some
bard pumping it becomes dry. Has the well failed? Was it dug in the wrong place?
More likely you are witnessing the phenomenon of drawdown, an effect every
pumped well has on the water table (see Figure 4).
Because water flows through sediments slowly, almost any well can be pumped dry
temporarily if it is pumped hard enough. Any pumping will lower the water level
to some degree, in the manner shown-in Figure 4. A serious problem arises only
when the drawdown due to normal use lowers the water table below the level of
-
-
----.e-----v-w
After the well has been dug about a meter (several feet) below the water table, it
should be pumped at abom the rate it will be used to see if the flow into the
well is adequate. If it is not suflicient, there may be ways to improve it. Digging
the well deeper or wider will not only cut across more of the water-bearing layer
to allow more flow into the well, but it will also enable the well to store a
greater quantity of the water that may seep in overnight. If the well is stili not
adcquatc and can be dug no deeper, it can be widened further, pcrhnps iengthencd
in one direction, or more wells can be dug. The goal of all these methods is to
intersect more of the water-be,aring layers, so that the well will produce more
water without lowering the water table to the bottom of the well.
Four important factors to consider in choosing a well site are:
0
0
0
0
Nearness to Surface Water
Topography
Sediment Type
Nearness to Pollutants
~e~~~~~§§ to S@ace Water
If there is surface water nearby, such as a lake or a river, locate the well as
near to it as possible. It is likely to act as a source of water and keep the water
table from being lowered as much as without it. This does not always work well,
however, as lakes and slow-moving bodies of water generally have siit and slime
on the bottom, which prevent water from entering the ground quickly.
There may not seem to ‘x much point to digging a well near a river, but the
tiitering action of the sod will result in water that is cleaner and mote free of
bacteria. It may also be cooler than surface water. ff the river level fluctuates
during the year, a well will give cleaner water (than stream water) during the
flood season, ahbough ground water often gets dirty during and after a flood. A
well wilt also give more reliable water during the dry season, when the water
level may drop below the bed of the river. This method of water supply is used
by some cities: a large well is sunk next to a lake or river and horizontal tunnels
are dug to increase the flow.
Wells near the ocean, and especially those on islands, may have not only the
problem of drawdown, but that of salt water encroachment (see Figure 5). The
7
underground boundary between fresh and salt water generally slopes inland:
bxx~use salt water is heavier than fresh water, it flows in under it. If a well
near the shore is used heavily, salt water may come into the well as shown. This
should not occm in wells from which only a moderate amount of water is drawn.
Ground water, being liquid, gathers in low areas. Therefore, the Lowest ground is
generally the best place to drill or dig. ff your area is flat or steadily sloping,
and there is no surface water, one place is as good as another to “tart drilling or
di-g&g. If the land is hilly. valley bottoms are the best places to look for water.
You may know of a hilly area with a spring on the side of a hill. Such a spring
could be the result of water moving through a layer of porous rock or a fracture
~orx in othcmise impervious rock. Good water sources can result from such
lc‘~iorrs.
Ground waicr occurs in porous or fractured rocks or scoi.~ents. Gravel, sand and
sandstone are more porous than clay, unfractured shale and granite or “hard
r~ozk.”
r’- ,ure 6 shows in a general way the relationship between the availability of
ground water (expressed by typical well discharges) and geologic material (sediments and various rock types). For planning the well discbarge necessary for
irrigating crops, a good rule of thumb for semi-arid climates-37.5cm (IS’) of
precipitation a year-is a IXk- to LWMters (400 to 500 U.S. gallons)-per-minute
well that will irrigate about 65 hectares (160 acres) for about six months. From
Figure 6. we see that webs in sediments are generally more than adequate.
However, enough ground water can be obtained from rock, if necessary, by
drilling a number of wells. Deeper water is generally of better quality.
Sand and gravel are normally porous and clay is not, but sand and gravel can
contain different amounts of silt and clay, which will reduce their ability to carry
water. The only way to find the yield of a sediment is to dig a well and pump it.
In digging a well, be guided by the results of nearby wells and the effects of
seasonal fluctuations on nearby wells. And keep an eye on the sediments in your
well as it is dug. In many cases you will find that the sediments are in layers,
some porous and some not. You may be able to predict where you will hit water
by comparing the layering in your well with that of nearby weiis.
Figures 7, 8, and 9 illustrate severa! sediment situations and give guidelines on
how deep to dig wells.
8
FIGURE 6:
Availabilily
of Ground Waicr
in Water
Bearing S&iments or Rock
Types
Sand. Gravel. and Clay
Sand and Clay
R0(‘K
~:~~~~,~~dS~s~“~~-----‘----~
VolwiicRock~--------
------,-------+
i~.ilnr-lane----*/----------------------,
S;mdSU%---.+----*
Sandsone
and Shale
Oranire wd
“Hard Rock”
Shale
-4
EXPLANAT[ON
- Average LPM (Generally Used)
- - - - + Maximum LPM Noted in Rep.xts
sediments) of Sand and Gravel. Generally ield 11,400
ut they may yield less depending on pump, wel rconstruc-
Aquifers of Limestone. General1
ield ktwceu 53 LPIM (1Qgpm) bui have been
known to vield more than {8&I L,PM (1000 gpm) due to caverns or nearness
of stream,‘etc.
Aqr$ers of Granite and/or “Hard Rock.” Generally yield 38 gpm (IOgpm) and may
yield less (enough fcr a small holischold).
Aqt~~crs c!f .‘%~le. Yield less than 38 LPRI ( IOgpm). not much good for anything
csccpl as a last resort.
10
If pollution is in the ground water, it moves with it. Therefore, a well should
always be uphill and 15 to Xl meters (50 to 100 feet) away from a la!rine,
barnyard, or other source of pollution. If the area is flat, remember that the flow
of ground water will be downward, like a river, toward any nearby body of
surface water. Locate a well in the upstream direction from pollution sources.
The deeper the water table, the less chance of pollution because the pollutants
must travel some distance downward before entering ground water. The water is
purified as it flows through the soil.
Extra water added to the pollutants will increase their flow into and through the
soil, although it will also help dilute them. Poilution of ground water is more
likely during the rainy than the dry season, especially if a source of pollution
such as a latrine pit is allowed to till with water. See also the Overview to the
Sanitary katrincs scc!ion, p. 149. Similarly, a well that is heavily used will
increase the fiow of ground water toward it, perhaps even reversing the normal
direction of ground-water movement. The amount of drawdown is a guide LO how
heady the well is being used.
Polluted surface water must be kept out of the well pit. This is done by casing
and sealing the well and providing good drainage around the well cover.
The purpose of casing and sealing wells is to prevent contaminated surface water
from entering the well or nearby ground water. As water wilt undoubtedly be
spilled from any pump, the top of the well must be sealed with a concrete slab to
let the water Row away rather than re-enter the well directly. It is also helpful
to build up the pump area with soil to form a slight hill that will help drain away
spilled water and rain water.
Casing is the term for the pipe, concrete or grout ring, or other material that
supports the well wall. It is usually impermeable in the upper part of the well to
keep out po!iuted water (see Figure 7) and may be perforated or absent in the
iower part of the well to let water enter. See also “Well Casing and Platforms,” p.
12, and “Reconstructing Dug Wells,” p. 57.
~
In loose sediment, the base of the well should consist of a perforated casing
surrounded by coarse sand and small pebbics; otherwise, rapid pumping may bring
into the well enough material to form a cavity and collapse the well itself.
Packing the area around the well hole in the water-bearing layer with tine gravel
will prevent sand from washing in and increase the effective size of the well. The
ideal gradation is from sand to bmm (t/4”) gravel next to the well screen. In a
drilled well it may be added around the screen after the pump pipe is installed.
Well development refers to the steps taken after a well is drilled to ensure
maximum Row and well life by preparing the sediments around the well. The layer
of scdimcnts from which the water is drawn often consis!s of sand and silt. When
the ;uell is first pumped, the line material will be drawn into the well and make
the water muddy. You will want to pump out this fme material to keep it from
muddying the water later and to make the sediments near the well more porous.
However, if the water is pumped too rapidly at first, the fine particles may
collect against the perforated casing or the sand grains at the bottom of the well
and block the flow of water into it.
A method for removing the line malerial successfully is to pump slowly until the
water clears, then at successively higher rates until the maximum of the pump or
well is reached. Then the water level should be permitted to return to normal and
the process repeated until consistently clear water is obtained.
Another method is surging, which is moving a plunger (an attachment on a drill
rod) up and down in the well. This canses the water to surge in and out of the
sedimentary layer and wash loose the line particles, as well as any drilling mud
stuck on the wail of the well. Coarse sediment washed into the well can be
removed by a bailing bucket, or it may be left in the bottom of the well to serve
as a litter.
Sources:
Anderson, K.E. Water II+0 Handbook. Rolla, Missouri: Missouri Water Wells
Drillers Association. 1%5.
Baldwin, H.L. and McGuinness, CL. A Primer 012 Grorrrtd Wurer. Washington, DC.:
U.S. Government Printing Office, 1964.
Davis, S.N. and DeWiest, R.J.M. Hydrogeeology. New York: Wiley & Sons, 1966.
Todd, D.K. Gro~rnrl Wafer Hjdrologv. New York: Wiley PC Sons, 1959.
Wagner, E.G. and Lanoiq J.N. IVater Scrppiy for Nurol Areas and hail Commr~nities. Geneva: World Health Organization, 1959.
Ground lV~prr!er and IV&. Saint Paul, Minnesota: Edward E. Johnson, Inc., 1966.
Small Water Supplies, Bulletin No. 10. London: The Ross Institute, 1%7.
U.S. Army. Wells. Technical Manual S-297. Washington, DC.: U.S. Government
Printing Office, 1957.
12
soii conditions permit, the tubcwcils described here will, if they have the
necessary casing, provide pure water. They are much easier to install and cost
much less than large diamctcr wells.
Where
Tubewells will probably work well where simple earth borers or ea.rth augers work
(i.e., alluvial plains with few rocks in the soil), and where there is a permeable
water-bearing layer 15 to 25 meters (50 to 8@ feet) below the surface. They are
sealed wells, and consequently sanitary, which offer no halard to small chiidren.
The small amounts of materials needed keep the cost down. These wells may not
yield enough water for a large group, but they would be big enough for a family
of a small group of families.
The storage capacity in small diameter wells is smail. Their yield depends largely
on the rate at which \yater flows from the surrounding soil into the well. From a
saturated sand layer, the flow is rapid. Watu flowing in quickly replaces water
drawn from the wcli. A welt that taps such a laler seldom goes dry. Rut even
when water-bearing sand is not reached, a well with even a limited storage
capacity may yield enough water for a household.
In home or village wells, casing and platforms serve two purposes: (1) to keep
well sides from caving in, and (2) to seal the well and keep any polluted surface
water from entering it.
Two low-cost casing techniques are described here:
I. Method A (see Figure I), from an American Friends Service Committee (AFSC)
team in Rasulia, Madhya Pradesh, India.
2. Method B, from an International Voluntary Sen;ices (IVS) team in Vietnam.
Tools and Materials
Casing pipe (from pump to water-bearing layer to below minimum water table)-Asbestos cement, tile, concrete, or even galvanized iron pipe will do
Sand
Gravel
Cement
Device for lowering and placing casing (see Figure 2)
Drilling rig - see “Tubewell Boring”
Foot valve, cylinder, pipe, hand pump
13
The well hole is dug as deep as
possible into the water-bearing
strata. The diggings are placed near
the hole to make a mound, which
later will serve to dram spille,d
water away from the well. This is
important because backwash is one
of the few sources of contamination for this type of well. The
entire casing pipe below water level
should be perforated with many
small holes no larger than 5mm
(3/16”) in diameter. Holes larger
than this will allow coarse sand to
be washed inside and plug up the
well. Fine particles of sand,
however, ars expected to enter.
These should be small enough to be
pumped immediately out through
the pump. This keeps the well
clear. The first water from the new
well may bring with it large
quantities of tine sand. When this
happens, the first strokes should be
strong and steady and continued
until the water comes clear.
Perforated casing is lowered, bell
end downward, into ihe hole using
the device shown in Figure 2. When
the casing is properly positioned,
the trip cord is pulled and the next
section prepared and lowered. Since
holes are easily drilled in asbestos
cement pipe, they can be wired
together at the joint and lowered
into the well. Be sure the bells
point downward, since this will
prevent surface water or backwash
from entering the well without the
purifying tiltration effect of the
soil; it will also keep sand and dirt
from filling the well. Install the
casing vertically and till the
remaining space with pebbles. This
will hold the casing plumb. The
casing should rise .3O to @cm (1’ to
2) above ground level and be
surrounded with a concrete pedestal
to hold the pump and to drain
spilled water away from the hole.
Casing joints within 3 meters (10
feet) of the surface should be
sealed with concrete or bituminous
material.
Plastic seems to be an ideal casing material, but because it was not readily
available, the galvanized iron and concrete casings described here were developed
in the Ban Me Thuot area of Vietnam.
Tools and Materials
Wooden Y-block, 23&m (7 l/2’) long (see Figure 3)
Angle iron, 2 sections, ‘30cm (7 l/2’) long
Pipe, 1Ocm (4”) in diameter, 23&m (7 l/2’) long
Clamps
Wooden mallet
Soldering equipment
Galvanized sheet metal: 0.4mm x Im x 2m (0.016” x 39 l/2” x 79”)
Iastic Casing
Black plastic pipe for sewers and drains was almost ideal. Its friction’ joints could
be quickly slipped together and sealed with a chemical solvent. It seemed durable
but was light enough to be lowered into the well by hand. It could be easily
sawed or drilled to make a screen. Care must be taken to be sure that any plastic
used is non-toxic.
Galvanized sheet metal was used to make casing similar to downspouting. A
thicker gauge than the 0.4mm (0.016”) available would have been preferable.
Because the sheet metal would not last indefinitely if used by itself, the well hole
was made oversize and the ring-shaped space around the casing was filled with a
thin concrete mixture which formed a cast concrete casing and seal outside the
sheet metal when it hardened.
The l-meter x 2-meter (39 l/2” x 79’j sheets were cut lengthwise into three
equal pieces, which yielded three 2-meter (79”) lengths of 1Ocm (4”) diameter pipe.
The edges we,re prepared for making seams by clamping them between the hvo
angle irons, then pounding with a wooden mallet to the shape shown in Figure 3.
The seam is made slightly wider at one
end than at the other to give the pipe a
slight taper, which allows successive
lengths to be slipped a short distance
inside one another.
The strips are rolled by bridging them over a 2-meter (7Yj V-shaped wooden
block and applying pressure from above with a length of Scm (2”) pipe (see Figure
4). The sheet metal strips are shifted from side to side over the V-block as they
are being bent to produce as uniform a surface as possible. When the strip is bent
enough, the two edges are hooked
together and the 5cm (2”) pipe is slipped
inside. The ends of the pipe are set up
on wooden blocks to form an anvil, and
the seam is firmly crimped as shown in
Figure 5.
After the seam is finished, any irregularities in the pipe are removed by
applying pressure by hand or with the
wooden mallet and pipe anvil. A local
tinsmith and his helper were able to
LV
F/6&Q?fi 5
make six to eight lengths (12 to 16
meters) of the pipe per day. Three
lengths of pipe were slipped together and soldered as they were made, and the
remaining joints had to be soldered as the casing was lowered into the well.
The lower end of the pipe was perforated with a hand drift to form a screen.
After the easing was lowered to the bottom of the well, tine gravel was packed
around the perforated portion of the casing to above the water level.
16
The cement grouting mortar used around the casings varied front pure cement to a
1:l l/2 cement : sand ratio mixed with water to a very plastic consistency. The
grout was put around the casing by gravity and a s&rip of bamboo about 10
meters (33 feet) long was used to “rod” the grout into place. A comparison of
volume around the casing and volume of grouting used indicated that there may
have been some voids left probably below the reach of the bamboo rod. These are
not serious however, as long as a good seal is obtained for the first 8 to 10
meters (26 to 33 feet) down from the surface. In general, the greater proportion
of cement used and the greater the space around the casing, the better seemed to
be the results obtained. However, insufficient experience has been obtained to
reach any fina! conclusions. In addition, economic considerations limit both of
these factors.
Care must be taken in pouring the grout. if the sections of casing are not
assembled perfectly straight, the casing, as a result, is not centered in the well
and the pressure of the grouting is not equal all the way around. The casing may
collapse. With reasonable care, pouring the grout in several stages and allowing it
to srt in-between should eliminate this. The grouting, however, cannot be poured
in too many stages because a considerable amount sticks to the sides of the well
each time, reducing the space for successive pourings to pass through.
This method can be modified for use in areas where the structure of the material
thrcagh which the well is drilled is such that there is little or no danger of
cave-in. In this situation, the casing serves only one purpose, as a sanitary seal.
The wctt will be cased only about 8 meters (26 feet) down from the ground
surface. To do this, the well is drilled to the desired depth with a diameter
roughly the same as that of the casing. The well is then reamed out to a
diameter 5 to Gem (2” to 2 l/4”) larger than the casing down to the depth the
casing will go. A flange &ted at the bottom of the casing with an outside
diameter about equal to that of the reamed hole will center the casing in the
hole and support the casing on the shoulder where the reaming stopped. Grouting
is then poured as in the original method. This modification (1) saves considerable
costly material, (2) a!lows the well to be made a smaller diameter except near the
top, (3) lessens grouting difficulties, and (4) still provides adequate protection
against pollution.
If the well is enlarged to an adequate diameter, precast concrete tile with
suitable joints could be used as casing. This would require a device for lowering
the t&s into the well one by one and rekasing them at the bottom. Mortar
would have to be used to seal the joints above the water level, the mortar being
spread on each successive joint before it is lowered. Asbestos cement casing
would also be a possibility where it was available with suitable joints.
17
The last possibility would be to use no casing at all. It is felt that when finances
or skiils do not permit the well to be cased, there are certain circumstances
under which an uncased well would be better than no well at all. This is particularly true in localities where the custom is to boil or make tea out of all
water before drinking it, where sanitation is greatly hampered by insufficient
water supply, and where small-scale hand irrigation from wells can greatly
improve the diet by making gardens possible in the dry season.
The danger of pollution in an uncased well can be minimized by: (1) choosing a
favorable site for the well and (2) making a platform with a drain that leads
away from the well, eiiminating ,&I spilled water.
Such a well should be tested frequently for pollution. if it is found unsafe, a
notice to this effect should be posted conspicuously near the well.
In the work in the Ban Me Thuot area, a Rat 1.75-meter (5.7’) square slab of
concrete was used around each well. However, under village conditions, this did
not work well. Large quantities of water were spilled, in part due to the enthusiasm of the villagers for having a plentiful water supply, and the areas around
wells bccamc quite muddy.
The conclusion was reached that the only really satisfactory platform would be a
round, slightly convex one with a small gutter around the outer edge. The gutter
should lead to a concreted drain that would take the water a considerable
distance from the well. It is worth noting that in Sudan and other very arid areas
such spillage from community wells is used to water vegetable gardens or
community nurseries.
If the well platform is too big and smooth, there is a great temptation on the
part of the villagers to do their laundry and other washing around the well. This
should be discouraged. In villages where animals run loose it is necessary to build
a small fence around the well to keep out animals, especially poultry and pigs,
which are very eager to get water, but tend to mess up the surroundings.
Koegel, Richard G. Report. Ban Me Thuot, Vietnam: International Voluntary
Services, 1959. (Mimeographed.)
Mot!, Wendell. Erp!anamy N&es on T;;Sewells. Philadelphia: American Priends
Service Committee, 1956. (Mimeographed.)
Two me,thods of dritliig a shallow tubewell with hand-operated equipment are
described here: Method A, which was used by an American Friends Service
Committee (AFSC) team in India, operates by turning an earth-boring auger.
Method 5, developed by an International Voluntary Services (IVS) team in
Vietnam, uses a ramming action.
This simple hand-dril~iag rig can be used to dig wells 15 to 2Ocm (6” to 8”) in
diameter up io 15 meters (50’) deep.
Tools and Materials
Earth auger, with coupling to attach to 2Scm (1”) drill line (see entry on
tubcwell earth augers)
Standard wcigbt galvanized steel pipe:
4 pieces: 2&m (I”) in diameter and 3 meters (10’) long (2 pieces have
threads on one end only; others need no threads.)
2 pieces: 2.Scm (I”) in diameter and 107cm (3 l/2”) long
For Turning W~~~ie:
2 pieces: 2.5cm (I”) in diameter and 61cm (2’) long
2.5cm (1”) T coupiing
For Joint A:
4 pieces: 32mm (1 l/4”) in diameter and 3Ocm (1’) long
Couplings for Joint R:
Ucm (9”) Section of 32mm (1 l/4”) diameter (threaded at one end only)
35.5~~1 (14”) Section of 38mm (1 l/2”) diameter (threaded at one end
only)
Reducer coupling: 32mm to 25mm (I l/4” to 1”)
Reducer coupling: 38mm to 25mm (I l/2” to 1”)
g IOmm (3/S”) diameter hexagonal head machine steel bolts 45mm (1
3/4:‘) long, with outs
2 lOmm (3/8”) diameter hexagonal head machine steel bolts Scm (2”)
long, wilh nuts
9 1Omm (3/S”) steel hexagonal nuts
19
For T
te Bolt:
13mm (l/8”) diameter countersink head iron rivet, 12Smm (l/2”) long
1 1Smm (l/16”) sheet steel, IOmm (3/8”) x 25mm (1”)
Drills: 3mm (l/8”), 17Smm (13/B?), 8.75mm (13/32”)
Countersink
Thread cutting dies, unless pipe is already threaded
Small Tools: wrenches, hammer, backsaw, files
For platform: wood, nails, rope, ladder
Basically the method consists of rotating an ordinary earth auger. As the auger
penetrates the earth, it fills with soil. When full it is pulled out of the hole and
emptied. As the hole gets deeper, more sections of drilling line are added to
extend the shaft. Joint A (Figures 1 and 2) is a simple method for attaching new
sections.
By building an elevated platform 3 to 3.7 meters (IO to 12 feet) feom the ground,
a 7.6-meter (25 foot) long section of drill line can be balanced upright. longer
lengths are too difficult to handle. Therefore, when the hole gets deeper than 7.6
meters (25 feet), the drill line must be taken apart each time the auger is
removed tor emptying. Joint B makes this operation easier. See Figures 1 and 3.
Joint C (see construction details for Tubewell Earth Auger) is proposed to allow
rapid emptying of the auger. Some soils respond welt to drilling with an anger
that has two sides open. These are very easy to empty, and would not require
Joint C. Find out what kinds of augers are successfully used in your area, and do
a bit of experimenting to find the one best suited to your soil. See the entries on
augers.
Joint A has been found to be faster to use and more durable than pipe threaded
connectors. The pipe threads become damaged and dirty and are difficult to start.
Heavy, expensive pipe wrenches get accidentally dropped into the well and are
bard to get out. These troubles can be avoided by using a sleeve pipe fastened
with two IOmm (3/S”) bolts. Neither a small bicycle wrench nor the inexpensive
bolts will obstruct drilling if dropped in. Be sure the 32mm (1 l/4”) pipe will fit
over your 25mm (I”) pipe drill. line before purchase. See Figure 2.
Four 3-m&r (lo’) sections and two 107cm (3 l/2’) sections of pipe are the most
convenient lengths for drilling a 15-m&r (SO’) well. Drill an 8.75mm (13/3T’)
diameter hole through each end of all sections of drill line except those attaching
to Joint B and the turning handle, which must be threaded joints. The holes
should be Fcm (2”) from the end.
When the well is deeper than 7.6 meters (25’). several features facilitate the
emptying of the auger, as shown in Figures 3 and 4. First, pull up the full auger
Will Pipe
drill line
17.5mn hole about
in the middle of
32mn oioe to clear
the lb& toggle
.bolt--mark location thru 3Emn pipe
-Stop bolt
1hoSteel bait
km long
until Joint B appears at the surface. See Figure 4A. Then put a 19mm (3/qj
diameter rod through the hole. This allows the whole drill line to rest on it
making it impossible for the part still in the well to fall in. Next remove the
toggle bolt. lift out the top section of line and balance it beside the hole. See
Figure 4B. Pull up the auger, empty it, and replace the section in the hole where
it will be held by the S9mm (3/4”) rod. See Figure 4C. Next replace the upper
section of drill fine. The IOmm (3/K’) bolt acts as a stop that allows the holes to
be easily lined up for reinsertion of the togle bolt. Finally withdraw the rod and
lower the auger for the next drilling. Mark the location for drilling the 8.75mm
(13/32”) diameter hole in the 32mm (1 l/4”) pipe through the toggle bolt hole in
the 38mm (1 l/2”) pine. If the hole is located with the 32mm (1 l/4”) pipe resting
on the stop bolt, the holes are bound to line up.
Sometimes a special tool is needed to penetrate a water-bearing sand layer,
because the wet sand caves in as soon as the auger is removed. If this happens a
perforated casing is lowered into the well, and drilling is accomplished with an
auger that fits inside the casing. A percussion type with a flap, or a rotary type
with solid wahs and a flap arc good possibilities. See the entries describing these
devices. The casing will settle deeper into the sand as sand is dug from beneath
it. Other sections of casing must be added as drilling proceeds. Try to penetrate
the water bearing sand layer as far as possible (at least three feet-one meter).
Ten feet (three meters) of perforated casing embedded in such a sandy layer will
provide a very good flow of water.
This earth auger (Figure 5) which is similar to designs used with power drilling
equipment, is made from a 15cm (6”) steel tube.
The auger can be made without
welding equipment, but some of the
bends in the pipe and the bar can
be made much more easily when
the metal is hot (see Figure 6).
An open earth
easier to empty
better suited for
auger cuts faster
Sand Auger.
auger, which is
than this one, is
some soils. This
than the Tubewell
Tools and Materials
Galvanized pipe: 32mm (1 l/4”) in diameter and 21Scm (8 l/2”) long
Hexagonal head steel bolt: 1Omm (3/8”) in diameter and 5cm (2”) long, with nut
2 hexagonal head steel bolts: 1Omm (3j8”) in diameter and 9.5cm (3 3/4”) long
2 Steel bars: I.25cm x 32mm x 236Smm (l/2” x 1 l/4” x 9 5/N’)
4 Round head machine scmws: 1Omm (3/8”) in diameter and 32mm (1 l/4”) long
2 Flat head iron rivets: 3mm (l/S”) in diameter and 12.5mm (l/T’) long
Steel strip: 1Omm x 1Smm x 2.5cm (3/f? x l/16” x 1”)
Steel tube: 15cm (6”) outside diameter, 62Scm (24 5/8”) long
Hand tools
U.S. Army and Air Force. IVeNs. Technical Manual 5-297, AFM 85-23. Washington,
D.C.: U.S. Government Printing Office, 1957.
23
FIGURE 6
TOP
l@min toogle holts
5cm X 32.5cm cut out
this side only.
'Seiiior! LiA-Grind
Ail cuttiny
edqcs
thus
24
Tubewell Sand Auger
This sand auger can be used to drill in loose soil or wet sand, where an earth
auger is not effective. The simple cutting head requires less force to turn than
the Tubewell Earth Auger, but it is more difficult to empty.
A smaller version of the sand auger made to
tit inside the casing pipe can be used to
remove loose, wet sand.
The tubewell sand auger is illustrated in
Figure 7. Construction diagrams are given in
Figure R.
To& and Materials
Steel tube: l&m (6”) outside diameter and
46cm (18”) long
Steel plate: 5mm x 16.5cm x 16Scm (3/W x 6
S/2” x 6 l/2”)
Acetylene welding and cutting equipment
Drill
WIls, Technicai Manual S-297, AFM 85-23, U.S. Army and Air Force, 1957.
Tubewell Sand hailer
The sand bailer can be used to drill from inside a perforated well casing when a
bore goes into loose wet sand and the walls start to cave in. It has been used to
make many tubewells in India.
Tools and Materials
Steel tube: 12Scm (5”) in diameter and 91.5cm (3’) long
Truck innertube or leather: 12.5cm (5”) square
Pipe coupling: 15cm to 2.5cm (5” to 1”)
Small tools
:::.
7::’
:i;:
:::
t:;
:/
I
. ..~~.::::::::::::
._
1
p-?-j
Li
25mm
tble
7.15
n
4
i
46
0"
15.7cm
I
I
-
DETAIL OF BOTTOM
FIGURE !3
Repeatedly jamming this “bucket” into the well will remove sand from below the
perforated casing, allowing the bucket to settle deeper into the sand layer. The
casing prevents the walls from caving in. The bell is removed from the first
section of casing; at least one other section rests on top of it to help force it
down as digging proceeds. Try to penetrate the water bearing sand layer as far as
possible: 3 meters (10’) of perforated casing embedded in such a sandy layer will
usually provide a very good flow of water.
Be sure to try your sand “bucket” in wet sand before attempting to use it at the
bottom of your well.
Explanatory Notes on Tubewells, Wendell Mott, American Friends Service Committee, Philadelphia, Pennsylvania, 1956 (Mimeographed).
US/NG A SA/L
j::::::::::::::::::::::::
:,:._... . . . ......._ ~~~:.~.:;.:,;:,.~..:.:.:.:.:.~:.:.:.:.:,:,;
:.:.:.:.:.:.:.~:.:.:.~.
A’GUG’E 9
IWLL FRO/w’ /NSfDEA WELL CAS/r/G
27
Ram Auger
The equipment described here has been used successfuhy in the Ban Me Thuot
area of Vietnam. One of the best performances was turned in by a crew of three
inexperienced mountain tribesmen who drilled 20 meters (65’) in a day and a half.
The deepest well drilled was a little more than 25 meters (80’); it was completed,
including the installation of the pump, in six days. One well was drilled through
about 11 meters (35’) of sedimentary stone.
Tools and Materials
For tool tray
Wood: 3cm x 3cm x 150cm (1 l/4” x 1 l/4” x 59”)
Wood: 3cm x 3Ocm x 45cm (11 /Y x 1Y x 17 314”)
For safety rod:
Steel rod: lcm (3/P) in diameter, 3Ocm (12”) long
Drill
Hammer
Anvil
Cotter pin
For auger supportz
Wood: 4cm x 45cm x3&m (1 l/3” x 17 3/4” x 12”)
Steel: 1Ocm x 1Ocm x 4mm (4” x 4” x 5/32”)
Location of the Well
Two considerations are especially important for the location of village wells: (1)
the average walking distance for the village population should be as short as
possible; (2) it should be easy to drain spilled water away from the site to avoid
creating a mudhole.
In the Ban Me Thuot area, the final choice of location was in all cases left up to
the villagers. Water was found in varying quantities at all the sites chosen. (See
“Getting Ground Water from Wells and Springs.“)
Starting to Drill
A tripod is set up over the approximate location for the well (see Figure 1). Its
legs are set into shallow holes with dirt packed around them to keep them from
moving. To make sure the well is started exactly vertically, a piumb bob (a string
with a stone tied to it is good enough) is hung from the auger guide on the
tripod’s crossbar to locate the
exact starting point. It is helpful
to dig a small startiny hole before
setting up the auger.
Drilling
Drilling is accomplished by ramming
the auger down to penetrate the
earth and then rotating it by its
wooden handle to free it in the
hole before lifting it to repeat the
process. This is a little awkward
until the auger is down 3&m to
6Ocm (1’ to 2’) and should be done
carefully until the auger starts to
be guided by the hole itself.
Usually two or three people work
together with the auger. One
system that worked out quite well
was to use three people, two
working while the third rested, and
then alternate.
As the auger goes deeper it will be
necessary from time to time to
adjust the handie to the most
convenient height. Any wrenches or
other small tools used should be
tied by means of a long piece of
cord to the tripod so that if they
are accidentally dropped in the
well, they can easily be removed.
Since the soil of the Ban Me Thuot
area would stick to the auger, it
was necessary to keep a small
amount of water in the hole at all
times for lubrication.
Emptying the Auger
Each time the auger is rammed
down and rotated, it should be
noted how much penetration has
been obtained. Starting with an
empty auger the penetration is
greatest on the first stroke and becomes successively less on each following one
as the earth packs more and more tightly inside the auger. When progress
becomes too slow it is time to raise the auger to the surface and empty it.
Depending on the material being penetrated, the auger may be completely full or
have 3Ocm (1’) or less of material in it when it is emptied. A little experience
will give one a “feel” for the most efficient time to bring up the auger for
emptying. Since the material in the auger is hardest packed at the bottom, it is
usually easiest to empty the auger by inserting the auger cleaner through the slot
in the side of the auger part way down and pushing the material out through the
top of the auger in several passes. When the: auger is brought out of the hole for
emptying, it is usually leaned up against the tripod, since this is faster and easier
than trying to lay it down.
Coupling and Uncoupling Extensions
The extensions are coupled by merely slipping the small end of one into the large
end of the other and pinning them together with a 1Omm (3/8”) bolt. It has been
found sufficient and time-saving to just tighten the nut finger-tight instead of
using a wrench.
Each time the auger is brought up for emptying, the extensions must be taken
apart. For this reason the extensions have been made as long as possible to
minimize the number of joints. Thus at a depth of 18.3 meters (60’) there are
only two joints to be uucoupled in bringing up the auger.
For the sake of both safety and speed, use the following procedure in coupling
and uncoupling. When bringing
-- up
_ the auger, raise it until a joint is iust above
the ground and sllip I:he auger support (see-Figures 2 and 3) into place,-straddiing,
the extension so that the bottom of
the coupling can rest on the small
metal plate. The next step is to put
the safety rod (see Figure 4)
through the lower side in the
coupling and secure it with either a
cotter pin or a piece of wire. The
purpose of the safety rod is to
keep the auger from falling into
the well if it should be knocked
off the auger support or dropped
while being raised.
Once the safety rod is in place,
remove the coupling bolt and slip
the upper extension out of the
lower. Lean the upper end of the
extension against the tripod be-
L
-
I
-
31
tween the two wooden pegs in the front legs, and rest the lower end on the tool
tray (see Figures 5 and 6). The reason for putting the extensions on the tool tray
is to keep diit from sticking to the lower ends and making it diff%xdt to put the
extensions together and take them apart.
To couple the extensions after emptying the auger, the procedure is the exact
reverse bf uncoupling.
TOOL TRAY
-
32
Drilling Rock
When stone or other substances the auger cannot penetrate are met, a heavy
drilling bit must be used.
Depth of Well
The rate at which water can be taken from a well is roughly proportional to the
depth of the well below the water table as long as the well keeps going into
water-bearing ground. However, in
village wells where water can only
be raised slowly by handpump or
bucket, this is not usually of major
importance. The important po’mt is
that in areas where the water table
varies from one time of year to
another the well must be deeo
enough to give sufficient water at
all times.
information on the water table
variation may be obtained from
already existing wells, or it may be
necessary to drill a well before any
information can be obtained. in the
latter case the well must be deep
enough to allow for a drop in the
water table.
Source:
Report by Richard ii. Koegel, International Voluntary Services, Ban Me Thuot,
Vietnam, 1959 (Mimeographed).
Equipment
The following section gives construction details for the well-drilling equipment
used with the ram auger:
0
0
0
0
0
0
Auger, Extensions, and Handle
Auger Cleaner
Demountable Rean,er
Tripod and Pulley
Bailing Bucket
Bit for Drilling rock
Auger, Extensions, and Handle
The auger is hacksawed out of standard-weight steel pipe about l.Ocm (4”) in
diameter (see Figure 8). Lightweight tubing is not strong enough. The extensions
(see Figure 9) and handle (see Figure 10) make it possible to bore deep holes.
Tools and Materials
Pipe: 1Ocm (4”) in diameter, 120cm (47 l/4”) long, for auger
Pipe: 34mm outside diameter (1” inside diameter); 3 or 4 pieces 3Ocm (12”) long,
for auger and extension socket
Pipe: 26mm outside diameter (3/4” inside diameter); 3 or 4 pieces 6.1 or 6.4 meters
(20’ or 21’) long, for drill extensions
Pipe: 1Omm outside diameter (l/2” inside diameter); 3 or 4 pieces 6cm (2 3/8”)
long
Hardwood: 4cm x 8cm x 5Ocm (1 l/2” x 3 l/8” x 19 3/4”), for handle
Mild steel: 3mm x 8cm x 15cm (l/8” x 3 l/8” x 6”)
4 Bolts: lcm (3/S”) in diameter and 1Ocm (4”) long
4 Nuts
Hand tools and welding equipment
In making the auger, a flared-tooth cutting edge is cut in one end of the 1Ocm
pipe. The other end is cut, bent, and welded to a section of 34mm outsidediameter (1” inside-diameter) pipe, which forms a socket for the drill line
extensions. A slot that runs nearly the length of the auger is used for removing
soil from the auger. Bends are made stronger and more easily and accurately when
the steel is hot. At first, an auger with two cutting lips similar to a post-hole
auger was used, but it became plugged up and did not cut cleanly. In some soils,
however, this type of auger may be more effective.
,,,,,
36
Auger Cleaner
Soil can be removed rapidly from the auger with this auger cleaner (see Figure
11). Figure 12 gives construction details.
Tools and Materials
Mild steel: 1Ocm (4”) square and 3mm (l/8’) tl+k
Steel rod: lcm (3/8”) in diameter and 52cm (20 l/2”) long
Welding equipment
Hacksaw
File
- /zo
/Otvr.
I
1
Z.=---I-
WELD
F/GLARE?1
AUGER
ClEAlvER
-,
,,,
37
Demountable Reamer
If the diameter of a drilled hole has to be made bigger, the demountable reamer
described here can be attached to the auger.
Tools and Materials
Mild steel: 2&m x 5cm x 6mm (6” x 2” x l/4”), to ream a well diameter of 19cm
(7 l/2”)
2 Bolts: 8mm (S/16”) in diameter and l&m (4”) long
Hacksaw
Drill
File
Hammer
Vise
The reamer is mounted to the top of the auger with two hook bolts (see Figure
13). It is made from a piece of steel Icm (l/z’) larger than the desired well
diameter (see Figure 14).
After the reamer is attached to the
top of the auger, the bottom of the
auger is plugged with some mud or
a piece of wood to bold the
cuttings inside the auger.
In reaming, the auger is rotated
with only slight downward pressure.
It should be emptied before it is
too full so that not too many
cuttings will fall to the bottom of
the well when the auger is pulled
up.
FlGURE /J
Because the depth of a well is
more important than the diameter
i n d e t e r m i n i n g t h e llow a n d
because doubling the diameter
means removing four times the
amount of earth, larger diameters
should be considered only under
special circumstances. (See “Well
Casing and Platforms,” page 12.)
Tripod and Pulley
The tripod (see Figures 15 and 16), which is made of poles and assembled with
16mm (5/8”) bolts, serves three purposes: (1) to steady the extension of the auger
when it extends far above ground; (2) to provide a mounting for the pulley (see
Figures 17 and 19) used with the drill bit and bailing bucket; and (3) to provide a
place for leaning long pieces of casing, pipe for pumps, or auger extensions while
they are being put into or taken out of the well.
When a pin or bolt is put through the holes in the two ends of the “L”-shaped
pulley braeke: (see Figures 15 and 18) that extend horizontally beyond the front
of the tripod crossbar, a loose guide for the upper part of the auger extensions is
formed.
To keep ihe extensions from falling when they are leaned against the tripod, two
3Ocm (12”) long wooden pegs are driven into drilled holes near the top of the
tripod’s two front legs (see Figure 19).
Tools and Materials
3 Poles: 15cm (3”) in diameter and 4.25 meters (14’) long
Wood for cross bar: 1.1 meter (43 l/2”) x 12cm (4 3/4”) square
For pulley wheel:
Woodz 25cm (10”) in diameter and 5cm(2”) thick
Pipe: 1.25cm (l/2”) inside diameter, 5cm (2”) long
Axle bolt: to fit close inside 1.25cm (l/2”) pipe
Angle iron: 8ocm (31 l/z’) long, 50cm (19 3/4”) webs, 5mm (3/X”) thick
4 Bolts: 12mm (l/2”) in diameter, 14cm (5 l/2”) long; nuts and washers
Bolt: 16mm (5/g”) in diameter and 4Ocm (15 3/4”) long; nuts and washer
2 Bolts: 16mm (5/E?‘) in diameter and 25cm (9 7/g”) long; nuts and washers
Bore 5 places through center of poles for assembly with 16mm bolts
Bore 5 places thru center of
poles far assembly with 16 DIA. bolts
F/GUZ?E 17
/i%S/
F/6URE 18
SCALE: l/4 size
MAT'L: HARDWOOD
SCALE: l/4 size
MAT'L: Mild Steel
42
Bailing Bucket
The baifmg bucket can be used to remove soil from the well shaft when cuttings
are too loose to be removed with the auger.
Tools and Materials
Pipe: about 8Scm ( 3 3/8”) in diameter, 1 to 2cm (l/2” to 3/4”) smaller in
diameter than the auger, l&m (71”) long
Steel rod: 1Omm (3/Y’) in diameter and 25cm (10”) long; for bail (handle)
Steel plate: 1Ocm (4”) square, 4mm (5/32”) thick
Steel bar: lOcm x lcm x 5mm (4” x 3/8” x 3/16”)
Machine screw 3mm (l/8”) in diameter by 16mm (5/8”) long; nut and washer
Truck innertube: 4mm (5/32”) thick, 1Omm (3/g”) square
Welding equipment
Drill
Hacksaw
Hammer
Vise
File
Rope
Both standard weight pipe and thin-walled tubing were tried for the bailing
bucket. The former, being heavier, was harder to use, but did a better job and
stood up better under use. Both the
steel bottom of the bucket and the
rubber valve should be heavy
because they receive hard usage.
The metal bottom is reinforced
with a crosspiece welded in place
(see Figures 20 and 21).
When water is reached and the
cuttings are no longer fum enough
to be brought up in the auger, the
bailing bucket must be used to
clean out the well as work
progresses.
For using the bailing bucket the pulley is mounted in the pulley bracket with a
14mm (5/8”) bolt as axle. A rope attached to the bailing bucket is then run over
the pulley and the bucket is lowered into the well. The pulley bracket is so
designed that the rope coming off the pulley lines up vertically with ths, well, so
that there is no need to shift the tripod.
The bucket is lowered into the well, preferably by two people and allowed to drop
e
L
44
the last meter or meter and one-half (3 to 5 feet) so that it will hit the bottom
with some speed. The impact will force some of the loose soil at the bottom of
the well up into the bucket. The bucket is then repeatediy raised and dropped 1
to 2 meters (3 to 6 feet) to pick up more soil. Experience will show how long
this should be continued to pick up as much soil as possible before raising and
emptying the bucket. Two or more people can raise the bucket, which should be
dumped far enough from the well to avoid messing up the working area.
If the cuttings are too thin to be brought up with the auger but too thick to
enter the bucket, pour a little water down the well to dilute them.
Bit for Drilling Rock
The bit described here has been used to drill through layers of sedimentary stone
up to 11 meters (36’) thick.
Tools and Materials
Mild steel bar: about 71x1 (2 3/4”) in diameter and about 1.5 meters (5’) long,
weighing about 80kg (175 pounds)
Stellite (a very hard type of tool steel) insert for cutting edge
Anvil and hammers, for shaping
Steel rod: 2.5cm x 2cm x 50cm (I” x 3/4” x 19 3/4”) for bail
Welding equipment
The drill bit for cutting through stone and hard formations is made from the 80kg
(175-pound) steel bar (see Figures 22 and 23). The N-degree cutting edge is hardsurfaced with stellite. A bail (or
handle) for attaching a rope or
cable is welded to the top. The bail
should be large enough CO make
“fishing” easy if the rope breaks. A
2.5cm (I”) rope was used at first,
but this was subject to much wear
when working in mud and water. A
lcm (3/8”) steel cable was substituF/G&WE22
ted for the rope, but it was not
“C4YY BIT FO.2 D.w“ING m2CH
used enough to be able to show
whether the cable or the rope is better. One advantage of rope is that it gives a
snap at the end of the fall which rotates the bit and keeps it from sticking. A
swivel can be mounted between the bit and the rope or cable to let the bit
rotate.
If a bar this size is difticult to find or too expensive, it may be possible,
depending on the circumstances, to make one by welding a short steel cutting en?
onto a piece of pipe, which is made heavy enough by being filled with concrete.
NGU..E 23
R
46
In using the drilling bit, put the pulley in place as with the bailing bucket, attach
the bit to its rope or cable, and lower it into the well. Since the bit is heavy,
wrap the rope once or twice around the back leg of the tripod so that the bit
cannot “get away” from the workers with the chance of someone being hurt or
the equipment getting damaged. The easiest way to raise and drop the bit is to
run the rope through the pulley and then straight back to a tree or post where it
can be attached at shoulder height or slightly lower. Workers hue up along the
rope and raise the bit by pressing down on the rope; they drop it by allowing the
rope to return quickly to its original position (see Figure 24). This requires five
to seven workers, occasionally more. Frequent rests are necessary, usually after
every 50 to 100 strokes. Because
the work is harder near the ends
,p\
of the rope than in the middle, the
\
1 !‘li $;
positions of the workers should be
rotated to distribute the work
/ 1;; ii ,‘,..,;:
evenly.
j :! I” :
\i
A small amount of water should be
r; (&+ ,.J$
kept in the hole for lubrication and
-’
to mix with the pulverized stone to
:,/r” ,+Jq
form a paste that can be removed
//
‘.-&X( ~-7
with a bailing bucket. Too much
tiI’ l/j’
water will slow down the drilling.
PJ ‘j\
The speed of drilling, of course,
<#l.\
.~ 0
depends on the type of stone
encountered. In the soft water‘.&WE 29
bearing stone of the Ban Me Thuot
area it was possible to drill several meters (about 10 feet) per day. However,
when bard stone such as basalt is encountered, progress is measured in centimeters (inches). The decision must then be made whether to continue trying to
penetrate the rock or to start over in a new location. Experience in the past has
indicated that one should not be too hasty in abandoning a location, since on
several occasions what were apparently thin layers of hard rock were penetrated
and drilling then continued at a good rate.
Occasionally the bit may become stuck in the well and it will be necessary to use
a lever arrangement consisting of a long pole attached to the rope to free it (see
Figure 25). Alternatively, a windlass may be used, consisting of a horizontal pole
used to wrap the rope around a vertical pole pivoted on the ground and held i,>
place by several workers (see Figure 26). If these fail, it may be necessary to
rent or borrow a chain hoist. A worn rope or cable may break when trying to
retrieve a stuck bit. If this happens, tit a hook to one of the auger extensions,
attach enough extensions together to reach the desired depth, and after hooking
the bit, pull with the chain hoist. A rope or cable may also be used for this
purpose, but are considerably more difficult to hook onto the bit.
.‘C’GLh?./? 25
Dry Bucket Well Drilling
The dry bucket method is a simple and quick method of driig wells in dry soil
that is free of rocks. It can be used for Scm to 7&m (2” to 3”) diameter wells in
which steel pipe is to be installed. For we& that are wider in diameter, it is a
quick method of removing dry soil before completing the bore with a wet bucket,
tubewell sand bailer, or tubewelf sand auger.
A 19.5meter (64’) hole can be dug in less than three hours with this method,
which works best in sandy soil, according to the author of this entry, who has
drilled 30 wells with it.
48
Tools and Materials
Dry bucket
Rope: 16mm (5/8”) or 19mm (3/4”) in diameter and 6 to 9 meters (20’ to 30’)
longer than the deepest well to be drilled
3 Poles: 2Ocm (4”) in diameter at large end and 3.6 to 4.5 meters (12’ to 15’) long
Chain, short piece
Pulley
Bolt: 12.5mm (l/2”) in diameter and 30 to 35cm (12” to 14”) long (long enough to
reach through the upper ends of the three poles)
A dry bucket is simply a length of pipe with a bail or handle welded to one end
and a slit cut in the other.
The dry bucket is held about 1Ocm (several inches) above the ground, centered
above the hole location and then dropped (see Figure 1). This drives a small
amount of soil up into the bucket. After this is repeated two or three times, the
bucket is removed, held to one side and tapped with a hammer or a piece of iron
to dislodge the soil. The process is repeated until damp soil is reached and the
bucket will no longer remove soil.
To make the dry bucket, you will need the following tools and materials:
Hacksaw
File
Iron rod: 1Omm (3/g”) or 12.5mm (l/2”) in diameter and 3&m (I’) long
Iron pipe: slightly larger in diameter than the largest part of casing to be put in
the well (usually the coupling) and 152cm (5’) long
Bend the iron rod iuto a U-shape small enough to slide inside the pipe. Weld it in
place as in Figure 2.
File a gentle taper on the inside of the opposite end to make a cutting edge (see
Figure 3).
Cut a slit in one side of the sharpened end of the pipe (see Figure 2).
Source:
John Brelsford, VITA Volunteer, New Holland, Pennsylvania
49
Driven Wells
A pointed strainer called a weU point, properly used, can quickly and cheaply
drive a sanitary well, usually less than 7.6 meters (25’) deep. In soils where the
driven weU is suitable, it is often the cheapest and fastest way to drill a sanitary
well. In heavy soils, particularly clay, drilling with an earth auger is faster than
driving with a weU pomt.
Tools and Materials
WeU point and driving cap (see Figure 1):
usually obtainable through mail order houses
from the United States and elsewhere
Pipe: 3cm (1”) in diameter
Heavy hammer and wrenches
Pipe compound
Special pipe couplings and driving arrangements are desirable but not necessary
A
F/Li.S?b- /
“,
B
Driven wells are highly successful in coarse sand where there are not too many
rocks and the water table is within 7 meters (23’) of the surface. They are usually used as shallow weUs where the pump cylinder is at ground level. If conditions for driving are very good, 1Ocm (4”) diameter points and casings that can
accept the cylinder of a deep weU can be driven to depths of 10 - 15 meters (33’
to 49’). (Note that suction pumps generally cannot raise water beyond 10 meters.)
The most common types of well points are:
0
a pipe with holes covered by a screen and a brass jacket with holes. For
general use, a #lO slot or 60 mesh is recommended. Fine sand requires a
finer screen, perhaps a #6 slot or 90 mesh;
0
a slotted steel pipe with no covering screen, which allows more water to
enter but is less rugged.
Before starting to drive the point, make a hole at the site with hand tools. The
hole should be plumb and slightly larger in diameter than the weU point.
The joints of the drive pipe must be carefully made to prevent thread breakage
and assure airtight operation. Clean and oil the threads carefully and use joint
compound and special drive couplings when available. To ensure that joints stay
tight, give the pipe a fraction of a turn after each blow, until the top joint is
51
permanently set. Do not twist the whole string and do not twist and pound at the
same time. The latter may help get past stones, but soon will break the threads
and make leaky joints.
Be sure the drive cap is tight and butted against the end of the pipe (see Figure
2). check with a plumb bob to see that the pipe is vertical. Test it occasionally
and keep it straight by pushing on the pipe while driving. Hit the drive cap
squarely each time or you may damage the equipment.
Several techniques can help avoid damage to the pipe. The best way is to drive
with a steel bar that is dropped inside the pipe and strikes against the inside of
the steel weU point. It is retrieved with a cable of rope. Once water enters the
well, this method does not work.
Another way is to use a driver pipe, which makes sure that the drive cap is hit
squarely. A guide rod can be mounted on top of the pipe and weight dropped over
it, or the pipe itself can be used to guide a falling weight that strikes a special
drive clamp. -
FIGURE 2
Cold Rolled Shaftins
Weight 20 to 25 lbs.
Welded Joint
'.'eiqht 25 to 30 lb
(4
i$.
Supporting Cable
Riser Pipe
-~Oriving Bar
Coupling
Sand Screen
~~Drive Head
Driving Point
'~-~ Riser Pipe
The table in Figure 3 will help identify the formations being penetrated. Experience is needed, but this may help you to understand what is happening. When
you think that the water-bearing layer has been reached, stop driving and attach
a handpump to try the well.
Type of Formation
----I
Slight but
continuous
Soti moist clay
Tough hardened clay
None
Frequent
rebounding
Fine sand
None
Frequent
rebounding
Come sand
Doll
None
Considerable
Rotation is easy and
accompanied by a
gritty sound
Rotation is irregular
and accompanied
by a gritty sound
Loud
Boulder and rock
FIGURE 3
Someiimes of
both hammer
and pipe
Dependent on typ
of fotmation pi
viously passed
through bv oioe
I
53
Usually, easier driving shows that the water-bearing level has been reached,
especially in coarse sand. If the amount of water pumped is not enough, try
driving a meter or so (a few feet) more. If the flow decreases, pull the point
back until the point of greatest flow is found. The point can be raised by using a
lever arrangement like a fence-post jack, or, if a drive-monkey is used, by
pounding the pipe back up.
Sometimes sand and silt plug up the point and the well must be “developed” to
clear this out and improve the flow. First try hard, continuous pumping at a rate
faster than normal. Mud and tine sand will come up with the water, but this
should clear in about an hour. It may help to allow the water in the pipe to drop
back down, reversing the flow periodically. With most pitcher pumps this is easily
accomplished by lifdng the handle very high; this opens the check valve, allowing
air to enter, and the water rushes back down the well.
If this does not clear up the flow, there may be silt inside the point. This can be
removed by putting a 19mm (3/4”) pipe into the well and pumping on it. Either
use the pitcher pump or quickly and repeatedly raise and lower the 19mm (3/4”)
pipe. By holding your thumb over the top of the pipe on the upstroke, a jet of
muddy water will result on each downstroke. After getting most of the material
out, return to direct pumping. Clean the sand from the valve and cylinder of the
pump after developing the well. If you have chosen too fine a screen, it may not
be possible to develop the well successfully. A properly chosen screen allows the
tine material to be pumped out, leaving a bed of coarse gravel and sand that
provides a highly porous and permeable water-gathering area.
The final step is to till in the starting borehole with puddle clay or, if clay is
not available, with well-tamped earth. Make a solid, water-proof pump platform
(concrete is best) and provide a place for spilled water to drain away.
Source:
Wagner, E.G. and Lanoix, J.N. JVater Snppiy for Rural Areas nnd Small Cornmunities. Geneva: World Health Organization, 1959.
DUG WELLS
A village well must often act as a reservoir, because at certain hours of the day
the demand for water is heavy, whereas during the night and the heat of the day
there is no call on the supply. What is suggested here is to make the well large
enough to allow the water slowly percolating in to accumulate when the well is
not in use in order to have an adequate supply when demand is heavy. For this
reason wells are usually made 183 to 213cm (6’ to 7’) in diameter.
Wells cannot store rainy season water for the dry season, and there is seldom any
reason for making a well larger in
diameter than 213cm (7’).
The depth of a well is much more
important than the diameter in
determining the amount of water
that can be drawn when the water
level is low. A deep, narrow well
will often provide more water than
a wide shallow one.
Remember that tubewells are much
easier to construct than dug wells,
and should be used if your region
allows their construction and an
adequate amount of water can be
drawn from them during the busy
hours (see section on Tubewells).
Deep dug wells have several
disadvantages. The masonry lining
needed is very expensive. Construction is potentially very dangerous;
workers should not dig deeper than
one and a half meters without
shoring up the hole. An open well
is very easily contaminated by
organic matter that fails in from
the surface and by the buckets
used to lift the water. There is an
added problem of disposing of the
great quantity of soil removed from
a deep dug well.
Sealed Dug Well
The well described here has an
underground concrete tank that is
connected to the surface with a
casing pipe, rather than a largediameter lining as described in the
preceding entry. The advantages are
that it is relatively easy to build,
easy to seal, takes up only a small
surface area, and is low in cost.
55
Many of these wells were installed in India by an American Friends Service
Committee team there; they perform well unless they are not deep enough or
sealed and capped properly.
Tools and Materials
4 reinforced concrete rings with iron hooks for lowering, 91Scm (3’) in diameter
1 reinforced concrete cover with a seating hole for casing pipe
Washed gravel to surround tank: 1.98 cubic meters (70 cubic feet)
Sand for top of well: 0.68 cubic meters (24 cubic feet)
Concrete pipe: 15cm (6”) in diameter, to run from the toP of the tank cover to at
least 30.5cm (1’) above ground
Concrete collars: for joints in the concrete pipe
Cement: 4.5kg (IO pounds) for mortar for pipe joints
Deep-well pump and pipe
Concrete base for pump
Tripod, pulleys, rope for lowering rings
Special tool for positioning casing when retilling, see “Positioning Casing Pipe,”
below
Digging tools, ladders, rope
,’
A villager in Barpali, India, working with an American Friends Service Committee
unit there, suggested that they make a masonry tank at the bottom of the well,
roof it over, and draw the water from it with a pump. The resulting sealed well
has many advantages:
It provides pure water, safe for drinking.
It presents no hazard of children FaUing in.
Drawing water is easy, even for small children.
The well occupies little space, a small courtyard can accommodate it.
The cost of installation is greatly reduced.
The labor involved is much reduced.
There is no problem of getting rid of excavated soil, since most of it is
replaced.
The casing enables the pump and pipe to be easily removed for servicing.
The gravel and sand surrounding the tank provide an efticient filter to
prevent silting, allow a large surface area for percolating water to till the
tank, and increase the effective stored volume in the tank.
56
On the other hand, compared to a well where people draw their own buckets or
other containers of water, there are three minor disadvantages: only one person
can pump at a time, the pump requires regular maintenance, and a certain amount
of technical skill is required t,o make the parts used in the well and to install
them properly.
A weIt is dug 122cm (4’) in diameter and about 9 meters (30’) deep. The digging
should be done in the dry season, after the water table has dropped to its lowest
level. There should be a full 3 meter (10’) reaccumulation of water within 24
hours after the well has been bailed or pumped dry. Greater depth is, of course,
desirable.
Spread l&m (6”) of clean, washed gravel or small rock over the bottom of the
well. Lower the four concrete rings and cover into the well and position them
there to form the tank. A tripod of strong poles with block and tackle is needed
to lower the rings, because they weigh about HOkg (400 pounds) each. The tank
formed by the rings and cover is lS3cm (6’) high and 9LScm (3’) in diameter. The
cover has a round opening which forms a seat for the casing pipe and allows the
suction pipe to penetrate to about 15cm (6”) from the gravel bottom.
The first section of concrete pipe is positioned in the seat and grouted (mortared)
in place. It is braced vertically by a wooden plug with four hinged arms to brace
against the sides of the wall. Gravel is packed around the concrete rings and over
the top of the cover till the gravel layer above the tank is at least 15cm (6”)
~ deep. Thii is then covered with 61cm (2’) of sand. Soil removed from the well is
then shoveled back until the shaft is tilled within 15cm (6”) of the top of the
first section of casing. The next section of casing is then grouted in place, using
a concrete collar made for this purpose. The well is tilled and more sections of
casing added until the casing extends at least 3Ocm (1’) above the surrounding
soil level.
The soil that will not pack back into the well can be used to make a shallow hill
around the casing to encourage spilled water to drain away from the pump. A
concrete cover is placed on the casing and a pump installed.
If concrete or other casing pipe cannot be obtained, a chimney made of burned
bricks and sand-cement mortar will suffice. The pipe is somewhat more expensive,
but much easier to install.
Source:
A Safe Ecorromicnl Well. Philadelphia: American Friends Service Committee, 1956
(Mimeographed).
51
Deep Dug Well
Untrained workers can safely dig a deep sanitary well with simple, light equipment, if they are well supervised. The basic method is outlined here.
Tools and Materials
Shovels, mattocks
Buckets
Rope-deep wells require wire rope
Forms-stee!, welded and bolted together
Tower with winch and pulley
Cement
Reinforcing rod
Sand
Aggregate
Oil
The hand dug well is the most widespread of any kind of well. Unfortunately, in
many places these wells are dug by people unfamiliar with good sanitation
methods and become infected by parasitic and bacterial disease. By using modern
methods and materials, dug wells can safely be made 60 meters (1%.8’) deep and
will give a permanent source of pure water.
Experience has shown ttrst for one person, the average width of a round well for
best digging speed is 1 meter (3 l/4’). However, 1.3 meters (4 l/4’) is best for
two workers digging together and they dig more than twice as fast as one person.
Thus, two workers in the larger hole is usually best.
Dug wells always need a permanent lining (except in solid rock, where the best
method is usually to drill a tubewell).
The lining prevents collapse of the hole, supports the pump platform, stops
entrance of contaminated surface water, and supports the well intake, which is
the part of the well through which water enters. It is usually best to build the
lining white digging, since this avoids temporary supports and reduces danger of
cave-ins.
Dug wells are Lined in two ways: (1) where the hole is dug and the lining is built
in its permanent place and (2) where sections of lining are added to the top and
the whole lining moves down as earth is removed from beneath it. The second
method is called caissoning; often a combination of both is best (Figure 2.)
If possible, use concrete for the lining because it is strong, permanent, and made
mostly of local materials. It can also be handled by unskilled workers with good
speed and results. (See section on Concrete Construction).
-Plumbing Peg
------l.Zm--.
WELL CONSTRUC
&place
lining
\Y’
ge curb
bottom
of builtin-place
linina
59
Masonry and brickwork are widely used in many countries and can be very
satisfactory if conditions are right. In bad ground, however, unequal pressures can
make them bulge or collapse. Building with these materials is slow and a thicker
wall is required than with concrete. There is also always the danger of movement
during construction in loose sands or swelling shale before the mortar has set
firmly between the bricks or stones.
Wood and steel are not good for lining wells. Wood requires bracing, tends to rot
and hold insects, and sometimes makes the water taste bad. Worst of all, it will
not make the weU watertight against contamination. Steel is seldom used because
it is expensive, rusts quickly, and if it is not heavy enough is subject to bulging
and bending.
The general steps in finishing the fust 4.6 meters (15’) are:
0
set up a tripod winch over cleared, level ground and mark reference points
for plumbing and measuring the depth of the well.
0
have two workers dig the well while another raises and unloads the dirt
until the well is exactly 4.6 meters (15’) deep.
0
trim the hole to size using a special jig mounted on the reference points.
0
place the forms carefully and till one by one with tamped concrete.
After this is done, dig to 9.1 meters (?O’), trim and line this part also with
concrete. A 12.5cm (5”) gap between the first and second of these sections is
fdled with pre-cut concrete that is grouted (mortared) in place. Each lining is
self-supporting as it has a curb. The top of the first section of lining is thicker
than the second section and extends above the ground to make a good foundation
for the pump housing and to make a safe seal against ground water.
This method is used until the water-bearing layer is reached; there an extra-deep
curb is constructed. From this point on, caissoning is used.
Caissons are concrete cylinders fitted ,with bolts to attach them together. They
are cast and cured on the strface in special molds, prior to use. Several caissons
are lowered into the well and assembled together. As workers dig, the caissons
drop lower as earth is removed from beneath them. The concrete lining guides the
caissons.
If the water table is high when the well is dug, extra caissons are bolted in place
so that the well can be finished by a small amount of digging, and without
concrete vvork, during the dry season.
60
Details on plans and equipment for this process are found in Wafer Supply for
Rural Areas and Small Communities, by E. G. Wagner and J. N. Lanoix, World
Health Organization, 19.59.
Reconstructing Dug Wells
Open dug weUs are not very sanitary, but they can often be rebuilt by relining
the top 3 meters (IO’) with a watertight iining, digging and cleaning the weti and
covering it. This method involves installation of a buried concrete slab; see Figure
3 for construction details.
CLOSED TOP PUMP
NOTE: Putmp stand ar
one piece, j()ined by flanged or
threaded CO", wction.
NOTE: Concrete well platform to be laid
after backfill has sufficiently
I!
steeled.
GL.
Weep hole to be placed below
frost depth to provide antifreeze
installation.
CR PUDDLED CLAY I
: NOTE: Excavate and remove old curbing
to point not less than 3mm from
61
Tools and Materials
Tools and materials for reinforced concrete
A method for entering the well
Pump and drop pipe
Before starting, check the following:
Is the well dangerously close to a privy or other source of contamination? Is
it close to a water source? Is it desirable to dig a new well elsewhere
instead of cleaning this one? Could a privy be moved, instead?
Has the well ever gone dry? Should you deepen it as well as clean it?
Surface drainage should generally slope away from the well and there should
be effective disposal of spilled water.
What method will you use to remove the water and what will it cost?
Before entering the well to inspect the old lining, check for a lack of
oxygen by lowering a lantern or candle. If the flame remains lit, it is
reasonably safe to enter the well. If the flame goes out, the well is dangerous to enter. Tie a rope around the person entering the well and have two
strong workers on hand to pull him out in case of accident.
Relining the ?#‘a11
The first job is to prepare the upper 3 meters (10’) of the lining for concrete by
removing loose rock and chipping away old mortar with a chisel, as deep as
possible (see Figure 4). The next task is to clean out and deepen the well, if that
is necessary. All organic matter and silt should be bailed out. The well may be
dug deeper, particularly during the dry season, with the methods outlined in “Deep
Dug Wells.” One way to increase the water yield is to drive a well point deeper
into the water-bearing soil. This normally will not raise the level of water in the
well, but may make the water flow into the well faster. The well point can be
piped directly to the pump, but this will not make use of the reservoir capacity
of the dug well.
The material removed from the well can be used to help form a mound around the
well so water will drain away from the opening. Additional soil will usually be
needed for this mound. A drain lined with rock should be provided to take spilled
water away from the concrete apron that covers the well.
Reline the well with concrete troweled in place over wire mesh reinforcement.
The largest aggregate should be pea-sized gravel and the mix should be fairly rich
with concrete, using no more than 20-23 liters (5 l/2 to 6 gallons) of water to a
.:.
_’
63
43kg (94 pound) sack of cement. Extend the lining 70cm (27 l/2”) above the
original ground surface.
Installing the Cover and Pump
Cast the well cover so that it makes a watertight seal with the lining to keep
surface impurities out, The cover will also support the pump. Extend the slab out
over the mound about a meter (a few feet) to help drain water away from the
site. Make a manhole and space for the drop pipe of the pump. Mount the pump
off center so there is room for the manhole. The pump is mounted on bolts cast
into the cover. The manhole must be 1Ocm (4”) higher than the surface of the
slab. The manhole cover must overlap by 5cm (2”) and should be fitted with a
lock to prevent accidents and contamination. Be sure that the pump is sealed to
the slab.
Disinfecting the Well
Disinfect the well by using a stiff brush to wash the walls with a very strong
solution of chlorine. Then add enough chlorine in the well to make it about half
the strength of the solution used on the walls. Sprinkle this last solution all over
the surface of the well to distribute it evenly. Cover the well and pump up the
water until the water smells strongly of chlorine. Let the chlorine remain in the
pump and well for one day and then pump it until the chlorine is gone.
Have the well water tested several days after disinfection to be sure that it is
pure. If it is not, repeat the disinfection and testing. If it is still not pure, get
expert advice.
Sources:
Wagner, E.G. and Lanoix, J.N. Wafer Supply for Rural Areas and Sntoll Contmurtifies. Geneva: World Health Organization, 1959.
Monuol 01 Individual Wafer Supply Systems, Public Health Service Publication No.
24. Washington, DC.: Department of Health and Human Services.
SPRING DEVELOPMENT
Springs, particularly in sandy soil, often make excellent water sources, but they
should be dug deeper, sealed, protected by a fence, and piped to the home. Proper
development of a spring will increase the flow of ground water and lower the
chances of contamination from surface water. If fissured rock or limestone are
present, get expert advice before attempting to develop the spring.
Springs occur where water, moving through porous and saturated underground
64
iayers of soil (aquifer), emerges at the ground surface. They can be either:
0
Gravity seepage, where the water bearing soil reaches the surface over an
impermeable layer, or
0
Pressrue or artesiau, where the water, under pressure and trapped by a hard
layer of soil, finds an opening and rises to the surface. (In some parts of
the world, all springs are called artesian)
The following steps should be considered in developing springs:
1)
Observe the seasonal flow variations over a period of a year if possible.
2)
Determine the type of spring-seepage or artesian-by digging a small
hole. An earth auger with extensions is the most suitable tool for that
job. It may not be possible to reach the underlying impermeable layer.
3)
Have chemical and biological tests made on samples of the water.
Dig a small hole near the spring to learn the depth of the hard layer of soil and
to find out whether the spring is gravity seepage or pressure. Check uphill and
nearby for sources of contamination. Test the water to see if it must be purified
before being used for drinking. A final point: Find out if the spring runs during
long dry spells.
For gravity-fed springs, the soil is usually dug to the hard, underlying layers and
a tank is made with watertight concrete walls on all but the uphill side (see
Figures 1 and 2). The opening on the uphill side should be lined with porous
concrete or stone without mortar, so that it will admit the gravity seepage water.
It can be backfilled with gravel and sand, which helps to keep fine materials in
the water-bearing soil from entering the spring. If the hard soil cannot be
reached easily, a concrete cistern is built that can be fed by a perforated pipe
placed in the water-bearing layer of earth. With a pressure spring, all sides of
the tank are made of watertight reinforced concrete, but the bottom is left open.
The water enters through the bottom.
Read the section in this handbook on cisterns before developing your spring. No
matter how the water enters your tank, you must make sure the water is pure by:
0
building a complete cover to stop surface pollution and keep out sunlight,
which causes algae to grow.
0
installing a locked manhole with at least a 5cm (2’) overlap to prevent
entrance of polluted ground water.
6.5
Fig. I.
PROPERLY PROTECTED SPRING (I)
A = Protective drzinagc ditch to keep drainage water a safe distance from spring
B = Original slope and ground line
C ::: Screened outlet pipe : can. discharge freely or be piped to village or residence
..a $2,
Springs can offer an economical and safe source of water. A thorough search should
be made for signs of ground-water outcropping. Springs that can be piped to the user by
gravity offer an ex:ellcnr solution. Rainfall variation may influence the yield, so dryweather flow should be checked.
Fig, 2 PROPERLY PROTECTED SPRING (II)
h
. .
‘.
‘..
.
.
.
..I.,...,,
.
.
:
.
:,..‘.‘..
._.,
A = Protective drainage ditch to keep drainage water a safe distance from spring
6 = Screened outlet pipe : to discharge freely or be piped co village or residence
.
66
0
installing a screened overflow that discharges at least 15cm (6”) above the
gro-uud. The water must land on a cement pad or rock surface to keep the
water from makmg a hole in the ground and to ensure proper drainage away
from the spring.
0
arranging the spring so that surface water must filter through at least 3
meters (10’) of soil before reaching the ground water. Do this by making a
diversion ditch for surface water about 15 meters (50’) or more from the
spring. Also, if necessary, cover the surface of the ground near the spring
with a heavy layer of soil or clay to increase the distances that rainwater
must travel, thus ensuring that it has to filter through 3 meters (10’) of
soil.
0
making a fence to keep people and animals away from the spring’s immediate
surroundings. The suggested radius is 7.6 meters (25’).
0
installing a pipeline from the overflow to the place where the water is to be
used.
Before using the spring, disinfect it thoroughly by adding chlorine or chlorine
compounds. Shut off the overflow to hold the chlorine solution in the well for 24
hours. If the spring overflows even though the water is shut off, arrange to add
chlorine so that it remains strong for at least 30 minutes, although 12 hours
z would be much safer. After the chlorine is flushed from the system have the
“, water tested. (See section on “Superchlorination.“)
Sources:
Wagner, E.G. and Lanoix, J.N. Wafer Supply for Rural Areas and Small Commurzides. Geneva: World Health Organization, 1959.
Manual of Itzdividzral Water SuppIy Sysfenzs, Public Health Service Publication No.
24. Washington, D.C.: U.S. Department of Health and Human Services.
Acknowledgements
John M. Jenkins III, VITA Volunteer, Marrero, Louisiana
Ramesh Patel, VITA Volunteer, Albany, New York
William P. White, VITA Volunteer, Brooklyn, Connecticut
ater Lifting and Transport
OVERVIEW
Once a source of water has been found and developed, four basic questions must
be answered:
1.
2.
3.
4.
What is the rate of flow of the water in your situation?
Between what points must the water be transported?
What hind and sire of piping is needed to transport the required flow?
What hind of pump, if any, is necessary to produce the required flow?
The information in this section will help you to answer the third and fourth
questions, once you have determined the answers to the first two.
wing Water
The first three entries in this section discuss the flow of water in small streams,
partially fdled pipes, and when the height of the reservoir and sire of pipe are
known. They include equations and alignment charts (also called nomographs) that
give simple methods of estimating the flow of water under the force of gravity,
that is, without pumping. The fourth tells how to measure flow by observing the
spout from a horizontal pipe.
Four entries follow on piping, including a discussion of pipes made of bamboo.
You wiil note that in the alignment charts here and elsewhere, the term “nominal
diameter,- inches, U.S. Schedule 40” is used along with the alternate term, “inside
diameter in centimeters,” in referring to pipe sire.
Pipes and fittings are usually manufactured to a standard schedule of sizes. U.S.
Schedule 40, the most common in the United States, is also widely used in other
countries. When one specifies ‘5%inch Schedule 40,” one automatically specifies the
pressure rating of the pipe and its inside and outside diameters (neither of which,
incidentally, is actually 2”). If the schedule is not known, measure the inside
diameter and use this for flow calculations.
Lifting Water
Next, seveal entries follow the steps required to design a water-pumping system
with piping. The first entry in this group, “Pump Specifications: Choosing or
Evaluating a Pump,” presents all the factors that must be considered in selecting
a pump. Fill out the form included there and make a piping sketch, whether you
plan to send it to a consultant for help or do the design and selection yourself.
The first pieces of information needed for selecting pmnp type and size are: (1)
the flow rate of water needed and (2) the head or pressure to be overcome by
the pump, The head is composed of two parts: the height to which the liquid must
be raised, and the resistance to flow created by the pipe walls (friction-loss).
The bidion-loss head is the most difficult factor to measure. The entry “Determining Pump Capacity and Horsepower Requirements” describes bow to select the
economic pipe sire(s) for the flow desired. With the pipe(s) selected one must
then calculate the friction-loss head. The entry “Estimating Flow Resistance of
Pipe Fittings” makes it possible to estimate extra friction caused by constrictions
of pipe fittings. With this information and the length of pipe, it is possible to
estimate the pump power requirement using the entry, “Determining Pump Capacity
and Horsepower Requirements.”
These entries have another very important use. You may already have a pump and
wonder “Will it do this job?” or “What size motor should I buy to do this job
with the pump I have?” The entry “Pump Specifications: Choosing or Evaluating a
Pump” can be used to collect all the information on the pump and on the job you
want it to do. With this information, you can ask a consultant or VITA if the
pump can be used or not.
There are many varieties of pumps for lifting water from where it is to where it
is to be delivered. But for any particular job, there are probably one or two kinds
of pumps that will serve better than others. We will discuss here only two broad
classes of pumps: lift pumps and force pumps.
A Ii& or suction pump is located at the top of a well and raises water by
suction. Even the most efficient suction pump can create a negative pressure of
only 1 atmosphere: theoretically, it could raise a column of water 10.3m (34’) at
sea level. But because of friction losses and the effects of temperature, a suction
pump at sea level can actually lift water only 6.7m to 7.6m (22’ to 25’). The entry
“Determining Lift Pump Capability explains how to find out the height a lift
pump will raise water at different altitudes with different water temperatures.
When a lift pump is not adequate, a force pump must be used. With a force pump,
the pumping mechanism is placed at or near the water level and pushes the water
up. Because it does not depend on atmospheric pressure, it is not hmited to a
7.6m (25’) head.
Construction details are given for two irrigation pumps that can be made at the
village level. An easy-to-maintain pump handle mechanism is described. Use of the
hydraulic ram, a self-powered pump, is described.
69
Finally, there are entries on Reciprocating Wiie Power Transmission for Water
Pumps, and on Wind Energy for Water Pumping. Further details on pumps can be
found in the publications listed below and in the Reference section at the back of
the book.
Margaret Crouch, ed. Sir Simple Pumps. Arlington, Virginia: Volunteers in
TechnicaI Assistance, 1982.
Molenaar, Aldert. Water tifring Devices ,for Irrigafion. Rome: Food and Agriculture
Organization, 1956.
Small Water Supplies. London: The Ross Institute, The London School of Hygiene
and Tropical Medicine, 1%7.
WATER TRANSPORT
Estimating Small Stream Water Flow
A rough but very rapid method of estimating water flow in small streams is given
here. In looking for water sources for drinking, irrigation, or power generation,
one should survey all the streams available. If sources are needed for use over a
long period, it is necessary to collect information throughout the year to deter~,
mine
flow changes-especially high and low flows. The number of streams that
,,,
must be used and the flow variations are important factors in determining the
necessary facilities for utilizing the water.
Tools and Materials
Timing d&x, preferably watch with second hand
Measuring tape
Float (see below)
Stick for measuring depth
IO
The following equation will help you to measure flow quickly:
Q = KxAxV,
where:
0
(Quantity) = flow in liters per minute
A
(Area) = cross-section of stream, perpendicular to flow, in square meters
V
(Velocity) = stream velocity, meters per minute
K
(Constant) = a corrected conversion factor. This is used because surface flow
is normally faster than average flow. For normal stages use K = 850: for
flood states use K = 908 to 950.
To Find Area of a Cross-Section
The stream wig probably have different depths along its length so select a place
where the depth of the stream is average.
0
Take a measuring stick and place it upright in the water about one-half
meter (1 l/2’) from the bank.
0
Note the depth of water.
0
Move the stick 1 meter (3’) from the bank in a line directly across the
stream. Note the depth.
0
Move the stick 1.5 meters (4 l/2’) from the bank, note the depth, and
continue moving it at half-meter (1 l/2’) intervals until you cross the
stream.
Note the depth each time you place the stick upright in the stream. Draw a grid,
like the one in Figure 2, and mark the varying depths on it so that a crosssection of the stream is shown. A
scale of lcm to 1Ocm is often used
for such grids. By counting the
grid squares and fractions it
squares, the area of the water ci:n
be estimated. For example, the grid
shown nere has a little less than 4
square meters of water.
F/GU&?Z
.----o /rvcl-SIP
To Find Velocity
Put a float in the stream and measure the distance of travel in one minute (or
fraction of a minute, if necessary.) The width of the stream where the velocity is
being measured should be as constant as possible and free of rapids.
A tight surface float, such as a chip, will often change course because of wind or
surface currents. A weighted float, which sits upright in the water, will not
change course so easily. A lightweight tube or tin can, partly filled with water or
gravel so that it floats upright with only a small part showing above water,
makes a good float for measuring.
Measuting wide Streams
For a wide, irregular stream, it is better to divide the stream into 2- or 3-meter
sections and measure the area and velocity of each. Q is then calculated for each
section and the Qs added together to give a total flow.
Example (see Figure 2):
Cross section is 4 square meters
Velocity of float = 6 meters traveled in l/2 minute
Stream flow is normal
Q = 850 x 4 x 6 meters
5 minute
Q = 40,800 liters per minute or 680 liters per second
Using English Units
If English units of measurement are used, the equation for measruing stream flow
is:Q = KxAxV,where:
Q
= flow in U.S. gallons per minute
A
= cross-section of stream, perpendicular to flow, in square feet
V
= stream velocity in feel, per minute
K
= a corrected conversion factor: 6.4 for normal stages; 6.7 to 7.1 for flood
stages
The grid used would be like the one in Figure 3; a common scale is 1” to lr’.
72
Example:
Cross-section is 15 square feet
Float velocity = 20’ in l/2 minute
Stream flow is normal
F/GURE 3
Q
= 6.4xlSx2Z?
.5 minute
Q
= 3,800 gallons per minute
Source:
Clay, C.H. Design of Fishways and Other Fish Facilities. Ottawa: P.E. Department
of Fisheries of Canada, 1961.
Measuring Water Flow in Partially-Filled Pipes
The flow of water in partially-tilled horizontal pipes (Figure 1) or circular
channels can be determined-if you know the inside diameter of the pipe and the
depth of the water flowing-by using the alignment chart (nomograph) in Figure 2.
This method can be checked
for low Row rates and small
pipes by measuring the time
required to fill a bucket or
drum with a weighed quantity
of water. A liter of water
weighs Ikg (1 U.S. gallon of
water weighs 8.33 pounds).
Tools and Materials
Ruler to measure water depth (if ruler units are inches, multiply by 2.54 to
convert to centimeters)
Straight edge, to use with alignment chart
The alignment chart applies to pipes with 2.5cm to 15cm inside diameters, 20 to
60% full of water, and having a reasonably smooth surface (iron, steel, or
concrete sewer pipe). The pipe or channel must be reasonably horizontal if the
result is to be accurate. The eye, aided by a plumb line to give a vertical
reference, is a sufficiently good judge. If the pipe is not horizontal another
method will have to be used. To use the alignment chart, simply connect the
proper point on the “K scale with the proper point on the “d” scale with the
73
straight edge. The flow rate can then be read from the “9” scale.
9
=
rate of flow of water, liters per minute 8.33 pounds = 1 gallon.
d
=
internal diameter of pipe in centimeters.
K
=
decimal fraction of vertical diameter under water. Calculate K by
measuring the depth of water (h) in the pipe and dividing it by the
pipe diameter (d), or K = h (see Figure 1).
d
Example:
What is the rate of flow of water in a pipe with an internal diameter of km,
running 0.3 full? A straight line connecting 5 on the d-scale with 0.3 on the Kscale intersects the q-scale at flow of 18 liters per minute.
Source:
Greve Bulletin 32, Volume 12, No. 5, Purdue University, 1928.
F/GURE 2
0.6
Q SCALE
K SCAL E
Determinin Probable Water Flow with Known
Reservoir IIfeight and Size and Length of Pipe
The alignment chart in Figure 1 gives a reasonably accurate determination of
water flow when pipe size, pipe length, and height of the supply reservoir are
known. The example given here is for the analysis of an existing system. To ~,, ,
design a new system, assume a pipe diameter and solve for flow rate, repeating
the procedure with new assumed diameters until one of them provides a suitable
fIow rate.
Tools and Materials
Straightedge, for use with alignment chart
Surveying instruments, if available
The alignment chart was prepared for clean, new steel pipe. Pipes with rougher
surfaces or steel or cast iron pipe that has been in service for a long time may
give flows as low as 50 percent of those predicted by this chart.
~,‘,~,~
,
1
The available head (h) is in meters and is taken as the difference in elevation
between the supply reservoir and the point of demand. This may be crudely
estimated by eye, but for accurate results some sort of surveying instruments are
necessary.
For best results, the length of pipe (L) used should include the equivalent lengths
of fittings as described in the section, “Estimating Flow Resistance of Pipe
Fittings,” p. 76. This length (L) divided by the pipe internal diameter (D) gives
the necessary “L/D” ratio. In calculating L/D, note that the units of measuring
both “L” and “D” must be the same, e.g., feet divided by feet; meters divided by
meters; centimeters by centimeters.
Example:
Given available head (h) of IO meters, pipe internal diameter (D) of 3cm, and
equivalent pipe length (L) of 30 meters (3,OOOcm).
Calculate L/D = 3.000cm = 1,000
3cm
The alignment chart solution is in two steps:
1.
Connect internal diameter 3cm to available head (10 meters), and make a
mark on the Index Scale. (In this step, disregard “Q” scale)
2.
Connect mark on Index Scale with L/D (l,OOO), and read flow rate (Q) of
approximately 140 liters per minute
:,
300
a50
zoo
(50
100
-6
--s
--I.+
s -’3.5
s -32 - 2.5---.
iit2
a:
i
I(,
90
30
25
1 20
-0.4
;: LO.8
82 -0.9
s -0:6
4
-0.s
- 0.9
- 0.3
Alignment chart for determining probable watar flow with known reservoir height and size and length of pipe.
source:
Crane Company Technical Paper #407, pages 54-55.
76
Estimating Water Flow from Horizontal Pipes
If a horizontal pipe is discharging a full stream of water, yea can estimate the
rate of flow from the alignment chart in Figure 2. This is a standard engineering
technique for estimating flows; its results are usually accurate to within 10
percent of the actual flow rate.
Tools and Materials
Straightedge and pencil, to use alignment chart
Tape measure
Level
Plumb bob
The water flowing from the pipe must completely Ii11 the pipe opening (see Figure
I). The results from the chart will be most accurate when there is no constricting
or enlarging fitting at the end of the pipe.
Water is flowing out of a pipe with an inside diameter (d) of 3cm (see
Figure 1). The stream drops 3Ocm at a point 6Ocm from the end of the
pipe.
Connect the 3cm iuside diameter point on the “d” scale in Figure 2
with the 6Ocm point on the “D” scale. This line intersects the “9” scale
at about 100 liters per minute, the rate at which water is flowing out
of the pipe.
Source:
Duckworth, Clifford C. “Flow of Water from Horizontal Open-end Pipes.” Ckemicd
June 1959, p. 73.
Processing
\
\
\
\
\
Determining Pipe Size or Velocity of Water in Pipes
The choice of pipe size is one of the first steps in designing a simple water
system.
The ahgnment chart in Figure 1 can be used to compute the pipe size needed for
a water system when the water velocity is known. The chart can also be used to
find out what water velocity is needed with a given pipe size to yield the
required rate of flow.
Tools and Materials
Straightedge
Pencil
Practical water systems use water velocities from 1.2 to 1.8 meters (3.9 to 5.9
feet) per second. Very fast velocity requires high pressure pumps, which in turn
require large motors and use excessive power. Velocities that are too low are
expensive because larger pipe diameters must be used.
It may be advisable to calculate the cost of two or more systems based on
different pipe sizes. Remember, it is usually wise to choose a little larger pipe if
higher flows arc expected in the next 5 to 10 years. In addition, water pipes
often build up rust and scale, reducing the diameter and thereby increasing the
velocity and pump pressure required to maintain flow at the original rate. If extra
capacity is designed into the piping system, more water can be delivered by
* . . to ihe pump capacity without changing aii the piping.
aoamg
To use the chart, locate the flow (liters per minute) you need on the Q-scale.
Draw a line from that point, through l.Sm/sec velocity on the V-scale, to the dscale. Choose the nearest standard size pipe.
For example, suppose you need a flow of 50 liters per minute at the time of peak
demand. Draw a line from 50 liters per minute on the Q-scale through l.Sm/sec
on the V-scale. Notice that this intersects the d-scale at about 2.25. The correct
pipe size to choose would bc the next largest standard pipe size, e.g., 1” nominal
diameter, U.S. Schedule 40. If pumping costs (electricity or fuel) are high, it
would be well to limit velocity to 1.2m/sec and install a slightly larger pipe size.
Source:
Crane Company Technical Paper #409, pages 46.47.
a SCALE
d
SCALE
80
Estimating Flow Resistance of Pipe Fittings
Gne of the forces a pump must overcome to deliver water is the friction/resistance of pipe fittings and valves to the flow of water. Any bends, valves,
constrictions, or enlargements (such as passing through a tank) add to friction.
The alignrxnt chart in Figure 1 gives a simple but reliable way to estimate this
resistance: it gives the equivalent length of straight pipe that would have the
same resistance. The sum of these equivalent 1eQgths is then added to the actual
length of pipe. This gives the total equivalent pipe length, which is used in the
entry, “Determining Pump Capacity and Horsepower Requirements,” to determine
total friction ioss.
Rather than calculate the pressure drop for each valve or fitting separately,
Figure 1 gives the equivalent length of straight pipe.
VdVCS
Note the difference In equivalent length depending on how far the valve is open.
1.
Gate Valve: full opening valve; can see through it when open; used for
complete shu: off of pow.
2.
Globe Valve: cannot see through it when open; used for regulating flow.
3.
Angle Valve: like the globe, used for regulating flow.
4.
Swing Check Valve: a flapper opens to allow flow in one direction but
closes when water tries to flow in the opposite direction.
Example 1:
?ipe with 5cm inside diameter
Equivalent Length in Meters
a. Gate Valve (fully open)
b. Flow into line - ordinary entrance
c. Sudden enlargement into 1Ocm pipe
(d/D = l/2)
d. Pipe length
10.0
Total Equivalent Pipe Length
12.4
.4
1.0
1.0
Resistance of Valves and Fittings
to Flow of Fluids
4s46363*14zoto/6,6-
Pipe with l&m inside diameter
Equivalent Length in Meters
4.0
lLc).o
Total Equivalent Pipe Length
14.0
Study the variety of tees and elbows: note carefully the direction of flow through
the tee. To determine the equivalent length of a fitting, (a) pick proper dot on
“fitting” line, (b) connect with inside diameter of pipe, then using a straight edge
read equivalent length of straight pipe in meters, and (c) add the fitting
equivalent length to the actual length of pipe being used.
Crane Company Technical Paper #409, pages 20-21.
Where bamboo is readily available, it seems to be a good substitute for metal
pipe. Bamboo pipe is easy to make with unskilied labor and local materials. The
important features of the design and construction of a bamboo piping system are
Bamboo pipe is extensively used in Indonesia to transport water to villages. In
many rural areas of Taiwan, bamboo is commonly used in place of galvanized iron
for deep wells up to a maximum depth of 150 meters (492’). Bamboos of 5Omm (2”)
diameter are straightened by means of heat, and the inside nodes knocked out.
The screen is made by punching holes in the bamboo and wrapping that section
with a fibrous mat-like material from a palm tree, Chamaerops humilis. In fact,
such fibrous screens are also used in many galvanized iron tube wells.
Bamboo piping can hold pressure up to two atmospheres (about 2.lkg per square
centimeter or 30 pounds per square inch), It cannot, therefore, be used as
pressure piping. It is most suitable in areas where the source of supply is higher
than the area to be served and the flow is under gravity.
Figure 1 is a sketch of a bamboo pipe water supply system for a number of
villages. Figure 2 shows a public water fountain.
83
84
Health Aspects
If bamboo piping is to carry water for drinking purposes, the only preservative
treatment recommended is boric acid: borax in a 1:l ratio by weight. The recommended trc:!iment is to immerse green bamboo completely in a solution of 95
percent water and 5 percent boric acid.
After a bamboo pipe is put into operation it gives an undesirable odor to the
water. This, however, disappears after about three weeks. If chlorination is done
before discharge to the pipe, a reservoir giving sufficient contact time for
effective disinfection is required since bamboo pipe removes chlorine compounds
and no residual chlorine will be maintained in the pipe. To avoid possible contamination by ground water, an ever present danger, it is desirable to maintain
the pressure within the pipe at a higher level than any water pressure outside the
pipe. Any leakage will then be from the pipe, and contaminated water will not
enter the pipe.
Design and Construction
Tools and Materials
Chisels (see tr xt and Figure 3)
Nail, cotter pin, or linchpin
Caulking materials
Tar
Rope
Bamboo pipe is made of lengths of bamboo of the desired diameter by boring out
the dividing membrane at the joints. A circular chisel for this purpose is shown
in Figure 3. One end of a short length of steel pipe is belled out to increase the
diameter and the edge sharpened. A length of bamboo pipe of sufticiently small
diameter to slide into the pipe is used as a boring bar and secured to the pipe by
drilling a small hole through the assembly and driving a nail through the hole. (A
cotter pin or linchpin could be used instead of the nail.) Three or more chisels
ranging from smallest to the maximum desired diameter are required. At each
joint the membrane is removed by first boring a hole with the smallest diameter
chisel, then progressively enlarging the hole with the larger diameter chisels.
Bamboo pipe lengths are joined in a number of ways, as shown in Figure 4. Joints
are made watertight by caulking with cotton wool mixed with tar, then tightly
binding with rope soaked in hot tar.
Bamboo pipe is preserved by laying the pipe beiow ground level and ensuring a
continuous flow in the pipe. Where the pipe is laid above ground level, it is
protected by wrapping it with layers of palm fiber with soil between the layers.
This treatment will give a life expectancy of about 3 to 4 years to the pipe; some
bamboo will last up to 5-6 years. Deterioration and failure usually occur at the
natural joints, which are the weakest parts.
Where the depth of the pipe below the water source is such that the maximum
pressure will be exceeded, pressure relief chambers must be installed. A typical
chamber is shown in Figure 5. These chambers are also installed as reservoirs for
branch supply limes to villages en route.
Size requirements for bamboo pipe may be determined by using the pipe capacity
alignment chart in Figure 6.
Source:
Water Supply Using Bamboo Pipe. AID-UNC/IPSED Series Item No. 3, International
Program in Sanitary Engineering Design, University of North Carolina, 1966.
F/&URC b
NOM3GRAPH FOR FLOW IN BAMBOO PIPE
EXAMPLE:
Given 0 = 6Om
1 = 0.0445nfm
Solution Q = 2.05 l/set.
V = 67.5 cm/+x.
a8
WATER LIFI’ING
Pump Specifications: Choosing or Evaluating a Pump
The form given in Figure I, the “Pump Application Fact Sheet,” is a check list
for collecting the information needed to get help in choosing a pump for a
particular situation. If you have a pump on hand. you can also use the form to
estimate its capabilities. The form is an adaptation of a stalrdsi-d pump specification sheet used by engineers.
Fill out the form and send it off to a manufacturer or a technical r&stance
organization like VITA to get help in choosing a pump. If you are doubtful about
how much information to give, it is better to give too much information than to
risk not giving enough. When seeking advice on how to soive a pumping problem
or when asking pump manufacturers to specify the best pump for your service,
give complete information on what its use will be and how it will be installed. If
the experts are not given all the details, the pump chosen may give you trouble.
The “Pump Application Fact Sheet” is shown filled in for a typical situation. For
your own use, make a copy of the form. The following comments on each numbered item on the fact sheet will help you to complete the form adequately.
1.
Give the exact composition of the liquid to be pumped: Fresh or salt water,
oil, gasoline, acid, alkali, etc.
2.
Weight percent of solids can be found by getting a representative sample in
a pail. Let the solids settle to the bottom and decant the liquid (or filter
the liquid through a cloth so that the liquid coming through is clear). Weigh
the solids and the liquid, and give the weight percent of solids.
If this is not possible, measure the volume of the sample (in liters, U.S.
gallons, etc.) and the volume of solids (in cubic centimeters, teaspoons, etc.)
and send these figures. Describe the solid material completely and send a
small sample if possible. This is important; if the correct pump is not
selected, the solids will erode and/or break moving parts.
Weight percent of solids =
100 x weight of solids in liauid samole
weight of liquid sample
3.
If you do not have a thermometer to measure temperature, guess at it,
making sure you guess on the high side. Pumping troubles are often caused
when liquid temperatures at the intake are too high.
4.
Gas bubbles or boiling cause special problems, and must always be mentioned.
89
PUMP APPLICATION FACT SHEET
NAME
AODRE
1.
Liquid to be handled:
2. Erosive effect of liquid.
(a) Weight percent of
(b Type of solids:
(c Size of solids:
3. Maximum temperature
4.
Special sitxations (expl;2):
(a) Gases in liquid:
(b) Liquid boiling:
A&
liters per minute
kilograms per hour-rnzn&++f
/*OR
AC0 47, &J,&~<li
nuCF G:cc ,fk ,>k
J'
6. Power source available:
(a) Electrical:
//c
5. Capacity required:
or:
or:
AC:
(b) Fuel:
(c) Other:
i
/
7. Differential head and suction head: AZ/~&k/
8.
Pipe material:
Suction:
Discharge:
9. Pump connections required:
Pipe size (inside diameter):
10.
Sketch of piping (all fittings and valves shown) n&i&l.
11. Other comments:
Figure 1. Pump Specification Fact Sheet. Make a copy of this form for your own use.
NOTE: For advice on pump selection or application, send the completed form (keeping
a copy for your own information)to a local university, a pump manufacturer or to
VITA.
* Actually this pipiny is the same as 2" U.S. Schedule 40.
Give the capacity (the rate at which you want to move the liquid) in any
convenient units (titers per minute, U.S. gallons per minute) by giving the
total of the maximum capacity needed for each outlet.
6.
Give complete details on the power source.
A.
If you are buying an electric motor for the pump, be sure to give your
voltage. If the power is A:<. (Alternating Current) give the frequency
(in cycles per second) and the number of phases. Usually this wilI be
single phase for most small motors. Do you want a pressure switch or
other special means to start the motor automatically?
R.
If you want to buy an engine driven pump, describe the type and cost
of fuel, the aititude, maximum air temperature, and say whether the air
is unusually wet or dusty.
C.
If you already have an electric motor or engine, give as much information about it as you can. Give the speed and sketch the machine, being
especially careful to show the power shaft diameter and where it is
with respect to the mounting. Describe the size and type of pulley if
you intend to use a belt drive. Finally, you must estimate the power.
The best thing is to copy the name plate data completely. If possible
give the number of cylinders in your engine, their size, and the stroke.
7.
The “head” or pressure to be overcome by the pump and the capacity (or
required flow of water) determine the pump size and power. The entry
“Determining Pump Capacity and Horsepower Requirements,” explains the
calculation of simple head situations. The best approach is to explain the
heads by drawing an accurate piping sketch (see Item 10 in the “Pump
Application Fact Sheet”). Be sure to give the suction lift and piping separately from the discharge lift and piping. An accurate description of the
piping is essential for calculating the friction head. See Figure 2.
8.
The piping material, inside diameter, and thickness are necessary for making
the head caiculations and to check whether pipes are strong enough to
withstand the pressure. See “Water Lifting and Transport-Overview” for
comments on specifying pipe diameter.
9.
Connections to commercial putups are normally flanged or threaded with
standard pipe thread.
10.
In the sketch be sure to show the following:
(a) Pipe sizes; show where sizes are changed by indicating reducing
fittings.
91
(b) All pipe fittings-elbows, tees, valves (show valve type), etc.
(c)
11.
Length of each pipe run in a given direction. Length of each size pipe
and vertical lift are the most important dimensions.
Give information on how the pipe will be used. Comment on such points as:
0
0
0
Indoor or outdoor installation?
Continuous or intermittent service?
Space or weight limitations?
Source:
Benjamin P. Coe, VITA Volunteer, Schenectady, New York.
92
Determining Pump Capacity and Horsepower Requirements
With the alignment chart in Figure 1, you can determine the necPJsary pump size
(diameter or discharge outlet) and the amount of horsepower needed to power the
pump. The power can be supplied by people or by motors.
An average healthy person can generate about 0.1 horsepower (HP) for a reasonably long period and 0.4HP for short bursts. Motors are designed for varying
amounts of horsepower.
To get the approximate pump size needed for lifting liquid to a known height
through simple piping, follow these steps:
1.
Determine the quantity of flow desired in liters per minute.
?
I.
Measure the height of the lift required (from the point where the water
enters thr: pump suction piping to where it discharges).
3.
Using the entry “Determining Pipe Size or Velocity of Water in Pipes,” page
74, choose a pipe size that will give a water velocity of about 1.8 meters
per second (6’ per second). This velocity is chosen because it will generally
give the most economical combination of pump and piping; Step 5 explains
how to convert for higher or lower water velocities.
4 .
Estimate the pipe friction-loss head (a 3-meter head represents the pressure
at the bottom of a 2-meter-high column of water) for the total equivalent
pipe length, including suction and discharge piping and equivalent pipe
lengths for valves and fittings, using the following equation:
Friction-loss head =
F x total eauivalent oiue length
100
where F equals approximate friction head (in meters) per 100 meters of pipe.
To get the value of F, see the table below. For an explanation of total
equivalent pipe length, see preceding sections.
5.
To find F (approximate friction bead in meters per 1OOm of pipe) when
water velocity is higher or lower than 1.8 meters per second, use the
following equation:
F =
F at I .8m/secx
I .8m/sec2
v=
where V = higher or lower velocity
‘DIO.0soP
z .aor’ ,S-------_ c
3
---__
--__
4 ,et *$ bR I-
94
Example:
If the water velocity is 3.6m per second and Fat l.(fm/sec is 16, then:
F= 16~3.6~ = 16x13 =64
I.82
6.
3.24
Obtain ‘Total Head” as folluws:
Total Head = Height of Lift c Friction-loss Head
Average friction loss in meters for fresh water flowing through steel pipe
ve!ority is 1.S meters (6 feet) per second
Pipe inside diameter: cm 2.5 5.1 7.6 1Q.2 15.2 20.4 30.6
8”
12”
inch& 1” T
3”
4”
6”
61.2
24
F(approximate
friction
loss in meters per 100
meters of pipe)
0.5
16
7
5
3
2
1.5
1
*For the degree of accuracy of this method, either actual inside diameter in
inches, or nominal pipe size, U.S. Scheduie 40, can be used.
‘, 7.
V&g a straightedge, connect the proper point on the T-scale with the
proper point on the Q-scale; read motor horsepower and pump size on the
other two scales.
Example:
Desired flow: 400 liters per minute
Height of lift: 16 meters, No fittings
Pipe size: 5cm
Friction-loss head: about 1 meter
Total head: 17 meters
Solution:
Pump size: Scm
Motor horsepower: 3HP
Note that water horsepower is less than motor horsepower (see HP-scale, Figure
1). This is because of friction losses in the pump and motor. The alignment chart
should be used for rough estimate only. For an exact determination, give all
information on flow and piping to a pump manufacturer or an independent expert.
95
He has the exact data on pumps for various applications. Pump specifications can
be tricky especially if suction piping is long and the suction lift is great.
For conversion to metric horsepower given the limits of accuracy of this method,
metric horsepower can be considered roughly equal to the horsepower indicated by
the alignment chart (Figure 1). Actual metric horsepower can be obtained by
muitiplying horsepower by 1.014.
Kuhnan, CA. Nomographic Charts. New York: McGraw-Hill Book Co., 1951.
Determining Lift Pump Capability
The height that a lii pump can raise water depends on altitude and, to a lesser
extent, on water temperature. The graph in Figure 1 will help you to find out
what a lift pump can do at various altitudes and water temperatures. To use it,
you will need a measuring tape and a thermometer.
the temperature of your water, Figure 1 will tell
stance between the pump cylinder and the lowest
aph shows that lift pumps are marginal or will not
ould be used. This involves putting the cylinder down
to the lowest expected water level to be certain of
The graph shows normal lifts. Maximum possible lifts under favorable conditions
would be about 1.2 meters higher, but this would require slower pumping and
would probably give much difticulty in “losing the prime.”
Check predictions from the graph by measuring lifts in nearby wells or by
experimentation.
Suppose your elevation is 2,000 meters and the water temperature is
25OC. The graph shows that the normal lii would be four meters.
Baumeister, Theodore. Mechanical Engineer’s Handbook, 6th edition. New York:
McGraw-Hill Book Co., 1958.
Example:
45
Suppose your elevation 4o
is 2000 meters and the
water temperature
is 25C. The graph
35
shows that the normal
lift would be 4 meters.
10
4
\\\\\
Figure 1. Graph showing lift pump capabilities at various altitudes &--J--J
0
2
3
and water temperatures.
Broken lines indicate
SUCTION
example given in text.
SIMPLE PUMPS
‘, Chain Pump for Irrigation
The chain pump, which can be powered by hand or animal, is primarily a shallowwell pump to lift water for irrigation (see Figure 1). It works best when the lift
is less than 6 meters (20’). The
water source must have a depth of
about 5 chain links.
Both the pump capacity and the
power requirement for any lit are
proportional to the square of the
diameter of the tube. Figure 2
shows what can be expected from a
1Ocm (4”) diameter tube operated
by four people working in two
shifts.
The pump is intended for use as an
irrigation pump because it is
difficult to seal for use as a
sanitary pump.
NGURE 2
L/F?-
QUANI*ITY
6 M.FIEPS cm FEEZ)
~~~9~
JMETERS (9 FEET I
I.5 To Z NETERS C4.5 7-O ii .=&ET)
Tools and Materials
Welding or brazing equipment
Metal-cutting equipment
Woodworking tools
1Ocm (4”) outside diameter, length as needed
Pipe:
5cm (2”) outside diameter, length as needed
Chair] with links about 8mm (5/X”) in diameter, length as needed
Greet steel, 3mm (l/S”) thick
Sheet steel, Gmm (l/4”) thick
Steel rod, 8mm (S/16”) in diameter
Steel rod, 12.7mm (l/2”) in diameter
Leather or rubber for washers
The entire chain pump is shown in Figure 3. Details of this pump can be changed
to fit materials available and structure of the well.
The piston links (see Figures 4,5,6 and 7) are made from three parts:
1.
a leather or rubber washer (see Figure 4) with an outside diameter about
two thicknesses of a washer larger than the inside diameter of the pipe.
2.
a piston disk (see Figure 5).
3.
a retaining plate (see Figure 6).
The piston link is made as shown in Figure 7. Center all three parts and clamp
them together temporarily. Drill a hole about 6mm (l/4”) in diameter through all
three parts and fasten them together with a bolt or rivet.
The winch is built as shown in Figure 3. Two steel disks 6mm (l/4”) thick are
welded to the pipe shaft.
Twelve steel rods, 12.7mm (l/2”) thick, are spaced at equal distances, at or near
the outside diameter, and are welded in place. The rods may be laid on the
outside of the disks, if desired.
.
:
i
:::
&
NGu@E \ :ij/: /:
3
99
A crank and handle of wood or metal is then welded or bolted to the winch
shaft.
The supports for the winch shaft (see Figure 3) can be V-notched to hold the
shaft, which will gradually wear its own groove. A strap or block can be added
across the top, if necessary, to hold the shaft in place.
The pipe can be supported by threading or welding a flange to its upper end (see
Figure 8). The flange should be 8mm to 10mm (Z/16” to 3/S”) thick. The pipe
passes through a hole in the bottom of the trough and hangs from the trough
into the well.
Robert G. Young,
Young, VITA
VITA Volunteer, New Holland, Pennsylvania
Molenaar, Aldert.
Molcnaar,
Aldert. Waler
Wurer .L.$iq
Lifting Devices
Devices for
for Iigation.
higation. Rome: Food and Agriculture
Organization, 1956.
100
F/GUrQE 8 P/FE S U P P O R T
101
Inertia Hand Pump
The inertia hand pump described here (Figure 1) is a
very efticient pump for lifting
water short distances. It lifts
water 4 meters (13’) at the
rate of 75 to 114 liters (20 to
30 U.S. gallons) per minute. It
liis water 1 meter (3.3’) at
the rate of 227 to 284 liters
(60 to 75 gallons) per minute.
Delivery depends on the number of persons pumping and
their strength.
The pump is easily built by a
tinsmith. Its three moving
parts require almost no maintenance. The pump has been
built in three different sizes
for different water levels.
The pump is made from galvanized sheet metal of the
heaviest weight obtainable
that can be easily worked by
a tinsmith (24- t o 2Sgauge
sheets have been used successfully). The pipe is formed
and made air tight by soldering all joints and seams.
‘The valve is made from the
metal of discarded barrels and
a piece of truck inner tube
rubber. The bracket for
attaching the handle is also
made from barrel metal.
Figure 1 shows the pump in
operation. Figure 2 gives the
dimensions of parts for pumps
in three sizes and Figure 3
shows the capacity of each
size. Figures 4, 5, and 6 are
construction drawings.
Tools and Materials
(for l-meter (33’) pump)
Soldering equipment
Drill and bits or punch
Hammer, saws, tinsnips
Anvil (railroad rail or iron pipe)
Galvanized iron (24 to 28 gauge):
Shield 61cm x 32cm, 1 piece (24” x I2 5/8”)
Shield cover: 21cm x 22cm, 1 piece (8 1,/4” x 8 $8”)
Pipe: 14Ocm x 49cm, 1 piece (55 l/8” x I9 l/4”)
Top of pipe: 15cm x 15cm, 1 piece (6” x 6”)
“Y” pipe: 49cm x 3Ocm, 1 piece (19 l/4” x 12”j
Barrel metal:
Bracket: 15cm x 45cm, 1 piece (6” x 21 l/4”)
Valve-bottom: 12cm (4 3/4”) in diameter, 1 piece
Valve-top: 18cm (7 l/8”) in diameter, 1 piece
Wire:
Hinge: 4mm (5/32”) in diameter, 32cm (12 5/8”) long
This pump can also be made from plastic pipe or bamboo.
There are two points to be remembered concerning this pump. One is that the
distance from the top of the pipe to the top of the hole where the short section
of pipe is connected must be 20cm (8”). See Figure 4. The air that stays in the
pipe above this junction serves as a cushion (to prevent “hammering”) and
regulates the number of strokes pumped per minute. The second point is to
remember to operate the pump with short strokes, 15 to 2Ocm (6” to 8”), and at a
rate of about 80 strokes per minute. There is a definite speed at which the pump
works best and the operators will soon get the “feel” of their own pumps.
In building the two larger size pumps it is sometimes necessary to strengthen the
pipe to keep it from collapsing if it hits the side of the well. It can be strengthened bi forming “ribs” about every 30cm (12”) below the valve or banding with
bands madt from barrel metal and attached with 6mm (l/4”) bolts.
The handle is attached to the pump and post with a bolt 1Omm (3/f?‘) in diameter,
or a large nail or rod of similar size.
source:
Dale Fritz, VITA Volunteer, Schenectady, New York,
103
-----?
104
-1
I
WDLE 0W,CUET
I.
Handle Mechanism for Hand Pumps
The wearing parts of this durable handpump handle mechanism are wooden (see
Figure 1). They can be easily replaced by a village carpenter. This handle has
been designed to replace pump handle mechanisms which are difficult to maintain.
Some have been in use for several years in India with only simple, infrequent
repairs.
The mechanism shown in Figure 1 is bolted to the top flange of your pump. The
mounting holes A and C in the block should be spaced to fit your pump (see
Figure 6). Figure 2 shows a pump with this handle mechanism that is manufactured by F. Humane and Bras, 28 Strand Road, Calcutta, india.
Tools aud Materials
Saw
Drill
Bits
Tap: 12.5mm (l/2”)
Tap: 1Omm (3/8”)
Chisel
Drawknife, spokeshave or lathe
Hardwood86.4cm x 6.4cm x 6.4cm
(Wx21/2”x21/2”)
Mild steel rod: 1Omm (3/4”) in diameter
and 465cm (16”) long
Strap iron, 2 pieces: 26.7cm x 38mm x 6mm
(10 l/TX 1 l/2” x l/4”)
BOLT HARDWARE
Number
of bolts Dia.
needed mm
Length
mm
Number Number
of nuts
of lockneeded
washers
Number
of plain
washers
1
1
2
10
10
12.5
38
76
89
0
0
2
0
0
4
0
2
4
2
1
12.5
12.5
?
?
2
1
2
1
2
0
Purposefastens:
76mm bolt to rod
Rod to handle
Link to handle
Link to block
Block to pump
Rod to piston
Handle
I--
Make the handle of tough hardwood, shaped on a lathe or by hand
shaving. The slot should be cut
wide enough to accommodate the
rod with two plain washers on
either side. See Figure 3.
Rod
The rod is made of mild steel as
shown in Figure 4. A 1Omm (3/8”)
diameter machine bolt 3Smm (1
l/2”) long screws into the end of
the rod to lock the rod hinge pin
in place. ‘Ihe rod hinge pin is a
1Omm (3/8”) diameter machine bolt
that connects the rod to the handle
(see Figure 1). The end of the rod
can be bolted directly to the pump
piston with a 12Smm bolt. If the
pump cylinder is too far down for
this, a threaded 12Smm (l/2”) rod
should be used instead.
Links
The links are two pieces of flat steel strap iron. Clamp them together for drilling
to make the hole spacing equal. See Figure 5.
Block
The block forms the base of the lever mechanism, serves as a lubricated guide
hole for the rod, and provides a means for fastening the mechanism to the, pump
barrel. If the block is accurately made of seasoned tough h;rrdwood without knots,
the mechanism will function well for many years. Carefully square the block to
22.9cm x 6.4~1 x 6.4cm (9” x 1 l/2” x 1 l/2”). Next holes, A, B, C, and D are
drilled perpendicular to the block as shown in Figure 6. The spacing of the
FIG 6
BLDCK
mounting holes A and C from hole B is determined by the spacing of the bolt
holes in the barrel flange of your pump. Next saw the block in half in a plane
3Scm (1 3/Y) down from the top side. Enlarge hole B at the top of the lower
section with a chisel to form an oil well around the rod. This well is filled with
cotton. A 6mm (l/4”) hole, F, is drilled at an angle from the oil well to the
surface of the block. A second oil duct hole E is drilled in the upper section of
the block to meet hole D. Use lockwashers under the head and nut of the link
bolts to lock the bolts and links together. Use plain washers between the links
and the wooden parts.
Abbott, Dr. Edwin. A Pump Designed for Village Use. Philadelphia: American
Friends Service Committee, 1955.
108
Hydraulic Ram
A hydraulic ram is a self-powered pump that uses the energy of falling water to
lift some of the water to a level above the original source. This entry explains
the use of commercial hydraulic rams, which are available in some countries. Plans
for building your own hydraulic ram are also available from VITA and elsewhere.
Use
of the Hydraul@ Ram
A hydraulic ram can be used wherever a spring or stream of water flows with at
least a 91Scm (3’) fall in altit,ude. The source must be a flow of at least 11.4
liters (3 gallons) a minute. Water can be lifted about 7.6 meters (25’) for each
30.5cm (12”) of fall in altitude. It can be lifted as high as 152 meters (SOO’), but
a more common lift is 45 meters (1503.
The pumping cycle (see Figure 1) is:
“,,,,
0
Water flows through the drive pipe (D) and out the outside valve (F).
0
The drag of :he moving water closes the valve (F).
0
The momentum of water in the drive pipe (D) drives some water into the air
chamber (A) and out the delivery pipe (I).
0
The llow stops.
0
The check valve (8) closes
0
The outside valve (F) opens to start the next cycle.
,,,
This cycle is repeated 25 to 100 times a minute; the frequency is regulated by
moving the adjustment weight (C).
109
The length of the drive pipe must be between five and ten times the length of
the fall (see Figure 2). If the distance from the source to the ram is greater than
ten times the length of the fall, the length of the drive pipe can be adjusted by
installing a stand pipe between the source and the ram (see B in Figure 2).
Once the ram is installed there is little need for maintenance and no need for
skilled labor. The cost of a hydraulic ram system must include the cost of the
pipe and installation as well as the ram. Although the cost may seem high, it
must be remembered that there is no further power cost and a ram will last for
30 years or more. A ram used in freezing climates must be insulated.
1,l~O
double-acting ram will use an impure water’supply to pump two-thirds of the
pure water from a spring or similar source. A third of the pure water mixes with
the impure water. A supplier should be consulted for this special application.
A
To calculate the approximate pumping rate, use the following equation:
Capacity (gallons per hour) = V x F x 40
E
V
F
E
= gallons per minute from source
= fall in feet
= height the water is to be raised in feet
Data Needed for Ordering a Hydraulic Ram
1.
Quantity of water available at the source of supply in titers (or gallons) per
minute
2.
Vertical fall in meters (or feet) from supply to ram
3.
Height to which the water must be raised above the ram
4.
Quantity of water required per day
5.
Distance from the: source of supply to the ram
6.
Distance from the ram to the storage tank
Sources:
Loren G. Sadler, New Holland, Pennsylvania
Rife Hydraulic E.ngine Manufacturing Company, Millburn, New Jersey
Sheldon, W.H. 77~ Hvdou~lic Ram. Extension Bulletin 171, July 1943, Michigan
State College of Agricuhure and Applied Science.
“Country Workshop.” Ausf;aliatz COU@S. September l%l, pages 32-33.
“Hydraulic Ram Forces Water to Pump Itself.” Po~nlar Sciertcc, October 1948,
pages 231-233.
“Hydraulic Ram.” 77re Home Craftsman, March-April 1963, pages 20-22.
111
RECIPROCA~NG
FOR WATER PUMP
RE POWER T
NS~I~SION
A reciprocating wire can transmit power from a water wheel to a point up to
0.8km (l/2 mile) away where it is usually used to pump well water. These devices
have been used for many years by the Amish people of Pennsylvania. If they are
properly installed, they give long, trouble-free service.
The Amish people use this method to transmit mechanical power from small water
wheels to the barnyard, where the reciprocating motion is used to pump well
water for home and farm use. The water wheel is typically a small undershot
wheel (with the water flowing under the wheel) one or two feet in diameter. The
wheel shaft is fitted with a crank, which is attached to a triangular frame that
pivots on a pole (see Figure 2). A wire is used to connect this frame to another
identical unit located over the well. Counterweights keep the wire tight.
Tools and Materials
Wire: galvanized smooth fence wire
Water wheel with eccentric crank to give a motion slightly less than largest
stroke of farmyard pump
Galvanized pipe for triangle frames: 2cm (3/4”) by 1~0 meters long (32.8’)
Welding or brazing equipment to make frames
Concrete for counterweight
2 Poles: 12 to 25cm (6” to l@) in diameter.
113
As the water wheel turns, the
crank tips the triangular frame
back and forth. This action pulIs
the wire. back and forth. One
typical complete back and forth
cycle takes 3 to 4 seconds.
Sometimes power for several
transmission wires comes from one
larger water wheel.
The wire is mounted up on poles to
keep it overhead and out of the
@’ way. If the distance from stream to
4%
courtyard is far, extra poles will be
needed to help support the wire.
Amish folks use a loop of wire
covered with a small piece of
garden hose attached to the top of
the pole. The reciprocating wire
slides back and forth through this
loop. If this is not possible, try
making the pole 1-2 meters higher
than the power wire. Drive a heavy
WIRS
nail near the pole top and attach a
chain or wire from it to the power
TEEL ROD OR PIPE
%?.uNK1NTOFOLE
wire as shown in Figure 3.
PIPE FRAME WELDED
OR BRAZED
Turns can bc made in order to
follow hedgerows by mounting a
small triangular frame horizontally
at the top of a pole as shown in
Figure 4.
Figures 5, 6, and 7 show how to
build and install a small water
wheel made from wood and bamboo.
DEVICE FOR
TURNING CORNERS
New Holland, Pennsylvania VITA Chapter.
4
115
116
117
WIND ENERGY FOR WATER PUMPING
overview
There are many places in the world where wind energy is a good alternative for
pumping water. Specifically these include windy areas with limited access to other
forms of power. In order to determine whether wind power is appropriate for a
particular situation an assessment of its possibilities and the alternatives should
be undertaken. The necessary steps include the following:
1.
Identify rhe users of the water.
2.
Assess the water requirement.
3.
Find the pumping height and overall power requirements.
4.
Evaluate the wind resources.
5.
Estimate the size of the wind machine(s) needed.
6.
Compare the wind machine oulpu.r with the water requirement on a
seasonal basis.
7.
Select a type of wind machine and pump from the available options.
8.
Identify possible suppliers of machines, spare parts, repair, etc.
9.
Identify alternative sources for water.
10. Assess costs of various systems and perform economic analysis to find
least cost alternative.
11. If wind energy is chosen, arrange for obtaining and installing the
machines and for providing for their maintenance.
Decision. Making Process
The following summarizes the key aspects of those suggested steps.
1. IdentiJL the Users
This step seems quite obvious, but should not be ignored. By paying attention to
who will use the wind machine and its water it will be possible to develop a
project that can have continuing success. Questions to consider are whether they
are villagers, farmers, or ranchers; what their educational lcvcl is; whether they
have had experience with similar types of technology in the past; whether they
118
have access to or experience with metal working shops. Who will be pan; g for
the projects? Who will be owning the equipment; who will be responsibie for
keeping it running; and who will be benefitting most? Another important question
is how many pumps are planned. A large project to supply many pumps may well
be different than one looking to supply a single site.
2. Assess the Water Requirements
There are four main types of uses for water pumps in areas where wind energy is
likely to be used. These are: 1) domestic use, 2) livestock watering, 3) irrigation,
4) drainage
Domestic use will de,pcnd a great deal on the amenities available. A typical
villager may use from 15 - 30 liters per day (4-8 gallons per day). When indoor
plumbing is used, water consumption may increase substantially. For example, a
flush toilet consumes 25 liters (6 l/2 gallons) with each use and a shower may
take 230 (60 gallons.) When estimating water requirements, one must also consider
population growth. For example, if the growth rate is 3 percent, water use would
increase by nearly 60 percent at the end of 15 years, a reasonable lifetime for a
water pump.
Basic livestock requirements range from about 0.2 liters (0.2 quart) a day for
chickens or rabbits to 135 liters (36 gallons) a day for a milking cow. A single
cattle dip might use 7500 liters (2000 gallons) a day.
Estimation of irrigation requirements is more complex and depends on a variety of
meteorological factors as well as the types of crops involved, The amount of
irrigation water needed is approximately equal to the difference between that
needed by the plants and that provided by rainfall. Various techniques may be
used to estimate evaporation rates, due for example to wind and sun. These may
then be related to plant requirements at different stages during their growing
cycle. By way of example, in one semi-arid region irrigation requirements varied
from 35,080 liters (9,275 gallons) per day per hectare (2.47 acres) for fruits and
vegetables to 100,000 liters (26,500 gallons) per day per hectare for cotton.
Drainage requirements are very site dependent. Typical daily values might range
from 10,000 to 50,000 liters (2,650 to 13,250 gallons) per hectare.
In order to make the estimate for the water demand, each user’s consumption is
identified, and summed up to find tire total. As will become apparent later. It is
desirable to do this on a monthly basis so that the demand can be related to the
wind resource.
119
3. Find Pumping Height and T Oral Power Requirement
If wells are already available their depth can be measured directly. If new wells
are to be dug, depth must be estimated by reference to other wells and knowledge
of ground water characteristics in the area. The total elevation, or head, that the
pump must work against, however, is always greater than the static well depth.
Other contributors are the well draw down (the lowering of the water tab!e in
the vicinity of the well while pumping is underway), the height above ground to
which the water will be pumped (such as to a storage tank), and frictional losses
in the piping. In a properly designed system the well depth and height above
ground of the outlet are the most important determinants of pumping head.
The power required to pump water is proportional to its mass per unit volume, or
density (1000 kg/m?), the acceleration of gravity (g= 9.8 m/s2, the total pumping
head (m), and the volume flow rate of water (m3/s). Power is also inversely
proportional to the pump ef!iciency. Note that 1 cubic meter equals 1000 liters.
E,xpressed as a formula,
Power = Den.sity x Gravity x Head x Flow rate
To pump 50 m3 in one day (0.000579 m3/s) up a total head of 15 m
would require:
Power = (loo0 kg/m3) (9.8m/s2) (15m) (.000579m3/s) = 85 watts.
Actual power required would be more because of the less than perfect
efficiency of the pump.
Sometimes needed pumped power is described in terms of daily hydraulic requirement, which is often given in the units of m3. m/day. For example, in the above
example the hydraulic requirement is 750 m3,m /day.
4. Evaluate Wind Resource
It is well known that the power in the wind varies with the cube of the wind
speed. Thus if the wind speed doubles, the available power increases by a factor
of eight. Hence it is very important to Irave a good understanding of the wind
speed patterns at a given site in order to evaluate the possible use of a wind
pump there. It is sometimes recommended that a site should have an average wind
speed at the height of a wind rotor of at least 2.5 m/s in order to have potential
for water pumping. That is a good rule of thumb, but by no means the whole
story. First of all, one seldom knows the wind speed at any height at a prospective windmill site, except by estimate and correlation. Second, mean wind speeds
generally vary with the time of dtiy and year and it makes an enormous difference
if the winds occur when the water is needed.
The best way to evaluate the wind at a prospective site is to monitor it for at
least a year. Data should be summarized at least monthly. This is often impossible,
but there should be some monit,oring done if a large wind project is envisioned.
The most practical approach may be to obtain wind data from the nearest weather
station (for reference) and try to correlate it with that at the proposed wind
pump site. If at all possible the station should be visited to ascertain the
placement of the measuring instrument (anemometer) and its calibration. Many
times anemometers are placed too near the ground or are obscured by vegetation
and so greatly underestimate the wind speed. The correlation with the proposed
site is best done by placing an anemometer there for a relatively short time (at
least a few weeks) and comparing resulting data with that taken simultaneously at
the reference site. A scaling factor for the long-term data can be deduced and
used to predict wind speed at the desired location.
Of course, possible locations for wind machines are limited by the placement of
the wells, but a few basic observations should be kept in mind. The entire rotor
should be well above the surrounding vegetation, which should be kept as low as
possible for a distance of at least ten times the rotor diameter in all directions.
Wind speed increases with elevation above ground, usually by 15-20 percent with
every doubling of height (in the height range of most wind pumps). Because of
the cubic relationship between wind speed and power, the effect on the latter is
even more dramatic.
5. Esti.mate wind Machines Size
A typical wind pump is shown in Figure 1. Most wind pumps have a horizontal
axis (that is, the rotating shaft is parallel to the ground). Vertical axis machines,
such as the Savonius rotor, have usually been less successful in practice.
In order to estimate wind machine’s size it is first necessary to have some idea
how it will perform in real winds. As previously mentioned, the power in wind
varies with the cube of the wind speed. It is also proportional to the density of
the air. Atmospheric density is 1.293 kg/m3 at sea level at standard conditions but
is affected by temperature and pressure. The power that a wind machine produces,
in addition, depends on the swept area of its rotor and the aerodynamic characieristics of its blades. Under ideal conditions the rotational speed of the rotor
varies in direct relation to the wind speed. In this case the efficiency of the
rotor remains constant and power varies as the cube of the wind speed (and
rotational speed).
With wind pumps, however, the situation is more complicated. The majority use
piston pumps, whose power requirements vary directly with the speed of the
pump. At high wind speeds the rotor can produce more power than the pump can
121
use. The rotor speeds up, causing its efficiency to drop, so it produces less power. The
pump, coupled to the rotor, also moves more
rapidly so it absorbs more power. At a
certain point the power from the rotor equals
the power used by the pump, and the rotational speed remains constant until the wind
speed changes.
The net effect of all this is that the whole
system behaves rather differently than an
ideal wind turbine. its actual performance is
best described by a measured characteristic
curve (Figure 2), which relates actual water
flow at given pumping heads to the wind
speed. This curve also reflects other important information such as the wind speeds at
which the machine starts and stops pumping
(low wind) and when it begins to turn away
in high winds (furling).
FKXIRE 1: Typical Wind Pump
Water
FIW
9
m /hr.
/
/
/
/
MO&l/------/
/
/
/
Ai
Vl /‘IVz
Mean Wind
I
I
2
4
FIGURE 2:
1
6
I
8
Speed m/s
I
I
10
(U’yofl and Hodgkinv. 1984)
Multiblade Windmill Performance, Observed And Model
Results, One Minute Average Readings
122
Most commercial machines and those developed and tested more recently have
such curves and these should be used if possible in predicting wind machine
output. On the other hand, it should be noted that some manufacturers provide
incomplete or overly optimistic estimates of what their machines can do. Sales
literature should be examined carefully.
In addition to the characteristic curve of the wind machine, one must also know
the pattern of the wind in order accurately to estimate productivity. For exampie,
suppose it is known how many hours (frequency) the average wind speed was
between O-l m/s, 1-2 m/s, 2-3 m/s, etc., in a given month. By referring to the
characteristic curve, one could determine how much water was pumped in each of
the groups of hours corresponding to those wind speed ranges. The sum of water
from all groups would be the monthly total. Usually such detailed information on
the wind is not known. However, a variety of statistical techniques are available
from which the frequencies can be predicted fairly accurately, using only the
long-term mean wind speed and, when available, a measure of its variability
(standard deviation). See Lysen, 1983, and Wyatt and Hodgkin, 19&l.
Many times there is little information known about a possible machine or it is
just desired to know very approximately what size machine would be apprcpriate.
Under these conditions the following simplified formula can be used:
Power = Area x 0.1 x (Vmeanp
where
Power = useful power delivered in pumping the water, watts
Area = swept area of rotor (3.14 x Radius squared), m2
Vmean = mean wind speed, m/s
By rearranging the above equation, an approximate diameter of the wind rotor can
be found. Returning to the earlier example, to pump 50 m3jday, 15 m would
require an average of 85 watts. Suppose the mean wind speed was 4 m/s. Then
the diameter (twrce the radius) would be:
Diameter = 2 [Power/(3.14) x 0.1 x Vmcan3)]
or
Diameter = 2 x [85/(3.14x 0.1 x 43)] = 4.1 m
6. Compare Seasortal Water Production to Requiremerzt
This procedure is usually done on a monthly basis. It consists of comparing the
amount of water that could be pumped with that actually needed. In this way it
can be told if the machine is large enough and conversely if some of the time
there will be excess water. This information is needed to perform a realistic
123
economic analysis. The results may suggest a change iu the size of machines to be
used.
Comparison of water supply and requirement will also aid in determining the
necessary storage size. In general storage should be equal to about one or two
days of usage.
7. Select Type of Wind machine and Pump
There is a variety of types of wind machines that could be considered. The most
common use relatively slow speed rotors with many blades, coupled to a reciprocating piston pump.
Rotor speed is described in terms of the tip speed ratio, which is the ratio
between the actual speed of the blade tips and the free wind speed. Traditional
wind pumps operate with highest efficiency when the tip speed rat:0 is about 1.0.
Some of the more recently developed machines, with less blade area relative to
their swept area, perform best at higher tip speed ratios (such as 2.0).
A primary consideration in selecting a machine is its intended application.
Generally speaking, wind pumps for domestic use or livestock supply are designed
for unattended operation. They should be quite reliable and may have a relatively
high cost. Machines for irrigation are used seasonally and may be designed to be
manually operated. Hence they can be more simply constructed and less expensive.
For most wind pump applications, there are four possible types or sources of
equipment. These are: 1) Commercially available machines of the sort developed
for the American West In the late 1800s; 2) Refurbished machines of the first
types that have been abandoned; 3) Intermediate technology machines, developed
over the last 20 years for production and use in developing countries; and 4) Low
technology machines, built of local materials.
The traditional, American “fan mill,” is a well developed technology with very
high reliability. It incorporates a step down transmission, so that pumping rate is
a quarter to a third of the rotational speed of the rotor. This design is particularly suitable for relatively deep wells (greater than 3Om--100’). The main
problem with these machines is their high weight and cost relative to their
pumping capacity. Production of these machines in developing countries is often
difficult because of the need for casting gears.
Refurbushing abandoned traditional pumps may have more potential than might at
tirst appear likely. In many windy parts of the world a substantial number of
these machines were installed early in this century, but were later abandoned
when other forms of power became available. Often these machines can be made
operational for much less cost than purchasing a new one. In many cases parts
from newer machines are interchangeable with the older ones. By coupling refur-
124
bishing with a training program, a maintenance and repair infrastructure can be
created at the same time that machines are being restored. Development of this
infrastructure will facilitate the successful introduction of newer machines in the
future.
For heads of less than 3Om, the intermediate technology machines may be most
appropriate. Some of the groups working on such designs are listed at the end of
this entry. These machines typically use a higher speed rotor and have no gear
box. On the other hand they may need an air chamber to compensate for adverse
acceleration effects due to the rapidly moving piston. The machines are made of
steel, and require no casting and minimal welding. Their design is such that they
can be readily made in machine shops in developing countries. Many of these wind
pumps have undergone substantial analysis and geld testing and can be considered
reliable.
Low technology machines are intended to be built with locally available materials
and simple tools. Their fabrication and maintenance, on the other hand, are very
labor intensive. In a number of cases projects using these designs have been less
successful than had been hoped. If such a design is de~sired, it should first be
verified that machines of that type have actually been built and operated successfully. For a sobering appraisal of some of the problems encountered in building
wind machines locally, see %7nd Errem~ Dev&~~~en~ in Ktwya (see Sources).
Although most wind machines use piston pumps, other types include mono pumps
(rotating), centrifugal pumps (rotating at high speed), oscillating vanes, compressed air pumps, and electric pumps driven by a wind electric generator.
Diaphragm pumps are sometimes used for low head irrigation (5-10 m or 16-32’).
No matter what type of rotor is used, the pump must be sized appropriately. A
large pump will pump more water at high wind speeds than will a small one. On
the other hand, it will not pump at all at lower wind speeds. Since the power
required in pumping the water is proportional to the head and the flow rate, as
the head increases the volume pumped will have to decrease accordingly. The
piston travel, or stroke, is generally constant (with some exceptions) for a given
windmill. Hence, piston area should be decreased in proportion to the pumping
head to maintain optimum performance.
Selecting the correct piston pump for a particular app!ication invo!ves consideration of two types of factors: 1) the characteristics of the rotor and the rest of
the machine, and 2) the site conditions. The important machine characteristics
are: 1) the rotor size (diameter); 2) the design tip speed ratio; 3) the gear ratio;
and 4) the stroke length. The first two have been discussed earlier. The gear
ratio reflects the fact that most wind pumps are geared down by a factor of 3 to
4. Stroke length increases with rotor size. The choice is affected by structural
considerations. Typical values for a machine geared down 3.91 range from 10 cm
(4”) for a rotor diameter of 1.8 m (6’) to 40 cm (lS)for a diameter of 5 m (16’).
Note that it is the size of the crank driven by the rotor (via the gearing) that
determines the stroke of the pump.
The key site conditions are: 1) mean wind speed and 2) well depth. These site
factors can be combined with the machine parameters to find the pump diameter
with the use of the following equation. This equation assumes that the pump is
selected so that the machine performs best at the mean wind speed.
/
(0.1) (N @mJ3 (WAN2 (GEAM
DP
= v (DENSW) (6) (HEIGHT) (TSR) (STROKE)
where:
DP = Diameter of piston, m
K = 3.1416
DIAMR = Diameter of the rotor, m
VMEAN = Mean wind speed, m/s
GEAR = Gear down ratio
DENSW = Density of water, 1000 k m3
G = Acceleration of gravity. 9.8 m/sgt
IIEIFHT = Total pumping head, m
TSR = Design tip speed ratio
STROKE = Pision stroke length, m
Example,:
Suppose the wind machine of the previous examples has a gear down ratio of
3.51, a design tip speed ratio of 1.0 and a stroke of 30 cm. Then the
diameter of the piston would be:
8. Identify Suppliers of Machinery
Once a type of machine has been selected, suppliers of the equipment or the
designs should be contacted for information about availability of equipment and
spare parts in the region in question, references, cost, etc. If the machine is to
be built locally. sources of material, such as sheet steel, angle iron, bearings, etc.
will have to be identified. Possible machine shops should be visited and their work
on similar kinds of fabrication should be examined.
9. IdentifL Alternative Power Sources for Wuter Pumping
There are usually a number of alternatives in any given situation. What might be
a good option depends on the specific conditions. Some of the possibilities include
126
pumps using human power (hand pumps), animal power (Persian wheels, chain
pumps), internai combustion engines (gasoline, diesel, or biogas), external combustion engines (steam, Stirling cycle), hydropower (hydraulic rams, norias), and solar
power (thermodynamic cycles, photovoltaics).
10. Evaluate Economics
For a99 the realistic options the likely costs should be assessed and a life cycle
economic analysis performed. The costs include the ftrst cost (purchase or
manufacturing price), shipping, installation, operation (in&ding fuel where
applicable), maintenance, spare parts, etc. For each system being evaluated the
total useful delivered water must also be determined (as described in Step 6). The
life cycle analysis takes account of costs and benefits that accrue over the fife of
the project and puts them on a comparable basis. The result is frequently
expressed in an average cost per cubic meter of water (Figure 3).
U.S. cents per m3. in.
1
2
3
I
I
I
4
5
7
6
UiwA 2.5 kW
Siesel 10 kW
!3ianasa S.I. engine:2kW
4.0 mis
3.0 m/s
2.5 mix
20 .winl2
15 hmJ
IOMJhW
l~~ydr~
Turbile pump
Mains electicily
Kerosene 2 kW
Dicscl 25 kW
Sifsel 10 kW
Biamss S.I. engine 2 kW
4.0 m/s
3.0 m/s
25 mix
20 MI/m2
15 MJhJ
10MJ/mw
nydrm
Turbine pump
Mains elcctricilv
Im
I
I
I
U.S. cents per 19. m.
P’ItiUKE 3: Expected tange o umt energy costs for two levels of demand,
. for different types of prime mover.
100 and loo0 m 5.m/day,
127
It should be noted that the most economic option is strongly affected by the size
of the project. In general, wind enerbr is seldom competitive when mean winds
are less than 2.5 m/s, but it is the Ieast cost alternative for a wide range of
conditions when the mean wind speed is greater than 4.0 m/s.
II. Install the Machines
Once wind energy has been selected, arrangements should be made for the
purchase or construction of the equipment. The site must be prepared and the
materials all brought there. A crew for assembly and erection must be secured,
and instructed. Someone must be in charge of overseeing the installation to
ensure that it is done properly and to check the machine out when it is up.
Regular maintenance must be arranged for.
With proper planning, organization, design, construction, and maintenance, the
wind machines may have a very useful and productive life.
Source:
James F. Manwcll, VITA Volunteer, University of Massachusetts.
References:
Fraenkel, Peter. Water-Pumping Devices: A Handbook for Users and Choosers.
London: Intermediate Technology Publications, 1986.
Johnson, Carry. ifind Errergv Sysfenzs. Englewood Cliffs, New Jersey: Prentice
Hall, Inc.
Lierop, WE. and van Veldheizen, L.R. W7nd Ehergy Development in Ketrya, Main
Report, Vol. 1: Past and Present Wind Energy Activities, SWD 82-3/VoI. 1
Anersfoort, The Netherlands: Consultancy for Wind Energy in Developing Countries, 19b2.
Lysen, E.H. Introduction to W7nd Energy. SWD 82-l Amersfoort, The Netherlands:
Consuhancy for Wind Energy in Developing Countries, 1983.
Manwell, J.F. and Cromack, D.E. Understanding Wind Enemy: An Overview.
Arlington, Virginia: Volunteers in Technical Assistance, 1984.
McKentie, D.W. “Improved and New Water Pumping Windmills,” Proceedings of
Winter Meeting, American Soc;ety of Agricultural Engineers, New Orleans,
December, 1984.
Vilsteren, A.V. Aspects of Imgatiort with WndmiNs. Amersfoot, The Netherlands:
Cons&army for Wind Energy in Developing Countries, 1981.
128
Wegley, H.L., et al. A Siting Handbook for Small Wind Energy Conversion Systems.
Richland, Washington: BatteIIe Memorial Institute, 1978.
Wyatt, AS. and Hodgkin, J., A Performance Model for Multiblade Water Pumping
WindmilIs. Arlington, Virginia: VITA, 1984.
Groups Involved with Wind Pumping in Developing Countries
Consultarmy for Wiid Energy in Developing Countries, P.O. Box 85, 3800 AB,
Amersfoort. The Netherlands
Intermediate Technology Development Group, Ltd., 9 King Street, Coven Garden,
London, WC2E 8HW, UK
IPAT, TechnicaI University of Berlin, Sekr. THZ, Lentzallee 86, D-1000 Berlin 33,
West Germany
Renewable Energy Research Laboratory, Dept. of Mechanical Engineering, University of Massachusetts, Amherst, Massachusetts OloG3, USA
SKAT, Varnbuelstr. 14, CHXIOO St. Gallen, Switzerland
The Danish Center for Renewable Energy, Asgaard, Sdr. Ydby, DK-7760 Hurup
Thy, Denmark
Volunteers in Technical Assistance (VITA), 1815 N. Lynn Street, Suite 280,
Arlington, Virginia 22209-2079 USA
Manufacturers of Water Pumping Windmills
Aermotor, PD. Box 1364, Conway, Arkansas 72032, USA
Dempster Industries, Inc., Beatrice, Nebraska 68310, USA
Heller Aher Company, Perry & Oakwood St., Napoleon, Ohio 43545, USA
re
Cisterns for family use are most practical in areas of adequate rainfall and where
ground water is difficult to obtain or where it contains too many minerals. A
seaied well usually requires no filtration, no chemical disinfection, and little
upkeep, while a cistern needs all of these. And cisterns generally cost more to
buiid than wells. Cistern water has few minerals, however, and is ideal for
washing clothes.
A cistern water supply has four basic parts: tank, catchment area, filter, and
pump. (Pumps are discussed in the section on “Water Lifting.“)
Cistern Tank
The tank described here can be used for sanitary storage of rainwater for family
use. It can be constructed of reinforced concrete sealed with asphalt sealing
compound.
The cistern tank must be watertight to prevent surface contamination from
polluting the supply. Reinforced concrete is the best material because it is strong,
it has a long life and it can be made watertight.
A manhole and drain must be provided so that the tank can be cleaned. (See
Figure 1.) A vent and a place through which chlorine can be added easily for disinfection are also necessary. (Note: Chlorine can be added through the vent by
removing the U elbow. Lubricate the threads of the elbow to make removal easy.)
The size of the cistern depends on the family’s daily needs and the length of
time between rainy periods. If a family needs 94.6 liters (25 U.S. gallons) of water
a day and there are 125 days between rainy periods, then the cistern must hold:
94.6 liters x 12.5 days = 11,835 liters
or
25 U.S. gallons x 125 days = 3,125 U.S. gallons
FE.1
CISTERN WITH SAND FILTER (PUMP INSTALLATION
OPTIONAL)
I ;.----.-..--------..........--------------.-.~.-..~..---..---.-.,....~ I
131
A ctstern with an inside size of 3 meters x 2 meters x 2 meters (7 l/2’ x 7 l/2
x 7 l/2’) holds 11,355 liters (3,000 U.S. gallons). The top surfaces of the cistern
walls should be about IOcm above ground.
‘To be sure that the cistern is watertight, use about 28 liters of water per SOkg
sack of cement (5 l/2 U.S. gallons per 94 pound or one cubic foot sack) when
mixing the concrete. (See section on “Concrete Construction.“) Tamp the concrete
thoroughly and keep the surface damp for at least 10 days. If possible, pour the
walls and floor at the same time. The manhole entrance must be 1Ocm (4”) above
the cistern surface and the cover should overlap by 5cm (2”). Slope the bottom of
the cistern, making one part lower than the rest, so that water cau be more
easily siphoned or bailed out when the cistern is being cleaned. You can do this
by scraping the bottom to the proper contour. Do not use fill dirt under the
cistern because this may cause the cistern to settle unevenly and crack. A
screened drain pipe and valve will make cleaning easier.
An overflow pipe is not needed if a roof-cleaning butterfly valve is properly used.
If the overtlow is installed, be sure to cover the outlet caretidly with copper
window screen. A screened vent is necessary if there is no overflow, to allow
displaced air to leave the cistern. The hand pump must be securely mounted to
bolts cast into the concrete cistern cover. The flanged base of the pump should
be solid, with no holes for contamination to enter, and sealed to the pump cover,
or the drop pipe must be sealed in with concrete and asphalt sealing compound.
A smaI1 pipe with a screw-on cap is needed to allow for measuting the water in
the cistern and adding chlorine solution after each rainfall. The amount of water
in the cistern is measured with a stick marked in thousands of titers (or thousands of gallons). To disinfect after each rainfall, add a 5 parts per million
dosage of chiorine (see section on “Chlorination”).
A newly built or repaired cistern should always be disinfected with a 50 parts per
million chlorine solution. The cistern walls and the filter should be thoroughly
washed with this strong solution and then rinsed. A small-pressure system can be
disinfected readily by pumping this strong solution throughout the system and
letting it stand overnight.
Catchment Area
A catchment area of the proper size is a necessary part of a cistern water
supply. Rainwater for a cistern can be collected from the roof of a house. The
method given here for estimating catchment size should be checked against the
actual size of nearby catchment installations.
The catchment or collecting area should be a smooth, watertight material, like a
galvanized sheet-metal roof. Wood or thatch roofs may taint the water and retain
dust, dirt and leaves; water from these roofs contains more organic matter and
132
bacteria than water from smooth surfaces. Stone, concrete, and plastic film
catchments are sometimes built on the ground. For family use, roofs are usually
best because humans and animals cannot contaminate them.
To estimate your required catchment area, estimate the minimum yearly rainfall
and the amount of water required by the family during one year. Sometimes the
government meteorological section can give you the minimum rainfall expected. If
they cannot, estimate the minimum rainfall at two-thirds of the yearly average.
Take the average amount of water needed by the family for one day and multiply
it by 365 to learn how much is needed for one year. Then use the chart to find
how much roof space is needed (Figure 2). Add 10 percent to the area given by
the chart to allow for water lost to evaporation and discarded at the beginning of
each rainfall.
Example:
With an average rainfall of 75cm a year, and a family needing 135 liters of
water a day, then:
2/3 x 75 = minimum annual rainfall of 50cm
365 x 135 liters/day = 49,275 liters a year.
Round this figure off to 50,000 liters a year. The example worked out on the
chart (Fi@re 2) shows that a catchment area of about 115 square meters is
needed. Add 10 percent to this area to allow for water loss, giving a total
required catchment area of about 126.5 square meters.
A collecting trough and downspout are needed. Be sure there is a good pitch to
the trough so that the water flows freely and does not hold small puddles that
can attract mosquitoes and other insects. Troughs and downspouts need periodic
inspection and cleaning. Extending the trough increases the catchment area.
Cistern Filter
The sand filter described here will remove most organic matter from water but it
will not produce safe drinking water by removing all harmful bacteria. Water
collected in the cistern tank should be chlorinated after each rainfall. A catchment area always collects leaves, bird droppings, road dust, and insects. A cistern
filter removes as much of this material as possible before the water enters the
cistern (Figure 3).
133
134
TO
CISTERN
Cast iron pipe with leaded joints
or wrouqht iron pipe with xvew
joints.
FIGURE 3
The sand Iilter is usuaby built at
ground level and the filtered water
runs into the cistern, which is
mostly underground. The largest
pieces, such as leaves, are caught
in the splash plate. The splash
plate also distributes the water
over the surface of the filter, so
that the water does not make holes
in the sand. Several layers of
copper window screen form the
splash plate.
If a filter is made too small to handle the normal rush of water from rainstorms,
the water will overflow the Iilter or dig a channel in the sand, ruining the filter.
The til!er area should be not Iess than one-tenth of the catchment area. A typical
filter would be 122cm x 122cm (4’ x 4’) for a family-sized unit where rainfall
intensity is average.
About every 6 months, remove the manhole cover and clean the filter. Remove all
matter From the splash plate and scrape off and remove the top 12Scm (l/T’) of
sand. When the sand is down to 3Ocm (12”) in depth, rebuild it with clean sand to
the original depth of 46cm (18”).
The first runoff from the roof,
which usually contains a great deal
of leaves and dirt, should be
discarded. The simplest way to do
this is to have a butterfly valve
(like a damper in a stovepipe) in
the downspout. After the rain has
washed the roof, the valve is
turned to let the runoff water
enter the filter. A semi-automatic
filter is shown in Figure 4.
TO CISTERN
In building the fdter, it is important to use properly-sized sand and
gravel and to make sure the filter
can be cleaned easily. Tim filter
must have a screened overflow.
135
Sources:
Wagner, E.G. and Lanoix, J.N. Water Supp& for Rural Areas and Small Cammunities. Geneva: World Health Organization, 1959.
Cisterns. State of Illinois, Department of Public Health, Circular No. 833.
Murmal of Individual Water Supply Syrrenrs. U.S. Department of Health, Education
and Welfare, Public Health Service Publication No. 24.
E~E~T~~~ A DAM SITE
A water reservoir can be formed by building a dam across a ravine. Building a
dam takes time, labor, materials, and money. Furthermore, if a dam holding more
than a few acre-feet of water breaks, a great deal of damage can be caused.
The.reforc, it is important to choose a dam site carefully, to guard against dam
collapse, and to avoid excessive silting, porous soil, polluted water, and water
shortages because the catchment area is too small. Careful selection of the dam
site wili save labor and ma!erial costs and help ensure a strong dam.
The preliminary evaluation described here will help to determine whether or not a
particular site wiil be good for building a dam. Remember that dams can Imve
serious environmental consequences and an imprope@ constructed dam can be
extremely dangerous. ConsuIt an expert before starting to build.
Six factors are important in site selection.
1. Enough water to meet your requirements and fill the reservoir.
2. Maximum water storage with the smallest dam.
3. A sound, leakproof foundation for the reservoir.
4. Reasonable freedom from pollution.
5. A storag;: site close to users.
6. Available materials for construction.
7. Provision for a simple spillway.
9. Authorization From local authorities to build the dam and use the water.
One acre-foot of water is equivalent to the amount required to cover an acre of
land (30cm of water covering 0.4 hectares) to a depth of 1 foot. One acre-foot
136
equals l&33.49 cubic meters. The annual rainfall and type of catchment (or
natural drainage) area will determine the amount of water the reservoir will
collect
Catchment Area
A catchment area with steep slopes and rocky surfaces is very good. If the
catchment area has porous soil on a leak-proof rock base, springs will develop
and will carry water to the reservoir, but more slowly than rocky slopes. Trees
with small leaves, such as conifers, will act as a windbreakers and reduce loss of
water from evaporation.
Swamps, heavy vegetation, permeable ground, and slight slopes will decrease the
yield of water from a catchment area.
The average catchment area will, in a year, drain 5 acre-feet (6,167 cubic meters)
into a reservoir for every inch (2.5cm) of annual rainfall falling on a square mile
(2.59 square kilometers); that is, about 10 percent of the rainfall.
Location
The best location for building a dam is where a broad valley narrows with steep
sides and a lirm base on which lo build the dam (see Figure 1). Ground that
contains large boulders, weathered or fissured bedrock, alluvial sands, or porous
rock is not good. The best bases for building a dam are granite or basalt layers
at or near the surface or a considerable depth of silty or sandy clay.
Location of a dam upstream from its point of use can lower pollution and may
allow for gravity feed of the water to its point of use.
It is best if stone is nearby when building a masonry dam. When building an earth
dam, rock will still be required for the spillway. The best soils for earth dams
contain clay with some silt or sand. There should be enough of this soil close to
the dam site for building the entire dam of reasonably uniform material,
SOLIKe:
Wagner, E.G. and Lanoix, J.N. Water S~~p,oly for Rural Areas and SmaN Cornmunifies. Geneva: World Health Organization, 1959.
137
Granite or basalt beae
for dam site
The purification of unsafe water requires some trained supervision if it is to be
done effectively. Such supervision is rarely available in the villages and the
procedure tends to be neglected sooner or later. Under these circumstances every
effort mwt be made to obtain a source that provides naturally wholesome water
and then to collect that water and pro&i it against pollution by the methods
already described. Thus, the necessity for treatment of the water may be avoided,
and the practical importance cf managing this cau hardly be overemphasized.
Water treatment under rural conditions should be restricted by the responsible
control agency to cases where such treatment is necessary and where proper plant
operation and maintenance is assured.
If the water needs treatment, this should, if at all possible, be done for the
whole community and certainly before, or on entry to the dwelling so that the
water from all the taps in the house is safe. The practice, common in the
Tropics, of sterilizing (by filtration and boiling) only the water to be used for
drinking, teeth cleaning, etc., though efficient in itself (when carefully done) is
frequently nulliied by carelessness. Furthermore, children are likely to use water
from any tap. Contrary to an all too common opinion, ordinary freezing of water,
though it may retard the multiplication of bacteria, does not kifl them, and ice
from a household refrigerator is no safer than the water from which it was made.
The principal methods of purifying water on a small scale are boiling, chemical
disinfection, and filtration. These methods may be used singly or in combinat:on,
but if more than filtration is needed the boiling or chemical disinfection should
be done last. Each method is discussed briefly below. Following this general
introduction are descriptions of a variety of water purification technologies: boiler
for drinking water, chlorination of polluted water, water purification plant, and
sand filter.
Boii is the most satisfactory way of destroying disease-producing organisms in
water. it is equally effective whether the water is clear or cloudy, whether it is
rclatlvely pure or heavily contaminated with organic matter. Boiling destroys all
forms of disease-producing organisms usually encountered in water, whether they
be bacteria, viruses, spores, cysts, or ova. To be safe the water must be brought
to a good “rolling” boil (not just simmering) and kept there for 15-20 minutes.
Boiling drives out the gases dissolved in the water and gives it a flat taste, but
if the water is left for a Few hours in a partly filled container, even though the
mouth of the container is covered, it will absorb air and lose its flat, boiled
taste. It is wise to store the water in the vessel in which it was boiled. Avoid
pouring the water from one receptacle to another with the object of aerating or
cooling it as that introduces a risk of recontamination.
139
Cblorinc is a good disinfectant for drinking water as it is effective against the
bacteria associated with water-borne disease. In its usual doses, however, it is
ineffective against the cysts of amoebic dysentery, ova of worms, cercariae which
cause schitosomiasis, and organisms embedded in solid particles.
Chlorine is easiest to apply in the form of a solution and a useful solution in one
which contains 1 percent available chlorine, for example, Milton Antiseptic.
Dakin’s solution contains 0.5 percent available chlorine, and bleaching powder
holds 25 percent to 30 percent available chlorine. About 37cc (2 l/2 tablespoons)
of bleaching powder dissolved in 0.95 liter (1 quart) of water will give a 1
percent chlorine solution. To chlorinate the water, add 3 drops of 1 percent
solution to each 0.35 liter (1 quart) of water to be treated (2 tablespoonfuls to 38
gallons), mix thoroughly and allow it to stand for 20 minutes or longer before
using the water.
Chlorine may be obtained in table form as “Sterotabs” (formerly known as
“H&zone”), “Chlor-dechlor” and “Hydrochlorazone,” which are obtainable on the
market. Directions for use are on the packages.
Iodine is also a good disinfecting agent. Two drops of ordinary tincture of iodine
are sufficient to treat 0.95 liter (1 quart) of water. Water that is cloudy or
muddy, or water that has a noticeable color even when clear, is not suitable for
disinfection by iodine. Filtering may render the water tit for treatment with
iodine. If the water is heavily polluted, the dose should be doubled. Though the
higher dosage is harmless it will give the water a medicinal taste. To remove any
medicinal taste add 7 percent solution of sodium thiosulphate in a quantity equal
to the amount of iodine added.
Iodine compounds for the disinfection of water have been put into table form, for
example, “Potable Aqua Tablets,” “Globaline” and “Individual Water Purification
Tablets”; ful! directions for use are given on the packages. These tablets are
among the most useful disinfection devices developed to date and they are
effective against amoeba cysts, cercariae, ieptospira, and some of the viruses.
Source:
Small W&T Supplies, Bulletin No. 10 London: The Ross Institute, 1967.
Other Useful References:
Mann, H.T. and Williamson, P. Wafer Treafmertt and Sanifufiorz. London: Intermediate Technology Publications, 1976.
Iomech Disinjection System, Iornech Ltd., 2063 Lakeshore Blvd. West Toronto,
Ontario, Canada, (undated).
140
Manual of Individual Water Supp@ Systems. Public Health Service Publication No.
24, Washington, DC. U.S. Department of Health amd Human Services, 1962.
Decade Watch newsletter. United Nations Development Program, Division of
Information.
International Reference Center for Community Wkter Supply and Sanitation,
newsletter. P.O. Box 93190,2559 AD, The Hague, Netherlands.
riding Water
The boiler described here (Figure 1) will provide safe preparation and storage of
drinking water in areas where pure water is not available and boiiig is practical.
When the unit was used in work camps in Mexico, a 2@3-liter (55gallon) drum
supplied 20 persons with water for a week.
Tools and Materials
2OS-liter (5gallon) drum
lOmm (3/4”) pipe nipple, 5cm (Y) long
Bricks for two 3Ocm (1’) layers to support drum
Sand and 1 sack of cement for mortar and base of fuepla::e
Large funnel and filter medium for tilling drum
Metal plate to control draft iu front of fireplace
19mm (3/4”) valve, preferably all metaL such as a gate valve, that can withstand
heat.
-Y-/
The fireplace for this unit (see Figure 2) is simple. It should be oriented so that
the prevailing wind or draft goes between the bricks from the front to the back
of the drum. A chimney can be provided, but it is not necessary.
-Iii., :.;i”.
\
I
142
When tilling the drum, do not fill it completely, but leave an air space at the top
as shown in Figure 1. Replace the funnel with a filler plug, but leave the plug
completely loose.
Water must boil at least 15 minutes Gth steam escaping around the loose filler
plug. Make sure that the water in the pipe nipple and valve reach boiling
temperature by letting about 2 liters (2 quarts) of water out through the valve
while the drum is at full boil.
Source:
Chris Ahrens, VITA Volunteer, Swannanoa, North Carolina
~o~iaating Wells, Springs, and Cisterns
Chlorination, when properly applied, is a simple way to ensure and protect the
purity of water. Guidelines given here include tables to give a rough indication of
the amounts of chlorine-bearing chemical needed. Instructions are also given for
super-chlorination for disinfecting newly built or repaired wells, spring encasements, or cisterns. Chlorine-bearing compounds, such as ordinary laundry bleach
made with chlorine are used because pure chlorine is difficult and dangerous to
use.
Determining the Proper-Amount of Chlorine
The amounts of chlorine suggested here will normally make water reasonably safe.
A water-treatment system should be checked by an expert. In fact, the water
should be tested periodically to make sure that it remains safe. Otherwise, the
system itself could become a source of disease.
Tools and Materials
Container to mix chlorine
Chlorine in some form
Scale to weigh additive
The safe,st way to treat water for drinking is to boil it (see “Boiler for Drinking
Water”). However, under controlled conditions, chlorination is a safe method; it is
often more convenient and practical than boiling. Proper treatment of water with
chlorine requires some knowledge of the process and its effects.
When chlorine is added to water, it attacks and combines with any suspended
organic matter as well as some minerals such as iron. There is always a certain
amount of dead organic matter in water, as well as live bacteria, viruses, and
perhaps other types of life. Enough chlorine must be added to oxidize all of the
organic matter, dead or alive, and to leave some excess uncombined or “free”
143
chlorine. This residual free chlorine prevents recontamination. Too much residual
chlorine, however, is harmful and extremely distasteful.
Some organisms are more resistant to chlorine than others. Two particularly
resistant varieties are amoebic cysts (which cause amoebic dysentery) and the
cercariae of schistosomes (which cause bilharziesis or schistosomiasis). These,
among others, require much higher levels of residual free chlorine and longer
contact periods than usual to be safe. Often special techniques are used to combat
these and other specific diseases.
It always takes time for chlorine to work. Be sure that water is thoroughly mixed
with an adequate dose of the dissolved chemical, and that it stands for at least
30 minutes before consumption.
Polluted water that contains large quantities of organic matter, or cloudy water,
is not suitable for chlorination. It is best, and safest, to choose the clearest
water available. A settling tank and simple filtration can help reduce the amount
of suspended matter, especially particles large enough to see. Filtration that can
be depended upon to remove all of the amoebic cysts, schistosomes, and other
parthogens normally requires professionals to set up and operate.
NEVER depend on home-made filters alone to provide drinking water. However, a
home-made slow sand filter is an excellent way to prepare water for chlorination.
Depending on the water to be treated, varying amounts of chlorine are needed for
adequate protection. The best way to control the process is to measure the
amount of free chloa.ine in the water after the 30 minute holding period. A simple
chemical test, which uses a special organic indicator called orthotoIidine, can be
used. Orthotolidine testing kits available on the market come with instructions on
their use.
When these kits are not available, the chart in Table 1 can be used as a rough
guide to how strong a chlorine solution is necessary. The strength of the solution
is measured in parts by weight of active chlorine per million parts by weight of
water, or “parts per million” (ppm).
The chart in Table 2 gives the amount of chlorine-compound to add to I,ooO liters
or to 1,lXHl gallons of water to get the solutions recommended in Table 1.
Usually it is convenient to make up a solution of 500 ppm strength that can then
be further diluted to give the chlorine concentration needed. The 500 ppm
solution must be stored in a sealed container in a cool dark place, and should be
used as quickly as possible since it does lose strength. Modern chlorination plants
use bottled chlorine gas, but this can only be used with expensive machinery by
trained experts.
TABLE 1
INITIAL CHLORINE DOSE TO SAFEGUARD
DRINKING WATER SUPPLY*
Water Condition
Inhid Chlorine Dose in Parts Per Miiliion @XII)
-_
No hard-toki
organism suspected
.______
very clear, few minerals
Get export Edvice; in w WeIgetN
5ppn
boil and cool water fuxt. then use
5 ppn to help pIwent ITcontamir
tion. If boiling is impossible. use
1OPpn.
A coin in the bottom of 114 liter (8
owe) &ss of the water lodrs hazy.
-.
‘OPP
Get expert advice; in an wergen
boil and mol fira If boiig is
impossible use15 ppm.
-__--
* Pans per million @pm) is the number of pans by weight of ddorine to a million pass by weight of water.
It is equivalent to milligrams of per liter.
AMOUNTS OF CHLORINE COMPOUND TO ADD
TO DRINKING WATER
Chlorine Compound
PUGSIlt
by
Weight
Active
Quantity to add to loo0 U.S.
gallons of water zlqdred
ClllOl-ilW
smgth
1OPPM
15PPM
SPPM
IOPPM
1 oz
2 oz
3 oz
8 gms
15 gms
23
l/zoz
5 01.
7lnoz
20gms
4Ogms
6Ogms
10 oz
15 07.
38gms
75~s
113gm!
702
13 oz
200-L
48gms
95gms
143gmlr
13 oz
26 oz
39 oz
95~1s
19ogms
285gm!
70%
Thlorinated Liie
25%
:zdium hypahlorite N&Cl
14%
5 07.
:xiium hypablorile
1w
uwally
5.25%
- - - --
Lleach-A solulion of Chlo1iJle
1 water
-
-gth
SPPM
.-___
Iigh test Calcium
iypxhlorite Ca(oCl~
2
Qmtity to add
to 1000 liters to get required
-_
-
15PPM
gms
145
Super-Chlorination
Super-chlorination means applying a dose of chlorine that is much stronger than
the dosage needed to disinfect water. It is used to disinfect new or repaired
wells, spring encasements, and cisterns. Table 3 gives recommended doses.
TABLE 3
RECOMMENDED DOSES FOR SUPER-CHLORINATION*
Reammended Dose
so ppm
Pnxedure
~~-..~1. Wash casing, pump exterior and drip
pipe with solution.
4. Leave solution in well at leasr 24 hours.
5. Fiush all chlorine fmm well.
50 ppm
Same as above.
--__
1. Flush with water to ranwe any
lcoppm
sediment.
2. Fill with dosage.
3. Let stand for 24 hours.
4. Ten for residual cblaine. If there is
ncme. repeat dosage.
5. Flush system with vested water.
-~_--___* To fmd the correct amounts of ctdorine amqnund needed for !he requixd dosage, multiply the amamts
given under IOppm in Tables 2 or 3 to get 5q?pn and by 10 to get 1oopPm.
Example 1:
A water-holding tank contains S,ooO U.S. gallons. The water comes from a
rapidly moving mountain stream and is passed through a sand filter before
storage. How much bleach should be added to make this water drinkable?
How long should the water be mixed after adding?
Solution:
In this case 5 ppm are probably sufficient to safeguard the water. To do this
with bleach requires 13 ounces per 1,000 gallons. Therefore the weight of
bleach to be added is 13 x 8 or 104 ounces.
Always mix thoroughly, for at least a half hour. A good rule of thumb is to
mix until you are certain that the chemical is completely dissolved and
146
distributed and then ten minutes longer. In this case, with an g,WO-gallon
tank, try to add the bleach to severat different locations in the tank to
make the mixing easier. After mixing, test the water by sampling different
locations, if possible. Check the corners of tank especially.
Example 2:
A new cistern has been built to hold water between rainstorms. On its initial
filling it is to be super-chlorinated. How much chlorinated time should be
added? The cistern is 2 meters in diameter and 3 meters high
Solution:
First calculate the volume of water. For a cylinder, Volume is
(D is diameter, H is height and is 3.14.)
> = H
4
Here D = 2 meters H = 3 meters.
V = 3.lJ x (2 meters) x (2 meters) x (3 meters)
4
V = 9.42 cubic meters = 9,4W liters (Each cubic meter
contains 1,ooO liters.)
From Table 3 we learn that a cistern should be super-chlorinated with 1OU
ppm of chlorine. From Table 2, we learn that it takes 40 grams of chiorinated lime to bring 1,tXM liters of water to 10 ppm Cl. To bring it to 100
ppm, then, will require ten times this amount, or 400 grams.
400 mams x 9.42 thousand liters = 3,768 grams.
thousand liters
Source:
Safvato, J.S. Environmental Sanitation. New York: John Wiley & Sons, Inc., 1958
Field Water Supply, TM 5-700.
147
Wh:%r Purification Plant
The water purification plant described here uses laundry bleach as a source of
chlorine. Although this manually-operated plant is not as reliable as a modem
water system, it will provide safe d&king water if it is operated according to
instructions.
Many factors in this system require operating experience. When starting to use
the system, it is safest to have the assistance of an engineer experienced in
water supplies.
TO& and Materials
3 barrels, concrete tanks, or 2% liter (5gallon) drums
2&m (a) funnel, or sheet metal to make a funnel
2 tanks, about 20 liters (5 gallons) in size
4 shut-off valves
Throttle or needle valve (clasps can be used instead of valves if hose is used)
Pipe or hose with fittings
Hypochlorite of lime or sodium hype-chlorite (laundry bleach)
The water purifi&ion plant is made as in Figure 3. The two tanks at the top of
the structure are for diluting the bleach. (The system can bc simplified by
eliminating the concentrate tank, the bleach is then added diiectiy to the mixing
tar&.)
The two smaller tanks on the shelf below are for holding equal amounts of diluted
bleach solution and water at a constant pressure; this makes the solution and the
water flow at the same speed into the hoses that lead to the mixing point. The
mix, which can be seen through the open funnel, is further controlled by the
valves. If a needle or throttle valve is not available a throttIe action can be
obtained by installing another shut-off valve in series with Valve #4.
Placing the two barrels at a height of less than 1.8 meters (6’) above the float
valve causes a pressure of less than 0.35kg per square centimeter (5 pounds per
square inch). Thus, the plumbing does not have to be of high quality except for
Valve #l and the float valve of the water hold-up tank, if the water supply is
under higher pressure.
A trial and error process is necessary to learn how much concentrate should be
put in the concentrate tank, how much concentrate should flow into the mixing
tank, and bow much solution should be allowed past the funnel. A suggested
starting mixture is l/4 liter (l/2 pint) of concentrated bleach for a mix tank
capacity of 190 liters (50 gallons) to treat 1,900 liters (500 gallons) of water.
-
149
The water in the distribution tank should have a noticeable chlorine taste. The
amount of bleach solution required depends on how dirty the water is.
1.
Mix concentrated bleach with water in the concentrate tank with all valves
closed. The mixing tank should be empty.
2.
Fii the pipe from the mixing tank to the solution tank with water after
having propped the float valve in a closed position.
3.
Let a trial amount of concentrate flow into the mixing tank by opening
Valve #2.
.a.
Use a measuring stick to see how much concentrate was used.
5.
Close Valve #2 and open Valve #l so that untreated water enters the mixing
tank.
6.
Close Valve #I and mix solution in the mixing tank with a stick.
7.
Remove the prop from the float valve of the solution tank so that it wit1
operate properly.
8.
Qpcn wide the needle valve and Value X4 to clean the system. Let 4 liters (1
gallon) drain through the system, if the pipe mentioned in the second step is
not permitted to empty before recharging the mixing tank.)
9.
Close down to needle valve until only a stream of drops enter the funnel.
10
Open valve #3.
The flow into the funnel and the taste of the water in the distribution tank
should be checked regularly to errure proper treatment.
Source:
Chris Ahrens, VITA Volunteer, Swannanoa, North Carolina
Sand falter
Surface water from streams, ponds, or open welts is very likely to be contaminated with leaves and other organic matter. A gravity sand filter can remove
most of this suspended organic material, but it will always let riws and some
bacteria pass through. For this reason, it is necessary to boil or chlorinate water
after it has been filtered.
150
By removing most of the organic matter, the filter:
0
Removes large worm eggs, cysts, and cercaria,e, which are diffrcuh to kill
with chlorine.
0
Allows the use of smaller and fixed doses of chlorine for disinfection, which
results in drinkable water with less taste of chlorine.
0
Makes the water look cleaner.
0
Reduces the amount of organic matter, including living organisms and their
food, and the possibility of recontamination of the water.
Although sand filtration does not make potlured water safe for driig, a
properly built and maintained filter will make rl.t:,iu;tion more effective. Sand
filters must be cleaned periodically.
The household sand filter described here should deliver 1 liter (1 quart) per
minute of clear water, ready for boiling or chlorinating.
Tools and Materials
Steel drum: at least 6tkm wide by 75cm (2’ x 29 l/2”)
Sheet metal, for cover: 75cm (29 l/2”) square
Wood: 5cm x IOcm (Y x 4”), 3 meters (5.8’) Long
Sand: 0.2 cubic meter (7 CUYC feet)
Gravel
Blocks and nails
Pipe, to attach to water supply
Optional: valve and asphalt roofmg compound to treat drum
The gravity sand filter is the easiest type of sand Fdter to understand and set up.
It uses sand to strain suspended matter from the water, although this does not
always stop smail particles or bacteria.
Over a period of time, a biological growth forms in the top 7.5cm (3”) of sand.
This Fdm increases the fdtermg action, It slows the flow of water through the
sand, but it traps more particles and up to 95 percent of the bacteria. The water
level must always be kept above the sand to protect this film.
Sand fdters can get partially clogged with organic matter; under some conditions
tbis cau cause bacterial growth in the filter. If the sand filter is not operated
and maintained correctly, it can actually add bacteria to the water.
The drum for the sand filter shown in Figure 4 should be of heavy steel. It can
be coated with asphalt material to make it last longer.
Sett 1 in g
Basin
-
/iii/j/jj/iiiiiiiij/iiiiiiii
:::::::::::
.................
.................
. .........
. . . . . . . .~
:::::::::::::::::.
::::::::::::i::::::::i::ijj
/i/jjj/j(//i//i/.ij.iiii:::
Plugging and extends
filter life
TRICKI SING SAND FILTER
Figure 4
Pipe must be flexible
enough to aliow
removal of lid 2~ -Sheet
Valve not necessary
but helps to
reoulate incamina
flow
metal
roofing
iid fits tiqht 1
or wished
/Overflow to drain area
irame
N
overha"gs
at
least
km to
prevent
dust and
rain from
filter
Y
3 0' more
blocks, high
enough to
allow pipe
or container under---
Drain should
r
I
Y
-Qutlet to
further
treatment and
storage
. container
must fit close
t" Prevent entrance
Of insects OP dust
f dischorqc:
152
The 2mm (3/32”) hole at the bottom regulates the flow: it moSa not be made
larger.
The sand used should be fme enough to pass through a window screen. It should
also be dean; it is best to wash it.
The following points are very important in making sure that a sand filter operates
properly.
0
Keep a continuous flow of water passing through the fdter. Do not let the
sand dry out, because this will destroy the film of microorganisms tbat forms
on tbe surface layer of sand. The best way to ensure a continuing flow is to
set the intake so that there is always a small overflow.
0
Screen the intake and provide a settling basin to remove as many particles
as possible before the water goes into the filter. This will keep the pipes
from becoming plugged and stopping the flow of water. It will also help the
filter to operate for longer periods between cleanings.
0
Never let the fdter run faster than 3.6 liters per square meter per minute (4
gallons per square foot per hour) because a faster flow will make the fdter
less efficient by keeping the biological fti from buildiig up at the top of
the sand.
0
Keep the falter covered so that it is perfectly dark to prevent the growth of
green algae on the surface of the sand. But let air circulate above the sand
to help the growth of the biological film.
0
When the flow becomes too slow to fill daily needs, clean the filter: Scrape
off and discard the top 1/2cm (l/4”) of sand and rake or scratch the surface
lightly.
After several deanings, the sand layer should be returned to its original thickness
by adding clean sand. Before doing this, scrape the sand in the filter dowri to a
dean level. The falter should not be cleaned more often than once every several
weeks or even months, because the biological growth at the top of the sand
makes the filter more efficient.
Source:
Hubbs, SA. Understanding Wuter Supply and Treatment for Individual and Small
Community Systems. Arlington, Virginia: VITA Publications, 1985.
Wagner, E.G. and Lanok, .J.N. Water Supp& for Rural Areas and Small Communities. World Health Organization, 1959.
155
VE
The proper disposal of human waste (called night soil in many parts of the world)
is one of the most pressing public health problems in many rural communities. The
use of sanitary latrines or privies can be very effective in helping to control
disease, which can be spread by water, soil, insects, or dirty hands. While it is
necessary to have a sanitary water and food supply, sufficient medical service,
and adequate diet to stop disease, the sanitary latrine breaks the disease cycle.
Some sicknesses that can be controlled by widespread use of sanitary latrines are
dysentery, cholera, typhoid, and worms. The human suffering and economic loss
caused by these is staggering. It has been said that half of the food eaten by a
person with intestinal parasites is consumed by the very worms that make the
person sick.
Most countries that have actively participated in the 1980-90 U.N. Decade of
Water Supply and Sanitation have developed latrine designs to meet the sanitary
and cultural requirements of their people. Before building latrines the local health
or development agency should be contacted for their advice and help. A latrine
program must reach most or all of the people. This means a carefully planned,
continuing long-range program with participation by government agencies,
community leaders and most of all by the individual families. Proper latrine
designs that tit the cultural pattern are economically possible and can satisfy the
sanitary needs of a successful latrine program. Selected plans and designs for
sanitary latrines are given in the entries that follow.
The recommended kinds of privies are:
0
Pit privies: a simple hole in the ground, covered with a properly built floor
and a shelter. It has two forms, the dry pit, which does not penetrate the
water table, and the wet pit, which does. The addition of a ventilating pipe
(see “The Ventilated Pit,” page 156 helps reduce odors and fly problems.
0
Water privies: where a watertight tank receives the nightsoil through a
drop pipe or chute. An overflow pipe takes the digested material to an
underground seepage pit or drainage area.
A water-seal slab may be used to cover either of these types of privies to
provide a completely odorless privy.
156
Other types of simple latrines are not recommended for general use, because they
usually fail to provide enough sanitary protection.
A good privy should fulfill the following conditions:
0
It should not contaminate the surface soil.
0
There should be no contamination of ground water that can enter springs or
wells.
0
There should be no contamination of surface water.
0
Nightsoil should not be accessible to flies or animals.
0
There should be no handling of fresh nightsoil; if it is necessary, it should
be handled as little as possible.
0
There should be no odors or unsightly conditions.
0
The latrine should be simple and inexpensive to build and use.
Other points to consider:
0
Superstructure can be made from any local building materiai that will give
privacy and shelter from rain.
0
The privy can be squat or sit-down type,
0
The opening should be covered when not in use.
0
In water scarce areas, a standard pit latrine can be used. When pit is full
after several years, latrine is moved to a new pit and old one is covered up
and marked.
0
If space is limited to change the pit, a permanent location can be maintained
with a double pit, as in the double septic tank (cornposting latrine) used in
Vietnam. The urine is collected separately and diluted for use on crops. The
composted material is used for fertilizer. One side is used until almost full,
then it composts while the other side is used.
0
If water is readily available, a water-seal bore hole latrine can be used.
When almost full, the latrine must be moved.
0
If a permanent Iocation is desired, a double bore hole can be used as in
India.
157
0
In most countries using water seal latrines the pan and trap are now
available commercially or from a government agency for a nominal fee or for
free.
0
Consider including a methane (biogas) generator when building new latrines.
Charles D. Spangler, VITA Volunteer, Bethesda, Maryland
Wagner, E.G. and Lanoix, J.N. Excrera Disposal for Rural Areas and Small
Contmunitie.s. Geneva: World Health Organization, 1958.
rivy Location
Outhouses or privies should be close to the home, but they should be lowe; ihan
water sources and far enough away from these sources that they will not p?:ute
the water.
The information given here covers most normal situations, but it is always best to
have a trained sanitary inspector or engineer review your installation or program.
‘4 latrine site should be dry, well-drained, and above flood level.
If the bottom of a privy pit is in dry soil and at least 3 meters (10’) above the
highest water table, there is very little danger that it will contaminate water
supplies. This is because the poflution will move downward no more than 3 meters
with only 1 meter (3.3’) of side movement. (See section on “Ground Water”). If
the privy pit enters the water table or comes close to it when the water is at its
highest level, pollution will spread to the ground water over a limited area and
may endanger health.
Figure 1 shows the movement of pollution through the soil. It is particularly
important to understand this movement when choosing a site for a privy or well.
Put the privy downhill from a water source, or as far to one side as possible. On
flat or gently sloping land, water moves toward the well as though it were going
downhill. This is because when water is removed from a well, water from the
surrounding soil flows toward it. Thus pollution from a nearby privy would move
toward the well. If the land is flat or if the well is downhill from the privy, do
not put the privy closer to the well than 10 meters (33’). In sandy soil, a
distance of 7.5 meters (25’) is sometimes enough because sand helps to stop
bacterial pollution.
These rules do not apply in regions containing fissured rocks or limestone
formation. Expert advice is necessary in these cases, because pollution can be
carried great distances through solution channels to the drinking water supply.
The source of contamination in these studies was human excwta nixed in a hole which penetrated the ground-watel
table.
Samples nositive for colifo~ri oroanisms were picked up quite won between 4m and 6m (Ilft and 19ft) from
the SOUPCP of contamination. The area of contamination widened out to a width of approximately Zm f7ft) at d
point about 5n (lfift) from the privy and tapered off at about ilm (36ft).
Contamination did not move "uostream"
After a few months the wii ~'round the privy became
or aqainst the direction of flow of the ground water.
clogged, and positive samples could be picked up at only Zm to 3m (7ft to loft) from the pit.
rho chemical pollution pattern is similar in shaoe to that of bacterial pollution but extends to much qreater
distances.
from the wint of view of sanitation, the interest is in the maximum miqrations and the fact that the direction
of migration is always that of the flow of ground water.
In iocatino wells, it must be remembered that the
NO mrt of the area of chemical a?
water within the circle of influence of the well flows towards the well.
bacterial contamination may be within w~ch of the circle of influence of the well.
159
It is important to keep the latrine close to the house so that it will be used, but
not too close. Putting the privy downhill also encourages use. People are more apt
to keep a privy clean if it is close to the house.
Remember that all privies have to be closed up or moved when flied. This should
be made easy or there will be a tendency to let them become overfull, which
results in very unsanitary conditions and extra work to put the system in proper
working order. A permanent location can have two pits that are used alternately.
One pit is in use while the other composts before being emptied.
Source:
Wagner, E.G. and Lanoix, J.N. Ercreta Disposal for Rural Areas and SntaN
Commmities. Geneva: World Heahh Organization, 19.58.
Several designs for privy shelters that have been found satisfactory in many parts
of the world are shown in Figure 2.
The shelter should be built to suit the abilities and desires of the local people,
because sanitary precautions are less important for the shelter than for the pit
and slab. For a properly built shelter:
0
Choose a standardized design for economy in building.
0
Build the shelter to last as long as the pit, 8 to 1.5 years.
0
Build the shelter to fit the floor slab. It should not be so large that people
will be tempted to use any part of the floor when the area around the hole
has been soiled by ear!ier users. The roof should be 2m (6 l/2’) high at the
entrance.
0
Openings at the top of the shelter’s walls, for airing the interior, should be
l&m to 15cm (4” to 6”j wide.
0
Some natural light should be let in, but the structure should give enough
shade over an uncovered seat or holes that flies will not be attracted.
0
The latrine should be kept neat and clean so that people will continue to
use it. Paint or whitewash the shelter. Cut back nearby vegetation. The roof
should have a large overhang to protect the walls and the mound from rain
damage and to keep the privy area from getting muddy.
WATTLE HOUSE WITH PALM THATCH ROOF
COMPLETED PRIVY, SHOWING PALM THATCH WALL
AND ROOF COVERING
HOUSE OF CUT LUMBER WITH CORRUGATED METAL
TYPE OF SUPERSTRUCTURE RECOMMENDED BY
UBLIC HEALTH SERVICE
HOUSE OF BRICK WITH TILE ROOF
l ._A = Vent pipe with lateral outlet
i
Adapted, by permission, from United States
,__
Public Health Service (1933) The dani.taq _
ptic!q, Washington, D.C. (Revised type No.
""',.
IV of Pube. Hctk Rei.'. f&ah.i, 5~~~1.108).
161
Here is a list of tools and materials needed to build one type of privy shelter:
Tools and Materials
Corrugated sheet metal rooting: 1.2m x 1.2m (4’ x 4’) or larger
Wooden posts: 5cm x 5cm (2” x 2”) and 2Om (66’) long
Boards: 2cm (3/4”) thick, 2Ocm (8”) wide, 4Om (132’) long
Nails
Hand tools
Paint: 2 liters (2 quarts)
Wagwr, E.G. and Lanoix, J.N. tkcreta Disposal for Rural Area and Small Communities. Geneva: World Health Organization, 1958.
FIG. 3 VARIOUS PARTS OF A
SANITIS PRIVY
The pit privy is the simplest
recommended latrine or privy. It
consists of a hand-dug bole, a
properly mounted slab, and a
shelter (Figure 3). The addition of
a ventilating pipe will help reduce
odors and flies. Of the many
existing designs for privies, the
sanitary pit privy is the most
widely applicable.
Tools and Materials
Materials for building the shelter
A
6
C
0
=
=
=
=
Pit
sase
Flocr
Mound
E = House,
including door
F = Ventilation
G = Roof
Hand tools for digging the pit,
making concrete, and building the
shelter
162
The Pit
The pit is round or square, about lm (3.3’) in diameter or lm (3.3’) on each side,
and usually from lm (3.3’) to 3m (10’) deep. The pit may have to be Lined with
brick, wood, bamboo, or some other material to keep it from caving in, even in
hard soil. The top 50cm (19 l/r) of the bole should be lined with mortar to make
a solid base for the siab and the shelter.
The table in Figure 4 will help you to estimate the depth of hole to make.
r :::::::“,:,::.:“:::::j
for hole with 1 square wter area
Figure 4. Privy capacities for a family of five. A wet-pit privy is one which
penetrates the water table. A dry-pit privy does not.
*Add 5Ocn to the depth given in the table. because the pit Glould be closed and
filled with earth .rhen the waste cores to within this distance from the surface.
The Ventilated Pit
The ventilated pit privy system was tield tested during the late 1970s by the Blair
Research Laboratories working with the Zimbabwe Ministry of Health (Figure 5).
The idea was to reduce the health hazard caused by flies attracted to the
standard pit privy. Thousands of the units are now in use in Zimbabwe, as well as
in many other areas where water is scarce.
The Blair design depends on the aerodynamic properties of an efficient flue pipe,
15Omm in diameter and about 2.5 meters high. The pipe is fitted onto the
concrete !atrine slab over a sealed tank or pit. The temperature difference
between the inside and outside of the pipe causes a convection updraft, drawing
the inside gases from the pit and thus causing a downdraft through the toilet
operling.
The toilet opening is km
covered between uses.
then attracted to odors 1
the pipe rather than t
Fhes that do get int
travel up the pipe to
light. There they are tra
screen over the pipe outle
The Ventilated PXlVy
FIGURE 5
It is essential that the
large enough to enable
to “breathe” efficiently r
allow sufficient light to
pit to attract flies into
Efficiency is increased I
the pipe black to incre;
flow and by facing it I
Equator so it receives
sunlight.
Cccelski, Elizabeth, “Appropriate Technology in Zimbabwe.” Energy Bn
News, July 1981.
The bare (see Figures 3, 6, and 7) serves as a solid, waterproof supf
floor. Ii also helps to prevent hookworm larvae from entering. If propel
a hard, strong material, it helps to keep burrowing rodents and surface : water out
of the pit. The pit lining will in most cases serve as a base although i
to be strengthened at the ground surface.
164
The Slab
concrete water-seal slab is best. It is inexpensive but it means added labor and
construction. A concrete open-hole slab is the next best, while a wooden floor is
adequate. A built-up floor of wood and compacted soil is sometimes used but it is
difficuit to keep clean; as it gets soiled, it is likely to spread hookworm.
A
The concrete should not be weaker than 1 part cement to 6 parts of aggregate
with a minimum of water. It should be reinforced with strips of bamboo about
2.5cm (1”) wide whose weaker fibers have been stripped away. Soak the bamboo in
water overnight before use.
Slabs (see Figure 8) are cast upside down in one operation. The footrests are
shaped by removing part of the wooden form so as to make two separate indentations in the wood. Sheet metal is placed around the form so that the metal
extends above the wood to the thickness of the slab. Side walls of the hole and
footrests are ma<!:: with a slight slope so as to come out easiiy. The form for the
open hole is removed when the concrete first sets. Slabs are removed from the
forms in about 40 hours and should be stored under water for 10 days or more.
Round slabs can be rolled some distance when carrying is difficult. This is
especially handy when the location of the privy has to be moved when the pit
tills up.
The hfound
The mound (see Figure 3) protects the pit and base from surface run-off that
otherwise might enter and destroy the pit. It should be built up to the level of
the floor and be very weil tamped. It should extend 50cm (20”) beyond the base
on all sides. The mound may be built much higher than the ground in areas where
protection is needed against floods and high tides. It will normally be built with
earth removed from the pit or the surrounding area. A stone facing will help to
keep it from being washed away by heavy rains. A masonry or brick step can be
built in front of the entrance door to help keep the floor clean.
Source:
Wagner, E.G. and Lanoix, J.N. ficreta Disposal for Rural Areas and Snail
Contmuttiries. Geneva: World Health Organization, 1958.
Water Privy
A water (or aqua) privy uses a watertight tank in which human excreta and urine
partially decompose. A sewer pipe connects the tank’s overflow pipe to an
underground drain area or seepage pit.
Tbii is a sanitary and permanent installation when it is properly built, used daily,
and maintained properly. It can be placed near a building. The first cost of a
water privy is high, but it is not expensive in the long run because it will be
used for many years. It needs some water and cannot be used in freezing
climates. And it is not practical in desert or water scarce areas, The water privy
may not be successful in rural areas with no organized sanitation and health
education services.
T?ze Process
The digesting or decomposing tank is usually made of watertight concrete (see
Figures 9, 10, and 11). A drop-pipe, 1Ocm (4’) in diameter, attached to the squatting plate or seat hangs down 1Ocm (4”) below the surface of the liquid in the
tank. This forms a water seal, which keeps bad odors from rising into the privy
shelter.
r
I
SECTION A-A
The decomposition process forms a sludge in the tank. The amount of sludge is
onlyy one-fourth the volume of the total waste deposited in the pit, because some
of the solid matter breaks down into very small pieces, liquid, and gas. The liquid
and the pieces of waste matter run out the overflow pipe to the drain field. The
material that Rows out is called eff7nertr. The gas escapes through a vent pipe.
The tank must be watertight. If the tank leaks, the liquid level will fall below the
drop pipe, odors will form, flies and mosquitos will breed, and the soil and ground
water will be polluted. Tanks made from bricks or stone and mortar must be faced
with a coat of rich cement plaster to make sure they are watertight.
167
N.sUe?E /o
ALL D/.wENS,ONS ,N -^M
l---75 -4
The tank can be made of plain concrete sewer pipes 90 or 12Ocm (36” to 47”) in
diameter and sealed at the bottom with concrete (see Figure 11).
Family-sized units should not be less than 1 cubic meter (35 cubic feet), which
will usually allow 6 years or more between cleanings. Thus the family water privy
need not be too deep, which is an advantage in rocky ground where the water
table is high.
~~o~-~i~e
The 1Ocm drop-pipe with its end 1Ocm below the surface, prevents water from
splashing and improves flushing. Nightsoil may stick in the pipe from time to time
and must be flushed or poked down to stop odors and to keep flies from breeding.
The pipe may be up to 2Ocm (8”) in diameter and reach 2Ocm below the surface of
the water in the pit, which will prevent sticking, but this size will release more
odors and cause splashing, and the pipe may crust over.
Disposal ofE@uent
Disposal of effluent from a family unit is usually done in seepage pits or by
below ground irrigation. The amount of effluent is equal to the amount of
nightsoil and water put into the digesting pit. This averages 4.5 liters a person
each day, but the drainage system should be designed to handle 9 liters a person
each day. When a -sater tap is inside the privy, the effluent disposal system must
be much larger. Too much water causes poor digestion of sludge.
The area of below ground irrigation ditches or seepage pits needed for a family
of five will be from 1.4 square meters (10.7 square feet) in very light soil to 5
square meters (53 square feet) in soils that are hard to penetrate.
These methods are not practical in regions where the water table rises to within
Im (3’) of the ground surface, or in clay soils or swampy land. Here some type of
sand filter may help, but this requires help and approval from local health experts
and continued maintenance.
‘/
‘/
169
Operation
The first step in putting a new water privy into operation is to till the tank with
water up to the overflow pipe. Digested sludge from another privy can bc added
to the tank; this will seed the water and start the decomposition process. If the
tank is not seeded, it will take about 2 months for the process to get going
efficiently. Once this level of operation is reached, the privy will keep the
process going, provided it is used daily. Cleaning and flushing the slab and bowl
daily with 25 SO 40 liters (G to 10 gallons) will give the tank the small amount of
water it needs to keep the process going.
Removing Sludge
The sludge that forms in the tank must be bailed out before the tank is half-full,
about 6 So 8 years after the privy is put into operation. A manhole, often located
outside the shelter, is made for this job.
Notice in Figure 9 that the tank floor slopes toward the manhole for easier
cleaning. Both the vent and the drain are easily reached. The drain has a Tshaped section that helps to keep hard surface scum from entering and plugging
the drain and whose shape makes it easy to clean. The overflow pipe in Figure IO
is an elbow.
Bury the sludge in shallow trenches about 4Ocm (16”) deep.
Source:
Wagner E.G. and Lanoix, J.N. Ekrera Disposal jor Rural Areas and Small Comnw
nifies. Geneva: World Health Organization, 1958.
Philippine
ater-Seal Latrine
A water-seal bowl improves a latrine by keeping flies out of the pit and preventing odors from escaping. The mold described hce (see Figure 12) has been made
and used successfully in sanitary
latrine programs in the Philippines.
The advantage of this mold over a
concrete mold is that it requires no
drying time.
175
Tools and Materials
Wood: 19mm (3/4”) thick, 31cm (12 l/2”) wide and 152Scm (5’) long
Galvanized iron: 0.75mm x 32cm x 40.5cm (l/32” x 12 l/2” x 16”)
Large nails: 18
Cement and clean sand
Galvanized wire: Smm (3/16”) in diameter and 30.&m (1’) long, for interior mold
handle
Bamboo pole or iron rod: 30Scm (1’) long, to position interior mold
Making the Mold
tf the materials for the mold are cm according to Figures 13 and 14, the bowl is
easy to make.
0
Nail the metal sheet around the curved back of the mold (see Figure 12).
0
Attach the two front pieces with large nails through the loose-fitting holes.
These holes make it easy to remove the front pieces. The extension at the
bottom of piece No. 1 is important in making sure that the bowl will seal
well below the water level.
5”,8cm ~~,~~.~~~~ ,,.~ .~.~~ ~~. ~~~
MOLD
51DE - TWO NEEDED
DIMENSIONS SHOW
LOCATION OF ONE
i7.5cm&--- 2*.gcm ~~~~----’
F/GURf-
/3
~Qki~l~ the Bowl
Since the mold has no bottom, find a flat place to work where the mold can be
propped against a wall. Fill the mold with a mixture of two parts fine sifted sand
to one part cement.
Use only enough water to make the mixture workable. Pack it in so that there
are no airpockets. Let it set for 15 to 20 minutes until the mivture is stiff. Next,
with a ruler, measure a .38mm (1 l/2”) wall aroilnd the top and outlet and dig out
the inside with a tablespoon (see Figure 15).
3.8 CM.
Keep a straw handy to gauge the
thickness of the walls of the bowl
white digging, because it is difficult
to judge otherwise.
/
Dig out the huge interior first,
then the outlet. The ftnished
interior of a bowl is shown in
Figure 16.
Be sure you can insert three fingers vertically, Scm (2”), through the hole leading
to the outlet. Be careful to release front piece No. 1 by inserting the spoon
around the edges (see Figure 16).
FGuRt-
/b
After the interior has been dug
out, the walls will have stumped
down about an inch. Use the
cement taken from the interior to
build the walls back up; then
smooth all exposed surfaces with
the back of the spoon as in Figure
18. To be sanitary, the bowl must
be as smooth as possible so that
germs cannot build up in crevices,
For a finishing coat, one of two methods may be used: (1) immediately after
smoothing, sprinkle dry cement over the still wet surfaces and smooth again with
the spoon (Figure 18); or (2) let the bowl set for half an hour and apply a
mixture of pure cement and watera coconut husk brush is good enough. Either
method gives good results.
112
For a luxury product, use white or red cement for the finishing coat; several
coats are necessary.
The finished bowl should be left in the mold to dry 4g hours. It can be removed
after 24 hours only if extreme care is taken. Pull out the front nails and remove
pieces No. 1 and No. 2; pull the sides and back away from the bowl.
Making an Interior Mold
Because digging by hand is tedious and because it must be done very carefully to
make the wails consistently thick, it is better and faster to use an interior mold.
After the First bowl has hardened thoroughly, till the outlet with dry sand so that
the cement cannot flow into it. This would make it impossible to remove the interior mold when it hardens (see
Figure 19). Line the large interior
with paper and Jill it with cement-a 4 to 1 sand-cement ratio is
good enough. Insert a heavy wire
loop in the top so that the interior
mold can be positioned on the
exterior mold with an iron bar or
bamboo pole.
When an interior mold is used, it is only necessary to dig out the outlet. It is a
good idea to have several interior molds, but not necessary to have one for each
exterior mold. The interior mold should be removed after 15 to 20 minutes so that
the bowi can be smoothed and tinished. Then it can be used to make the next
bOWi.
l-73
Using the Interior Mold
To use the interior mold, fill the wooden mold about 12Scm (5”) from the bottom
and insert the interior mold in the correct position (see Figure 20). Push the
cement around the mold with
a stick and pack it well to
get rid of air spaces.
After the molds are removed,
the finished bowl should be
left to dry until it is rock
hard-a week is usually
safe-before delivery.
F/G&WE %l
A sand-cement ratio of 2 l/2 to 1 has been used successfully with the bowls. A
ratio wider than this may make them too expensive. There are many ways to
strengthen cement; experiments may b&g a cheaper solution. One possibility is to
add short coconut husk or abaca fibers.
Installing the Toilet
For use in private homes, dig a pit about 1.5~: (5’) deep and Im (3’) square. The
deeper the pit and the smaller the width the better, since a small slab is cheaper
(see “Pit Privy” Section). It can even be dug under the house-especially in
cities-because the toilet gives off very little odor, unless this position endangers
the household water supply. The pit may be lined or unlined, depending upon the
soil. Hard clay soil need not be lined. But, if the house is near the sea or on
sandy soil, the pit should be lined with, for example, bamboo poles or hollow
blocks as shown in Figure 21.
t:,:.
.:,
UGUQE 2 /
Place boards around the outside of the pit 1.5cm (6”) from the edge of the pit to
form the perimeter of the slab (see Figure 22). Place large pieces of bamboo split
in half across the pit as a base for the slab. Place the bowl between two of the
174
bamboo pieces with a piece of wood under the front and back; nail these to the
bamboo. After the bowl is positioned in thii way, pour water into it to be sure it
will seal off the outlet. The top of the bowl should be 7Scm (3”) above the
bamboo base.
Now put bamboo slats across the pit at right angles to the large pieces of
bamboo, completely covering the pit. Cover this with several thicknesses of
newspaper. Pour cement around the bowl until the slab is about 5cm (4”) thick. A
mixture of two parts gravel, two of sand, and one of cement is good. The slab
can be reinforced by placing bamboo slats between two layers of cement. Make
sure that the outer edge of the slab is higher than the bowl and slants towards
the center, so that the toilet can be easily cleaned. Apply a finishing coat of
pure cement to the slab. Many people prefer to add foot rests and urineguard-there is room for imagination.
It is extremely important to have an ample wafer supply at hand. About 1 liter (1
quart) of water is needed to flush the toilet, and people wilt be discouraged from
using the latrine properly if they have to go some distance for water. It is a
good idea to have an oil drum or a small concrete tank nearby to supply water
for the latrine.
Do not use the latrine for at least 3 days-a week is best-after it is installed.
A pit with the suggested dimensions should last a family of eight about five
years. One person uses about 28 liters (1 cubic foot) a year.
Source:
Gordon Zaloom, Peace Corps Volunteer.
The Thailand Water-Seal Privy Slab, made from concrete, is useful for large-scale
privy programs. The slab, which includes a bowl and trap, is used to cover an
ordinary pit privy.
175
Master molds for the bowl and trap
are used to make secondary molds
from which the bowl and trap are
actually made. The master molds
can be made from the plans in the
entry that follows. The master
molds can sometimes be purchased
from local health officers.
The finished slab is quite strong
because its three parts are cast at
the same time (see Figure IO). The
m e t h o d described here can be
applied to other water-seal slab
designs
The water-real trap is curved back under the bowl as shown in Figure 2a. This
makes flushing more difficult, but prevents erosion of :he back of the pit on
loose soii. The same general method could be used to make a forward flushing
trap (see Figure 2b).
The basic method for making these water-seal slabs is to cast the slab, bowl, and
water-seal trap using three fo:ms:
1.
2.
3.
A wooden form for shaping, the slab (see Figure 6).
A concrete bowl core for shaping the inside of the bowl (see Figure 3).
A concrete core for shaping the inside of the water-seal trap (see Figure 9).
Tools and Materials
Master molds
Materials for making concrete
Wool for platform forms
Reinforcing rod and wire
Clay
Crankcase oil
Beeswax and kerosene (optional)
Steel bars: 19mm x 19mm x 7Scm (3/4” x 3/4” x 5”)
176
The forms used when making a slab must stay in place until the concrete is
strong enough, usually 24 hours. For this reason, many sets of forms are necessary if a reasonable number of slabs are to be cast every day. Here is where the
three master molds are needed: one of them to cast the bowl core, and the other
two to cast the trap core (see Figures 14 and 18).
Casting the Bowl Core
Qil the inside of the master bowl mold and insert a 19mm x 19mm x 7.5cm (3/4” x
3/4” x 3”) steel bar into the bottom.
Add a fairly ioose mixture of cement and water, called neat cement, to a depth of
about 1Scm (6”). Then till to brim with a 1:l cement-sand mixture. The I:1 should
be firm, not runny, and should be laid into the loose neat cement without stirring
to insure a smooth finish on the bowl core.
After the bowl core has become firm enough, scoop a depression into the surface
to install hvo steel hooks made from the reinforcing rod. They should be about
22Scm (9”) apart, and should not protrude above the surface of the concrete (see
Figure 3).
Let the concrete set at least 24
hours before removing the bowl
core from the master molds. The
bowl core can be used to make
another master mold and the master
mold can be used to make more
cores.
Casiing the Trap Core
Add about 2.5cm (1”) of 1:l cement-sand mix to the oiled trap master mold and
put in some wire for reinforcing. Then fill it with 1:l almost to the brim (see
Figure 4).
Put the oiled insert mold into place
and scrape off excess (see Figure
5).
After 4.5 minutes, remove the insert
and put a square sheet metal pipe
19mm (3/4”) high into the cubical
indentation left by the insert. The
pipe is made by wrapping sheet
metal around a t9mm x 19mm (3/4”
177
x 3/4”) steel bar. Let the concrete
dry in the mold for 24 hours.
Remove the finished trap core by
ta~pping the master mold gently
with a wooden block.
Make a wooden platform 9Ocm x 9Ocm (35 l/2” x 35 P/2”) out of 2Scm (1”) thick
planks. This is the base of the form. The finished slab will measure 80cm x 80cm
(31 :,/2” x 31 l/2”). See Figure 6.
FIw4r;ar 6
RIIW SUB OwLrwc
Ccrt out of the platform a hole IOcm x 33,cm
(4” x 13”) for the hooks of the bowl core to
extend into. The back of the hole should be
28cm (II”) from the back of the platform. To
determine the location of this hole, draw the
outline of the bottom of the bowl on the
platform, with the back of the bowl outline
23cm (9”) from the back of the platform.
(This is 17&m from the edge of the slab, as
shown in Figure 6.) The back of the hole
should be 2&m (II”) from the back of the
platform.
Using 38mm x 38mm (1 l/T x 1 l/2’) wood, make a frame with inside dimensions
of 80cm x POcm (31 l/2” x 31 f/2”) (see Figure 7).
Gouge out the footrest with a wood chisel. The inside of the foot-rests should be
about 12.5mm (I/;‘) from the outline of the bowl.
178
Cczsting
the Slab
With these three forms finished, you are ready to cast the
tki
waterseal slab.
If desired, coat the bowl core and the trap core with a layer of wax about 3mm
(l/8”) thick. Prepare the wax by dissolving lkg (2.2 pounds) of melted beeswax in
0.5 hter (1 pint) of kerosene. Apply the wax with a paintbrush. The wax coating
will last 5 to 6 castings. Wax makes removing the cores much easier, but it is not
absolutely necessary. Let it dry before oiling.
Place the bowl core on the wooden slab form and fill all cracks with clay (see
Figure 8). Oil the bowl, platform, and frame.
Apply a 6mm (l/3”) thick coat of
pasty cement and water mixture to
the bowl core and platform. (Many
people prefer to spend a little more
for an attractive polished slab. To
do this, use a mix of 5 cement: 5
color: 1 granite chips instead of a
mixture of cement and water. After
the forms are removed, polish with
a Carborundum stone and plenty of
water.)
Cover the bowl core with a I:2 cement-sand mixture to a total thickness of
12Smm (I/2”). Make a smooth lip on the cement IOmm (3/P”) from the top of the
bowl core as in Figure 9. This Lip is your water seal, Use fairly dry cement; let it
set for 15 minutes before cutting the lip.
Place the trap core on the bowl core and seal
the crack with clay. Also add a little clay on
each side of the form (near the thumb in
Figure 9) to prevent cement from getting to
the front lip.
Cove: with 1:2 cement-sand mixture to a
thickness of 12Smm (l/z’). Do not exceed the
12Smm (l/2”) thickness below the trap core
or you will not be able to remove this core.
Pill the slab form with a mixture of 1 cement: 3 clean gravel or crushed rock
almost to the top. In preparing the concrete, first mix cement and sand, then add
gravel and water. Use water conservatively. The looser the mixture, the weaker
the concrete will be.
Press in 4 pieces of 6mm (l/1”) steel reinforcing rod (see Figure 10). Fill to top
of f&me and smooth. Allow at least 24 hours for set&g. Remove the frame by
tapping lightly with hammer.
Turn the slab form over on a wooden stand and use simple levers to remove the
bowi core. You must remove the bowl core before the trap core (see Figure 11).
Tap the trap core gently and slip it out. Add a little water and check to see if
your seal is 1Omm (3/8”).
Keep the slab damp and covered for a minimum of three days and preferably a
week to gain strength.
F!GUP.. II. U&UOl’~ffG %‘&BOWL CORE.
F/GU&’ /O PLACIN.5 REhW-O,?C/NS
ROD.
Master Molds for the Thrtiland Water-Seal Pri’vy Slab
This entry describes how to make the three master molds from which cores can
be cast. The cores in turn are used for casting Thailand Water-Seal Privy Slabs.
Tools and Materials
Cardboard
Materials for making concrete
Steel rod, 19mm (3/J”) square
Sheet metal (tin-can metal is satisfactory)
Reinforcing wire
Clay
Oil (used crankcase oil is satisfactory)
Paint brush
It may he necessary to make master molds rather than to purchase them. S’udy
the entry “Thai1ar.d Water-Seal Privy Slab” before starting to make these master
molds:
0
0
0
The Master Bowl Molds,
The Master Trap Molds, and
The Trap Mold Insert.
150
Making the Master
Enlarge the template:
templates of the bowl outlines on Figure 12 (increase all dimensions
by one third). Cut
CI out profiles from your larger templates.
,------------L-------------s-7
r------------------------s-7
I
\
\
181
Shape a mound of clay using the cardboard profiles as a guide (Figure 13). Form
a little square pipe, Dmm (3/4”) long, of sheet metal on the 19mm (3/5”) square
steel rod. Make several of these as
they will be used later when
casting the cores. Fii the square
pipe with clay and press it into the
top of the clay mound a little bit.
This will be used later to “key’ the
cores together.
Use a paint brush to paint the clay
mound with oil; old crankcase oil is
fme.
Cover the clay mound with a stiff mixture of cement and water to a thickness of
12Smm (l/2”). If the clay mound was properly prepared, the inside f&h of the
bowl mold will need no further smoothing.
After this cement has set 30 minutes,
build up the thickness to 38mm (1 l/2”)
with 1:l cement-sand mix. Let this set
24 hours and carefully lift the fmished
master bowl mold from the clay mound.
The finished bowl mold is shown in
Figure 14.
Making the Master
Trap
Mold
Make cardboard profiles of the trap from Figure 17 as you did above with the
bowl. Shape the outside of the trap from clay and let it harden overnight.
Shape the under side by hand with a trowel using Fiie 15 and the insert profile
from Figure 17 as guides. Mark the locations for a 19mm (3/4”) square metal pipe
by holding the clay trap over the
clay mound used to shape the bowl
mold, and letting the square sheet
metal cube mark the trap.
F/G‘W..,5. CLAY T-RAP
Insert the sheet metal pipe into the
clay trap and scoop out the clay
from inside (see Figure 15).
Check the clay trap on the bowl mound again to be sure it lines up properly.
Oil the clay trap.
182
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-----_ - --.-
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183
Put a heel-shaped piecs of clay under the clay trap and trim the sides. This I&II
prevent the cement from running under the mold (see Figure 16).
Cover with cement and water to
19mm (3/C), add steel reinforcing
wire, and cover with 19mm (3/4”)
more of 1:l cement-sand mixture.
Flatten the top and insert wire
handles. Let it set at least 24
hours. This completes the master
trap mold.
~a~rtg the Trap Mold Insert
Turn the master trap mold over carefully and remove the heel-shaped clay plug.
Oil all inner surfaces and till to t’le brim with 1:l cement-sand mix.
Insert a small wire handle and let the concrete set for at least 24 hours before
separating the fmished molds.
Figure 18 shows the completed master trap mold and insert.
Karlm, Barry. 77aaiiund’s Wafer-Seal Ptigs Program. Karat, Thai!and: Ministry of
Public Health.
Bilharziasis (also called schistosomiasis) is one of the most widespread human
diseases caused by parasites. This entry explains in general terms what is
necessary for personal protection from bilharlia and for ridding an area of the
disease. Further information from the references given is needed. Cooperation
with government or other programs is essential.
An estimated 150 to 250 million people suffer from the disease. It is found in
much of Africa, the Tigris and Euphrates valleys, parts of Israel, northern Syria,
Arabia, Iran, Iraq, parts of Puerto Rico, Venezuela, Dutch Guiana, Brazil, Lesser
Antilles, Dominica, Taiwan and parts of China, the Philippines, Japan, and a few
villages in sorthern Thailand.
E
ASITES
A basic understanding of the life cycle of the parasites, called schistosomes, and
the characteristics of each phase is the first step in preventing the disease (see
Figure 1).
The disease has been found, besides in humans, in baboons, monkeys, rodents,
water buffalo, horses, cattle, pigs, cats, and dogs. When water is contaminated by
urine or feces from a victim of the disease, the eggs contained in these hatch out
larvae that penetrate certain types of fresh-water snails. In the snail host, the
larvae develop into cercariae, whick work their way out of the snail and become
free-swimming; this is the form that infects people. It can survive in water for a
few days under favorable conditions.
The disease is contracted by contact with water containing cercariae. Typical
ways are bathing, drinking, washing teeth, wasking pots and clothes, walking
through water, irrigating, and cultivating crops. Once the parasite has contacted a
host, five minutes may be enough for it to penetrate the skin.
It is important to note tkat bilharziasis cannot be passed from human to human;
it depends on the snail intermediary. A victim must live in or have visited an
area where tke parasite is found.
187
At the spot where the parasite penetrates the host, a red itching eruption lasting
several days usually develops. After the host is infected, symptoms relate particularly to the large bowel, the lower urinary tract, liver, spleen, lungs, and the
central nervous system. The most characteristic symptoms are bladder and colon
irritation, ulceration, and bleeding. Three to 12 weeks after infection, a victim
will likely develop fever, malaise, abdominal pain, cough, itchy skin, sweating,
chills, nausea, vomiting, and sometimes mental and neurological symptoms. Later
developments may include frequent painful urination with blood in the urine,
dysentery with blood and pus in the stool, loss of weight, anemia, and enlargement of the liver and spleen. Numerous complications are possible.
Typically the acute phase subsides and host and parasite live together over a
period of years, sometimes as long as 30, with the host suffering a variety of
symptoms of intermittent and variable types. Bladder and bowel troubles are the
most characteristic symptoms in this period,
The variety of vague and general symptoms is considerable and may not be very
specitic. Examination of urine and/or feces is very important; special concentration techniques may be necessary to reveal the eggs. Tissue tests and skin tests
can be used by medically-trained personnel to identify the disease.
EATMENT
The disease can bc treated with drugs, but only well-trained persons should
undertake to treat a victim. Supportive treatment, which includes good diet,
nursing care, rest, and treatment of other ailments and infections, is important.
The disease can be prevented by:
0
Using uncontaminated water-a properly built sealed well or an improved
sealed spring is safe. (See section on “Water Resources.“)
0
However, it is important to remember that all water used must be safe.
Never bathe in or touch water you wouldn’t drink. Avoid suspected water. If
it is necessary to use questionable water, boil it, or treat it with iodine or
chlorine. If you must enter suspected waters, wear rubber gloves and wading
boots, and put repellent on your skin; insect repellent (either diethyl
toluamide or diiethyl phthalate), benzyl benzoate, cedar wood oil, or
tetmosol give effective protection for about eight hours if applied to the
skin before contact with the water. In case of accidental contact, rub your
188
skin immediately with a dry cloth. Once cercariae have penetrated the skin,
no preventive measures are possible.
0
Chlorination-Chlorine kills cercariae slowly, but properly chlorinated water
systems are almost always free of the larvae. Use 2 halazone tablets in a
iiter (quart) of clear water; 4 tablets if the water is cloudy. in a water
system, use 1 part per million chlorine. Iodine is even more lethal to
cercariae. See section on “Chlorination of Polluted Water.”
0
Fi!tering-Cercariae are just big enough to be seen with the unaided eye, and
can be faltered from the water. However, dependence on filtration is
questionabie, since improperly made or operated filters will not only allow
cercariae to pass, but may even provide a place for the host snail to live. In
short, BItering is a poor technique.
0
Storage-Storing water at temperatures over 21C (70F) completely isolated
from snail hosts for four days will allow the cercariae to die; at cooler
temperatures they may live as long as six days. This is seldom a practical
approach.
Eliminating the snai! intermediate host is at present the most effective single
method of controlling bilharziasis. The following methods are recommended:
0
Use a sealed, covered well or properly developed spring for a water supply.
Make sure it is covered; this prevents access of organic matter that snails
eat, cuts out light that would allow plants to grow for snail food, and
prevents infected people from bathing in or contaminating the water.
0
If surface water must be used, put long-lasting (copper) screens on the
imake; draw lake water far from vegetated shorelines, and preferably 2.4m
(8’) deep; take stream water from a fast moving spot.
0
Be sure filters and reservoir tanks are kept covered and dark and keep them
clean.
0
Since snails prefer the stagnant water of canals, irrigation ditches, and
dams, control has been possible where the water level in ditches has been
varied, where it has been turned off completely for periods, and where
canals have been lined with cement or pipes have been used. Although the
latter is initially expensive, it pays dividends not only in better health, but
also in less water evaporation.
0
Poison the snails with copper sulfate, copper chromate, or other copper
salts. Use a dose of 15-30 parts per million by weight of copper and try to
hold the copper-treated water over the snails for 24 hours. All or most of
the aquatic vegetation should be stripped from the stream bed or pool before
189
treatment. Results for other than small controlled pools have been poor.
Before attempting to treat streams, lakes, or other natural waters, study the
reference material and seek experienced help.
ING AN AREA OF ~~LHA~~~SIS
Education is a major step in a continuing campaign against biiarziasis. Basic
steps involved in improving your local waters so they will not spread the disease
are as follows:
0
Inform yourself. Study this article, locate reference material cited below,
consult any available health officials.
0
Learn to identify dangerous snails; for Africa, Professor Mozley’s book is
very helpful. To find the percentage of snails harboring schistosomes, collect
a large sample of suspects (use rubber gloves, repellant, and snail scoop),
put individually in test tubes or glass jars of water. Those shedding cercariae are readily detected, as the cercariae (OSmm long and easily visible to
the naked eye) are released in clouds. This test reveals only the snails
harboring mature cercariae. Observe precautions at all times when collecting
and handling snails!
0
Find dangerous snails loca!ly, collect (again using rubber gloves, repellent,
and snail scoop) and kill them. Mail empty shells to an expert to confirm
your identification. Visit the expert if possible. Find out about government
or other programs and participate in these.
0
Make a personal survey on foot (wearing boots) of local waters, using maps
and keeping exact records to Locate all dangerous snails. Local people can
often help here. Aerial photographs are also helpful.
0
Survey types and intensity of bilharzia present in populace. Differences may
help localize infection points. Keep special records for three- to six-yearolds, who are the most recently infected; these records will show most
accurately the incidence of new infections.
0
Educate the public as much as possible, and get them to participate in the
program. Better sanitation facilities, medical care, and improved nutrition are
critical, but improved sanitary facilities are worthless if nobody uses them.
Encourage people to live in villages away from infected waters, and to
construct culverts or bridges at places where paths cross streams. The
number of such crossings should be reduced. Any improvement should cater
to local customs or offer au attractive alternative.
190
0
Personally supervise, participate in, and measure the effectiveness of
poisoning the snails.
0
Take continuing steps to destroy the natural breeding places of snails,
particularly at sites where &mans and snails congregate. For example, the
place where a stream crosses a road is a focal point: people stop to drink
and bathe; they cook and wash out pots, providing food for snails. The
culvert and embankments slow and impound the water, making ideal breeding
c..>nditions. Finally, a favorite sheltered place to defecate is under a bridge.
Filling in places where water stands, changing drainage patterns, and
eliminating snaii food sources are possible techniques.
0
Maintain a continuing surveillance of focal spots and repeat poisoning
periodiwily when necessary.
Sources:
Mozley, Alan. The Snail Hosts of BiNmrria in r@ica:
Dcsrnrction. London: H. K. Lewis Sr Co. Ltd.
77reir Occurrence and
Schisfoswn2rris, Bulletin No. 6. London: The Ross Institute, The London School of
Hygiene arrd Tropical Medicine.
Acknowledgements:
Mason V. Hargett, M.D., Hamilton, Montana
Dr. Guy Esposito
Dr. Thomas W. M. Cameron, Montreal, Canada
Other References:
Craig, C. F. and Faust. Clinical Purusiroiogy. Philadelphia: Lea and Fibeger, 1964.
Hinman, E.H. World Eradication of Infectious Diseases. Springtieldm Illinois:
Charles C. Thomas, 1966.
Markell, Edward K. and M. Voge. Medical Pamsifoiogy. Philadelphia: W.B. Saunders
co., 1965.
77ae Merck hfanuaf
of Diagnosis & 77rerapy. Rahway, New jersey: Merck.
Manson, Patrick. Tr~pk~i Discuses. Baltimore: William & Wilkins Co., 1966.
In addition, up-to-date information
Organization, Geneva, Switzerland.
ten
be obtained from the Wor!d Health
A second major sanitation-related disease is malaria. A serious resurgence of
malaria is taking place in many countries. Between 300 and 400 million people
suffer from malaria, and tive million die from it annuafly. The disease Ls caused
by the malaria parasite, Plasmodium falciparum (and three other Plusmodium
species), which are transmitted by anopheiine mosquitoes from an infected person
to a healthy person. Tropicai ~9 subtropical regions of the world suffer the most,
from malaria.
EMURES
Mosquitoes generally stay within about one mile (1.6 km) of where they hatch.
The cycle from egg laying to hatching as mosquitoes usually takes about eight
days. These facts make it easier for local mosquito eradication or control
programs to be effective. But over time, persons infected with malaria can visit
the local area or mosquitoes carrying the malaria parasite can be brought in with
vegetable baskets, water containers, etc. Therefore, to be effective, anti-mosquito
programs must be ongoing, and any spraying should be done on a regular basis.
Other community based anti-malaria activities include:
0
Eliminate or reduce the amount of stagnant water near the community by
dig&g drainage ditches. The malaria mosquitoes must have water for their
egg, larval, and pupal stages of development. Even small accumulations of
water, as in whcef ruts or hoofprints of cattle may increase mosquito
breeding if the water remains a week or more.
0
Plan for the elimination of standinh water in new water and flood control
projects.
0
“Supercharge” unlined irrigation ditches about every 6 days. To do this, raise
the water level of the irrigation ditch three inches (8 cm) or more for a
period of about an hour. This will cause mosquitoe larvae to float upward on
the vegetation that lines the ditch. Do this in the morning on a sunny day.
Then quickly drop the water level about five inches (13 cm.) or more and
leave it at this level for several hours. The mosquito larva will be hung up
on the dry vegetation and will die.
0
Develop a voluntary reporting system for persons in the community who
192
develop fevers, so that health care can be provided to them, and so that
trends iu the occurrence of malaria wiff be evident.
Mosquito-eating fish can reduce the number of mosquitoes in rice fields. This is
not practical where rice cultivation includes alternate flooding and drying.
Regular use of mosquito-proof bed nets by aff or most community inhabitants has
been shown to reduce malaria rates. Programs with community participation in
local production and repair of bed nets deserve field trials
To reduce the probabiity of malaria:
1.
Inspect your living and sleeping quarters and install or repair screens in
doors and windows.
2.
Spray the walls, floors, and ceilings of your residence with insecticides.
3.
Sleep under a mosquito-proof bed net.
4.
Use mosquito repellents when you walk tn the woods or other likely
mosquito areas.
To reduce the risk of malaria, you should begin taking cbloroquine two weeks
prior to departing for regions of the world where malaria is found. Up to date
information on the status of malaria and drug resistance can be obtained from
references (1) and (2) below.
No vaccine is currently available against malaria. Breakthroughs have been made,
but pharmaceutical availability is still many years away. The most effective drug
against malaria is cbloroquine, but in some areas of the world, the parasite is
beginning to show some resistance to the drug. An alternative drug that is much
more expensive is sold under the label “Fansidar.” This drag is effective, but can
cause serious allergic reactions in some people. Local health care providers should
be consulted as to what drug to use.
The search for a vaccine against malaria is complicated by the fact that while
Plasmodium fakiputium is responsible for most malaria deaths, there are other
plasmodium species, and each species may react differently to the drugs used to
treat it.
193
In addition, the parasite goes through a series of stages of growth as it passes
from the mosquito into the human bloodstream, back to the mosquito, and then
back into a human host. Each stage requires its own separate defense.
For example, at one stage of the parasite’s life it is calfed a gametocyte, a tiny
body that will produce gametes or mature sexual reproduction cegs. The gametocytes must pass into an anopheles mosquito to develop.
The mosquito bites a person whose blood contains the gametocytes. The gametocytes develop in the body of the mosquito and eventually produce sporozoites,
tiny bodies that wilf grow into adult plasmodia. The infected mosquito then passes
tbe sporozoites to another human host and the cycle begins again.
A vaccine against the sporozoite would keep the second person from getting the
disease from the mosquito. It would not, however, defend against, say, contaminatcd blood used in a transfusion, nor one of the other infectious stages of the
parasite’s life.
The challenge to scientists is to develop vaccines that would be effective iu three
different ways. One would work against the sporozoite, preventing it from
developing in its human host. Another would work against the gametocyte to
prevent its growth iu the body of the mosquito. Both of these vaccines could
effectively block the transmission of the disease.
They would not, however, protect the person who was infected as a result of a
blood transfusion. Such a person could become ill with malaria and would then be
a source of infection to mosquitoes and ultimately to other people. Thus scientists
are also working on a third type of vaccine, which would protect against this
type of transmission.
In the meantime, the best protection for people living in malaria areas is to
interrupt the cycle by getting rid of the mosquitoes or by trying to keep from
being bitten. Malaria control is a community problem, not just a challenge to
science. Use the measures described above to eliminate mosquito breeding areas
around your home, farm, and community. Remember to protect yourself and your
family from the mosquitoes by using window screens and mosquito-proof bed nets.
Use mosquito repellents, and spray with appropriate insecticides where needed.
sources:
Dr. Donald Pletsch, VfTA Volunteer, Gainsville, Florida
Dr. Alan Greenberg, Center for Disease Control, Atlanta, Georgia
“Taking the Bite Out of Malaria,” VITA News, January 1986, pp. 4-5.
194
Reierenes:
1.
Tropical Disease Office, Pan American Health Organization (PAHO/WHO), 525
23rd Street, N.W., Washington, D.C. 20037 USA
2.
Malaria Division, U.S. Public Health Service Center for Infectious Diseases,
Chamblee, Georgia 30333 USA
3.
“Malaria: Meeting the Global Challenge,” USAID Science & Teclmology in
Development Series. Boston, Massachusetts: Oelgschlager, Gmm & Main Inc.,
1985
4.
Vi~jur con Safud Division of Public Information, World Health Organization,
Geneva, Switzerland.
_5.
Manual on Environmental Management for Mosquito Control, World Health
Organization, 1211 Geneva, Switzerland.
Every parent knows that diarrhea is one of the commonest ailments of childhood.
It affects hundreds of millions of children around the world an average of three
times a year. And especially in areas where water and sanitation are poor, it can
be a problem for adults also.
But children are most vulnerable to the problems caused by diarrhea, especially
children who are poorly nourished and in poor health to start with. UNICEF and
the World Health Organization estimate that more than three million children in
developing countries die each year from serious bouts of diarrhea-the most
~rn~o~nt single cause of death and malnutrition among young children.
ON-A CAFE-THREATENING CONDITION
Most of the children who die from diarrhea die because their bodies have become
dehydrated. That is, they have lost more fluid than they have taken in. As body
fluids are lost, essential salts, minerals, and other nutrients are also lost and the
body is no longer able to function properly. Severe dehydration may cause rapid
weak pulse; fever; fast, deep breathing; or convulsions. Untreated, it is fatal.
The diarrhea that causes the dehydration can and should be treated before the
problem becomes so serious. The idea is to give the child (or adult) as much Ruid
as possible and to restore the balance of salts and other nutrients. The treatment
is called oral rehydration therapy (ORT). It works almost as fast as an intravenous (IV) feeding and is safer, simpler, and cheaper. Any mother can treat her
child at home for just a few cents, versus the high cost of an IV or other
medications. WHO estimates that use of ORT saved over 200,000 lives in 1984.
Use of ORT is so effective that as of January 1988 some 90 countries around the
world had national programs to promote its use and it is becoming the treatment
of choice in many hospitals in industrialized countries. Many organizations have
programs to teach medical workers as well as parents about the treatment and to
train them in its use.
NG OR PREENING DEHYDRATION
.
A mixture-called rehydration salts-of salt, sugar, sodium, potassium (and perhaps
other nutrients), and water is fed to the child frequently throughout the day and
night. The salt-sugar mix is usually available in packets or tablets to be mixed
with clean water. In some places, the bottled mixture may also be available. If the
salt-sugar mixture is not available, you can make your own rehydration drink at
home (see box).
Mix up the drink at the first signs of diarrhea. Give the person sips of the drink
every few minutes, day and night, that they are awake-even if they don’t feel
like drinking it and even if they vomit. An adult should drink three or more
liters a day and a small child should have at least one liter a day or one glass
for each watery stool.
YDRAT~ON DRIN
TO PREVENT AND TREAT DEHYDRATION
pi&rrof
(better;
boiied, but
Pat
2 level tableqxons (30 g)
of SUGAR or honey
and
do not lose
time)
l/4 te$n (.75 g)
BARING SODA
(bicarbonate of soda).
CAUTION:
Before giving the Ikink, taSte
it and be sure it is no more
salty than tears.
If you do not have SC&, use
ano;her l/4 teaspoon salt.
(1.5 g tota@
if available, add half a cup of orange juice or coconut water, CT a little
mashed ripe banana to the Drink.
197
Diarrhea is often caused by malnutrition, but if it goes on long enough the
diarrhea itself contributes to the malnutrition. Be sure that tbe person who has
diarrhea eats good, easily digestible food along with the rehydration drink. This is
especially important for children, but anyone who is thin and weak should get
plenty of protein and energy foods all the time that they have diarrhea. If they
arc too sick to eat much, they should take broth, porridge, rice water, and/or
cooked and mashed beans or fruit, in addition to the rehydration drink. Babies
should continue to bc fed breast milk. As soon as they can, the sick persons
should begin eating well again.
(It should be noted that doctors often have different ideas about how to treat
people with diarrhea, especially regarding the types and quantities of food the
sick person should eat. Many doctors feel that people with diarrhea should aot
eat anything but thin soups or cereals. Other doctors say that the sick person
should be allowed to eat almost any good healthful food they feel like eating. You
should be prepared to follow the advice of your doctor or health worker.)
Unless the diarrhea is caused by some other disease, such as amebic dysentery,
the person should respond quickly to the treatment. If the diarrhea gets worse, or
if there are other disease symptoms such as fever, and the person seems to be
dehydrating, get help from a doctor or health worker immediately. Remember that
children arc affected more quickly than adults, and dehydration is very dangerous
for babies.
Look for these signs of dehydration:
0
dry, tearless, sunken eyes
0
sudden weight loss
o
dry skim, mouth, and tongue
0
sudden weight loss
0
sunken “soft spot” on a baby’s head
0
little or no urine, and what there is is dark yellow
Dehydration also causes the skim to lose its elasticity: a pinch of skin does not
fall back to normal, but stays up in a lnmp. Dehydration may also cause rapid,
deep breathing; a fast but weak pulse; fever; and/or convulsions.
source:
Werner, David. where There Is No Doctor. Palo Alto, California: Hesperian
Foundation, 1980. Fist published in Spanish as Donde No Iiuy Doctor. Now
198
available in English, Spanish, French, Portuguese, and Swab& Available throogb
VITA in English, Spanish, and French.
7Xe Project for Approptiate Technology for Health, Seattle, Washington USA.
Grant, James F. Swe of the World’s Children 1988. New York: Oxford University
Press, for UNICEF (United Nations Children’s Fund), 1988.
Moving soil for irrigation and road-building is important to good farming. Carefui
preparation of land for irrigation and good water usage saves water, labor, and
soil, and improves crop yields. Improved roads make communication easier between
farmers, their suppliers, and their markets.
Although modern heavy equipment is ofte,n sought for such work, it is not
necessary. Land can be prepared effectively with small equipment that can be
made by farmers or small manufacturers and can be pulled by animals or farm
tractors. Descriptions of yokes and harnesses are given in Anintal Tructio,~, by
Pctcr R. Watson, published by Peace Corps and TransCentury Corporation (1981).
The following seven entries describe such small equipment:
o Drag Grader
o Fresno Scraper*
o Esrrcl Fresno Scraper
o Float with ad,justable blade
o Buck Scraper*
0 V-Drag*
o Multiple Hitches
* The fresno scraper, buck scraper, and V-drag are designed for use with large
horses.
This simple metal-edged wooden grader is designed for two medium-sized work
horses or oxen. The grader can be scaled down for use with one horse or with
smaller animals.
Road-building does not require giant tractors and earth movers. The grader
described here was used for dirt and gravel roads in the midwestern United States
in the 1920s. Similar graders were used in the original construction of U.S.
Highway No. I from Maine to Florida.
202
Tools and Materials
Lumber: 7Scm x 30.5cm (3’ x 12”)
2 pieces: 243cm (8’) long
1 piece: 152cm (5’) long
2 pieces: 30.5cm (:‘) long
Lumber: 7.5cm x L5cm (3” x 6”)
1 piece: 37 cm (4 l/2”) long
4 Metal edges: 6mm to 12.5mm (l/4” to 1,/2”) thick, 1Ocm (4”)
wide, 243cm (8’) long
17 Lag screws: 16mm (5/f?‘) in diameter, l&m (7”) long
2 Eye bolts, 7.5cm (3”) diameter, and large lock washers
Weavy chain: 3.7m (12’)
32 Flathead steel wood screws, 7.5cm (3”) long. (Carriage bolts with lock washer:
would strengthen,the grader.)
Construction details for the grader are shown iu Figure 1. The metal edge over.
hangs the surfaces of the 243cm (8’) beam by 2.5cm (1”). Each edge is attache<
with eight large wood screws 01
carriage bolts. Lock washers shoulc
be used throughout to keep strain
V-C= -Y and tensions from loosening the
nuts. The metal edges are attache<
to both top and bottom so the
grader can be turned over tc
reverse the direction in which thl
soil is cast.
If the grader is to be used fo
cleaning ditches, the angle betweei
the 152cm (5’) and 243cm (8
beams should be 30 degrees.
The drawing position of the grader is adjusted by changing the hitching point OI
the chain. The hitch link should be such that when the small end is put over
link it will not slide. Reverse the hitch ring to slide it along the chain.
If welding equipment is available, the same design can be used for making stec
road graders, with cutting edges bard-surfaced to make them last longer.
Source:
Richard Hunger, John McCarthy and John Rediger, VITA Volunteers, Peori;
Illinois.
Vernon E. Moore, VITA Volunteer, Washington, D.C.
FRESNO SC
Thii scraper is used for moving larger amounts of earth from higher spots to low
areas. It can be made at low cost by farmers or small manufacturers, if materials
and a well-equipped blacksmith shop are available. The scraper can do the work
of larger, more expensive equipment.
Implements that slide soil on soil are inefficient. They require a large amount of
power to move a small amount of soil. The fresno scraper can move soil more
easily because it slides on its metal bottom. It is a large metal scoop that can be
built in a number of sizes, depending on the number of animals that can be used
to pull it. Good results will be obtained by using the size described here with two
oxen or two to four horses. Construction details are giveu in Figures 2 to 5.
To use the scraper, first plow the high spots that you want to remove. This will
make it easier to load the fresno and save a great deal of power.
The fresno is made so that the power used to pull it will also help in loading and
unloading. The rope in the handle is used for pulling the scoop into position for
loading and io spread the soil evenly when unloading.
Always be careful when operating the fresno. Do not have any part of your body
directly above the handle. Always keep a firm grip on the handle, while loading
or getting ready to unload. A sudden jerk or unseen rough spot may cause the
handle bar to fly up and strike you.
To load the fresno, simply lift the handle until the front of the bit goes into the
ground at a depth the animals can pull. Do not try to make too deep a cut or the
fresno will be pulled over or the animals pulled to a stop. You will soon learn
how to hold the handle for the proper cut and smooth loading.
When the fresno is full, push down on the handle and it will go forward without
touching the ground until you are ready to unload it. Lift the handle when you
are ready to unload and the pull of the animals will turn it into the dumping or
spreading position. The stop bar across the top of the fresno can be moved to
change the depth of the spreading of soil. Move it forward for a shallow depth or
back for a deeper spread.
After it has been emptied and returned to the point of loading give the rope a
hard pull and the fresno will fail back into position for loading.
Usual hitches for animals pulling the fresno are:
o two horses
0 two oxen
o three horses
Two lines are used. Each outside horse is tied back to the hame or collar of the
center horse. The center horse is then guided by the inside strap from the lines.
Tools and Materials
2 steel plates for sides:
6mm x 4Ocm x 6Ocm
(l/4” x 15 3/4” x 23 5/q
2 draft bar rod stock:
20mm x 1.2 meters
(25/32” x 47 l/4”)
1 steel plate for blade:
6mm x 35cm x 1.24 meters
(l/4” x 13 314” x d9 7/R”)
2 draft bar rod stock:
20mm x 95cm
(25/32” x 37 3/8”)
1 steel plate for backplate:
6mm x 52cm x 1.24 meters
(l/4” x 20 l/2” x 48 718”)
2 draft bar loop stock:
20mm x 45cm
(25132” x 17 3/4”)
4 steel plates for stiffener plates.
6mm x 1Ocm x lgcm
(l/r x 4” x 7 1/q
2 draft bar loop stock:
20mm x 38cm
(25/32” x 15”)
1 steel plate for stiffener plate:
6mm x IOcm x 2&m
(l/4” x 4” x,11”)
2 eye bolts with nuts and washers:
20mm x 25cm
(25132” x 9 7/V)
205
75 ftathead rivets:
15mm x 3cm (19/32” x 1 l/8”)
12 flathead rivets:
20mm x 3cm (25/3T’ x 1 l/8”)
2 strap iron clevis stock:
lOmmx4cmx6Ocm
(318” x 19/w x 23 5/8”)
2 machine bolts with nuts & washers:
13mm x 1Ocm
(l/z’ x 4”)
2 angle irons for runner:
6mm x 4Smm x 45mm x 1.57 meters
(l/4” x 13/Y x 13/W x 62 13/W)
2 steel plates for shoes:
6mm x 12.5cm x 66cm
(1/4”X5”X26”)
1 oak draft bar:
6cm x 15cm x 1.52m
(2 3/a” x 6” x 59 7/w)
4 machine bolts with nuts & washers:
13mm x 6cm
2 strap irons for bar brace:
1Omm x 4cm x 32cm
(3/w x 19/w x 12 5/q
1 iron bar for handlebar
15mm x Scm x 1.6 meters
(9/W x 2” x 63”)
1 rope:
13mm x 2 meters
(l/T’ x 78 3/W)
2 side plates, draft clamp stock:
20mm x 21cm
(25/32” x 8 l/4”)
(l/T’ x 2 3/8”)
8 machine bolts with nuts & washers:
13mm x 4cm
(l/2” x 19/l@)
1 oak stop bar:
4cm x 8cm x 1.45 meters
(19/W x 3 l/8” x 57 l/8”)
2 stop bar stock:
threaded one end
2 stop bar halt nnts & washer:
13mm (l/2”)
2 machine bolts with nut and washer:
13mm x 4cm (l/2” x 19/W)
source:
Forsberg, Carl M., Metzger, James B. and Steele, John C. Consfmction and Use of
Small Equipment for Fame Imkation. USOM/Turkey, in cooperation with the
Turkish Ministry of Agriculture.
SIDE
FIGURE 2 -
CROSS SECTION
END
PLATE
FRESNn
\
\
x 6mn. RIVET TO
END PLATES AND
BLADE 15mn
^^....T?^ -......
L”“NltKwNR
RIVETS 1Dcm C.C.
BEND TO FIT SHAPE
OF END PLATE
4 1Ocm x 18cm x fimn
i-1Ocm x 28cm x 6mn
RIVET TO BACK PLATE
WITH 4-15mn
COUNTERSUNK RIVETS
FIGURE 3 - ARRANGEMENT 0F BLADE, B A C K
AND STIFFENER PLATES, END
'/IN.
END PLATE
\J
\
\
\
‘r
I
I
RIVET TO END PLATES
AND BACK PLATE
15mn COUNTERSUNK
RIVETS lOcm C.C.
207
SHOES
12.5cm x 6mn x 66cm plate
Rivet to Runners, 6-Z0mm countersunk rivets
k--e-----
I----24cm
5,: &-m --.-----+
------/
FIGURE 4 FRESNO RUNNER AND SHOES
4.5cm x 4.5cm x 6mn Angle
157cm long (overall)
209
EL FRESNQ SCRAFER
The barrel fresno scraper (Figure 1) is a lighter, simpler version of the fresno
scraper described in the preceding entry. It is a low-cost implement to move soil
efficiently. It can be pulled by a
team of bullocks and is operated by
one person.
The scraper, which is well-adapted
to production by a village blacksmith, is made from an old barrel
and scrap metal. The scraper can
be adapted for heavy duty use.
,r,~upr ,. BARLWL FR.zmW
SCR4PER
The barrel fresno scraper presented here was built and tested in Afghanistan. It
was found that it could move approximately twice as much soil as the shovel
board normally used by the Afghan farmer. The scraper worked better when the
high spots were plowed with a mold-board plow, which breaks up the soil, making
it easier to pick up. Using the local wooden plow was satisfactory but it left the
soil cloddy.
It is estimated that it could be used for 8 to 10 years under normal farm use on.
Under other conditions, particularly where the soil is sandy or where the scraper
is used for road or terrace construction, its life would be much shorter.
FIGURE
2
To& and Materials
Heavy hammer
Chisel - for cutting barrel
Punch - for making holes in barrel
Saw - for cutting wood
Drill - for boring holes in wood
Pliers
210
Welder or access to the services of a welder
Barrel, 208~titer (.55-U.S. gallon) as new and strong as possible. Rust weakens the
metal and a rusty barrel should not be used.
Blade, metal, 1 piece, 5 to 8mm (3/K? to 5/16”) thick, 88cm (34 5/8”) long. Have
a blacksmith taper the blade until it has this shape -J-L- when viewed from the
end. The blade should be sharp. Old truck springs make good blades.
Blade holder, metal, 2 pieces, 5 to 8mm (3/16” to 5/E”) thick
Handle, wood, 1 piece, if soft wood 4 by 8cm (1 9/16” x 3 l/8”) or pole 8cm (3
l/8”) in diameter at large end, 3m (9’lV)
Handle brace, wood, 1 piece, 3cm by 8cm by 15tJcm (13/X” x 3 l/8” x 59”)
Block wood, 1 piece, 3cm by 8cm by 12cm (1 3/16” x 3 l/8” x 4 3/4”)
Bolt, 1 piece, lcm diameter by 1Ocm (3/8” x 4”)
Nai!s, 5 pieces, 9cm (3 l/2”) long
Wire, heavy - at least 3mm (I./s”j thick, 12m (39’) long
Chain, 4m (13’), made from 7mm (9/32”) rod, with hook at each end. Set Figure 1.
Rope, 12mm (l/2”) diameter, 3m (9’10”) long
onstruction
Cut the barrel, starting next to the welded seam, as shown in Figure 3 below
(also set Figure I). The cut is exactly half way around the barrel.
4cci-6-- ?.
h.
CI
Pull the cut-out section forward and flat~ten it with a hammer (Figure 4). Fold the
cut-out section back 17 to 20 cm (6 3/4” to 7 7/8”) from the end of the cut,
depending on the width of the blade, to form a double bottom (see Figure 5).
The blade can be installed by welding or by riveting.
211
To install the blade by welding (see Figure i):
-
Butt the blade (see Tools and Materials) against the barrel fold and
spot weld it. Five spots of welding 3cm (1 3/10”) long, evenly spaced,
are enough.
-
The lower tip of the blade holder (see Tools and Materials) should be
even with the end of the cut).
-
Weld the blade holder at the outside of the barrel to the heavy rim.
-
Weld the blade to the bottom of the blade holder.
To install the blade by riveting:
-
No blade holder is required.
-
The metal for the blade should be 5 to 8mm (3/16” to .5/X”) thick, 8
to 12cm (3 l/8” to 4 3/4”) wide and 164cm (64 l/2”) long. Taper and
sharpen !he blade before bending.
-
Bend the blade up at right angles 4&m (15 3/4”) from each end. This
will leave the main part of the blade 86cm (33 7/8”) long to tit
inside the barrel.
- Insert the blade.
-
Drill holes and rivet as shown in Figure 6.
- The folded part of the barrel bottom should extend 3cm (1 3/16”)
under the blade and be riveted to the bottom of the blade.
212
Install the handle and handle brace (Figure 7):
-
Position the barrel so the edge of the blade is exactly 4c.m above the
floor.
- Taper the end of the handle and place it in the position shown in
the sketch, making sure it is in the center of the barrel.
WCIEN ro 4 BY* CM M4bv0‘~ /* UJBD.
n& *CM w,and IS “lim/CcIL 4MD )-YE
L.46~30 CM SHKwsw lNrrr P “.&VOLE
-
-
FlGURE 7 ,Nbm“/n6 ?-#e “ANPAE AN0 Y&v47LO aclaC&
Punch a hole through the bottom of the barrel, drill a hole through
the end of the handle, and bolt the handle to the barrel.
Bend 2 1/2cm of the edge of the barrel metal up as shown in Figure
1. Punch 2 small holes in the metal and drive 2 nails through the
holes into the end of the wooden brace.
- Making sure the blade is still 4cm from the Iloor, nail the wooden
block against the end of the wooden brace.
-
Drive a nail through the end of the brace into the handle.
Install the brace wires and rope (Figure 8):
-
Punch holes through the side and end of the barrel halfway between
the bolt and brace end.
213
- Fii 4 strands of wire through the holes and around the brace and
handle.
-
Twist the wires with a small stick to tighten the wire braces, making
sure the handle is at right angles to the barrel.
- Drill a 1 1/2cm hole, 20cm from the end of the handfe. Thread the
end of the rope through the hole and make a knot at each end.
Make holes for installing chain (Figure 9).
Installchain (see Figures 1 and 2).
Operation
When operating the barrel fresno scraper, always be careful not to have any part
of your body directly above the handle.
Keep a !irm grip on the handle while loading, during operation, and getting ready
to unload. An unseen rough spot may cause a sudden jerk, which will make the
handle fly up and strike you.
Bcforc using the scraper, plow the high spots that you want to remove. This will
make it easier to load the soil.
The power used to pull the scraper will also help in loading and unloading. Use
the rope in the handle to pull the scraper into position for loading and for
spreading the soil evenly when unloading.
To load the scraper, simply lift the handle to let the blade go into the soil. Do
not make too deep a cut: this would either pull the scraper over or pull the
animals to a stop.
You will learn by experience how to hold the handle for a proper cut and smooth
handling.
214
When the scraper is full, push down on the handle to let the loaded scraper slide
forward without picking up more so!! to where you want to unload it.
To unload, lift the handle. The pul! of the animals will move the scraper into
dumping position. To spread the soil evenly, hold the rope tight. To dump the soil
in a pile, let the rope go.
airing the Barrel Fresno Scraper
To repair the scraper when the bottom starts to wear through, cut off the unworn part of the cut-out section of the barrel and weld or rivet it over the old
bottom. When the rims of the barrel, which serve as runners, start to show wear,
weld or rivet old truck springs or similar heavy strap iron over their entire
length.
To adapt the barrel fresno scraper for heavy duty, the two wearing points, the
bottom and the runners, must be reinforced. To reinforce the scraper bottom,
cover it with a heavy iron plate 4 to 6mm (S/32” to S/4”) thick from the rear of
the blade to the bolt that holds the handle. Weld or rivet the plate in p!ace.Reinforce the runners by welding or riveting old truck springs or other heavy strap
iron as described in the paragraph on repairing the scraper.
Source:
Dale Fritz, VITA Volunteer, Schenectady, New York
FLOAT
ADJUSTABLE BLADE
The float is very useful for leveling a field before planting a crop. It can be
made by a small manufacturer or a carpenter-blacksmith with locally-available
materials (Figure 1).
A F L O A T FL’<
a F/EL0 BEFOUS
/s P.LaNrEzD
215
All earth moving operations, where any quantity of soil is moved, leave the land
surface in an uneven condition. The float is the best piece of equipment for
obtaining a smooth, even surface. It is difficult to do a perfect job of leveling
the first season after earth has been moved. The areas from which the soil has
been removed are usually hard and the areas to which it has been moved are soft
so that uneven settling results. Also, general tiilage and plowing operations sometimes roughen the land surface. Using the float over the entire tield each season
before planting the crop will help answer these problems. Best results may be
obtained by floating the field in both directions (at 90 degrees), going back and
forth. The last floating should be in the direction of the irrigation flow.
When borders are built in a field for border irrigation it is usually best to use
the float over the entire area between the borders before seeding.
The float can be built in various widths according to the available power. It is
necessary, however, that the float be at least 5 meters (16”) long to ensure a
good job of leveling the earth. The adjustable blade is optional but it is often
desirable if a buck scraper is not available. Common hitches for the float are the
same as used with the fresno.
Tools and Matwials
Wood:
2 runners, 5cm x 30cm x 5.5 meters (2” x 12” x 18’)
3 blades, 5cm x 3&m x 1.8 meters (2” x 12” x 70 7/8”)
2 cross braces, 5cm x 20cm x 1.9 meters (2” x 7 7/8” x 74 13/W)
2 diagonal braces, 5cm x 15cm x 3.75 meters (2” x 5 7/8” x 12’4”)
2 diagonal braces, 5cm x 1.5cm x 3 meters (2” x S 7/8” x 9’9”)
4 side blocks, 5cm x 3Ocm x 45cm (2” x 12” x 17 3/4”)
1 lever, 5cm x 1Ocm x 1.5 meters (2” x 4” x 59”)
2 strap iron runner plates, 7mm x 50mm x 6 meters (9/32” x 2” x 19’7”)
3 angle iron cutting edges, 7mm x 5Omm x 1.8 meters (9/32” x 2” x 70 7/8”)
2 steel tie rods (threaded both ends), 7mm x 2 meters (9/32” x 78 3/4”)
4 nuts, 7mm (9/32”)
8 washers, 7mm (9/3T’)
1 pipe axle, 5cm (2”) diameter x 2 meters (78 3/4”)
2 steel plates, 1Omm x 20cm x 20cm (3/V x 7 7/8” x 7 7/8”)
3 u-bolts, with nuts and washers, 13mm x 20cm (l/2” x 7 7,W)
2 hitch stocks, 7mm x 50mm x 70mm (9/32” x 2” x 27 9/W’)
50 flat head screws, 4cm (19/W) (No. 14)
I5 flat head stove bolts, with nuts and washers, 6mm x 8cm (1!4” x 35/3T’)
4 carriage bolts, with nuts and washers, 13mm x 13cm (l/2’ x 5 l/8”)
l.jkg nails, 13cm (4Od) (5 l/8”)
1.5kg nails, 1Ocm (20d) (4”)
1 rope, 1Omm x 4 meters (3/8” x 13’)
1 chain or cable hitch, 5 meters (WS’)
216
FLOAT WITH ADJUSTABLE BLADE
I 06 ,e
A!!E
Use No 14 flat head screws
6Ocm C.C.
_----____
Use 6mx8cm flat head stove bolts - front
__-.
oET*IL G R No 14 flakhead sci-ews - bottom.
DETAIL A
-__
I
-
-
FIGURE 2
Source:
For&erg, Carl M., Metzger, James D., and Steele, John C. Corwtruction and Use
of Smdl Equipnte~rf for Fumt Imptim. USOM/Turkey in cooperation with Turkish
Ministry of Agriculture.
217
This buck scraper, which has been designed for use with large horses or oxen,
may be used for leveling small humps of earth where the haul distance is short. It
can be made by a small manufacturer or by a carpenter-blacksmith if equipment
and materials are available.
F/GUUE /
&epr 5c&qPE* FOR WET AND DRY LE~ELm+s
After using the fresno to move large amounts of soil from high spots to low
spots, the surface of the cut and fill areas will usually be rough. The buck
scraper is useful for smoothing out the uneven spots caused by the fresno. It can
be used for tilling ditches or for smoothing border irrigation systems. After the
border levee has been made, it is very important to smooth the area between and
close to the levees. The buck scraper can be used very effectively for this
purpose by shortening the hitch on one side and allowing the blade of the scraper
to run at an angle, thus shoving the soil into the the rough areas around the
newly-built levee.
Earth moving may be aided by loosening the soil to be moved by plowing before
using the buck scraper.
The buck scraper is loaded by pushing down on the handle as the equipment
moves forward. The handle must be held down while the soil is being transported.
The scraper is unloaded by lifting up on the handle. A shallow spread is made by
lifting the handle slightly and a deeper spread by pzhing the handle farther
forward.
The most common hitches with the buck scraper are:
0 2 oxen
o 2 horses
o 3 horses
218
The buck scraper may be made in different sizes according to the available power.
Tools and Materials
1 buck board, Scm x 3Ocm x 183cm (2” x 12” x 6’)
1 trailer board, 5cm x 3Ocm x 122cm (r x 12” x 4’)
1 iron pipe handle, 3cm x 2cm (13/W x 3/4”)
1 strap iron cutting edge, 6mm x 1Ocm x 183cm (l/4” x 4” x 6’)
4 strap iron hinges, 6mm x 4cm x 3Ocm (l/4” x 19/N x 12”)
2 strap iron, 6mm x 4cm x 30cm (l/4” x 19/W’ x 12”)
2 strap iron pipe clamps, 6mm x 4cm x 1Scm (l/4” x 19/W x 6”)
2 band strap iron pipe clamps, 6mm x 4cm x 20cm (l/4” x 19/W x 7 7/8”)
1 bolt for binge, 16mm x 46cm (S/8” x 18 l/8”)
2 eye bolts, 16mm x 9cm (5/8” x 3 l/2”)
2 carriage botts, 13mm x 13cm (l/2’ x 5 l/s”)
4 carriage bolts, 13mm x lOcm (X/2” x 4”)
22 carriage bolts, 13mm x 8cm (l/T x 3 l/S’)
2 washers, 16mm (5/8”)
28 washers, 13mm (l/2”)
I chain or cable hitch, Smm (3/W)
Porsberg, Carl M., Metager, James D., and Steele, John C. Corrsfn~tio~r and Uk
of Snrall Eqmprne~tf Jar Farm Itigafiort. USOM/Turkey in cooperation with Turkish
Ministry of Agriculture.
hnn,rlDcnxl83cm Biade
Bent "' 3cm bipe-flattened at BUCK SCRAPER
eearlnq
FlGllRF
- _ _ 2
FOR
WET AND DR' / LEVELING
219
The V-Drag (Figure 1) is used for makmg ditches for irrigation and drainage of
fields and roads. It can also be used to make levees (banks) or borders for border
irrigation. The V-Drag can be made locally by carpenter-blacksmiths or small
manufacturers if materials are available. (See Figure 2 for list of materials and
construction details.)
After the desired ditch line has been established by means of a level or transit,
the plow may be used to make a furrow where the line has been staked. Plow
along the line one way, then turn and plow back again in the same furrow but
throwing the soil the other way.
When the furrow has been plowed, use the V-Drag to move the soil out of the
furrow. By making a complete round (down and back) the soil can be thrown out
on both sides of the ditch. By alternately plowing and using the V-Drag to throw
the soil out, any desired depth of ditch can be obtained.
The method of hitching the animals is important. If two horses are used, it is
necessary to hitch them far enough apart so that both can walk outside the ditch.
If two oxen are used it is important that the yoke be long enough to permit each
animal to walk on the outside of the ditch.
If the soil is hard and more power is required, three horses can be used and one
horse can walk in the ditch and one on each side.
The depth of cut made by the V-Drag can be adjusted to the available power.
Shortening the hitch will reduce the depth of cut as will shifting your weight to
the back of the drag.
221
Either lengthening the hitch or shifting your weight to the front will increase the
depth of cut.
The handle of the V-Drag can be used to vary the width of the ditch. Pressing
down will widen it while lifting up will narrow the width.
birding
vees or Borders for Border Irrigation Systems
After the desired location has been selected for constructing a levee, or border,
the plow may be used to plow down and back twice and throw the soil into the
border line. The V-Drag can then be used to crowd the soil into a ridge.
When a border irrigation system is constructed in this manner it is necessary to
smooth around the border with a buck scraper (see page 217). If the bitch on the
scraper is shortened on one side it will roll the dirt into the border.
T
itch
The hitch on the V-Drag is the same for construction of a ditch or a border. Two
horses, two oxen, or three horses are usually satisfactory.
Source:
Forsberg, Carl M., Metzger, James D., and Steele, John C. ~onstmclion and Use
of Small Equipment for Farm Inigation. USOM/Turkey in cooperation with Turkish
Ministry of Agriculture.
~UL~~L~
Multiple hitches or load eveners are necessary when more than one animal is used
for pulling equipment to adapt the proper power to the load and the job. Correctly-made hitches enable each animal to do its share of the work and exert an
even pull on a piece of eqelpment.
Various combinations of hitches may be used, according to the job. The most
common hitches are:
o
o
o
o
double trees, or ‘L-horse evener
3-horse evener
4horse evener
6-horse evencr
Figure 1 shows a four-horse evener and a three-horse evener. This illustration is
helpful in reading the construction details in Figure 3.
The major parts of the hitches can be adapted for use with oxen or bullocks.
Figure 2 shows simpler eveners that can be used with horses, oxen, or bullocks.
Sources:
NGOE'L 2
Hoffen, H . J . b;hmr Itnplcr71er1ts f o r
Arid and Tropical Regions. Rome:
Food and Agriculture Organization
of &he United Nations, 1960.
Forsberg, Carl M., Metzger, James
D., and Steele, John C. Canstmction and Use of Small Equipment
f o r Farm Irrigafion. USOM/Turkey,
in cooperation with the Turkish
Ministry of Agriculture.
Watson, Peter R. Animal Traction.
Washington, D.C.: Peace Corps and
TransCentury Corporation, 1981.
Tools and Materials
Z-horse evenerr
1 oak plank, 4cm x l&m x 1 meter (19/E” x 4” x 3? 3/8”)
2 oak bars, 4cm x 6cm x 77cm (19/16” x 2 3/S” x 30 5/16”)
4 strap irons, 1Omm x 4cm x 22.5cm (3/8” x 119/N x 8 7/8”)
4 machine bolts with nuts and washers, 13mm x 8cm (l/2” x 3 l/S”)
2 carriage bolts with nuts and washers, 1Omm x L&m (3/V x 4 3/4”)
3-horse evener:
I oak plank, 4em x 12cm x 1.52 meters (19/N x 4 314” x 59 7/S”)
1 oak bar, 4cm x 6cm x 77cm (19/l@ x 2 3/8” x 30 15/B”)
2 strap iron, 1Omm x 4cm x 46Scm (3/g x 19/16” x 18 5/16”)
223
2 strap iron, 1Omm x 4cm x 34cm (3/8” x 19/W x 13 3/8”)
4 machine bolts with nuts and washers, 13mm x 8cm (l/z’ x 3 l/8”)
2 carriage bolts with nuts and washers, 1Omm x 14cm (3/V x 5 l/2”)
Plus material for one 2horse evener
4-horse evener:
1 oak plank, 4cm x 16cm x 1.96 meters (19/W x 6 S/16” x 78”)
4 strap iron, 1Omm x 4cm x 4Ocm (3/8” x 19/W x 15 3/4
4 machine bolts with nuts and washers, 13mm x 8cm (l/2” x 3 l/8”)
2 carriage bolts with nuts and washers, 1Omm x 18cm (3/8” x 7 l/16”)
Plus materials for Iwo 2-horse eveners
&horse evener:
1 oak plank, 6cm x 2Ocm x 2.84 meters (2 318” x 7 7/8” x 9’ 3 3/4”)
4 strap iron, 1Omm x 5cm x .45cm (3/8” x 12Scm x .5/32”)
2 machine bolts with nuts and washers, 20mm x 8cm (3/4” x 3 l/8”)
2 machine bolts with nuts and washers, 20mm x 1Ocm (3/4” x 4”)
2 carriage bolts with nuts and washers, 1Omm x 22cm (3/V x 8 5/8”)
Plus materials for two 3-horse eveners
Clevis (U-shaped piece by which draft animal is connected to hitch):
1 clevis stock, 20mm x 70cm (3/4” x 27 l/2”)
1 machine bolt with nut and washers, 20mm x 12cm (3/4” x 4 3/4”)
(one clevis is needed for each horse)
3sHORSE EVENER
(with 2 Horse Evener)
6-HORSE EYENER
The galvanized metal siphon tube described here can be used for irrigation (see
Figure 1). It can be easily made and repaired by tinsmiths. A siphon can also be
made from a piece of rubber hose or by bending a piece of plastic tubing. Construction details are given in Figure 2.
The purpose of this siphon tube is to carry water out of a ditch without cutting
a hole in the ditch bank. In many soils a small hole cut in the ditch bank soon
becomes a large hole because of erosion. Imported plastic siphons are often
expensive, easily broken and usually impossible for local people to repair.
There are several good ways to start a siphon tube. The simplest way is to put
the tube. in the ditch until it filfs with water. .4olding one hand over the end of
the tube, so that air cannot get in, lift the tube out and place it as shown in
Figure 1. Be sure the other end of the tube does not come out of the water while
placing the tube. When the tube is in place, remove your hand and the water will
begin to flow. The end of the tube outside the ditch must be lower than the level
of the water in the ditch.
Dale Fritz, VITA Volunteer, Schenectady, New York
226
LE FOR I~~IGA
ON AND DRAINAGE
An irrigation or drainage system made with the concrete tiles described here can
help to keep a garden in production during both wet, and dry seasons. It wilt
make good use of irrigation water and, during the wet season, will drain off
surplus water.
The entries that follow exp!ain how to make a concrete-tile machine and how to
use the machine.
In regions of heavy rainfall, the tile drainage can be combined with good surface
drainage by making raised beds in gardens, shoveling out 3Ocm (1’) wide pathways
that will be 15cm (6”) lower than the beds. Put the beds over the tile lines and
make them 1 meter (3’) wide. Use the pathways also as drainage ways and
connect them with a good outlet to lower ground.
This system of under-ground irrigation (and drainage) can serve under fruit trees
or gardens. it can also be used around the foundations of buildings where
drainage is a problem.
Concrete irrigation tiles, whether for irrigation or drainage or both are iaid 3&m
(12”) deep in lines 12m (4’) apart (the lat.ter measurement depending on the
texture of the soil: more distance between lines for clay soils and less for sandy
soils). The garden should be almost level, with good surface drainage. Upright
“elbows” at the ends of the lines give access to the tile at either end (see Figure
1,). A garden hose can deliver the water from it.s source to the upright ends of
the tile fines. While tile lines must be levei, they do not have to be straight; they
can follow a contour hoe or double back to make a more convenient system of
installation with four or more lines connected to make one unit (Figure 2).
In dry seasons, the tiles supply water to the plant roots. In wet seasons, the
water escapes through the sand and gravel around the tile and follows the
concrete tube formed by the tiles to a drainage outlet (see Figure 2). While
passing downward through the soil to the tile, the water draws air into the soil
and supplies oxygen to the helpful bacteria and to the plant roots.
Concrete tile
Cement for mortar, concrete.
Sand for mortar and tile covering
Gravel or crushed stone for concrete
Wood for plugs
Optional - Brass outlet box collar
Shovels, concrete-mixing tools
To install the tiles:
0
Grade the garden plot to within 5cm to 7cm (2” to 3”) of level and make
trenches 3Ocm “12”) deep, according to the design in Figure 2. This will give
an even distribution of the water. Check the bottom of the tile ditches to
be sure they are level. Oniy the drainage outlet will have a drop.
0
Lay the tile end to end in the bottom of the trench. Use au “elbow” (made
of two tiles cut to 45degree angle) to make a place for putting the hose at
one ex& and use other elbows to turn corners,
0
Put a piece of tar paper or used linoleum over each joint (Figure 3) to keep
t h e dirt o u t o f t h e f i n e . A
p i e c e Scm x 12Scm (Z x 5”)
is large enough. .
0
Cover the tile with sand to
give the water an opportunity
to soak out into the soil or
(in the case of drainage), to
seep into the tile. The bottom
12Scm (5”) of the trench are
filled with sand or gravel
(around the tile) and the top
17Scm ( 7 ” ) a r e filled w i t h
soil.
228
0
Near the outlet, make au upright concrete box with two holes near the
bottom to let drainage water run through and on out to an outlet. The box
should be large enough so that one can reach into it to install a plug in the
drain side of the box when the system is used for irrigation. A brass or
aluminum collar installed in the concrete will make it easier ta close this
hole completely and thus avoid a loss of water.
0
Put covers over both ends to keep out small animals (see Figure 1).
0
Do not water more frequently than once or twice a week, so that plant
roots will not enter the tile line to obstruct it.
0
Be careful not to damage the tile with tillage equipment.
0
For irrigation, the tile system is used with its drain plug securely closed
(see Fiie 2). Water is run into the line once. or twice a week, by means of
a hose, until the soil becomes moist. For drainage, simply pull the plug.
ng a Concrete Tile
This ah-steel tile-making machine (Figure 1) can be made of scrap metal in any
shop with welding equipment. The machine makes 80 to 100 tiles to a sack of
cement. One worker
can make about 300
tiles in an S-hour
day. Construction of
the machine is a
good welding project for students.
A tile-making machine made from
wood is illustrated
i n F i g u r e 15. T h e
tiles made with this
machine a r e t h e
same sire as those
made with the allmetal machine.
229
AU the drawings of the form and its several parts in this entry show the form in
its upside-down, or emptying position.
The machine can be made of used or new materials. To make the form, it is
desirable to have both electric and acetylene welding equipment, although either
will serve. The thicker parts are assembled by arc welding and the thinner parts
have to be put through other parts before welding, as will be explained below. We
shall refer to each individual part by its number, which appears on the sketches.
The assemblies made of parts No. 10, 11, and 12 (Figures 8 and 14) are simply a
convenient means of taking hold of the levers to open the end doors. These
levers are made of parts No. 5 and 13 as described below and shown in Figures 9,
10, and 11. They work against the two springs that hold the doors shut-the
tension being made sufficient to hold the doors closed against the force of
tamping.
The hole in the end door is shown as 3mm (l/S”) larger than the diameter of the
pipe that shapes the interior surface of the concrete tubes. This 3mm (l/g”) is an
allowance of clearance necessary to keep the sand particles from making the pipe
difficult to remove after the mortar is tamped around it. Greater clearance would
hurt the uniformity of the tile. The finished tile should have a uniform 13mm
(l/2”) wall and part No. 1 must be shaped and so related to the pipe that the
thickness of the tile wall will be correct (see Figure 6).
Parts No. 7 are bronze welded to the sides of No. 1 (see Figure 6). These parts,
like other parts that touch the hands, should be dressed to a smoothness sufficient to avoid injury to the operator. The outside of the form should be well
painted but the inside cannot be painted, as paint would cause the mortar to stick
to the inside. When the form is not in use, the inside should be kept oiled.
The pipe may need to be dressed lightly in the lathe to make it easier to remove
from the form after the mortar is tamped around it. I Q turning, it is advisable to
make the end opposite the handle end OJmm (I/64”) smaller, as this will facilitate
its removal in the emptying process. This lathe work should be done after the end
of the pipe opposite the handle end has been welded shut with a disc of galvanized sheet metal. If this end is not closed, cement will enter the pipe and thus be
spilled into the inside of the tile to become an obstruction there.
Part No. 19 is a wire of 3mm (3/32”) diameter steel welding rod with the shape
shown in Figure 2, but one of the eyes has to be formed after the part has been
threaded through the hole in part
No. 8 (see Figures 1 and 8).
S”.‘?PS a= Pm?T NO. 14
The following paragraphs are listed by part
1.
numbers:
The inside walls of the form are made of 16-gauge galvanized iron. Part No.
1 as shown in Figure 1 is made from a sheet cut to a true rectangle, 26.6cm
x 30&m (10 l/2” x 12”). This is bent to shape by putting a 6mm (l/4”) fold
on each of the 30&m (12”) sides; bendii Wmm (3/4”) more of same sides
to a right angle; and then shaping the sheet according to the curve shown
in Figure 3. This lining is then
&ted into the cradle made of parts
No. 2 and 3. Parts No. 6 will be
the end doors, which are also made
of 16-gauge sheet iron. The inside
of the form should not be painted,
Fh=mz4c .3
as this interferes with its operaWAP,.WS PA&?T NO.,
tion.
2.
For part No. 2, two pieces of angle iron, 38mm x 38mm x 3mm x 3OScm (1
l/T x 1 I/Z x l/8” x 12”) are needed.
3.
Angle iron, 3Etmm x 38mm x 5mm (1 l/2” x 1 l/2” x 3/W), 95mm (3 3/J’)
long. Two are needed. Parts No. 2 and 3 are welded together to form the
cradle. Parts No. 8 are welded in place on parts No. 2 and corrections are
made for shape before No. 1 is tack welded into the cradle thus formed. The
design above gives some idea of final relationship to be kept between the
sheet metal liig of the form and the metal pipe. Notice that the tile wall
w-ill be uniformly 13”s) thick (see Figures 4 and 8).
4.
Mild steel rods, 1Omm x 15.2cm (3/g” x 6”) (see Figure 13). Two are needed.
These are welded in place to make the form stand a little taller so the
levers will not touch the work bench while the mortar is being tamped into
the form. They also provide a wider base.
5.
Mild steel rods, 1Omm x 22.9cm (3/8” x 9”) (see Figure 10). Four are needed.
These are bent to form the levers and are welded into pairs by means of the
,.GV*r
2.31
comrecting piece, No. 13 (see Figure 9). Notice the tiny tabs welded to the
handle end of the levers. These are to keep the hand hold from turning or
s&ding endwise from its proper position. By the “hand hold” we mean the
assembly made of Parts No. 10,ll and 12.
!
6.
Galvanized sheet metal, X-gauge, l&m x 16Scm (5 l/2” x 6 l/Z). Two are
needed. These are the doors and the parts that hold the center pipe in its
proper position. They should be cut and shaped after Part No. 1 has been
tack-velded in its place (see Fie 5).
7.
Galvanized sheet metal, 16-gauge, 38mm x 10.2cm (1 Y/Z x 4”), bent to
angle as shown in Figure 6. Two are needed. These are handles for lifting
the form. They are dressed smooth and bronze welded to the sides of No. 1
after the doors are p
232
8.
Mild steel bar, 19mm x 6mm x 7cm (3/4” x l/4” x 2 3/4”). Four are needed
(see Piie 1). They are welded to No. 2 to complete the cradle for the
fining of the form. Then the lining, part No. I is welded to No. 8 at the
fold in the edge of No. 1. Check to see that Lhe space for the thickness of
the tile wall remains 13mm (l/T).
~- 63 MM
t--CBE‘=Oe@ sra.G-cw~~6)
b; _ _ -_ _ _ _--I
_ _ _ ~
- - - -
- - - - -
9 .s-S~~~ DO04
d
9.
~~~t~~~n~~~~~~
out to form eyes. Two are
needed (see Figure 7).
NGURE 7
M&WE nwo sw.4165
1 0 . C h a n n e l i r o n , 3 1 m m x 19mm x 8.2cm (1 l/4” x 3/4” x 3 l/4”). Two a r e
needed. Countersink hole for screw head. Dress parts No. 10 and 11 smooth
as they are handles.
11.
Strap iron, 2&m x 3mm x 8.2cm (1” x l/8” x 3 l/4”). Two are needed (see
Figures 8 and 14). Drill and thread hole to match the screw hole in part No.
10. Make guide holes for the round
tabs that are welded to the end of
the levers, No. 5. The tabs on No.
5 is made by sawing off a 1Omm
(3/8”) l e n g t h o f 1Omm (3/8”)
diameter rod and bronze welding it
to the end of the handle as shown.
12.
Machine screw, flat head, 6mm x 19mm (l/4” x 3/4”). Two are needed. This
unites No. 10 and 11.
13.
Mild steel rod, 9mm x 12.7cm (3/8” x 5”). Two are needed (Figure 9 and 11).
Parts No. 5 are made in pairs by welding to the ends of part No. 13. Before
welding, insert part 13 in the
,9,,,,,,,.o. tube, No. 14, which wig become the pivot (after No. 14
is welded to the inside angle
of No. 3). Thus we have the
levers that open the doors.
14. Pipe, 1Omm (3/8”), 7.6cm (3”)
long; two are needed. They
form the pivots for levers.
15.
-5vL4lR~En
WA%+ LEFr w4.vo
~fe7R.e ,o NmrE t LC”ew, 2 R/‘s.ur “.,v(Y A,vO
2 lt3-r YPND
Steel welding rod, 6mm x
10.8cm (l/4” x 4 l/4”).
The ends are ground flat
and smooth. Two are
needed (see Figure 14).
These are the hinge pins
for the doors.
After the hinge holes,
No. 16, are welded to
part No. 3, parts No. 15
are put in place in the
holes.
Then parts No. 6, the doors, are put in place, checked for exact position and
bronze welded to the hinge pins, No. 15. This weld extends almost the entire
distance between one pivot hole (part No. 16) and the other. The weld holds
the door to the hinge pin and prevents the hinge pin from sliding out of
place.
16.
Steel bar, 19mm x 2Scm x 6mm (3/4” x 1” x l/4”) (see Figure 13). Four are
needed. Bore 6mm (l/4”) hole for the hinge rod as shown. No. 15 pivots in
these holes to make hinges for the doors. Parts No. 16 are welded to part
No. 3 in such position as to be as far to the outside edge of the door as
possible. It is best to make a trial positioning of the door and parts No. 15
and 16 by tack welding No. 16 lightly before welding it permanently. Then it
is possible to make sure that the door is going to be in such place that the
pipe will have its proper position.
17.
Common nails, 6 penny, with strong heads (see Figure 14). Four are needed.
Connect the nail to the spring by a wire through the hole in No. 8. Put the
wire through the holes before forming the second end loop.
234
18.
Pi&on, 5cm (2”) galvanized pipe, 4O.fkm (16”) long. (The 5cm (2”) mea?zrement is the inside diameter of the pipe.) Weld one end shut by bronze
welding a metal disc to the end. Then &ess lightly in the lathe, making the
dosed end OSmm (l/64”) smaller than the other. It will serve well without
turning, but will be easier to operate it dressed.
19.
Wiie or welding rod, 2mm (3/32”) to make the connection between parts No.
9 and 17 (see. Figures 2 and 14).
236
Making the Tile
It is possible for one worker to make two tiles per minute, although a good day’s
work would be 3tX1 or more. The mortar remains in the form only a few seconds.
The cement mixture is tamped into the form with a tamper. Then the form is
immediateiy turned upside-down on a (slightly oiled) concrete floor and emptied,
leaving the tile completed and ready to start its curing process. The same general
me!hod can be adapted for the wooden tile-making machine in Figure 15 of the
preceding entry.
Tools and Materiais
Fresh Portland Cement
Clean sand, screened through a 6mm (l/4”) screen
Clean water
.411-metal tile machine
Metal tamper
Plastering trowel
Work bench
Shop with concrete floor
One (II-liter) bucket
D-handled shovel (square point)
Large hoe for mixing cement
A strong dust pan without a handle.
Gloves
237
Make the tile by following these steps:
1.
Screen the sand and spread out 28 liters (1 cubic foot) on the shop floor.
Use a 2&hter (1 cubic foot) measuring box without a bottom.
2.
Spread 7 liters (l/4 cubic foot) cement over the sand. Measure in the box,
tilling it l/4 full.
3.
Mix thoroughly with shovel and hoe. Turn over the pile four to six times.
4.
Spread the pile out and scatter the mixing water over it. The amount of
water should be no more than 2/3 the volume of cement, incfuding any water
in the damp sand. The mix should be as dry as possible and still be plastic.
5.
hlake the batch into tile before 45 minutes of time elapses. Cement loses its
strength if put into the form too long after mixing.
6.
Fill the form (without the pipe) l/4 full and tamp the ends with two strokes
with the (gloved) left hand. This gives the tile perfect ends.
7.
Insert the pipe and fill the form with mortar, using one dip from a strong
dust pan without a handle.
Y.
Tamp the sides of the tile. Make three strokes with the iron tamper.
9.
Fill the form again, vrith another dip from the dust pan.
10.
Turn the tamper over and pack the cement again. Give three strokes with
the flat surface of the tamper.
11.
Use the trowel to finish the tile. Strike off the surplus with one stroke and
!eave the surface trowelled level with a second stroke.
12.
Carry the tile and form to a place where the floor has been lightly oiled. In
carrying the form, do not touch the pipe.
13.
Place the form carefully on its side on the floor and then tip it quickly to
an upside down position. Hesitation in the middle of the tipping action may
cause the mortar to fall out.
14.
Pull out the pipe, turning it slightly first. Hold the form down with one
hand. If the pipe is too hard to remove, it may have irregularities and need
to be dressed lightly in the lathe.
15.
Lay the pipe on top of the form. This gives the form a slight jar.
238
16. Gripping the sides of the form with both hands, push down on the levers,
which open the hinged ends, and then lift the form off the tile. In lifting
use leg action and hip action. Bending the elbows may knock an end off the
tile.
17.
Leave the tile in its place on the floor over night. Sprinkle very lightly with
water if it begins to get dry. To dry at this stage would ruin it.
18.
The nt.it day the tile can be picked up by gripping it at its middle with the
hand. Stack the tile at the side of the shop to clear the center floor space
for another day of produ. en. The first day, stack only two layers high, as
the tile is not strong yet. The second day, ihey can be siacked as high as
desired.
19.
When tr!es are one day old, it is z good time to make 45degree ends on tile
that have been injured in manufacture. A’iout 5 percent (or more) of the tile
made will need a 45.degree end for use in turning corners in the tiIe iine.
20. Keep the tile wet at least a week The strength is increased by each day
that the tiles are kept wet.
If you need further instruction on the fundamental principies of good concrete
construction, study the entries on concrete.
Source:
Brown. J. Dscar. A Mac/&e for Making Concrete Tile for Inigation and Drainage.
O.T.S. Information Kit, Vol. 2, No. 2. Washington, D.C.: U.S. Department of
Commerce, 1961.
s
CLEANE
This seed cleaner was developed in Afghanistan to remove round seeds of weeds
from wheat grains. The round seeds could not be separated by a sieve because
they were the same size as the wheat grams. The cleaner described here takes
advantage of the round shape of the weed seeds to separate them from the wheat.
The wheat grains, which roll down the chute slowly, collect at the base of the
inclined platform (“x” in Figure 1); while the round seeds roll faster and fall off
the side opposite the chute (“-y” in Figure 1).
Tools and Materials
Hammer, saw
Nails or screws
inclined Platform:
Galvanized iron sheet: 70cm x
7Ocm (2’3” x 2’3”)
Wood: 2 c m x 4 c m x G&m ( 4
pieces) (3/4” x 1 l/T’ x 2’2 3/Y)
WoM1: 2cm x km x 2&m (1 piece)
(3/4” x 1 l/2” x KY)
Attached to platform to support
chute
Wood: 2cm x 8m x 34cm (2 pieces)
(3/4” x 3” x 1’3 l/2”)
Legs for platform
Chute:
Galvanized iron sheet: 24cm x 14&m (9 l/2” x 4’7”)
Woods 2~51 x 8cm x 8&m (1 piece) (3/4” x 3” x 2’7”)
Wood: 2cm Y 8cm x 8Ocm (1 piece) (3/4” x 3” x 12”)
As shown in Figure 1, the chute is attached at the top of the f&m (2’7”) support
by nails whose heads have been removed. This makes it easy to remove the chute
when it is not being used. The chute’s Io.ver end sits on the 2cm x 4cm x 25cm
(3/4” x 1 l/2” x 10”) support a:tached to the piatform.
2Ao
The seed should first be cleaned with sieves to remove as much diit and chaff as
possible. To use the seed cleaner, drop the seed very slowly onto the top of the
chute.
Source: Dale Fritz, VITA Volunteer, Schenectady, New York
NING SIEVES
An important step for improving crop production is the effective cleaning of crop
seeds. The sieves described here have been f6und effective in many countries.
Tonis and Materials
Wood: 12 pieces: 2Scm x Scm x 46cm (I” x 2” x 1S”)
W’ood strips: 12: lcm x 2Scm x 43.5cm (l/2” x 1” x 17’)
Galvanized screen:
6mm (l/4” mesh: 46cm (18”) square
5mm (3/16”) mesh: 46cm (18”) square
3mm (l/S”) mesh: 46cm (18”) square
Hammer, saw, nails
The exact size of these sieves is not importat, but 3mm (l/S”), 5mm (3/16”), and
6mm (114”) mesh make convenient siis for cleaning wheat, barley, corn, and
seeds of similar size. The sieves are also useful for grading certain seeds. Grading
consists of removing the small, weak seeds, which will produce small weak plants
or will not grow at all. Less seed can be p!anted per acre, if it is properly
cieaned and graded, and still produce a good crop.
3 C$ N A I L S , 5 PEW SIDE
,I’
‘L--#Jy u4 /BIN- .-.. --.1-’
NGJXQE
I
source:
Dale Fritz, VITA Volunteer, Schenectdy, New York
YING G
N WITH WOODEN
Small blocks of wood treated with calcium chloride, a low-cost chemical, can be
used to dry grain to be used as seed. The blocks, which absorh moisture from the
gram, can be used repeatedly by drying them in an oven after ‘use. Tbe biocks
can absorb water up to one-fourth their weight.
In a test using balsa blocks, the moisture content of gram dropped from 17
percent to 12 percent in three days. The blocks were not dried at this point; in
the next five days, moisture content did not change. The blocks were then dried
in an oven and put back in with the grain. Three more days of drying brought
the moisture content down to 10 percent, at which grain resists mold and insects.
Tools and Materials
0
Balsa or cedar: Cedar absorbs water and is durable. Ralsa absorbs more
water, but it breaks easily. Other wood can also be used.
0
Ca!cium chloride (CaCl2): Add enough to a liter of water to make the
solution w+gh 1/2kg (or to a quart of water to make the solution
weigh 2.5 pounds).
0
Waterproof chest that wiil keep out vapor, to dry and store the grain.
A steel drum or sheet metal cabinet would be good. A wooden chest
can be. used if it is vapor-proof, as in Figures 1,2, and 3.
0
Coarse Screen: 2.5cm (1”) mesh
preparing the Blocks
0
Cut the wooden blocks so that as much as possible of the surface is end
grain. A good sire is 3cm x 3cm x 0.75cm (l” x 1” x l/2”).
0
Dry the blocks in a 90-loO°C (194212’F) oven or double boiler to remove
all moisture (see Figures 4 and 5).
EICYZS 4 MaQ5e~
*,=r,oIy 2 /.u JZCTlOX I
ArrPC+d CUT.cOGE5
?aOMP-YZQ CUT Ho1E
Eoo 5rEew -csc4PE
0
Cook the blocks in the calcium chloride solution for four hours at a
temperature just below the boiling point, 100°C (212OF).
0
Let the solution cool; let the blocks soak in the solution for 24 hours.
0
Dry the blocks again.
0
When the blocks are dry, wipe off any calcium chloride on their surface
before putting them in the grain.
Mix the blocks with gram in a container. The blocks should bc spaced
throughout the container so that the grain will dry evenly in the shortest
time possible. The blocks should not take up more than 10 percent of the
container’s space. Small containers (see Figure 1) are helpful when there are
several kids of grain to dry. They also make it easier to remove and
replace the blocks. These containers are placed in the waterproof chest.
After three to five days, remove the blocks. They can be separated from the
grain easily with a coarse screen. Dry the blocks again.
Continue re-drying the blocks in an oven or double boiler and placing them
back in the gram until the blocks no longer absorb moisture. To fmd out
when this point is reached, weigh the blocks after three or four days in the
grain: if they weigh the same as dry blocks, the grain is dry.
Ives, Norton C. Grain Diying and Storage for Warm, Humid Ciimales. Turriaiba,
Costa Rica: Inter-American Institute of Agricultural Sciences, 19.51.
The bucket sprayer described here has been designed primarily to meet the need
for a sprayer that can be built in an area where production facilities are limited.
This sprayer, which can be made by the local artisans, is intended only for water
solutions of insecticides or fungicides.
Two people operate it; one sprays while the other pumps.
Tools and Materials
Galvanized iron: 3Ocm x 3&m (1’ x
1’) plus 1Ocm x 2Ocm (4” x 8”)
Barrel metal: 10r.m x2&m (4” x 8”)
6mm (l/4”) hose (high pressure) 4m
(u’) long
6mm (l/4”) pipe (truck brake line
may be used) 5Ocm (19 5/S”) long
Wood for handle: 2cm x 15cm x
3Ocm (3/q x 6” x 12”)
2.5cm (1”; Galvanized iron pipe
(thin-walled) 12Ocm (4’) long
4mm (5/32”) wire: 2Ocm (8”)
Truck inner-tube material: 1Ocm x
2ocm (4” x 8”)
lmm (l/32’) Galvanized wire, Xkm
(12”) long
4 - 5mm (3/X”) bolts x lcm (3/S”)
2 - 5x11 (3/N”) b o l t s x 3Scm ( 1
3/g”)
The sprayer pump operates on the same principle as the Inertia Pump (see page
101). The top of the 2&m (1”) iron pipe is plugged and a simple valve is located
Scm (3 l/S”) from the top. The valve is a piece of truck inner-tube rubber
wrapped around the pipe and held in place by wire. One corner of the rubber is
over a hole In the pipe. Some careful adjustment is necessary when placing the
rubber to make sure it works properly and does not leak.
-8.5cm
-Wire (lmn galvanized)
Valve in place
Clamps - 2 required 4nn
galvanized wire.
Hole .5mn
Galvanize
I PO"
-Hole lcm
-valve, Inner Tube
Rubber
.Iron pipe 2.5cm
galvanized,
total length 120cm
Holes lmn
drilled at
angle
.w7
i~Pressure tank
galvanized Iron
6mn pipe soldered
/to tank
6m hose
7
Galvanized ir
disk with 6mn pipe
soldered on truck
f====q
hydraulic line may be
%,Tank Flange usea
FIGURE 3
,,Barrel Metal
DISK NOZZLF
-Rubber
5mnBolt'
i
f------‘~Gp;a~~
--,
Wooden Handle
FIGURE 2
PUMP CROSS SECTION
irl
245
The pressure tank encloses the valve assembly and, as the liquid is pumped into
the tank, builds up pressure sufficient to operate the simple disk type spray
nozzle. The tank is built so that it can be removed in order to service the valve.
The length of the hose can be determined by the maker of the sprayer but it
should be about 4m (13’) to allow the worker doing the spraying to cover quite a
large area before having to move tbe bucket. Also, the length of the small pipe
and the angle of the spray nozzle will be determined by the kind of crops being
sprayed.
At times it will be necessary to “prime” the sprayer pump: if the valve rubber is
too tight and the air cannot bc forced through tbe valve, or if the rubber is
stuck to the pipe. To prime ihe pump turn it upside-down and ffi the pipe with
water. Holding your thumb over the pipe, turn the pump over, lower it into the
bucket of liquid and start pumping in the usual manner. If miming does not start
the pump it will then be necessary to remove the pressure tank to inspect and
repair the valve.
Only very clean water should be used to make the mixture for spraying. ft should
be strained through a cloth after mixing to remove any particles that might cause
the nozzle to plug. If a very fine brass screen is available, it should be put in
the nozzle to keep the dirt from plugging the holes.
Source:
Dale Fritz, VITA Volunteer, Schenectady, NW York
BAC~ACR CROP DUSTE
The backpack duster described here, designed so that it can be easily made by
tinsmiths, has been used by Afghan farmers to dust sulfur on their grapes to
control powdery mildew. The duster is made from easily available materials. Its
feed rate is adjustable (see Figure 1).
The springs needed for the duster can bc made with the simple spring winder
shown on p. 251.
Soldering equipment
Sheet-metal working tools
Carpentry tools
246
247
Part Name
No.
Material
DcTxYiption
1
Bellows
Support
Wood
3&m ‘i 7cm x 2cm (15” x 2 ?/4” x 314”).
2
Screws
3
Bellows Plug
Wood
22cm (8 5/g) in diameter, 2Scm (1”) thick.
4
Valve
Rubber
4cm x Scm (19/X” x 2”). See Figure 2.
5
Screws
6
Feeder Rod
Anchor
Barrel
Metal
7
Peeder Rod
6mm (l/4”) rod See Figure 3. Tota) length 5Ocm (19 3/4”).
8
Bellows
Truck innertube rubber
33cm (12’) long on long side. Tube measures
29cm (II 3/&Y) from edge when laid flat.
9
Bellows
Support
Barrel metai
2Ocm (8”) long. See Figure 4.
10
Brace
Galvanized
tin
33cm (13”) long. See Figure 4.
11
Nails
12
Rivets
13
Bolt
6mm (l/4”) rod See Figure 5.
14
Ciamp
Barrel metal
15
Nut
6mm (l/4”) nut See Figure 5.
16
Agitator
Spring
Tire bead
wire
3&m (13/4”) diameter. See Figure 6.
17 Feeder
Spring
Tire bead
wire
9mm (11/32”) diameter. See Figure 3.
18 Pipe
Galvanized
tin
3Scm (13/e) diameter, 71cm (28”) long.
See Figures 6 and 7.
4c.m (I 9/16”) long.
2cm (3/4”) long.
See Figure 3.
3cm (13/16’;) long.
See Figure 5.
248
19 Hopper
Galvanized tin
22cm (8 5/8”) diameter, 48cm
(18 7/8”) high. See Figure 7.
20 F l o o r
Galvanized tin
Make to fit. See Figure 7.
21 Strap
Holder
Galvanized
wire
4mm (S/32”) diameter.
Soldered to hopper.
22 Strap
Webbing
6cm (2 3/8”) wide, 3m (9’10”) long. Tied at
waist.
23 Handle
8mm (5/l@‘)
rod
Total length 1 meter
(39 318”).
24 Pipe
Galvanized
tin
3Scm (13/4”) diameter,
14Ocm (55 l/4”) long. See
Figure 1,h and 8.
249
23
uster Operates
In operating the duster, the rod (23) is used to pump the inner-tube bellows,
which pivots about point A (see Figure 1).
Air is admitted to the bellows through valve (4), a!so made of iMertube rubber,
and passes down the pipe (18). A measured amount of dust is injected into pipe
(18) at point B. The feed mechanism consists of a 6mm (l/4”) rod (7) covered by
a spring (17). As the bellows is worked up and down, the rod and spring go in
and out of the hole (at point B) in the delivery pipe (18). The dust lodges
between the loops of the spring and is carried into the pipe. The amount of dust
delivered is controlled by stretching the spring on the rod so that there is more
space between the loops. The greater the space between the loops, the greater
the amount of dust carried into the pipe. An easily adjustable clamp (l3) and (14)
is provided on the rod to regulate the amount of dust applied to the plants. The
air-dust mixture is blown out the dekvery pipe at (24).
The bellows of the duster is made from truck innertube rubber. There are several
sizes of innertubes. If the size shown in the list of parts is not used, the
diameter of the hopper must be adjusted to the size of the tubes available. The
hopper is made from gakanized tin, from 24 to 28 gauge.
In the illustrations, the feeder rod (7) is shown as being straight. However, it is
necessary to bend the rod to allow it to work in and out of the hole in the
delivery pipe without binding.
To fit the duster, slip the bellows off of the top of the hopper. The hopper must
not be filled above the top of the delivery pipe. The top of the delivery pipe (18)
is cut so as to prevent dust from spilling in the tube during tilling, and to
provide a means for fastening it to the hopper (1,9).
To increase tke amount of dust being applied:
0
Slip the bellows (8) off of the top of the hopper (19).
0
Loosen the bolt (13).
0
Pull up on the clamp (14) stretching the spriq (17).
0
Tighten the bolt (13).
0
Replace the bellows and test the amount of dust delivered to see if it is
satisfactory.
251
To decrease the amount of dust, the procedure is the same except that the clamp
is pushed down on the rod.
Filling the
Before filling the duster, make sure that all lumps of dust have been broken up.
Putting the dust through a piece of window screen is a good way to break up the
lumps. This will also remove any foreign matter.
source:
Dale Fritz, VITA Volunteer, Schenectady, New York
ng errings for the Duster
Tkis method for winding springs can be used to make springs of any size. Figures
1 and 2 show spring winders for springs that wig be the right size for use in the
Backpack Crop Duster described in the preceding entry.
Tools and Materials
Diik
Dril! bit: 2mm (l/12”)
Drip bit: 6mm (l/f)
Drill bit: 12Smm (l/2”)
Wood: lOcmxIOcmxlm(Cx4”x39”)
Metal .od: 6mm (t/4”) by lm (3Y) long
Metal pipe: 12.5mm (l/2”) by 3Ocm (12”) long
4 small naib
Steel spring wire
A good source of spring wire is from the bead of an old tire. The rubber should
not be burned off as this destroys the spring-strength of tke wire.
One winder is made of tke 6mm (l/4”) rod. The other winder is made from the
12.5mm (l/2”) pipe with a section of the rod used as a handle. Cut a piece of the
6mm (l/4”) rod about Mcm long. Bend to form handle shown in Figure I; set
asioe. Bend remaining piece as shown in Figure 2.
Drill a 6mm (l/4”) hole in one end of the wood block and a 12Smm (l/2”) hole in
the other end. Drill a 2mm (l/12”) hole through the longer section of 6mm (l/4”)
rod and through the 12Smm (l/2”) pipe to insert the end of the wire. Drill a
6mm (l/4”) hole through the 12.5mm (l/2”) pipe to hold the length of the rod to
be used as a winding kandle. Drive two nails close together, about 1Smm to 2mm
(l/12” to l/16”) from each hole in the wood block. Put the pieces together as
shown in Figures 1 and 2.
252
The wire is fed through the nail wire guide and then through the l/12 inch hole
in the rod or pipe spool. The spool is then turned ia a clockwise direction until
the desired length of spring is wound. The springs for the backpack duster are
9mm (11/32”) from the 6mm (l/4”) spool and 3.5cm (1 3/S”) from the 12Smm
(l/2”) spool.
Dale Fritz, VITA Volunteer, Schenectady, New York
I
00
E FOR 200 CHICKS
This chick brooder (see Figure 1) is hinged for easy access to corral and brooder.
The brooder has been used successfully in Ecuador and elsewhere to raise broilers
for a cash crop.
The brooder is heated by a regular electric light bulb, placed under the brooder
floor. Dependiig on the temperature rise required, the wattage of the light bulb
will have to be chosen by experimentation. The metal floor and roof prevent
predators such as rats from entering the brooder. If electric power is not
r-vailable, an excavation can bc made for a lantern. Be sure the lantern has
adequate ventilation.
FIGURE 1
Corral lid covered with
Roof cut away to show
burlap suspended - lea
Fioor Of corral made af
hardware cloth may need
wooden supports
To& and Materials
Small carpentry tools
Wardware cloth 1.2 x Zm (4’ x 6’ 6 3/4”), 2 pieces this size needed.
Aluminum roofii:
1 piece: 1.2m x 1.6m (4’ x 5’3”)
1 piece: 1.2m x 1.7m (4’ x ST)
Wood, approximately 3&m x 2cm x 2Om (1’ x 314” x 6%“)
Steel rod lcm (3/8”) diameter x 3.2m (lo’ 6”)
4 binges about Scm (3 l/S”) long
Woodscrews for hinges
2 buckets cleaa dry sand
Nails, tacks, staples
Kreps, George. Article in Rural Missions, #122, Agricultural Missions, Inc.
OSEN
B BROO
FOR 75 TO 100 CHICKS
This brooder has been used by more than 300 farmers in eastern Nigeria.
‘C6
rl
es I 15 x 80 CM. pmsj
a.sX7xE*cn.r‘~s>
F&wRE 2. 77iE 1E.55 .4m .%waro
m MES‘D~J.
Nail legs to side (see Figure 2). If
desired, make the height of the
brooder adjustable by driig a row
of holes in each leg and bolting
the legs to the sides.
Assemble and nail top support rails icm (3/S”) below the upper edge of the sides
(see Figure 3).
Make the top of plywood, sheet metal, or wooden boards so that the top fits
inside the frame and rests on the support rails (see Figure 4). The hole in the
center of the top is for ventilation. A swinging metal cover regulates the sire of
the opening.
255
A bush or hurricane lamp is placed inside wire mesh or a perforated tin can to
protect the chicks and to help radiate the heat (see Figure r).
The dimensions given in the illustrations can be altered slightly to use available
materials.
The wicks of the lanterns should bc cleaned daily to cut down on soot.
W. M. McCluskry, Poultry Science Depzrtment, Oregon State University, Corvallis.
Thii brooder (see Figure 6) is similar to the other two brooders. It can be used
with either lanterns or electric light bulbs. If lanterns are used, their wicks
should be cleaned daily. Construction detaib are given in Figure 7.
*source:
Stopper, W.W. “Brooder for 300 Chicks”. New Delhi: U.S. Technical Cooperation
Mission to India. (Mimeographed).
-
-
257
BOO POULTRY HOUSE
This bamboo poultry house has a thatch roof and slat walls to provide good
ventilation. The elevated slat floor keeps chickens clean and healthy while the
egg catch and feed troughs simplify maintenance. It has been used successfully in
the Philippines and Liberia.
Tools and Materials
Bamboo
Nails
Thatching materials
Small tools
The house is built on a frame of small poles, with floor poles raised about Im (3’)
from the ground, (See section on construction with bamboo, p. 302.) The floor
poles are covered with large bamboo stalks, split into strips 3t3mm (1 l/2”) wide,
spaced 3Smm (1 l/2”) apart. Ploors so constructed have several advantages: better
ventilation, no problem of wet moldy titter during rainy reason or dry dusty litter
daring dry season; droppings fall between split reeds to ground away from
chickens. This eliminates parasites and diseases normally passed from hen to hen
through droppings remaining warm and moist in litter. However, it has been
suggested that tide spacing of floor and wall slats might invite marauders such as
weasels and snakes.
Metal shields on all the support poles will keep rats and other pests from
climbing (see Figure la). Be sure you don’t inadvertently leave a hoc or other
tool leaning against the house, or the rats will climb that. (Note: A VITA grain
storage project in Central African Republic has had good results protecting
granaries-not poultry houseswith a flat band of metal
[Figure lb] that is simply
wrapped around each granary
support. This kind of guard is
cheaper and easier to install
and maintain than the flared
collar. Make the guard about
25cm wide and about 20 cm
from the ground. You may
have to experiment a bit to
match the size and placement
of the guard to the sire and
cliibmg ability of the rats in
your neighborhood.)
258
Walls are made from vertical strips of bamboo 3&m (1 l/T) wide, spaced 6cm to
&m (2 l/2” to 3”) apart. This also allows ample ventilation, needed to furnish
oxygen to the chickens and to allow evaporation of excess mosture produced in
the droppings. In the tropics the problem is to keep chickens cool, not warm.
Using a closed or tight-walled poultry house with a solid floor would keep them
too warm and result in lowered production and increased respiratory problems.
Shade over and around these houses is very important. If the ground around the
houses is not shaded, heat will bounce into the houses.
The roof must protect the chickens from the weather. In Liberia thatch rooIing
keeps the birds cool, but it must be replaced more often than most other
materials. Since it is cheap and readily available to the small farmer or rural
family, it is most likely to be used. Aluminum, which reflects the heat of the sun,
and asbestos, an efftcient insulator, are desirable roofing materials in the tropics.
Zinc, which is commonly used to roof houses in Liberia, is undesirable for chicken
houses because it is an efficient conductor of heat.
Whatever the roofing material, the roof must have an overhang of lm (3’) on all
sides to prevent rain from blowing inside the house. It may be desirable to slope
the overhang toward the ground.
Feeders
Feeders and waterers are made from 1Ocm to 12Scm (4” to 5”) diameter bamboo
of the desired length (see Figure 2). A node or joint must be left intact in each
end of the bamboo section to keep the feed or water in. A section 7.5cm to lt?cm
(3” to 4”) wide around half the
circumference o f t h e b a m b o o ,
except for 7Scm (3”) sections on
the ends, is removed to make a
kind of trough. All nodes between
the ends are removed. These
feeders must be fastened at the
base, to keep them from rolling.
F/GOR~,g. 85sG CATCH .‘?ND E..D mv~@
,.w BAMADO POULTR)’ WOu5E.
The feeders are fastened to the
outside of the walls about 15cm
(6”) above floor level. The hens
place their heads through the
bamboo strips to feed or drink,
thus conserving floor space for
additional chickens.
259
Nests
The demonstration nests are 3&m (15”) long, 3Ocm (12”) wide, and 35Scm (14”)
high (see Fire 3). The strips used on the floor of the nest are about 13mm
(l/2”) wide, spaced 13mm (l/2”) apart, and must be very smooth. The floor slopes
13mm (l/Z) from front to back, so that when the eggs are laid they wilI roll to
the back of the nest. An opening 5cm (2”) high at the back of the nest allows
the eggs to roll out of the nest into an egg catch (see Figure 1). This type of
nest results in cleaner eggs and fewer broken eggs. It also yields better quality
eggs because they begin to cool as soon as they roil out of the nest. In addition,
the eggs are outside the nest where egg eating hens cannot reach them. Placing
the egg catch so it protrudes outside the wall of the house allows the eggs to be
gathered from outside. Placing the nests 1 meter (3’) above the floor consewes
floor space and permits more laying hens to be placed in the laying house. One
nest is out in for every five hens,
In laying houses, nests are also constructed of split bamboo for unobstructed
ventilation. Conventional lumber nests are hotter; this may cause hens to lay eggs
on the floor instead of in lhe nests. This means more dirty eggs, more broken
eggs, and more likelihood of the hens eating the broken eggs. The only way to
cure a hen of eating eggs once the habit is formed is to kill her. In addition, as
the hens enter the nests they sit on eggs laid previously by other hens, keeping
them warm. The quality of eggs deteriorates very fast under these conditions.
source:
USAID, Monrovia, Liberia, described in OTS Information Kit, vol. 1, No. 5, May
1961.
259
Nests
The demonstration nests are 3&m (15”) long, 3Ocm (12”) wide, and 35Scm (14”)
high (see Fire 3). The strips used on the floor of the nest are about 13mm
(l/2”) wide, spaced 13mm (l/2”) apart, and must be very smooth. The floor slopes
13mm (l/Z) from front to back, so that when the eggs are laid they wilI roll to
the back of the nest. An opening 5cm (2”) high at the back of the nest allows
the eggs to roll out of the nest into an egg catch (see Figure 1). This type of
nest results in cleaner eggs and fewer broken eggs. It also yields better quality
eggs because they begin to cool as soon as they roil out of the nest. In addition,
the eggs are outside the nest where egg eating hens cannot reach them. Placing
the egg catch so it protrudes outside the wall of the house allows the eggs to be
gathered from outside. Placing the nests 1 meter (3’) above the floor consewes
floor space and permits more laying hens to be placed in the laying house. One
nest is out in for every five hens,
In laying houses, nests are also constructed of split bamboo for unobstructed
ventilation. Conventional lumber nests are hotter; this may cause hens to lay eggs
on the floor instead of in lhe nests. This means more dirty eggs, more broken
eggs, and more likelihood of the hens eating the broken eggs. The only way to
cure a hen of eating eggs once the habit is formed is to kill her. In addition, as
the hens enter the nests they sit on eggs laid previously by other hens, keeping
them warm. The quality of eggs deteriorates very fast under these conditions.
source:
USAID, Monrovia, Liberia, described in OTS Information Kit, vol. 1, No. 5, May
1961.
Intensively cultivated vegetable gardens can supply a great deal of a family’s food
from very little land. However, to maintain their productivity, these gardens
require a lot of fertilizer and some special techniques, which are discussed below.
As one crop is finished, another is put in its place throughout the growing
season. Without additional fertilizer the soil would soon bc worn out. Cost of the
garden can bc kept low by using compost and a crop rotation system that also
includes poultry or other livestock, which can give a steady supply of manure.
This virtually eliminates fertilizer costs. The best way to ensure a large supply of
manure is to keep the animals in a pen, barn, or corral, especially at night.
Fertile soil includes organic matter and minerals. The best soil is loose and has a
crumbly texture that breaks easily into small pieces a few millimeters in diameter.
The deeper the crumb structure exists in the soil the better.
If the soil is compacted or dense, it can be loosened by first plowing or tilling to
break up the soil. Tiling also controls weeds. This work can bc done with a pick
and shovel, a hoe, or a heavy fork. A small tractor, or animal drawa tools, may
be helpful in a very large garden.
The soil can bc improved by: 1) adding manure or compost, or by returning to the
soil plant materials that you or your animals do not eat, 2) rotating crops, 3)
working the soil only when it is dry enough. Test for dryness by taking a handlid
of soil and squeezing it. If it sticks together tightly, it is still too wet to work.
Make planting beds no wider than you can reach to the middle of for planting,
weeding, and harvesting. In that way you won’t have to step on the beds and
compact the soil. One meter (three feet) is a typical width. Lay the beds across
any slope to slow water runoff and reduce erosion. The soil may be raised in long
mounds so that it will warm more readily and be less subject to flooding. Edge
the mounds with stone, brick, concrete block, heavy boards, or other material to
hold the soil in place. Thii is not essential, but makes the garden easier to care
for in the long run.
262
t,eave~ a footpath between the beds that is wide enough to walk in and to allow
some space for the tops of the growing plants. You will want to be able to work
between the beds without damaging plants. Build a secure fence around the garden
to keep out chickens, rabbits, cattle, and other animals.
If there is a stream or a tubewell nearby, the garden can be watered by running
water in furrows between the beds, or by hand watering. Widely spaced individual
plants, such as tomato, pepper, or
eggplant, can bc watered by burying a jar with a tiny hole near the
bottom in the ground near the
plant (Figure 1). The jar is filed
with water, which seeps out to be
used by the plant as needed. This
is quite a bit of work, but can be
very effective in very dry areas.
Bury the jar when you set out the
plant so you don’t disturb t,he roots
later. Check the water level in the
- - - jar about once a week, oftener if
need be.
Figure I: Automatic watering
using a buried jar of water.
FE~~L~ZING THE SOIL
Growing plants take nutrients from the so& which must bc replaced or crop
yields will slowly diminish, and intensive cultivation uses up nutrients rapidly. The
major nutrients are nitrogen, phosphorus, potassium, and calcium. These can bc
bought as chemical fertilizers, but arc also found in plant matter and manure.
An inexpensive way to enrich the
soil is to use compcst from a
compost pit or crib that is located
near the garden (Figure 2). Pile the
materials into layers as shown
Keep moist. Turn and mix every
week or so as they decay. When
the compost gets to be dark and
crumbly, it is ready for the garden.
Composting will not usually supply
all the fertilization needed, but will
add nutrients to the garden soil
and improve soil texture.
Figure 2: Compost Pile
The simplest way to fertilize and improve soil texture at the same time is to use
animal manure. If you use fresh manure, spread it over the garden at the end of
the growing season and work it into the soil. During the growing season, it is
best to use only seasoned manure.
If only fresh manure is available, a small amount of it may be used to make a
weak ‘tea” that can bc poured around the growing plants. To make the “tea” put
a shove&d of fresh manure into a bucket of water and let it stand for about a
week. Dilute the liquid until it is the color of weak tea and use it to water your
plants about once a week.
.SE~EC~~N OF CROPS
S&xi crops that suit the climate and your family’s tastes. If you want to grow
vegetables to sell, consider community tastes as well. Try to choose an assortment
that will give you something fresh from the garden throughout the season. Unless
you have some way to preserve the produce, don’t plant more than you can eat,
give away, or seU fresh. But do plant vegetables you like a lot or want in
quantity at intervals of a couple of weeks so that you will bc able to harvest
them over a long period. Keep in mind that in a well-ferti!ized garden plants can
be more closely spaced and will yield a larger harvest for tbe space.
Some crops may be planted directly in the beds while o:hers are best started in a
seed box and later transplanted into the garden beds. The table below gives a
partial Listing of both types of vegetables.
Seeds To plant and Seedlings To Transplant
Vegetables that should
be Transplanted
Vegetable Seeds to Blant Directly in the Garden
Broccoli
Cabbage
Cauliiower
Chinese cabbage
Eggplant
Indian spinach
Black Colocasia
(roots)
Beet
Bitter gourd
carrot
Collard
Coriander
Cowpea
Cucumber
Field bean
French bean
Green Amaranth
Jute
Kohlrabi
LCllUCC
Mustard
Pepper
Spinach
Tomato
Okra
Onion
Pigeon pea
Pointed gourd
Potato (tuber)
Radish
Red Amaranth
Soybean
Sweet corn
Sweet potato
(cuttings)
Sweet pumpkin
Sword ~bean
Turnip
264
It is a good idea to rotate the vegetables in the beds each season. That is, plant
one type of vegetable one season, another type the next season, and so on. Each
type or famiJy of vegetable is subject to similar pests and soil diseases. Planting a
different type vegetable in the beds each season helps prevent the build up of
these pests and diseases and gives the soil a rest.
There are four basic families of vegetables-root vegetab!es, leafy vegetables,
legumes, and fruiting vegetables-so the rotation would span four seasons.
Peas, beans, and such are legumes, which means that they can make their own
nitrogen plant food and so enrich the soil. Plant vegetables that need a lot of
nitrogen in the bed when the legumes are fdhed. Root vegetables are grown
primarily for their thick fleshy roots-radish, carrot, onion, beet. Tire leaves of
some root vegetables, Jike beet, are often eaten as greens. Fruiting crops include
peppers, eggplant, tomato, and white potato.
Leafy vegetables-cabbages of various kinds, lettuces, spinach, collard-are grown
for their leaves, which are rich in vitamins and minerals. Some leafy vegetables
tolerate cold weather better than others and some do weU when it is hot, so it is
possible to have some kind of fresh greens from the garden almost all year round.
When you are planning your crop rotation, include broccoli and cauliflower in the
leafy group, even though you don’t eat the leaves, because they are attacked by
some of the same pests as the leafy vegetables.
Plan the beds so that as one crop is finished another takes its place (with the
addition of a little compost or seasoned manure). Save space by planting ties
like beans and cucumbers on trellises at the edge of the garden, situated so they
don’t shade other crops. Stake tomatoes, peppers, etc., with posts of bamboo or
whatever is available to keep the fruit from rotting on the ground.
Cover the soil around seedlings with a thick layer of grass clippings, leaves,
straw, or other material. Some people use black plastic, which is expensive, or
even layers of newspaper. The idea is to keep the soil from drying out so fast
and to keep weeds from sprouting. Mu!ching may seem lie a lot of extra work in
the beginning, but it saves a lot of work over the season. It also saves water,
and the organic mulches, like grass and straw, enrich the soil as they decay.
Paul J. Abrahams. VITA Volunteer, Atlanta, Georgia
J.W. and J.B. Fitts, VITA Volunteers, North Carolina
Harlan H.D. Hatfield, VITA Volunteer, Bend, Oregon
James M. Corven, VITA Volunteer, Washington, D.C.
The small dairy farmer who maintains five or six cows on two or three hectares
(four or five acres) of fodder and pasture grass is usually faced with a serious
decline in milk production during dry or cold periods. The decline in milk
production is nearly always the result of the seasonal scarcity of fresh, succulent,
nutritious feed. Without good feed, cows are obliged to eat dry, strawy, weedy
grass, which not only lacks nutritive value, but often causes digestive troubles,
constipation, and difficuh birth. These troubles can be dealt with easily and
cheaply; good health and a high level of production can be maintained-by the use
of silage.
Silage can bc stored in permanent
or temporary silos. Permanent silos
can be either upright tower-shaped
structures (see Figure 1) or
horizontal, like the trench silo (see
Figures 2, 3, and 4). Upright stack
silos (see Figure 5) and fence silos
are examples of temporary silos.
The use of successive rings of
fencing is becoming widespread;
these silos can bc lined with plastic
or paper or they can be unlined.
Many farmers have saved the
money needed for permanent silos
by using temporary silos for several
year 5.
Losses of silage vary with the type of silo, the crop e&led, its stage of maturity
and moisture content, fineness of chopping, and the extent to which air and
water have been excluded from the silage. Losses run from 5 to 20 percent in
permanent upright silos; from 10 to 30 percent in permanent horizontal silos; from
15 to 50 percent in temporary trench, fence, and stack silos.
A silo should be located near the barn to keep to a minimum the time and labor
involved in feeding.
Detailed instructions on silo building are given “Farm Silos,” Miscellaneous
Publication No. 810, Agricultural Research Service, U.S. Department of Agriculture,
I%7 (revised).
It is not worthwhile to make a silo of less than four tons capacity, except under
very special conditions. Spoilage in smaller silos is often excessive. A cow of
average sire not provided with any other fodder will consume about 23kg (5Ct
pounds) of silage in 24 hours; on this basis a farmer knowing the number of cows
to be provided for and the approximate length of the period during which &age
is to be used, may estimate the quantity needed; for example:
Xl cows @23kg (50 pounds) per day
for 90 days
5 heifers @14kg (30 pounds) per day
for 90 days
5 calves @7kg (15 pounds) per day
for 90 days
41,400kg ( 90,000 pounds)
6,300kg ( 13,502 pounds)
3.lMke ( 6.7M wundsJ
50,850kg (110,250 pounds)
51 metric tons
(56 short tons)
The bare requirements would be 51 metric tons (56 short tons) of silage, and an
allowance for wastage should be added. The tables may be used to estimate the
dimensions of a silo.
A silo of ten tons capacity or less should be filled in two operations, that is, on
two separate days with two or three days between operations. Similarly, a large
silo should be fded in proportionate operations, though this is not so essential as
with the smaller size. Table 1 gives trench silo capacities.
267
Dimensions in Meters (Feet)
Top Width Bottom Width Depth
2.4( 8) 1.8( 6)
3 ( 1 0 ) 2.1( 7)
3.7(12) 2.4( 8 )
2.4( 8) 1.8( 6)
3 ( 1 0 ) 2.q 7)
3.?(Q) 2.4( 8 )
3 ( 1 0 ) 1.8( 6 )
3.7(12) 2.4( 8 )
4.3(14) 3 ( 1 0 )
1.8(6)
1.8(6)
1.8(6)
2.0
2.1(?)
247l
2.4(8)
2.4(8)
2.4(8)
Approximate Kilograms
(Pounds) of Silage Per
3Ocm (1’) of Length
756 (1680)
918 (2040)
1080 (zaoo)
882 (1960)
1071(238Q)
1260 G=v
1152 (2560)
1440 (3aoo)
1728 (3840)
Material for silage varies considerably. Corn, guinea corn, sugar cane leaves, uba
cane leaves, napier grass, guatemala grass may be used singly or in mixtures; the
important point to be borne in mind is that the material should be young, fresh,
and green. Uba and sugar cane should be cut before the stem is formed, guinea
grass should be cut before flowering and seeding takes place; napier, guatemala,
and elephant should be cut while the stems are still tender and green. If only
fresh, leafy growth described above is used, there is no need for chopping the
material as it is brought to the silo. It should be scattered thinly over the entire
surface of the silo, and should be constantly trampled to cause consolidation.
Trampling close to the wags is especially important.
Siiage that is considerably more nutritious than grass silage can be produced by
combining fresh young leguminous fodders with grass when filling of the silo. Cow
peas, edua peas, soya beans, Bengal beans, and St. Vincent plum fodders have
been used with success at the level of 20-25 percent of the total bulk. This
material must be chopped.
The use of molasses is recommended in all silos, for increased palatability,
increased nutritive value, and in the case of young grasses, or silage with
leguminous mixtures, as an aid to the essential fermentation. Molasses should be
used at the rate of lOkg per metric ton (28 pounds per ton) of grass material, as
follows: if the material is wet with ram or dew, add two parts of water to one of
molasses before application; if the material is dry, add four parts of water to one
of molasses. As each layer of material, several centimeters or a few inches thick,
is laid down, sprinkle on the molasses-water mixture, unless a blower with a
continuous molasses sprayer attached is used. In leguminous mixtures 25 percent
more molasses should be used.
When it is not possible to obtain young, fresh material, and older material must
be used, then chopping is essential. Once the material has been chopped the
remaining operations are similar to those described above, with the exception that
only 6kg of molasses need be used per metric ton (12 pounds per ton) of grass
material plus 35 percent more if legumes are included.
After a silo has been tilled level with the top and has been thoroughly trampled,
the silage will settle gradually over a period of several days, bringing the need
for refilling once or perhaps twice to compensate for shrinkage. After the final
refill a thick layer of dried grass should be laid over the silage and trampled
down; finally, a few heavy logs laid over the dried layer will assist consolidation.
A poiatcd roof over the silo with eaves reaching down below the rim will shed
ram water.
Silage made in the spring of the year when grass is young and nutrilious will
keep perfectly until the .winter or drought period comes; ihen it is possible to
supp1y cows with feed every bit as nutritious and as palatable as fresh grass in
the natural state. It is true that some
cows do not take naturally and readily
to
silage, but they may be taught to
+s; -4:i.
consume it with relish.
)-,’ ‘75
,,,
~,,:,::,“pi,
,,,
~,
N&‘/PC 5.
, ,‘,
.,,~.‘:: ,l’,v:,.. ‘:, ,‘~
_,
When a silo is opened to feed cows,
logs and the dried grass layer should
be removed. It is commonly found that
a layer of siiage several centimeters (a
few inches) thick from the top
downward will have spoiled--turned
black or slimy with white streaks of
fungus here and there. This should bc
thrown away.
270
The color of the good silage exposed below may be green, yellow-green, or
brownish-green, and it will have a strong pleasant smeU; there will be no
sliiiaess or streaks of fungus. The silage may be fed at will to cattle, care being
taken only that each day’s supply should be removed from the whole surface of
the silage rather than from one spot; in this way an even surface will be
maintained and no one section will be over-exposed to air. After each day’s
supply has been taken out, the surface of the silage should be covered with old
bags to prevent drying out; if it should become necessary to interrupt the feeding
of silage for more than a day or two, then the silage must be sealed off as it
was when the silo was first filled.
WARNING - GAS DANGER IN SILOS
Suffocating and, in some cases, poisonous gas~may be ,present: around silos.:+ :
Suffocating gas from fermenting silage, mostly carbon diadde, forms,,&& ‘:
silos shortly after fflmg begins and continues ‘until fermentation, stoRs.‘;‘~ ,~
Poisonous gas, when present, is nitrogen dioxide. Its color ,‘and density ,vary’,
with temperature. At room temperature it is orange yellow ,and, 2~1/2~&nes, ‘~
as heavy as air. As the temperature rises, its color becomes darker and its
density becomes lighter. The gas, being heavier than air, cx5jlect.s ‘aud
remains in any depression or enclosed space when ,there is no strong free
movement of air. Danger of nitrogen dioxide gas occurs only during fi&ng
and for about a week after.
Many lives have been lost because of carelessness in entering a silo where
and raise it a number of times with the rofre.
source:
77te Fanner’s Guide. Marvin D. Van Peursem, VITA Volunteer, Newton, Iowa.
Kingston, Jamaica: Jamaica Agricultural Society, 1962.
s
You work hard when you grow food and prepare it to eat. Buying food takes
money that you have worked hard to earn. Yea do not want to waste it. To keep
food clean and safe in the home you must have good storage space, suitable
containers, and a way to keep foods cool and dry.
lMP0RTANT
Only water that is pure enough to drink should be used for washii or
cooking fiood. If the purity of water is in doubt, it should be boiled for
10 minutes or disiiected. See section on water purification, p. 138; for
proper disinfection procedures.
ow TO CA
S OF FOOD
Different kinds of food need special sare. Treating each food properly will make
it keep longer.
airy Foods
Fresh milk is safe if it is boiled. If you do not have refrigeration, boiled milk
will keep longer than milk that has been pasteurized. Cream witI keep longer if it
is boiled.
‘After milk and cream are boiled, then cooled, store them in clean containers.
These foods will keep longer if stored in a refrigerator, ice chest (see p. 2301, or
evaporative cooler (see p. 28). If
refrigeration is not available store
them in the coolest place you can
find.
Use boiled water to reconstitute
canned, evaporated, condensed, or
dried milk or add water and boil
for 10 minutes. Unsafe milk should
not be used for any purpose.
274
Cooked foods using milk or cream spoil very quickly. Use them immediately in hot
climates. Do not stem.
Dried milk in i&s original container will keep for several months in a cupboard or
on open shelves. Close the container tightly after using. The milk will take up
moisture and become lumpy if exposed to air. Then it is hard to mix with water
and food A glass jar with a tight lid, or a tin can with a press-in lid, are
recommended to store dry milk powder after the package has been opened.
After dried milk has had safe water added to it, store it the same as fresh fluid
milk.
Canned evaporated milk may be stored at room temperature until opened. Before
opening shake the can to mix thoroughly. After opening, cover tightly and store
the same as fresh fluid milk.
Canned sweetened condensed milk may be stored in the cupboard or on open
shelves. After the can has been opened it can be stored in the same place as the
unopened can but it needs protection from ants and other insects. Sweetened condensed milk does not require refrigeration unless it has been diluted with water.
Butter should be kept in a cool place, in a covered container.
Keep hard cheese in a cool place. Wrap tightly in a clean cloth or paper to keep
out air. Put in a box or metal container if possible. Before using, trim away any
mold that forms on the surface.
Soft cheeses should be stored in a tightly covered container in a refrigerator or
other cool place.
Fresh Meat, Fish, Poultry
The moist surfaces of dressed meats, poultry, and fish attract bacteria that cause
spoilage. Keep these foods clean, cold, and dry. They should be allowed some air
when stored. Wrap loosely with a
clean cloth or paper. Wipe or
scrape off any dirt before wrapping.
F/&z&E 2
These foods spoil very quickly.
They should not be kept long in
warm, moist climates.
Rubbing cured or smoked meats with dry baking soda may help prevent molding.
If meat is attacked by insects or shows spoilage, cut out the bad part.
275
Sort eggs as soon as they are brought from the poultry yard or market. Cracked
ones should be removed and cooked for immediate use. Spoiled eggs should be
thrown away. Rough handling and high temperatures shorten eggs’ keeping quality.
j$
*
f $,
: -cc
i’i : \
‘Keep eggs in a covered container
in a cool, dry, clean place. Eggs
keep fresh longer if stored in an
airtight container.
Don’t wash the eggs unless you
want to sell them. Water remove,s
t h e t h i n fti on the shelf that
protects the egg. This film helps to
stop evaporation, the entranCe of
harmful bacteria, and the absorp
iion of odors. Do wash eggs just
before using them. Wash with
cooled boiied water.
Fresh Fruits and Vegetables
Fresh fruits and vegetables need to be kept clean and in a cool place with good
air circulation and out of direct sunlight. Such conditions help to prevent
spoilage. Avoid breaking or cutting the skin.
Sort fruits and vegetables before storing. Use bruised ones immediately, throw
away decayed or spoiled ones. Ripe fruits and vegetables should be used in two or
three days. Allow them to ripen in the open air out of the sun. Wash fruits and
vegetables in clean water before using them.
Fruits and vegetables stored in boxes, baskets, barrels, and bins should be sorted
frequently to remove decayed or spoiled ones. Some fruits such as oranges and
apples may be wrapped in separate
papers. The wrappers help to keep
the fruit from bruising each other
and also help to prevent mold.
FlGLtUE4
Soft fruits and vegetables such as
berries, peaches, papayas, figs,
tomatoes, and plums should be
spread out on clean wrapping paper
or in shallow pans or platters
rather than deep containers.
276
Potatoes and other starchy tubers should be sound, dry, and free from so& cuts,
and bruises when put into storage. Wet tubers rot more quickly than dry tubers.
Store potatoes in a dark place because h&t promotes the formation of green skin
and the poisonous glycoalkaloid called solanine in the potato.
Potatoes keep better if cured witbii l-3 days after harvest. The easiest way to
cure potatoes is to keep them in a container with restricted ventilation (to
establish a high relative humidity of about 85 percent) for about 15 days at lS°C
(600P), or 10 days at 2o°C (6SoP), or 6 days at ZS°C (7i°F). After curing, ftdfy
open the container to allow free air movement and store in a cool, dark place.
Keep all fats cool, covered, and in lightproof containers. Heat, light, and air help
to make fats rancid. Use no iron, copper, or copper allay vessels or equipment to
store or handle fats and oils because traces of iron or copper make them tUM
rancid quickly.
Fats and oils should be kept dry with no moisture mixed with them. Mold on the
surface of fats shows moisture is present. Remove the moid carefuliy. If possible,
heat the fat to drive off the moisture.
Foods like nuts and chocolate, which have some fat, may get rancid. Nuts keep
best when left in shells. Keep these foods cool, dean, and dry in light-proof
containers.
Peanuts that are much darker in color than the rest of the batch should be
thrown out. They are probably contaminated with aflatoxin, which causes cancer
of the liver.
Baked Goods
Cool bread, cakes, pies, cookies, and other baked goods rapidly after they are
taken from the oven. Be sure the p!ace is free from dust and insects. Wrap bread
with a clean cloth or paper when cool.
Stored baked goods in a clean tin
box or other suitable container off
the floor
Molds grow on bread. Scald and air
the bread box at least once a
week. In hot humid weather do not
shut the bread box tightly when it
is tilled with fresh bread.
I
277
Store crackers, crisp cookies, pretzels, and other crisp baked goods in airtight
containers to retain crispness. A tin can with a press-in lid is ideal. If not
available use a sealed plastic bag made from thick plastic.
ried Foods
Dried meats and dried fruits and vegetables may be kept in closely woven cloth
bags if the bags of food are kept in a cool, dry place. If these dried foods are
hung in a damp place they are likely to mold.
Properly dried foods are best stored in airtight contaioex if you live in a humid
climate. A tin can with a press-in lid or a large glass jar with a tightly litting
lid will prevent moisture pickup from the humid atmosphere. Look at the product
occasionally and check that it is in good condition. If there is any sign of mold
it means the food is not dry enough.
Open bags of dried foods should be kept in a pottery or metal container. Seal the
container tightly to keep out insects and rodents.
Canned Goods
Canned foods should be kept in a clean dry, cool place. Destroy any swelled or
leaking cam. Do not eat or even taste the food in swelled or leaking cans. Don’t
even open the can. Dispose of it.
The outside of the cans will
become rusty if they are stored in
a damp place or in humid atmosphere. The contents of rusty cans
are safe to eat provided there are
no holes, leaks, or bulges in the
cans and the contents appear
normal when can is opened.
Leftover Cooked Foods
Moist zooked foods, particularly those made with milk, eggs, meat, or fish, spoil
easily. Leftover cooked foods should be cooled quickly. Store in refrigerator, ice
chest, or evaporative cooler. Use at the next meat if not refrigerated.
en is Food Spoiled?
Food gcnerdly shows when it is spoiled. Check it often. It may have an unpleasant appearance, taste, or smell. Look for these signs of food spoilage:
0
0
0
0
0
0
0
0
slime on the surface of meats and other moist foods
bad odors
sour taste in bland foods
gas bubbles, or foaming
discoloration
liquid t,hat has become cloudy, thick, or slimy
texture becomes very soft
signs of moid growth
ft is important to destroy spoiled foods as soon as they are found. Throw away
any food that has a bad smell. Chopped meat, eggs, and sea food usually spoil
rapidly. Watch grams for signs of weevils. Look for insects and mold in dried
foods. Destroy the part that has insects or mold at once.
y Food Spoils
Foods may be spoiled by:
0
0
0
0
0
0
bacteria, molds, and yeasts
parasites of meat animals
insects and rodents
warm air, freezing temperatures, light
too little or too much moisture
storing too long
DirtadcareIesa
increase food spoilage. Good care of food in the home
can help avoid waste. Keep food in a clean and safe place. Bacteria are living
things so small you can’t seem them. Many are harmful. They live ahnoti everywhere. Sometimes food is made unsafe because bacteria causing disease have
gotten into it. Food can carry these and many other diseases:
amoebic dysenteries
o typhoid
0
botulism
0
0
0
0
tuberculosis
diphtheria
sahnonellosis
People may appear healthy and still carry these disease bacteria in their bodies.
When they handle food, the bacteria may be passed on to the food. Then the food
is unsafe for others.
need water to live. Removing water prevents their growth. Foods are
preserve them. Then they are kept dry. Some foods that are dried are
meat, fish, beans, peas, grapes, figs, currants, cereal grain% flour, spaghetti
noodles and other pasta products, dates. They are dried in the sun or smoked
over a fire.
Bacteria, molds, and yeast iu foods may be destroyed by heating and some
chemical preservatives. They cannot grow in properly dried foods. They grow more
slowly at refrigerator temperature than at room temperature.
Molds can be harmful. They grow where it is damp. Molds look like delicate
velvety or powdery growths of various colors spread through food.
If meat, cheese, or jam have mold on the surface, cut away the moldy part. The
food that is left may bc eaten.
Parasitea, such as tapeworm and trichina, live in meat animals. The tiny larvae of
these parasites may be in the lean meat. They are waiting to complete their
development in the human body or some other place.
Thorough cooking of meat is the best way to destroy these parasites. Preservatives such as salt and smoke do not destroy them. There is great danger in eathig
uncooked or lightly cooked sausages, for example, even though they have been
smoked.
Many chemical substances either destroy certain harmful bacteria or prevent their
growth. For food, two of the simplest to use are common salt and sugar. Salt is
used for meat and vegetables. Sugar is used IO preserve fruits. Sugar and salt
have to be used at a high level to bc effective.
nts eat some food and damage several times as much as they eat
Imeetsand
with urine, feces, and hairs. They may also leave dangerous bacteria on them.
The house fly spreads typhoid
fever,
cholera,
dysentery,
tuberculosis, a n d m a n y other
diseases. Keep flies away from
foods. A cloth net fastened to a
simple wire frame keeps flies out
of contact with food (Figure 7).
The “fly specks” often found on
food or dishes may have disease
germs and mice destroy many types
of food.
To help keep insect and rodent pests out of food:
0
0
0
keep food covered or in closed containers
get rid of garbage and trash
keep the storage area clean
Poisoned bait, powders, or sprays may be necessary to rid storage areas of bousehold insects and rodents. Ask your health department, sanitation, or other official
what pesticide to use, where to get it, and bow to use it. These people have
special training on how to control household pests. They can help you.
Use pesticides with care. They are POISONOUS to people and animals. Keep them
out of reach of children. Never store insecticides in the same place you store
food. Always wash off any dust, spray, or solution that gets on you. When spraying, remove dishes, pots and pans, other cooking utensils, and food from the
room. If you have a cupboard with solid, tight littiag doors store t,he dishes and
cooking equipment there while spraying. Never use oil spray or solutions near a
Tue.
Rats and mice can bc caught in traps or killed with poison bait. Destroy or block
up all places where they are likely to nest and breed. Rodents cannot chew
through metal, glass, or pottery containers so try to use containers made from
these materials for storage of food.
Temperature affects food. Fruits ripen more quickly, vegetables become old and
wilt more quickly, and nuts, fats, and oils become rancid more quickly as the
temperature increases. Insects, bacteria, molds, and yeasts grow more quickly at
higher temperature. Therefore, store food in a cool place. Do not store food near
a hot stove.
Food in direct sunligrt gets hotter and spoils more quickly than food in the
shade. Food should never bc left in direct sunlight unless it has been put there
for a limited time to dry it or to drive out insects.
Freezing temperatures can ruin the texture and flavor of some foods. Frozen
potatoes, for example, are watery and have an unpleasant flavor. Frozen and
thawed foods are safe to eat but may have an off flavor or bad texture.
~Moisture in the air is necessary where green leafy vegetables are stored. If there
is not enough moisture in the air, the moisture from these vegetables will
evaporate into the air. Then they become wilted or limp and look bad even
though they are still safe to eat. These vegetables keep best when stored in a
sealed plastic bag or box and kept in a refrigerator, ice chest, or evaporative
cooler.
281
It is very important to have gocd containers for storing f4. Some foods must be
stored in containers with tight fitting covers. Generally each food is best stored
in a separate container. Label food containers to save time and avoid mistakes.
pes of Containers
Dry foods should bc stored in glass, pottery, wooden, or tin or other metal
containers. Tlte type of container will depend on the food to be stored and
whether the container can be washed. Dry tin quickly to avoid rust.
For moist aad watery foods the choice of containers is more limited. Leakage
must bc avoided. You must consider the effect acids in watery foods have on the
container, especially metals. A
container that can be washed and
aired before fresh supplies are
stored in it is best.
Pottery jars are good for storing
many kinds of food. Jars that are
glared on the inside are best. They
can bc washed easily. If the jars
do not have a tight fitting cover,
make one. Use a plate, saucer, or
piece of metal. A good cover helps
to keep out insects and rodents.
Glass jars with tight lids are also good for storing many foods. Foods that are
affected by light should not be stored in glass jars unless the jars can bc stored
in a dark place. Glass jars can be used again. Wash them in hot soapy water.
Rinse them with hot water that has been boiled for 10 minutes. Dry them in the
sun if possible.
Bottles are good for storiug liquids and some dry foods. In many countries people
preserve fruit and vegetable juices in bottles.
Coconuts, gourds, and calabashes may be used for storing some dry foods for a
short time. Covers can be made of closely woven materials. Insects tend to eat
away the soft lining of these comaiuers, so they are not good for storing meal
and flour for long. Wash these containers often to keep out weevils. Dry in the
SIUI.
A simple cupboard can bc made from a wooden box with shelves. The door is
made of chicken wire so air can circulate. Use it to store root vegetables and
some fruits.
/AI -Frrcap/n COVEREL7 BES,vcpI;s .‘wE M,‘NG F..n,n n& .7AL7&?5
~6U.E 9.
5roe7.G DRTE.9 fir’u/Td &va VE6PTAsLES AWD B.?.F/?o.
727
Tin cans of all sizes are good for storing foods. Sometimes the lids of cans
containing food have been removed with a hand or mechanical can opener. Then
the lid does not fit. If you use these cans to store food, make a cover out of a
plate, saucer, or a piece of metal.
Use a food cover to keep out flies and other insezts when you store food on a
table in an uncovered container. You can make a food cover out of mosquito
netting and a metal or wooden frame (see Figure 7). Store foods this w--. for a
short time only.
A bread box may be made of metal or wood. Punch holes in each end for air
circulation.
Open baskets are good for storing fresh fruits and vegetables for short periods. A
tight cover is not needed for these foods.
Care of Food Containers
Food containers must be kept clean. Wash and dry containers before fresh
supplies are stored in them.
Water for washing containers shoula be clean and hot. Use soap or detergent
Rinse the containers carefully with clear clean water. Dry them in the sun if you
can.
Do not store food in containers that have held kerosene, gasoline, heavy oil,
chcmicais, or pesticides.
Containers holding food that does not need to be kept cool may be stored on
sb+es or on a table.
ES
GE AREA
A good storage area is:
0
0
clean and neat
cool and dry
0
0
well ventilated
free of rodents and insects
You may store food in the kitchen in cupboards on open shelves, or in a closet
with shelves. Sometimes a separate room next to the kitchen, called a pantry, is
used for storing food. Also cellars, caves, and outdoor pits are used in some parts
of the world for food storage.
284
Ventilation
Ventilation is important for good food storage. Good circulation is needed around
food to carry off odors and to keep the right temperature and the right amount
of moisture.
eep the Storage Area Cool and Dry
Many fresh fruits soon spoil in a warm place. Then they are unsafe to eat.
Cooking oils, table fats, and other foods with fat in them may get a stronger
flavor if stored in a warm place. A dry storage area helps to prevent mold on
foods such as bread, cheese, and berries. It also prevents rust on tin cans in
which food may be canned or stored.
the Storage Area Clean
There is no substitute for cleanliness. Scrub shelves, cupboards, and floor> often.
Paint, whitewash, or line shelves with clean paper. Clean the walls, then paint or
whitewash them. Keeping the storage area clean helps to keep away household
pests.
Remember, cleaning removes insecticides. Apply them again after you clean, not
before.
Some foods are quite perishable. They are:
0
0
0
0
fresh meat, fuh, poultry
some fresh fruits and vegetables
milk. butter, margarine, cream
leftover cooked foods
In a warm climate it is best to buy these foods in small quantities and
L.,. “, th<.,rrr +itkiy rather than store them. If you have to store these
foods, keep them as cool as possible. This is one way to keep them
fresh and prevent spoilage.
There are several ways to keep foods cool. Some ways work better than others:
1.
Mechanical refrigerators are the most effective in cooling and preserving
foods, but are expensive and require an outside fuel source.
2.
Ice chests come next; if ice is available they are quite effective.
3.
Evaporative coolers follow ice chests.
4.
Window boxes are the poorest devices.
5.
In some situations, it is possible to enclose food in watertight containers and
place in a cool stream or spring.
6.
Keep food in shade, out of the sun, if no other means is available to protect
it.
Obviously there is direct relationship between effectiveness and price. Each family
should install the best cooling system it can afford, that is, option 1 is better
than option 2, bvt 2 is better than 3, etc.
The information given in this section wiU help you to choose a practical way to
keep foods cool given your particular situation.
286
0
FOOD COOLER
The evaporative food cooler is
cooled by the evaporation of water
from its cloth cover. The cloth is
moistened as capillary action moves
water from the pans through it.
If the climate is d$ and the cooIer
is kept in a breezy spot in the
shade, it wiII cool food considerably below the prevailing temperature.
To be safe, the cooler must be
kept clean. The cooPer’s doth cover
k e e p s flying i n s e c t s o u t . T h e
water-ftied lower pan discourages
roaches and other crawling insects.
I t s h o u l d bc e m p h a s i i d t h a t
coolers based on the principle of
evaporation of water need readily
available water of reasonab!y good
quality and a low humidity environment. The coolers do not cod in
a humid dimate.
Tools and Materials
Saw
Hammer
Nails, tacks
Burlap or other cloth: 2m x 2m (78 3/4’ x 78 3/4’)
Wood for frame: 3cm x 3cm x 13m (1 l/4’ x 1 l/4” x 42.7’)
Pan: 1Ocm (4”) deep, 24cm x 3tkm (9 7/16” x 1113/16”) for top
Screen, hardware cloth, or galvanized iron: 2m x 2m (78 3/4” x 78 3/4”) (nonrustingj
Hinges: 2pair
Pan larger than 3&m x 36cm (11 13/W x 14 3/W) for legs to stand in
Paint for wooden and metal parts
Buttons or lacing material for cover
Make the wooden frame to lit the upper pan (see Fire 2). This might bc the
bottom of a discarded 2tMiter (5-gaUon) oil can. The tip of the pan fits over the
top of the frame to keep the pan from raging into the compartment. Hinge the
door carefully so that it swings easily, and make a simple wooden or thong latch.
Paint or oil ah the wooden parts. The upper and lower pans should aIs0 Ix
painted to prevent rust. Cover the shelves (see Figure 3) and frame with screenkg or hardware cloth and task it in place.
The frame can be strengthened by putting the screen on diagonally, although this
wiil take more material than applying it with the wires parallel to the frame.
Make the shelves adjustable by
CO”E& wow SC-M
providing several shelf supports.
OR O-H-Fe su/rss.&c
Flatten the pointed ends of the
M4?X%&?L
nails slightly to keep the wood
from splitting when it is fastened.
Make two covers of canton flannel, jute burlap (not sisal or henequin burlap), or
heavy-grade absorbent coarse cloth to fit the frame. Wash and sun one cover
while using the other. On the front, fasten the cover to the door iwtead of the
frame. Allow a wide hem to overlap tke door closing. To form wicks that will
carry water from the pans into the cover, the top and bottom of the frame and
door covers should extend into the upper and lower pans. If the cloth cover does
not stay moist, extra pieces of cloth can be placed at the top of the frame to
serve as additional wicks.
?%I8
PCELES§ COOLER
A wd type: of cooler may be made from a basket witi a hse fitting craver. It
may be made of bamboo or other slender wood with open weave. The size depends
upon the family’s needs. In addition to the basket, you will need a container to
set the basket in. This may be square or round, of earthenware or metal. A clean
oil drum could be used. This container should be about 3&m (12”) high and wider
than the basket. Other materials include bricks or stones and soft jute burlap.
To build the cooler (see Figure 4):
0
Select a cool place in the kitchen away from the stove for your cooler.
0
Place the outer container here.
0
Arrange the bricks or stones in the container so the basket will balance
evenly on them.
0
Sew burlap around the rim of the basket. Let it hang loose arouod the
bottom and extend into the earthenware or metal container.
0
Sew burlap loosely over the cover of the basket.
Set the basket on the bricks. riace food in the basket. Cover. Put water in the
bottom of the container. Wet the cover of the basket the first time the basket is
used. Later do this just occasiona!ly. The basket itself should not be in the water,
The burlap cover should bang down into the water.
289
In some counttics window boxes are used to store foods during the cool months
of the year. They must have good ventilation and tight covers to keep out rain or
snow. An ordinary light wooden box may be used or you can make one.
To install a, window box:
0
Pit the box to the outside of the window. The window is the door. Select
the window that is in the shade longest during the day. Keep the window
closed when the box is not actually in use. This will keep the box from
getting too warm and the room from getting too cold.
0
Put a shelf on the window sill. Support the shelf with wooden braces.
0
Set the box on the shelf. Fasten the box to the window case with screws or
nails.
0
Fit a sloping top over the box to shed the rain.
0
Make holes in the end of the ‘box so air can circulate. Screen the boles.
0
Shelves may be made of heavy screening, poultry wire, or wood.
0
Rest the shelves on cleats fastened to the sides of tbe box.
0
Paint the box inside and out. It wiIl he easier to keep clean. Wash the inside
with soap and water from time to time.
0
Food placed in the box should be in clean covered containers.
A similar food storage closet may also be built on the outside of the house. You
can make it open into-a room by a special door through the wall.
e
ER ~A~~ TO KEEP FOO
or is ideal for storing perishable foods. However, refrigerA medbsnicpt
e in all parts of the world and are often very expensive to
ators are not avat
buy and operatt. Where a refrigerator is used, it needs special care.
Clean and defrost it regtdarlv. To do this, turn it off. Allow the ice to melt.
Wash the inside of the refrig-.rator thoroughly, using warm water and soap. Pay
special attention to the corners.
An ice. chest can be made at home. Line a wooden packing case witb galvanized
iron. You will need to put insulation between the wooden box and the iron to
keep out heat. Use sawdust, cork, or similar material. Be sure to insulate the top
and bottom as well as the sides. Make a bole at the bottom for water to drain
out as the ice melts. Keep the ice chest clean. Wash it with soap and water
often.
To pack the chest, allow at least one fourth to one third of the volume of the
chest for the ice. Block ice lasts longer than chopped or crushed ice. Keep the
packed chesi out of the sun and away from sources of beat. Cool cooked foods to
room temperature before placing them in the chest.
A
keg lined with cement makes a good food cooler. You may store leafy
vegetables such as spinach and lettuce here. The vegetables can be kept in a
strong paper or plastic bag. Hang the bags on a hook screwed into a cover of the
keg. Pill the bottom with water.
On some farms cold water pumped from deep wells may first be used to cool
foods, by running it through a suitable storage box. Also, a house or box may be
built over a spring or brook to keep foods cool.
Special wells or caves are sometimes built for cool storage of foods.
In some countries the climate is too cold to grow foods the year around. Farmers
and gardeners in many parts of the world have found good ways to store some
vegetables and fruits.
Some of their methods may he ones you will want to study and teU others about.
agricultural adviser can help you decide which type of storage is best for your
climate and the foods grown in your area. Storage methods described here are
practical only in areas where outdoor winter temperatures average -1’C (30°F) or
lower. They do not work when the climate is warm all year long.
An
like tomatoes, can be planted late in the season so that they
can be picked just before frost. If picked when white or turning red, tomatoes
will ripen in a warm room. To store them for longer periods, they can be packed
in boxes of sawdust; when they are to be used, the boxes are opened and the
tomatoes are put in a warm room to ripen.
Dry bean seeds can be kept for winter use by picking the pods as soon as they
are mature and spreading them in a warm, dry place until dry. Tbe beans are then
shelled, stored in bags, and bung in a cool, dry, ventilated place until needed.
Cellars are usually too damp for storing dry beans. Dry beans of all kinds,
soybeans, and peas can he stored thii way. Keep the beans as dry as possible,.
such as beets, carrots, celery, kohlrabi, turnips, titer radiih, and
Rout
are not stored until late fall. When the soil is dry, the roots are
horser
pulled and the tops are removed. Cone-shaped pits make good storage places for
root crops ia areas where they can be kept from freezing. Turnips may be left in
the garden until later than most crops but are hurt by alternate thawing aad
freezing. Parsnips may be left in the ground an&l needed as freezing does not
hart them, but put a few in storage for use when the ground is frozen.
potatoes store best in a warm, moderately dry place. A small supply can be
placed near a cooking stove or a warm cbiiney or some other place where tbe
temperature will stay around lZ°C to 15OC (5S°F to @OF).
L&e
* D pmupldn and sqasb can b e k e p t i n r o w s o u t o f d o o r s u&I !ate
winter. Tbey can also be kept on shelves in an area with a temperature ranging
from I2OC to lS°C (55oF to 6OOP).
292
Some helpful pointers on storing fruits and vegetables:
0
Different vegetables and fruits need different storage conditions and methods
0
Anything showing decay or injury should not be stored.
0
Vegetables and fruits will dry out unless the storage place is damp and the
temperature low but not freezing.
0
Ventilation not only changes air and removes odors, it also helps maintain
desirable temperature and humidity.
0
Windows and ventilators should be kept open when temperature is not
freeziug.
0
Walls and ceilings should be insulated so moisture will not condense and drop
on stored foods.
The following sections show how to build some kinds of storage facilities.
ST FUNK
CELLAR
Tbii type of storage cellar is low in cost, but does not last long because the
wood will decay. (See Figure 1). If creosote or other waterproofing material is
available, paint the wood with it to slow down decay.
0
Dig a bole big enough to hold the foods to be stored and 12&m (4’) deep,
0
Keep the soil piled nearby to use to cover the roof and bank the sides.
‘““:“.‘.‘g
aa,
0
Set two rows of posts of the
same beight in the bottom of
the pit near the side walls.
0
Set a middle row of posts
about 15Ocm (Y) higher than
the outside posts. Put a ridge
pole ‘on the center row. Lay
planks on the two outside
rows.
0
Next place a roof of planks.
-
cl
Close the ends and cover the whole cellar except the door with soil. The
door may be made of planks or other durable material. The thickness of the
cover depends upon the climate.
0
Be sure that water drams away from the cellar. Extend a pipe from the
storage area up through the dirt for ventilation.
BAGE PITS
A good way to store cabbage, collards, and other greens is in a pit made of
stakes and poles covered with straw (see Figure 2).
0
Dig a trench long enough to
hold the number of cabbages
to be stored.
0
Pull the plants by the roots
and set them side by side in
the trench.
0
Pack soil around the roots.
0
Build a frame about @cm (2’) high around the bed. Thii may be of boards,
poles, or stakes driven into the ground.
0
Bank soil around the frame.
0
Place poles across the top tc ho!d a covering of straw, hay, leaves, or corn
fodder.
Cabbages can also be stored above ground in an area protected by drams from
excess moistme (see Figure 3). Cabbage plants are pulled otn by the roots, placed
head down in the storage area and covered with soil. The advantage of this
method of storage is that you can remove a few heads of cabbage without
disturbing the rest of the pit.
I
GE CONES
0
Build the cones either on the surface of the ground, or in a hole 15cm to
2Ocm (8” to 10”) deep in a well-drained location.
0
Spread a layer of clean straw, leaves, or similar material on the ground.
0
Stack the food to be stored on the litter in a cone-shaped pile.
Cover the food with more straw, leaves, etc.
Cover the entire pile with 7cm to 1Ocm (3” to 4”) of soil.
Fin the soil with the back of a shovel to make it waterproof. More soil
may be needed in very cold weather.
Dig a shallow drainage ditch around the cone to carry away water.
Ventilation or air circulation is necessary.
Small cones with 100 to 150
liters (a few bushels) of
vegetables will get enough air
i f t h e s t r a w between t h e
vegetables and soil extends
through the soil at the top
opening. To keep out rain,
cover the top with a board or
piece of sheet metal held with
a stone.
Large corms - Place two or three rough boards or stakes up through the center
of the pile of vegetables to form a flue. Cap the flue with two boards nailed
together at right angles.
0
Opening the cone - Once the cone is opened it is best to remove all the
food at once. It is better to make several small cones rather than one large
one, and place small amounts of vegetables in each cone. When several kinds
of vegetables are stored in the same cone, separate them with straw or
leaves.
0
Cones should be made in a different place every year to avoid decay from
spoiled food left in an old cone.
Fish cart be an important source of protein, and more and more people are adding
fmh to their diets. Whether fish are caught from the sea or raised in a pond, a
problem many people face is that they have more tish on hand at one time then
they can eat or self fresh.
If the proper equipment and a reliable supply of energy are available, fish cau be
kept for long period.s by canning or freezing. Without these resources, salting
and/or smokbtg are good low-cost choices for preserving fish.
Whichever method is chosen, quality and cleanliness are especially important:
0
The qua&y of the fib to be preserved-the fish must be top qua& salting
and smoking will not help poor quality, old, or rotting fish, aud
0
CIeanlines in ail operations-ail water used must be unpolluted, all waste
must be removed from working and drying areas; whatever comes in contact
with the f=h, including all the equipment, must be kept clean.
Salting, one of the oldest methods of preserving food, is an art as welt as a
science. The process of salting fuh is influenced by weather, size and species of
tish, and the quality of salt used. Therefore, experience is needed to adapt the
process outlioed here to your situation. Start by salting small lots of different
varieties of the available fuh. By salting small amounts of tish at first, ycu will
learn bow much time is required for each step. Salted fish, if properly packed to
protect it from excessive moisture, will not spoil.
One word of caution: Start by salting noo-fatty, white-meated varieties of fsh.
The salting of fatty fsh brings up problems of rancidity, rusting, and spoilage
that can be handled better after you have experience in salting.
The process of salting Fmh has four operations:
0
0
0
0
Preparing the FBk
Salting
Washing and drying to remove excess salt
Air drying
IMPORTANT POINTS TO REMEMBER
0
0
0
0
0
0
Use only top quality tish
Work cleauly
Work fast
Keep the brine saturated-when in doubt, add more salt.
Try to follow local custom in style and length of cure
All water used must be unpolluted
Tools and Materials
A dean sharp knife
Salt: the amount varies with local conditions, but figure about 1 part salt (by
weight) to 5 parts of raw, prepared fish. Use good quality salt. Salt that is dirty,
discolored, or has a bitter taste is unsuitable for salting Fuh.
Clean containers for washing fish
Clean, flat working surfaces; such as tables
Clean containers for removing waste
Waterproof vats: one or more, depending on the amount of Fuh to be salted. The
dimensions are not too important; a good size is lK3cm x 152cm and 91cm deep
(6’ x 5’ x 3’). But Iish can be salted in a ccntainer as small as a wide-mouthed
glass jar. Metals other than stainless steel should not be used. Wooden boxes will
work because moisture will swell the wood and seal it effectively.
Clean boards and weights (for pressing).
Clean slats or lines for hanging fish (see Figures 3 and 4).
Portable thatch-roof shelters or small roofed sheds (see Figure 5).
Preparing the Fish
Fiih should be gutted and beheaded as soon as possible after cat&ii.
Remove the head by cutting it off on a slanted line followiug the gills. Sharks
cao be beheaded at the last tine of gill slits. (Only the “wings” of rays or skates
are usually considered edible.) Fish that weigh 2SOgm (l/2 pound) do not have to
be beheaded but they should generally be gutted. Local custom will determine
whether or not they should be beheaded.
297
FASURE J
In gutting a fish, cut from the gill
cavity along the ventral fo: ~0 the
anal vent (see Figure I). AlI the
guts must be removed. It is also
good comer -r&l practice to remove
the black membrane located in the
visceral cavity (the hollow in the
body of the Fmh which contains the
guts) of many species.
The next step is to bleed the F&. All species of fish must be thoroughly bled: if
the head has not been removed, cut the throat; remove the gigs and all blood
vessels. Blood clots can cause discoloration, as well as bacterial infection that
would make the fish u&t for eating.
Cut the Fish according to local
custom. As a rule of thumb: under
OSkg (1 pound), the fish may be
left whole; from OSkg to Skg (1 to
10 pounds) it should be split in
half from bead to tail (see Figure
2); over 5kg (10 pounds), split the
fish in hvo again from head to tail.
The collarbone behind the gigs
shou!d be left intact when a fish is
split in half.
SaXting
To salt fish, follow these steps carefully:
Sprinkle a thin layer of salt in a waterproof vat. Use just enough to cover
the bottom completely.
Place a layer of Fsh, PLUSH side up, with enough room for each fish to
avoid overlapping. Try for a neat pattern, alternating head to tail and tail to
head.
Cover the Frsh with salt - a thin layer, but with no open spaces.
Continue to layer the fish flesh side up, up to two or three layers from the
top of the vat.
Reverse. the fsh, packing them SKIN side up to the top of the vat, altemating with layers of salt. The top layer must bc salt.
0
The salt will extract moisture from the fish, forming a brine. Use boards and
weights to keep all the fish under the salt.
0
The brine must be kept saturated (90 on a Salinometer, or when no more
salt can be dissolved) at aII times. As moisture is extracted, more salt must
be added to keep the brine saturated. With too little salt the fish will spoil.
As moisture is extracted from the Fib, the level of fuh in the vat will fall. More
fish can bc added, skin side up, alternating a layer of fiih with a layer of salt,
the top layer always being salt. Continue to add salt to keep the brine saturated.
The fish are “struck through,” or thoroughly salted, in 12 to 15 days in warm
weather. In cold weather, the fish should stay in the brine for 21 days or more;
in the tropics, I5 days may bc a good limit. The higher the temperature, the
quicker the fish wiIl bc struck through. When properly salted, the flesh of the
fish is translucent but the eyes are opaque and no longer translucent. The flesh is
fum but yields to gentle pressure. It has a whitish salt cover. An odor of fish
and brine should prevail. There should be no spoilage odors.
shing and Drying to emove Excess Salt
0
When tbe Iish are struck through, remove them from the vat and wash in
unpolluted sea water or fresh brine to remove excess salt.
0
Then place tbe fuh on flat surfaces, using any arrangement of boards and
weights to press them as tlat as possible:
to remove excess moisture; and
to make the fish thinner, which will reduce the length of the air-drying process and improve the appearance of the fuh for marketing.
The fmal drying can bc done either by sunlight and natural air currents or by
artificial heat and air currents generated by fans. In most areas, in the proper
season, drying can bc done outdoors in the sun and fresh air. Chc se an open
area to get the most sunlight and wind. Avoid swampy areas, locaG3n.s near
human or aaimal waste, and, especiaIly, fly-breeding areas.
When freshly salted fish is first brought out to dry, there is danger of sunburn.
If fish is exposed at this stage to the direct rays of the sun, it may harden on
the outside and turn yellow. This will keep the inside from drying properly. To
avoid this, keep the fuh under shade or semi-shade for the fust day.
After the fust day, expose the fLsh to as much sunlight and wind as possible. One
method is to lay the Iish on triangular slats--so that the fish rests on the least
possible amount of surface-fresh
side facing the sun (see Figure 3).
Another method is to hang the fiih
by the tail (see Eqpre 4).
Protect the drying fish against dampness. The tish can be sheltered by portable
thatch roofs (see Figure 5) or moved into small roofed sheds built nearby for
protection from rainfall and
night-time dampness. The fish
should be free of discoloration,
mold, or other defects. Split Ssh
should not have ragged edges.
Generally, six warm days with
winds of more than !5km (3 miles)
per hour should dry the fish
enough to prevent spoiling in
storage or shipping, provided the
fish is properly packed to protect
it from excessive moisture.
Using Salted Fish
Salted f&r is usually soaked overnight, with at least one change of water, to
remove most of the salt before it is eaten. The longer it is soaked, the more salt
is removed. Then it is used in the same way as fresh fish, except that it is not
good for frying,
350
source:
Daniel Carper, Product Manager, Seabrook Farms, Co., Seabrook, New Jersey
S
NG FISH
Smoked f&h does not last as long as salted fsb, and must bc refrigerated, froxn,
or canned if it to bc stored for any length of time. Smoked fish are prepared in
a smokehouse, which is simply a shed or box over a fire that is controlled so
that it produces smoke instead of flames. The tish are hung inside the smokehouse
so that they are surrounded by smoke. It takes about six hours to smoke f=h for
eating or storage.
Prepare the f& as you would for salting. Bleed and gut the f&h and split them
froa head to tail. Wash the tisb in fresh, clean water. Place in a salt water brine
for about one hour. Remove the fish from the brine and wash again in clean fresh
water. Drain, and hang in a cool breezy place for about an hour.
Build a fue in the smokehouse. When the fire is burning properly-that is,
producing lots of smokeplace the fish on hooks and hang or tie them in the top
of the smokehouse. Make sure the
fish are placed securely so they
will not fall. Watch the fire
carefully to make sure that it is
smoking the fish and not burning
them-and also to bc sure that the
smokehouse itself doesn’t catch on
fire.
After the fuh are smoked for about
six hours they can be eaten
immediately, stored in jars (to be
canned), or frozen or refrigerated
until they are eaten.
Smoked fsh do not last as long as salted fsh, so do not smoke all of the fish
unless it will bc used soon after harvest.
Source:
Chakroff, Marilyn. Freshwater Fish Pond Cube and Management. Arlington,
Virginia: Volunteers in Technical .4ssistance, 1978.
Carruthers, Richard T. Utderstanding Fish Processing and Presetvatiort. Arlington,
Virginia: Volunteers in Technical Assistance, 19%.
Concrete is a strong and inexpensive construction material when it is properly
prepared and used. This introduction explains the importance of a good mixture
and describes the materials used in the mixture. Following this are entries on:
0
0
0
0
0
0
0
0
Calculating amounts of materiab for concrete
Mixing concrete by machine or by hand
Testing concrete mixtures
Making forms for concrete
Placing concrete in forms
Curing concrete
Making quick-setting concrete
Useful sources of information on concrete
Concrete is made by combining the proper proportions of cement, water, fine
aggregate (sand), and coarse aggregate (gravel). A chemical reaction, hydration,
takes place between the water and cement, causing the concrete to harden or set
rapidly at first, then more slowly over a long period of time.
Importance of a Good Mixture
After concrete has set, there is no simple non-destructive test to find out how
strong it is. Therefore, the entire
responsibility for making concrete
as strong as a particular job
demands rests with the supervisor
a n d t h e people w h o p r e p a r e ,
measure, and mix the ingredients,
place them in the forms, and watch
over the concrete while it hardens.
The most important factor in
makmg strong concrete is the
amount of water used. Beginners
are likely to use too much. In
general, the lower the ratio of
water to cement, the stronger the
concrete will be.
304
The proper proportioning of all materials is essential. The section on “Calculating
Amounts of Materials for Concrete” provides the necessary information.
Aggregates: Gravel and Sand
To make strong concrete, the coarse aggregate (gravel) and fine aggregate (sand)
must bc the right size, have the right shape, and be properly graded.
Coarse aggregate sizes can vary from 0.5cm (l/4”) to 4 or 5cm (1 l/2” or 2”) in
diameter. The maxirrum size depends on the nature of the work. In general, the
largest particles should not bc more than one-fourth the thickness of the smallest
dimension of the section. Sand can vary from sires smaller than 0.5c.m down to,
but not including, silty material.
Very sharp, rough, or fiat aggregate should not bc used iu concrete. The best
aggregate is cubical material (from a rock crusher) or rounded gravel (from a
stream bed or beach).
Proper grading means that there are not too many grains or pebbles of any one
size. To visualize this, think of a large pile of stones all 5cm (2”) in diameter.
There would be spaces between these stones where smaller pebbles would fit. We
could add to the pile just enough smaller stones to till the largest spaces. Now
the spaces would be smaller yet, and even smaller pebbles could till these hoIes;
and so forth. Carried to an extreme, the pile would become neariy solid rock, and
only a very small amount of cement would bc needed to lill the remaining spaces
and hold the concrete together. The resulting concrete would be ‘very dense,
strong, and economical.
It is extremely important that the aggregate and sand bc clean. Silt, clay, or bits
of organic matter wig ruin concrete if too much is present. A very simple test
for cleanliness makes use of a clear wide-mouth jar. Fill the jar to a depth of
5cm (2”) with the fine aggregate (sand) and then add water until the jar is three
quarters full. Shake the mixture
vigorously for a minute. The last
few shakes should be sideways to
let the sand level off. Then let it
stand for three hours. If there is
silt in the sand, it will form a
S,iT--distinct layer above the sand. If
-IS&-d‘---5cP7
the layer of very fine material is
Amore than 3mm (l/S”) deep, the
F,6cs?& 2
concrete will bc weak.
If there is too much fme or silty material, another source of sand should bc
found. If this is impractical, it is possible to remove the line particles. This can
be done by putting the sand in a container like a drum. Cover the sand with
water, stir or agitate vigorously, let it stand for a minute, then pour off the
liquid. A few such treatments will remove most of the fine and organic matter.
In very dry climates, the sand may be perfectly dry. Very dry sand will pack into
a much smaller volume than sand that is moist. If 2 buckets of water are added
to 20 buckets of bone dry sand, you can carry away about 27 buckets of damp
sand. If your sand is completely dry, add some water to it.
Another point to consider in selecting an aggregate is its strength. About the
only simple test is to break some of the stones with a hammer. If the effort
required to break the majority of stones is greater than the effort required to
break a piece of concrete of about the same size, the aggreage will make strong
concrete. If the stone breaks easily, the concrete made of these stones will bc no
stronger than the stones themselves.
The water used to prepare concrete must be clean, and free of organic matter.
Water acceptable for drinking is preferable. Any clear, fresh water is acceptable.
Salt water may be used if fresh water is not readily available, but it will reduce
the strength of concrete about 15 percent.
If you must use dirty or muddy water, let the water settle in a huge pan or tank
to remove most of the dirt.
Cement for concrete, if it is a U.S. brand, comes in 42.6kg (94 pound) sacks, and
is 28.4 liters (exactly 1 cubic foot) in volume. It must be kept perfectly dry prior
to use, or the chemical action will begin and the cement will be ruined.
Mixing the materials, getting them in place rapidly, tamping or compacting to a
dense mixture, and proper curing are important parts of the construction process.
These will be discussed in the sections on mixing and curing concrete.
Concrete reinforced with steel rods is used for structures such as large buildings
and bridges. Proper design of reinforced concrete and placement of steel reinforcing is a complex procedure that requires the help of a trained engineer.
TERIALS FOR CONCRETE
Three methods are given here for finding the correct proportions of cement,
water, and aggregate for concrete:
0
0
0
A “Concrete Calculator” fold-out chart
Using water to estimate proportions
A “rule of thumb
306
Using the Concrete Calculator
The amounts of materials needed for a concrete construction job can be estimated
quickly and accurately with the “Concrete Calculator” chart. The chart is given iu
both English (Chart A) and metric (Chart B) units.
To use one of tbe charts, you must know:
0
0
0
0
The area of concrete needed in square meters or square feet.
The thickness of concrete needed in centimeters (inches).
The kind of work to bc. done (see below).
The wetness of the sand (see below).
To use the calculator, fol!ow these steps
0
Make a light pencil mark on Scale 1, representing the area of concrete
needed. If the volume is less than 400 liters or 15 cubic feet, multiply it by
a convenient factor (for example, 10); then, when you find the amounts of
materials the chart says to use, divide them by the same factor to get the
actual amounts needed.
0
Make a similar mark on Scale 2, the slanted scale indicating thickness.
0
Draw a straight line through the two marks intersecting Scale 3 to fiid the
vohtme of concrete needed.
(If the shape of the area is complex, measure it in sections, add up the
volumes of all the parts and mark the total volume on Scale 3.)
0
Mark the kind of work on Scale 4. A tine through the marks on Scales 3
and 4 to Scale 5 will give the amount of hne aggregate needed.
0
Continue on a zig-zag course as shown in the KEY to calculate the rest of
the materials.
0
Add 10 percent to the amounts indicated by the chart to allow for wastage
and miscahtdation.
0
If the mix is too wet or too stiff, see page 312 for instructions on adjusting
it.
To
Materials can bc measured in buckets. Most buckets are rated by the number of
gallons they hold.
convert to liters, multiply gallons by 3.785. To convert to
cubic feet: 1 cubic foot = 7.5 gallons. A 4-gallon bucket would hold 15.15 liters or
0.533 cubic feet.
- "5" means "5 gallon paste" which is concrete subjected to severe wear, weather, or weak acid and alkali solutions.
Examples would be the floor of a comnercial dairy.
- "6" mans "6 gallon paste" for concrete to be watertight or subjected to moderate wear and weather. Examples:
watertight basements, driveways, septic tanks, storage tanks, structural beams and columns.
- "7" means "7 gallon paste" for concrete not subjected to wear, weather, or water. Examples: Foundation walls,
foot;ngs, mass concrete, etc. where water tightness and abrasion resistance are not important.
Fine Aggregate - Sand or rock screenings up to one quarter inch in diameter. Should be free from fine dust, loam, clay and vegetable
wtter or the concrete will have low strength. Particles should vary in size, not all fine or coarse.
Coarse Aggregate - Pebbles or broken rock from l/4" up to l-l/Z". Nothing coarser than 3/4" should be used for a 5 gallon paste.
Condition of Sand - Dry--feels slightly damp but leaves very little water on the hands.
Averape--feels wet; leaves a little water on the hands.
Wet--dripping wet, leaves quite a bit of water on the hands.
- The chart is based on the U.S. Gallon. (This is 0.835 of one Imperial Gallon.)
Gallons
t*
Kind of work
IiY.inoti, U.S.A.
CONCRETE CAlCUL
CHART
A - E N G L I S H UNITS
An eXai?Iple: If the area is 100
square feet, the thickness is 6
inches, the "kind of work" is
6-gallon paste and the condition
of the sand is average: the
volume of the job will be 50 cubic
feet and you will need 28 cubic
feet of fine aggregate, 38 cubic
feet of coarse aggregate, 12 cubic
feet of cement and 52.5 gallons of
water.
r
KEY
Note- use the number Of sacks Of
cement required, and the kind of
work to locate this point on the
reference line. A line through
this point and the condition of
sand will give the amount of water needed.
CONCRETE CALCULATOR
CHAKr
I
I
1
I\i
I
300
\
6d0,
- 1,700
- I , 600
700 .\,
I
I
I
\\
‘\
4
5
67 1
9 __-- _93
L5
2,000
400
$00
UNIT6
2,200
2,100
lt
I
I
B ME+mc
\
\
\
\
\\
\
400
\
\
\
- ,ioo
\ \ - ,‘700
\-I 6 0 0
1
500
400
\
950
\
\
\
\
500
550
600
309
The deftitions used in the chart are:
Kind of Work:
“5” means “S-gallon paste” (5 gallons or 19 liters of water to one sack of
cement), for concrete subjected to severe wear, weather, or weak acid and alkali
solutions. An example is the floor of a commercial dairy.
“C means %-gallon paste,” for concrete that is to be watertight or subjected to
mod,iace wear or weather. Examples: watertight basements, driveways, septic
tanks, storage tanks, structural beams and columns.
“7” means “7-gallon paste,” for concrete not subjected to wear, weather, or water.
Examples: Foundation walls, footings, and mass concrete where water tightness
and abrasion resistance are not important.
te
Hoe
Sand or rock screenings up to OScm (l/4”) in diameter. It should be free from
fine dust, loam, clay, and organic matter or the concrete will be weak. The
particles should vary in size.
Coarse
te:
Pebbles or broken rock from OScm (l/4”) up to 4 or 5cm (1 l/2” or 2”). Nothing
larger than 2cm (3/4”) should be used with a 5-gallon paste.
Condition of Sand:
Dsy: feels slightly damp but leaves very little water on the hands.
Average: feels wet, leaves a little water on the hands.
Wet: dripping wet, leaves a lot of water on the hands.
Gallons: Chart A is based on the U.S. gallon (0.835 Imperial Gallon).
Using the Water Displacement Method
The “Concrete Calculator” chart assumes that the aggregate is well graded. When
the aggregate is not well graded, an alternate method can be used to find the
correct proportions for a concrete mixture. The advantage of this method is that
only a small sample of the ungraded aggregate needs to be divided into coarse
and tine particles.
Well-graded aggregate seldom occurs naturally. Some “pre-mix” processing would
be needed to grade it.
310
Remember that when you make concrete, you are filling the spaces in the
aggregate with cement mortar or paste. The amount of cement paste needed can
be found by adding water to a known volume of aggregate. To do this:
1.
Divide a sample of the aggregate into coarse and Fme particles by sifting it
through a 05cm (l/4”) screen.
2.
Fii a pail with the coarse aggregate (dry).
3.
Fill the pail with water. The amount of water used equals the amount of
fine aggregate and cement paste needed to till the spaces.
4.
Into another pail, put an amount of fme aggregate equal to the volume of
water used in Step 3.
5.
Fill the pail with enough water to bring the water level to the top of the
fme aggregate. The volume of water used equals the volume of cement paste
needed to fil the remainiug spaces.
Add about 10 percent to this volume to allow for waste and to make the mix
more workable.
6.
To fmd the correct ratios of materials, divide the volume of cement paste
needed into the volumes of fme and coarse aggregates.
7.
Add these two ratios to get the ratio for ungraded aggregate. For example:
If you are using a 19-liter (Igallon) pail, and it takes 12.8 liters (3.4
gallons) of water to ffi the pail in Step 3, put 12.8 liters (3.4 gallons) of
fine aggregate in the second pail (Step 4). If Step 5 takes 6.4 titers (1.7
gallons) of water, this is the volume of cement paste needed. Divide this
volume into the volumes of fine and coarse aggregates to get the ratios of
materials:
19 liters (coarse aeereeatek = 3
6.4 liters (cement paste)
12.8 liters iline aeareeatej = 2
6.4 titers (cement paste)
The sum of the two ratios is 5, so the ratio of ingredients in this case is 1:5, or
1 part cement paste to 5 parts ungraded aggregate, by volume.
To find t.he ratio of water to cement, see “Kind of Work” page 309. For directions
on adjusting a mixture that is either too wet or too stiff, see page 312.
311
Using“Rule of Thumb” Proportions
For a variety of small concrete construction tasks and for repair and patch-work,
the following simple “rule of thumb” can be used as a simple guideline.
Use the ratio 1:2:3, by volume, to proportion the cement and aggregate and use a
water-cement ratio of 6 gallons water to 1 sack of cement. That is, for every
sack of cement (28.4 titers or 1 cubic foot) used, add 56.8 liters (2 cubic feet) of
fme aggr=:.~‘cte and 85.2 titers (3 cubic feet) of coarse aggregate. Add 28.7 liters
(6 gallons) of water for each sack of cement.
A home-made box of 28.4liter (l-cubic foot) volume will help in proportioning
the mixture. The volume of concrete produced by a one-sack batch using the
..oportions given above wig be about 142 liters (5 cubic feet).
The most common mistakes made by inexperienced persons are using too much
cement, which increases the cost, and using too much water, which produces weak
concrete.
IXI~G CONCRETE
Concrete must be thoroughly mixed to yield the strongest product. For machine
mixing, allow 5 to 6 minutes after all the materials are in the drum. First, put
about 10 percent of the mixing water in the drum. Then add water uniformly with
the dry materials, leaving another 10 percent to be added after the dry materials
are in the drum.
Making a
ixing Boat or Floor
On many self-he:p projects, the amount of concrete needed may be small or it
may be difficult to get a mechanical mixer. Concrete can be mixed by hand; if a
few precautions are taken, it can be as strong as concrete mixed in a machine.
Tools and Materials
Lumber, 2 pieces: 183cm x 91Scm x 5cm (6’ x 3 x 2”)
Galvanized sheet metal: 183cm x 91Scm (6’ x 3’)
Nails, Saw, Hammer
Or:
Concrete for a mixing floor: about 284 titers (10 cubic feet) of concrete is needed
for a 244 cm (8’) diameter mixing floor that is 5cm (2”) thick with a l&m (4”)
highrim
Shovel
312
The first requirement for mixing by
The ends of the wood and metal
mixing boat are curved to make it
easier to empty. The raised edge of
the concrete mixing floor prevents
loss of water while the concrete is
being mixed.
The procedure is:
~
0
Spread the fine aggregate evenly over the mixing area.
0
Spread the cement evenly over the fine aggregate and mix these materials by
turning them with a shovel until the color is uniform.
O
0
Spread this mixture out evenly and spread the coarse aggregate on it and
mix thoroughly again.
Form a hollow in the middle of the mixture and slowly add the correct
amount of water and, again, mix thoroughly.
The mixture should be pIaced in the forms within 2Q minutes after it is completely mixed.
When work is fmished for the day, be. sure to rinse concrete from the mixing
area and the tools to keep them from rusting and to prevent cement from cakiig
on them. Smooth shiny tools and boat surfaces make mixing surprisingly easier.
The tools wig also last much longer. Try to keep born getting wet concrete on
your skin because it is caustic. If you do, wash it off as soon as possible.
A workable mix should be smooth and plasticneither so wet that it will run nor
so stiff that it will crumble.
If the mix is too wet, add small amounts of sand and gravel, in the p r o p e r
proportion, until the mix is workable.
If the mix is too stiff, add small amounts of water and cement, maintaining the
proper water-cement ratio, until the mix is workable.
313
Note the amounts of materials added so that you will have the correct proportions
for subsequent batches.
If a concrete mix is too stiff, it wiII be diEcult to place iu the forms. IT it is
not stiff enough, the mix probably doe.s not have enough aggregate, which is
uneconomicaL
iomp
Slums
Tests
Cone
A “slump coce” is a simple device for testing a concrete mixture to see that it
has the &ht proportion ofmaterials.
Tools and Materials
Heavy gaknized iron sheet: 35Scm x 63Scm (14 l/8” x 25 l/Z)
Iron strap: 3mm x 2Scm x 7Scm (l/8* x 1” x 3”) 4 pieces
16 Iron rivets: 3mm in diameter and 6mm long
Wooden dowel: 16mm in diameter and 61cm long
Testing
To perform the test:
0
Dampen the slump cone and set it on a flat, moist, non-absorbent surface.
Stand on the clips at the bottom of the cone to hold it down.
0
Fii the cone in three layers approximately equal in volume. Because the
diameter at the bottom of the cone is large, the first layer should NI the
cone to about one-fourth its height.
0
Stroke each layer 25 times
with the wooden dowel.
0
After the top layer has been
stroked with the dowel,
smooth the surface of the
concrete so the cone is ftied
exactly.
Carefully lift the cone off the
concrete.
0
0
Place the empty cone alongside the concrete. Measure the
difference between the height
of the cone and the height of
the concrete. This difference
is the slump.
Suggested slumps for various types of construction are:
0
Reinforced wags and footings: 5cm to 13cm (2” to 5”)
0
Unreinforced walls and footings: 2.5cm to 10cm (1” to 4”)
0
Tbii reinforced walls, columns and slabs: 7.5cm to 15cm (3” to 6”)
0
Pavements, walkways, culverts, drainage structures, and heavy mass
concrete: 2.5cm to 7.5cm (I” to 3”)
Correcting the Ibfikture
If the slump is not within the desired range, or if the mixture is obviously either
too fluid or too stiff, the proportions of the mixture must be changed. To make
*he mixture more fluid and increase the slump, increase the proportion of water
and cement without changing the water-cement ratio. To make the mixture stiffer
and decrease the slump, increase the proportion of the aggregates without
changing the IIne aggregate-coarse aggrwqate ratio. Do not add just water to
make the mix more fluid, this will weaken the concrete.
NG FORMS FOR CONCRETE
Fresh concrete is heavy and plastic. Forms for holding it in place until it hardens
must be well braced and should have a smooth inside surface. Cracks, knots, or
other imperfections in the forms may be permanently reproduced in the concrete
surface.
315
Wood is commonly used for forms, because of its light weight and strength. Since
cracks between boards can mar the concrete surface, plywood, which has a special
high-density overlay surface, is often used. The fmish on plywood provides a
smooth casting surface and makes it easier to remove the forms for reuse.
If unsurfaced wood is used for forms, oil or grease the inside surface to make
removal of the forms easier and to prevent the wood from drawing too much
water from the concrete. Do not oil or grease the wood if the concrete surface
wilt be painted or stuccoed.
Forms for flat work, such as pavements, may be 5cm x lOan (Z x 4”) or Scm x
15cm (2” x 6”) lumber, the size depending on the thickness of the slab. Stakes
spaced 122cm (4’) apart hold the forms in place.
Figures 9 and 10 show forms for straight-wall construction. To prevent the forms
from bulging, opposite studs should be tied together with lo- to 12-gauge wire,
which should be twisted to draw the form wails tight against wooden spacer
blocks. (The blocks are removed as the concrete is placed.)
The ties should be spaced about 76cm (2 I/2’) vertically on the studs. When the
forms are removed, clip the wires close to the concrete and punch them back. Pit
holes caused by punching back the wires should be pointed up with mortar.
Forms should be easy to Ml with concrete and easy to remove once the concrete
has hardened. Screws or double headed nails which can be taken out easily can be
a great help in removing wooden forms without damaging the concrete.
Forms are sometimes made of other materials. For example, metal forming is more
economical for repeated work, such as curbs, slip forming for monolithic concrete
tanks or silos, and reinforced concrete floors for multistory buildings.
316
FIGURE IO--Forms for a basement or cellar wall. The earth can be used as
the outside form if sufficiently firm.
The finest natural finish on a concrete surface can be obtained by casting on
polyethylene. Sometimes polyethylene forms are used for decorative work, or a
kraft paper with a polyethylene film surface is used as form liner.
ETE IN F8
To make strong structures, it is important to place fresh concrete in the forms
correctly, The wet concrete mix should not be handled roughly when it is being
carried to the forms and put in the forms. It is very easy, through joggling or
throwing, to separate the fme aggregate from the coarse aggregate. Do not let
concrete drop freely for a distance greater than 90 to 12tkm (3’ to 4’). Concrete
is strongest when the various sires of aggregates and cement paste are well
mixed. The concrete mix should be fumly tamped into place with a thin iron rod
(about 2cm or 3/4” in diameter), a wooden pole, or a shovel.
When the forms are filled, the hard work is done, but the process is not fimished.
The concrete must be protected until it reaches the required strength. It starts to
harden almost immediately once the water is added, but the hardening action may
not be complete for several years.
The early stage of curing is extremely critical. Special steps should be taken to
keep the concrete wet. In temperate cliiates, the mixture should be kept wet for
at least 7 days; in tropical and subtropical climates, it should be kept wet for at
least 11 days. Once concrete dries, it will stop hardening; after this happens, rewetting will NOT t-e-start the hardening process.
317
Newly-laid concrete should be protected from the sun and from drying wind.
Large areas such as floors or walls that are exposed to the sun or wind should be
protected with some sort of covering. Protective covers often used are: canvas,
empty cement bags, burlap, palm leaves, straw, and wet sand. The coveriig shoiiid
also be kept wet so tkat it wig not absorb water from the concrete.
Concrete is strong enough for light loads after 7 days. In most cases, forms can
be removed from standing structures like bridges and walls after 4 or 5 days, but
if they are left in place they will help to keep the concrete from drying out. In
small ground-supported structures such as street drains, the forms can be removed
within 6 hours of completion provided this is done carefully. Plans will usually say
if forms should be left in place longer.
Concrete is usually expected to reach the strength for which it was designed
after 28 days. Concrete that is moist cured for a month is about twice as strong
as concrete that cures in the open air.
NGCONCRETE
Quick-setting concrete is often useful; for example, when repeated castings are
needed from the same mold. A concrete mixture that contains calcium chloride as
an accelerator will set about twice as fast as a mixture that does not. The mixed
batch must be put into the forms faster, but since quick-setting batches are
usually small, this is not a problem. Calcium chloride does not lessen the strength
of fully-cured concrete.
No more than lkg (2 pounds) of calcium chloride should be used per sack of
cement. It should be used only if it is in its original containers, which should be
moisture-proof bags or sacks or air-tight steel drums.
To add the calcium chloride, mix up a solution containing 1/2kg per liter (1 pound
per quart) of water. Use this solution as part of the mixing water at a ratio of 2
titers (2 quarts) per sack of cement (42.6kg or 94 pounds). Solid (dry) calcium
chloride must never be added to the concrete rnk only use it in solution.
sources:
VITA Volunteers:
John Bickford, Connecticut; Robert D. Cremer, New York; Kenneth D. Hahn,
California; R. B. Heckler, Florida
A Building Guide for Self-Help Projects, Accra, Ghana: Department of Social
Welfare and Community Development, l%l.
318
Design and Control
of Concrete
M&hues, Chicago: Portland Cement Association
&e of Concrete on Ihe Farm, Farmers’ Bulletin No. 2203, Washington, D.C.: U.S.
Department of Agriculture, 196.5.
Other Useful Publications:
Basics of Concrete, Ideas and Methods Exchange No. 49, Washington, D.C.: U.S.
Department of Housing and Urban Development, Divisios of international Affairs
Concrete Technology: Srudent Manual, Albany, New York: Delmar Publishers
H o b b s , W e s l e y . Making Qua& Concrete for Agricult~ml and Home Sfmchires,
University, Addis Ababa, Ethiopia: Haile Sellassie
Useful sources of information ou concrete, including how-to-do-it manuals:
Portland Cement Institute
18 Kew Road
Richmond
Johannesburg, South Africa
Institute del Cement0 Portland Argentino
San Martin 1137
Buenos Aires, Argentina
Cement and Concrete Association of Australia
147-151 Walker Street
North Sydney, Australia, N.S.W.
Associacao Brasileria de Cimento Portland
Caixa Postal 30886
Sao Paula, Brazil
Cement and Concrete Associatio?
52 Grosvenor Gardens
London, S.W. 1, England
The Concrete Association of India
P.O. Box 138
Bombay 1, India
Portland Cement Association
33 West Grand Avenue
Chicago, Illinois 60610 USA
Bamboo is one of the oldest materials people have used to increase their comfort
and well-being. In today’s world of plastics and steel, besides continuing to make
its traditional contributions, bamboo is growing in importance. Outstanding
varieties of bamboo from throughout the world are being tested to
find out how they can contribute
to local economies.
As the best species are identified
and disseminated, their use will
help to improve the lives of many.
With a few plants of superior
bamboos in the backyard, a family
will have at hand the wherewithal
to fence the garden, build a pigpen
or chicken coop, or add a room to
the house. The family will also be
able to increase its daily income by
making baskets or other specialties
for sale or exchange.
FIGU?E l--Frw
Posts
to rafters
.._~._
..___.suooortinq
1
,~.
and shea:hing. this
this cottage
cottage in the Ecuaduran
loulands ii
ii imx!e
iiade entirely
entirely of
of native
IIyLlv bamboo.
Guadua anwstifolia.
annucrifiilin. The
Thl? posts
on<t< may
mi serve
+?LIJ~
for five
f?'
years: the sidinq may remain in
serviceatJie condition
serviceahie
c"nd!tio" for
i
decades.
Bamboos are prominent elements in
the natural vegetation of many
parts of the tropical, subtropical
and mild temperate regions of the
world, from sea level to altitudes
or more than 13.000 feet (4WOrnl.
People have widened the distribution of many species of bamboo,
but some of the more valuable
species have not been distributed
as much as they could be.
Bamboo can be prepared for use in construction with simple tools. Once prepared,
bamboo can be used extensively in the construction of houses: in making foundations, frames, floors, walls, partitions, ceilings, doors, windows, roofs, pipes, and
troughs. For further detail, see Bamboo as a Building MateriaI, by F. A. McClure.
320
The entries that fokow explain:
0
0
0
0
Splitting and preserving bamboo
Bamboo joints
Making bamboo board
Bambco wags, partitions, and ceilings
NGB
BOO
litting Bamboo
To prepare bamboo for use iu construction, the cukns (stems) must be carefuky
split.
Tuols and Materials
Iron or hardwood bars, 2Scm (I”) thick
Ax
Steel wedges
Wooden posts
Splitting knives (Figure 4)
Several devices cau be used for splitting culms. When bamboo is split the edges of
the bamboo strips can be razor-sharp; they should be handIed carehrlly.
Splitting Small Culrns
Small cukus can be split to make withes (strips) for weaving and lashing:
0
Use a splitting knife with a short handle and broad blade to make four cuts,
at equal distances from each other, in the upper end of the cuku (Figure 2).
0
Split the cukn the rest of the way by driving a hardwood cross along the
cuts (Figure 3).
321
0
Using a long-handled knife (see Figure 4), cut each strip in half (see Figure
5). A strip of bamboo can be held on the blade to make it thicker and speed
up the work.
0
Use the sarnc knife to split the soft, pithy inner strip from the hard outer
strip (see Figure 6). The inner strip is usually discarded.
Splitting Heavy Culms
0
Build a cross of iron or
hardwood bars about 2Scm
(1”) thick, a n d p l a c e i t o n
firmly set posts about l&m
(4”) thick and 9Ocm (3’) kigh
(see Figure 7).
At the top end of the cukn,
use an ax to make hvo pairs
of breaches at right angles to
each other (see Figure 7).
Hold the breaches open with
steel wedges placed a short
.
.
F _.
arstance rrom ore end of tke
culm, until the cukn is on the
cross as shown irr Figure 7.
Push and pull the culm until
the cross splits the whole
culm.
322
0
To split the cukns again after they are split into four strips, use a simple
steel wedge mounted on a post or block of wood (see Figure 8).
0
Paired wedges solidly mounted on a block or heavy bench can be used to
split strips into three narrower strips (see Figure 9).
boo Preservation
Most bamboos are subject to attack by rot fungi and wood-eating insects.
Bamboos with higher moisture and starch content seem to bc more prone to
attack, and insect pests may be more of a problem in some seasons than others.
So bamboo should be cut if possible in the bugs’“off-season.” There are many
methods for making bamboo more resistant to attack. A simple method that
combines proper curing and the use of a pesticide (insecticide and/or fungicide) is
described here.
If bamboo is to be used to hold food or water, the only treatment recommended
is immersion of green bamboo in a borax-boric acid solution (see Bamboo Piping).
Tools and Materials
Machete and hacksaw for felling and trimming bamboo culms
Pesticidc-ckoice depends on the insect or fungus pests that are prevalent in your
area. Consult your local extension agent or farmers in the neighborhood about the
type and its use. Follow directions carefully.
Talcto mix with dry pesticide according to package instructions,, If talc is not
available, other dry dusty materials suck as finely powdered dried clay is used.
Dusting bag (made from cloth with an open weave)
Bamboo should not bc cut before it is mature. This is usually the end of the third
season. Freshly-cut bamboo culms should be dried for 4 to 8 weeks before being
used in building.
A clump-curing process tested by the U.S. Department of Agriculture Federal
Experiment Station in Puerto Rico kelps to reduce attack by insects and rot
fungi. The steps are:
323
0
Cut the bamboo off at the base, but keep it upright in the clump.
0
Dust the fresh-cut lower end of the culm at once by patting it with a
dusting bag filled with the pesticide-talc mixture. An alternative method of
dusting is to dip the ends of the cukns into a tray containing the mixture.
0
To keep the bamboo from beiig stained or rotted by fungi, raise each cukn
off the ground by putting a block of stone, brick, or wood under it.
0
Leave the culms in this position for 4 to 8 weeks, depending on whether the
weather is dry or damp.
The culms should be as dry as possible before being placed near buildings, where
wood eating insects usually are.
0
When the culms have dried as muck as conditions will permit, take them
down and trim them. Dust all cut surfaces immediately with the pesticidet.alc mixture.
0
Finish the seasoning in a well-aired shelter where the culms are not exposed
to rain and dew. Rain will stain the culms when they become dry.
This method will prevent damage by wood-eating insects while the cuIms are
drying.
If the bamboo is to be stored for a long time, stacks and storage shelves should
bc sprayed every six montks with the appropriate pesticide mixed in water or
light oil. Local conditions may shorten or lengthen the time between sprayings.
In both storage and use, bamboo cukns are best preserved when they are protected against rain in a well-ventilated place where they do not touch the ground.
BOO JOINTS
A number of methods of joining bamboo for making implements or for construction are shown iu Figures 10 and 11.
Tools and Materials
Bamboo
Lashing material cord or wire
Machete, hacksaw, knife, drill, and other bamboo working tools
Bamboo is useful for heavy construction because it is strong for its weight. This
is because it is hollow with the strongest fibers on the outside where they give
H
FIWRE 10.-Details of bamboo construction: n, fittinq and binding
culms at joints in roof and frame; 6, fitting and securino bamboo
boards of fioor; C and E, saddle joTnt; E and i, use of inset block
to support horirsntal load-bearing elem&s; G-and W, use of stump
of branch at node of post to support horizontal loax-bearing elements
326
the greatest strength and produce a hard attractive surface. Bamboo has solid
diaphragms across each joint or node, which prevent buckling and allow the
bamboo to bend considerably before breaking.
Any cut in the bamboo, such as a notch or mortise, weakens it; therefore, mortise
and tenon joints should not be used with bamboo. However, notches or saddle-like
cuts can be made at the upper ends of posts which hold cross pieces (see Figure
10, Can D).
Bamboo parts are usually lashed together because nails will split most culms. The
withes (strips) for lashing are often split from bamboo and sometimes from rattan.
When ali local bamboo yields brittle withes, lashing must be done with bark, vines
or galvanized iron wire.
In bending bamboo-for example, for the “Double Butt Bent Joint” in Figure D-you
can help to keep the bamboo from splitting by boiling or steaming it and bending
it while it is hot.
Local artisans often know the best species of bamboo and they have frequently
worked out practical methods for making joints.
Bamboo culms can be split and flattened to form boards for use in sheathing,
walls, or floors.
Tools and Materials
Machete
AAightweight, with a wedge-shaped head
Spud-a long-handled shovel-lie implement with a broad blade set at an angle to
work parallel to the surface of the board.
Large bamboo cuims
Not all of the tools listed above are necessary, but they speed up the work when
a large quantity is being produced.
0
Remove the thick-walled lower part of the culm.
0
Use an ax with a well-greased blade to split each node of the cuhn in
several places (see Figure 12). This should be done carefully to avoid
injuring one’s feet.
0
Spread the cuhn wide open with one long split.
327
0
Remove the pith at the joints with a machete, adz, or spud (see Figure 13).
0
Store the boards as shown in Fig
FIGI!!- 12.-An ax with a wellqreased hii is used in Ecuador
for nakinq bamboo hoards. Each
node ii snlit in several Places:
t!~en with one ionq split. the
Not
cult: is ~ilread wide own.
us& 'or hoards is the thickwalled bass, part of the c!lll~
FIGIJRE 13.-Final step in making a
bamboo hoard--removing diaphragm
fragments frov the newly o~fned
c,,,n. It may be done with a
machete, as here. or with an adie
01‘ a long-handled, shovellike
curved spud.
328
A~BOO WALLS, I’AR
ONS, AND CEILINGS
Bamboo buildings can be built to meet a variety of requirements for strength,
fight, ventilation, and protection against wind and rain. A few of the methods of
building with bamboo are described here.
The parts of a building that are not usually made from bamboo are the foundation
and the frame.
Both split and unsplit bamboo culms are used in buihiing. They can be used either
horizontal!y or vertically. Culms exposed to the weather, however, will last longer
if they are vertical because they wit! dry better after rain.
Tools and Materials
Local bamboos
Bamboo-working tools, such as machete, hacksaw, chisel, drill
Lashing material: wire or cord
Nails
Barbed wire
Plaster or stucco
alls
A method commonly used in Ecuador for making walls is to lash wide bamboo
strips or thin bamboo culms, horizontally and at close intervals, to both sides of
hardwood or bamboo uprights. The spaces between the strips or culms are fded
with mud alone or with mud and stones.
In Peru, BexibIe bamboo strips are woven together and then plastered on one or
both sides with mud.
An attractive but weaker wag can be built by using bamboo boards, stretched
laterally as they are attached, as a base for plaster or stucco. Barbed wire can be
nailed to the surface to provide a better bond for the stucco. The exterior can be
made very attractive by whitening it with lime or cement.
Partitions are usually much hghter and weaker than walls. Often they are no more
than a matting woven from thin bamboo strips and held in place by a light
framework of bamboo poles. Bamboo matting is often used to finish ceilings and
both interior and exterior walls; bamboos with thin-walled, tough culms are
usually used for this.
329
FIGURE 15--Types
of wall construction used with bamboo.
330
Ceilings
CeiJings can be built with small, unsplit culms placed close together or with a
lattice of lath-like strips split from larger culms. There should be some space to
let smoke from kitchen fires escape.
source:
McClure, FA. Bamboo a.r 4 Building Material. Washington, D.C.: Foreign
Agricultural Service, U. S. Department of Agriculture, 1953, reprinted 1963 by
Office of International Housing, Department of Housing and Urban Development.
Sources of information of bamboo are:
Forestry Division
Joint Commission on Rural Reconstruction
37 Nan Hai Road
Taipei, Taiwan
Forest Research Institute
P.O. New Forest
Debru Dun, India
Tropical Development & Research institute
55-62 Grays Inn Road
London, WC 1
England
Federal Experiment Station in Puerto Rico
U.S. Department of Agriculture
Mayaguez, Puerto Rico
Soil is a universal building material and is one of the oldest known to humanity.
Simple soils (without additives), or soils improved by adding stabiizing materials
such as bitumen or cement, are suitable for homes, schools, roads, and other construction.
For construction purposes, soil is usually formed into blocks. Two general types of
blocks are described here: adobe block and stabilized earth block formed under
great pressure. Adob, blocks are made from moistened soil that may be mixed
with straw or other stabilizers. They are formed without pressure and usually
cured in the sun. Stabilized earth blocks (sometimes called rammed earth blocks)
are made from soil mixed with stabilizing material such as Portland cement,
formed into blocks under high pressure, and cured in the shade.
Low cost is a primary advantage of soil biock construction. An overall cost
reduction of about 50 percent over conventional construction can bc realized.
Other advantages are that building materials are usually readily available and
little skill and training are required for their use. The material is culturally
acceptable in nearly all countries, including the United States.
The composition of soil varies from one region to another, and with soil depth. In
any one area, it may be desirable to mix soils from several locations or depths to
obtain a composition more suitable for construction.
The primary components of soil that are of importance in construction are sand,
clay, and siit. (Organic materials are also found in surface soil. These tend to
reduce the quality of the blocks.) The fraction of clay in the soil is important
because it acts to bind the larger soil particles together but the clay content
should not exceed one-third. Above that, deep cracks and weakening of the dried
blocks are likely to occur. Silt, which is usually found mixed with the sand,
should not exceed one third because silt is vulnerable to erosion from wind and
rain.
Proportions of sand, silt, and clay vary widely. One of the few soil block
standards that exist is California’s Uniform Building Code Specification, which
332
recommends 55 to 75 percent sand, and 25 to 45 percent clay and silt. A good
mixture for most blocks might be:
sand.... 65 percent
clay.... 20 percent
silt.... I.5 percent
To assure that the composition to be used is suitable for construction, several
test blocks should be produced using various mixtures. After curing, the test
blocks should be hard and resist a scratch or prick from a knife. Striking two
compressed/stabilized blocks together should produce a click sound. The blocks
should sustain a drop of two feet (.6 meter) without breaking. If the block
crumbles or breaks, the sand or organic content is probably too high, and clay
should be added to the mix. On the other hand, if large cracks appear during
curing, the clay content is probably too high and sand should be added to the
mix.
SING THE SOIL
Soil tests should be made before any block production is started. If the testing is
not done first, a great deal of time and money may be wasted in the production
of unusable blocks. The agricultural departments of most countries can provide
laboratory tests at modest costs. If field tests must be made instead, some simple
methods to determine the soil’s suitabiity can be tried.
Composition Test
0
Pass the soil through a l/4” (6mm) screen to remove stones and other
large particles.
0
Pour the screened soil into a wide mouth jar until it is half full.
0
Fill the jar with water. (You may add two tablespoons of salt to make
the soil settle faster)
0
Cover the jar tightly, and shake vigorously for two minutes.
0
Let settle for at least 30 minutes.
The small gravel and sand will settle rapidly to the bottom of the jar. The clay
and silt will settle more slowly. After 30 minutes, the jar should look like the
drawing in Figure lc. Hold a scale vertically on the side of the jar to measure
the amounts of sand, silt, and clay. Record the sample number and the amounts.
Then convert the amounts to percentages.
Clay/Silt
Sand
W&W1
1. fill the jar
halfway with
earth.
2. Add 2 teaspoonfuls
of salt; fill with
water; cover jw
and shake far
2 minutes.
3. Let settle for
about 3F minutes.
Figure 1. Soil Particle Composition Test
In addition to the soil composition test, a compaction test should be done to
determine the packing quality of the clay, which depends on the percentage of
clay in the sample and the quality of the clay itself. A simple field test cart be
done as follows:
0
Take a haudful of dry, screened earth and add some water to it until it
is damp enough to form a ball when squeezed in the hand, but not so
damp that it leaves more than a slight trace of water in the hand when
squeezed.
0
Drop he ball from a height of about 3 feet (1 m) onto hard ground. If
the ball breaks into a few small pieces, the packing quality is good to
fair. If it disintegrates the quality is poor and a soil mix with more
clay should be prepared and tested.
If stab&zing material such as Portland cement is to be added to the soil, a
shrinkage test of the soiI should also be made This test will indicate the
suitability of the soil and also the best cement-to-soil ratio to use. It measures
the shrinkage of soil that contains no stabilizer. As shown in Figure 2, the box
should have these inside measurements: 24” x l-l/2” (4 cm x 4 cm x 60 cm).
Figure 2. Box for Box Test
334
To test soil with this method:
0
Oii or grease the inside surface of the box thoroughly.
0
Pack the box weII with moist soil (previously passed through a 6mm to
lttmm (l/4” to 3/8”) mesh screen. The soil should be moistened to pack
well, but it should not be muddy.
0
Tamp, especially at the comers.
0
Smooth off the surface with a stick.
0
Place the box in the sun for three days or in the shade for seven days.
It should be protected from rain.
Measure the contraction (shrinkage) by pushing the dried sample to one end of
the box.
s
Cement to soil Ratio
Not over l/Z (15 mm)
1 part to 1.8 parts
Between l/2” and 1” (15 mm - 30 mm)
1 part to 16 parts
Between 1” and l-l/z (30 mm - 45 mm)
1 part to 14 parts
Between l-l/T and 2” (45 mm - 60 mm)
1 part to 12 parts
When time is used instead of cement use do&k the amount. Do not use the soil
if it has many cracks (not just three or four); if it has arched up out of the box;
or if it has shrunk more than Z (60 mm).
KING ADOBE BLOCKS
To make adobe blocks, add water to the soil mix until it is plastic enough to
mold. Water content should be between 16 and 20 percent of the soil by weight.
The water and soil must be throughly mixed. Since ah except the dryest soils will
already contain some water, it is advisable to test the sample for water content
first. Do this by weighing a soil sample, drying it, and then reweighing it to
cahulate water content.
Even the best adobe blocks may develop some cracks. To reduce the number of
cracks, and aho to make the blocks more weatherproof, stabilizing materials are
often added to the mix. When stabilizers are used they must be thoroughly mixed
335
with the soil or much of their benefits will be lost. The most widely used
stabilizers are straw, rice husks, asphalt emulsion, Portland cement, and time.
Asphalt emulsion can improve the waterpreoling quality of the blocks, and also
their elasticity and toughness, so that they are less likely to break during
handling. Add asphalt emulsion between 5 and 15 percent by weight to the dry
soil mix. For soil mixes with high sand content (55 to 75 percent sand) the
asphalt emu&on should be nearer the 5 percent figure.
Portland cement stabilizers improve the bonding properties and add strength to
the blocks. Only 5 to 6 percent cement by weight is needed for soil mixes with
high sand content, but up to 20 percent by weight may be required for soils bigb
in clay and silt. If the soil requires a large percentage of cement, it can be
comb&d with an equal amount of lime, which costs less.
Equipment required for making adobe. blocks is shown in Figure 3. The number of
shovels, molds, etc, will depend on the size of the job. Using this equipment, and
sunolied with the mixed adobe. a team of two molders can produce about 1,OOO
blocks (10 x 4 x 14”) per day.
Wheelbarrow
Shovei
SCPSI
Hopper
Wheelbarrow
Mold
Figure 3. Equipment to Make Adobe Blocks
Select a large level area for mixing, molding, and curing the adobe. Mixing can be
done in a hopper, or by making a shallow mixing pit in the ground. If possible,
make the blocks near the construction site. If the mix is lumpy even after
repeated working, let it soak overnight.
Block molds can be made in various sizes to lit the needs of the construction.
But adobe blocks should not be larger than glcm (32”) around the outside. A gang
form that will mold eight blocks of .009 cu. meter (one l/3 cubic foot) can be
operated by one worker. Before starting work, the mold should be thoroughly
soaked with water to prevent the adobe mud from sticking to it.
3%
Production steps are as follows:
0
Rake or drag a large ground area level.
0
Place mold on level area, on a piece of building paper if available, and
dump the mud from a wheel barrow or hopper into the mold. Work the
mud fnmly into all comers of the mold.
0
Scrape off excess mud from top of mold to leave a smooth, flat
surface.
0
Remove the mold by lifting it slowly and evenly up from the ground
level. Move the mold to the next adjacent level area and repeat the
process.
Blocks must be allowed to cure for about 14 days. After several days, the
partially cured blocks may be carefully turned on edge so they dry more evenly.
On very hot days, in direct sunlight the blocks may dry too rapidly and crack. To
prevent this, cover the blocks with paper, leaves, or straw. Since rain will
destroy unstabilized blocks, waterproof tarps may be needed.
To store the blocks after they are cured, stack them on edge. If left stacked flat,
they will break of their own weight.
NG ~O~~BESSED EAR
BLOCKS AND TILES
Compressed earth blocks can be made by ramming the earth in forms, or by using
a block making machine, such as the CINVA-Ram Block Press. Blocks made by
machine are less costly and have superior uniformity.
Some machiie made blocks tested by the U.S. National Bureau of Standards had
compressive strengths up to 808 pounds per square inch (56 Kg/cm), with 300 to
500 psi strength as the average. (This is three to eight times the compressive
strength of adobe blocks). These test blocks contained SO percent sand, and 50
percent clay and silt, mixed with 8 percent cement by weight.
Although one worker can make blocks with the CINVA-Ram, the process is best
as a team effort with two to four workers each performing one task. (It is good
to rotate tasks among the workers on an hourly or daily basis.) The CINVA-Ram
is portable and can easily be moved about the work site to reduce carrying raw
materials or finished blocks.
Floor tiles can also be made with the machine, using inserts to adjust for the
thinner tiles. The mixture for floor tiles is two parts line sand to one part
cement. Mineral coloring sari be added to produce colored tiles.
337
Average production rates and cement required arc:
0
Average number cement blocks or tiles
(made by two workers per day)
300-500
0
Average no. blocks for a two room house
2!ioo
0
Typical block size: !Ix14~29cm (3l/2%-l/z”xll-l/2”)
1OxlMOcm (4x6xl2 inches).
which lay up to:
0
Average number blocks per 100 Ibs cemenl:
1543
Stacking the blocks for curing requires care. The blocks should be stacked on
edge on clean planks. If planks are not available, stack on ifat ground that has
been covered with paper or leaves. The blocks should be covered with plastic or
old cement bags that have been cut open. Stacks should not be greater than five
blocks high, and some air space should be left between the blocks. For the fust
four days, sprinkle the bkxks tightly with water to prevent them from drying too
quickly. The total curing time is about 14 days, depending on the weather.
LDING WITH STABILIZED EA
A fum, flat, water-resistant foundation should be built frst using biocks with a
bigher percentage of cement and lime. Blocks should be joined by mortar about
one half inch (1.25 cm) thick. The recommended mortar mix (by weight) is:
0
0
0
one part cement
two parts lime
nine parts soil (used to make the blocks)
Let the applied mortar dry for about a week; then paint the mortar joints with a
thin, milk-like mix of cement and water. Stir this mixture often. After a day, the
ftished walls can be coated (3 coats recommended) with this same mixture, or
with a coat of lime. Or, a waterproofing coat of silicone based wash may be
added.
sources:
Alfred Bush, Chris Abrens, Balla Sidibe, VITA volunteers
References:
Making Building Blocks with the CIWA-Ram Biock Press. Arlington, Virginia:
VITA, W?i’.
338
Bush, Alfred. Understanding Stabilized E&h Construction. At!&ton, Virginia:
Volunteers in Technical Assistance, 19%%
“Building Materials and Structures Report BMS 78”, Gaitbersburg, Maryland US
National Bureau of Standards
Sidibe Balla. Understanding Adobe. Arlington, Virginia: Volunteers in Technical
Assistance, 1985
U.S. Agency for International Development, “Handbook for Building Homes of
Earth”, Action Pamphlet No. 4200.35, Woifkill, Dunlop, Callaway, Washington, DC,
Peace Corps, 1979.
Ferm, Richard. Stnbilized Emh Construction: An Insbuctional ManuoL Washington,
D.C.: The International Foundation for Earth Construction.
~f~~uf8ctu~~
The CINVA-Ram Block Press is manufactnred in Bogota, Colombia, by METALIBEC,
SA. The press may also be purchased in the USA for $4C!S (1987) from S&wader
Bellows Inc., 2.00 West Exchange Street, Akvon, Ohio 44369-0631. Telephone: (216)
375-5202. Siiiku, locally manufactured presses cart often be found in other
developing countries.
CAVERN GLUE
Strong water-resistant casein glue, which produces joints as strong as or stronger
than most of the common species of wood, is made from skim milk and common
chemicals. Casein glue joints are water-resistant but not waterproof. They will
withstand occasional soaking, but if soaked and dried, they will fail.
Tools and Materials
Mixer: paddle and bowl of wood, iron, or other material that won’t be corroded
by the alkali in the glue.
Containers
Sde or balance
Skim milk
Hydrated lie, Ca(OH)> also known as slaked lime. This should be a good quality
lie: high in calcium and low in magnesia.
Silicate of soda, also called “waterglass” or sodium silicate. The preferred solution
should have a density of about 40 degrees Baume (Density 1.38) with a ratio of
silica to soda of approximateIy 3.25 to 1.
Cupric cbloride, CuCI2 (cupric sulfate, CuSG4, also caged “blue vitreol” can be
substituted)
Wine screen or ?&mesh sieve with 0.033” (0.84mm) openings
Cloth for queering moisture out of curds
ng Casein Powder
Casein powder is made from skim milk by the following steps:
0
Let the milk sour naturally or scur it by slowly adding dilute hydrochloric or
sulfuric acid until curds form. The milk will separate into curd and whey.
0
Dram the whey off. Wash the curd by adding water and draining it off.
0
Press the curd iu a cloth to remove most of the moisture.
0
Break the curd into small particles and spread it out to dry.
0
Grind the dry curd to a powder and pass it through a U)-mesh screen.
340
aping Casein Glue
ProporUons fur Glue
Formula 11 (not restricted by patent), U.S. Forest Products Laboratory
Partsby Weight
Caseiu (powder)
Water
Hydrated Lime (powder)
Water
Silicate of soda (solution)
Cupric chloride (powder)
Water
100
I.50 to 250
mto30
100
70
2to3
3oto50
If hydrated lime is not available, quickliie (CaO) can be used in the following
ways:
A mixture of 15.1 parts CaO and 104.9 parts water by weight can be substituted
for 20 hydrated lime and 100 water.
A mixture of 23.5 CaO and 106.5 water can substitute for 30 hydrated lime and
100 water.
When CaO is added to the water, it must be stirred for 15 minutes to get a
uniform slurry.
The bowl and paddle for m’kdng casein glue should be made of wood, iron, or
some other material that will not be corroded by the alkali in the glue and can
be cleaned easily. All the ingredients should be weighed rather than measured by
volume so that the proportions will be accurate. It is especially important not to
use too much water.
0
Put the casein and water in the mixing bowl and mix them well enough to
distribute the water throughout the casein. If the easein used has been
ground to pass through a 20-mesh screen, let it soak in the water for I5 to
30 minutes before going on to the next step. The soaking period can be
reduced if the casein is ground more fmely.
0
Mix the hydrated Lime and water in a separate container.
0
Dissolve the cupric chkxide in water in a separate container and add it,
while stirring, to the moistened casein.
341
0
Immediately pour the hydrated time-water mixture into the casein mixture.
When casein and lime are mixed, large lumps form at fust but they break up
rapidly and finally disappear. The solution becomes somewhat thinner.
Thorongb~bveryimportantatthispoint.
0
About a minute after the lie is mixed with the caseiu, the ghte begins to
thicken. Add the silicate of soda at this time.
0
The glue will thicken momentarily, but continue stirring the mixture until
the glue is free of lumps. This should take no longer than 20 minutes.
If the glue is a little too thick, a small amount of water can be added. If it
is too thin, start the whole process over again, using a smaller proportion of
water.
The working life of glue is the length of time it stays fluid enough to be
workable. The silicate of soda extends this time. The glue produced by the
formula used Here will be useable for more than 7 hours at temperatures between
21C and 24C (70F and 75F). Working life will be shorter at higher temperatures.
Casein glue is fluid enough to be spread by a roll spreader or by hand ui& a
brush or scraper. Very heavy spreads are wasteful because excess glue will be
squeezed from the bond. Very light spreads can produce weak joints. A suggested
minimum is 29.5 kilograms (6.5 pounds) of wet glue per 92.8 square meters (1,000
square feet) of glue-joint area.
To obtain good contact between wooden members of a joint, apply pressure while
the glue is still wet. There is not much drying before 15 or 20 minutes. Under
ordinary circum:!ances, a pressure of 105,450 to 140,600 kilograms per square
meter (150 to XK? pounds per square inch) will give good rest&s.
If casein glue joints are exposed for long periods to conditions that favor the
growth of molds, they wig eventually fail. The joints will be permanent only if
the moisture content of the wood is not greater than 18 to 20 percent for long
or repeated periods.
Dry casein can be kept for a long time in a cool, dry place.
sourl!es:
Carein Glues: Their Manufacrure, Prepamion, and Application. Madison, Wisconsin:
Forest Products Laboratory, Forest Service, U.S. Department of Agriculture.
Dr. Louis Navias, VITA Volunteer, Schenectady, New York
342
LIQUID FISH GLUE
Cold liquid glue can be made from the heads, skins, and skeletal wastes of cod,
haddock, mackerel, hake, and pollack. A great advantage of liquid fish glue is
that it remains in liquid form and consequently has an almost permanent working
life. An advantage of using it to make wood joints is that it sets slowly and
therefore penetrates further than other glues before hardening.
Since liquid fish glues are not very water-resistant, a casein or other glue should
be used where water-resistance is needed. Thick Fish glues produce stronger joints
than thin solutions.
Tools and Materials
Fish heads, skins, and skeletal waste
Large pan for washing fish parts
Steam bath or double boiler
Paddle for stirring
Fihcr. soch as cheese cloth
To make the glue:
Wash the fish material thoroughly to remove blood, dirt and salt. If salted
fish are used, wash them in running water for 12 hours.
Once the material is washed and drained, put it into a large container, cover
it with water, and cook it slowly at a low temperature, about 60°C (14OOP).
Cooking in an open pot helps to eliminate unpleasant odors in the glue. A
steam bath or double boiler should be set up so that live steam surrounds
the pot. Stir the contents occasionally. The length of the cooking period
varies with the kind of fish material used.
Let the cooked mixture settle. Skim off and discard the grease. Pour the
remaining contents of the pot onto a filter.
Concentrate the filtered fluid by slow heating to the desired thickness. This
is the glue; it can bc stored in convenient containers.
Take the fish material remaining on the filter and cook it again to extract
more glue, then repeat the filtering and concentrating.
EncycIopedia of Chemical Technology.
Paul I. Smith. Glue and Gelafine, Chemical Publishing Co., Inc., 1943.
Thomas D. Perry. hfo&m Wood Adhesives. Pitman Publishing Co., 1944.
as
ines
g
~L~~~ER TYF’E CLOTHES WASHER
This hand-operated washer, which is simple for a tinsmith to build, makes washing
clothes easier. It has been used successfully in Afghanistan.
Tools and Materials
Tinsnips
Pliers
Hammer
Soldering equipment
Heavy galvanized sheet metal:
14Ocm x 70cm (55 l/8” x
27 9/W) for tub
1001~1 x 5Ocm (39 3/l” x
1 9 11/N’) for lid and
bottom
36cm x l&m (14 3/16” x
7 l/16”) for agitator
W o o d e n h a n d l e 14Ocm (55
l/V) long, about 4cm (1 l/2”)
diameter
Making the Washer
Figures 1 to 4 show how this washing machine
is made. The tub, lid, and agitator are made
of heavy galvanized sheet metal.
WOODEN HANDLE .
--I
/
Using the Washer
To operate the washing machine, work the agitator up and down with a quick
motion but with a slight pause between strokes. The movement of the water
caused by the agitator will continue for a few seconds before additional agitation
is needed. On the upward stroke the agitator should come completely out of the
water. The agitator should not hit the bottom of the tub on the downward stroke
because this would damage both the tub and the clothes.
Dale Fritz, VITA Volunteer, Schenectady, New York
HAND-OPERATED WASHING MACHINE
This easily-operated washing machine can be built by a good carpenter from
materials easily found in most countries. It is easy on clothes, effective, and
sanitary. The machine, which can take 3-kilogram (6-pound) load of clothes, can
be shared by several families.
347
Clothes will last much longer if they are washed in this washing machine rather
than beaten or scrubbed on rocks. Washing with the machine is also much less
work. Under test conditions, a cornparis& with standard electric commercial
washers was very favorable. If the cost of the machine is too much for one
family, it can be used by several. However, if there are too many users, competition for times of use will become keen and the machine will wear faster.
The machine reverses the principle used in the usual commercial washer, in which
the clothes are swished through the water for various degrees of a circle until
the water is moving, and then reversed. In this machine, the clothes stay more or
less stationary while water is forced back and forth through the clothes by the
piston action of the plungers. One plunger create, suction as it rises and the
other plunger creates pressure as it moves downward. The slopes at the ends of
the tub bottom help the churning action of the water caused by the plungers (see
Figure 1).
-IWO PIECE COVER ~~~~~
COVER IN PLACE
REMOVABLE
PIN
~~---
348
A rectangular tub is best for this method of operation. This is fortunate since the
rectangular box is easy to build. In general, any moderately strong wood that will
not warp excessively (such as cedro in Iatin America) will be satisfactory. The
sides should be grooved for the ends and bottom of the tub as indicated in Figure
1 and bolted with threaded rods extending through both sides with washers to
draw them tight. The bolting is necessary to prevent leaks.
The size described in the drawings is large enough for an average family in the
United States. The same principle may be used for a larger or smaller machine
provided the basic proportions are maintained. The tub should be slightly less
than half as wide as it is long to get a proper surge of water. The pistons should
be wide enough to move witbin a couple of inches of each side of the tub. The
lever pivot should be high enough to permit the plungers to move up and down
several inches without the edge of the lever hitting the edge of the tub. Liiewise, the length of the rods on the plungers must be such that the plungers go
well into the water and the clothes, and then come completely out of the water
at the highest position.
Tools and Materials
Tub Constnretion - Moderately firm soft-wood free from large heartwood growth:
Tub
Sides-2 pieces, 2.5 x 45.7 x %Scm (1” x 18” x 38’)
Ends-2 pieces, 2.5 x 30.5 x 40.6cm (1” x 12” x 16”)
Bottom-2 pieces, 2.5 x 15.2 x 40.6cm(l” x 6” 16”)
Bottom-l piece, 2.5 x 40.6 x66&m (1” x 16” x 26”)
Legs-4 pieces, 2.5 x 10.2 x 76.2cm (1” x 4” x 30”)
Round Plungers
2 pieces, 2.5 x 25.4cm diameter (1” x 10” diameter)
2 pieces, 3.8 x 12.7cm diameter (1.5” x 5” diameter)
Cover (may be omitted)
2 pieces, 2.5 x 20.3 x 91.4cm (1” x 8” x 36”)
6 pieces, 2.5 x 7.6 x 20.3cm (1” x 3” x 8”)
Operating parts - Moderately firm hardwood:
Lever-l piece, 2.5 x 7.6 x 122cm long (1” x 3” x 48”)
Plunger stems-2 pieces, 2.9cm square 38.lcm long (1 l/8” square W
h9
r
349
Uprights
2 pieces-2.9 x 7.6 x 61.&m long (1 l/8” x 3” x 24”)
Pivot and Handle
2 pieces, 3.2cm diameter x 45.7cm long (1 l/4” diameter x 18”)
Metal Parts
Plunger connections
4 pieces iron or brass plate, .64 x 3.8 x 15.2cm long (l/4” x 1 l/2” x
6’)
10 rods, 3.6 or .79cm diameter (1.4” or 5/W) 45.7cm (18”) long with
threads and nuts on each end-iron or brass
20 washers about 25cm (1”) diameter with hole to fit rods
1 rod, 64 x 15.2cm long (l/4” x 6”) with loop end for retaining pivot
6 bolts, 64 x 5.lcm long (l/4” x 2” long)
24 screws, 4.4cm x #10 flat head (I 3/4” x #lo)
50 nails, 6.3&m (2 l/2”)
Strip sheet metal with turned edge, 6.4cm wide, 152&m long (2 l/T
wide, 72” long)
Small quantity of loose cotton or soft vegetable fiber for caulking seams
f/GL/RE
J
F/l?%wzGL
---‘FURNED ECGF
SHEET METAL EDGE
PLUNGER SECTION
TOP VIEW OF
PLUNGER
350
MinimnmToolsNecdcd
Tape measure or ruler
Hammer
Saw
Wood chisel 1.3 or 1.9cm wide
(l/2” or 3/4”)
Screwdriver
Pliers
Adjustable wrench
0.64cm (l/4”) drill, gimlet or similar tool
Draw knife or plane and coping saw
aking the Washing Machine
Mark and groove sides for end and bottom members (see Figures 1 and 4).
Drill holes for cross bolts.
Cut off corners and trim ends of side member to length.
Bevel ends and bottom pieces to fit into groove in side members.
Miter bottom and end members together.
Assemble and bolt.
Cut and install legs.
Caulk seams between ends and bottom members with loose cotton or other
vcgetable fiber to make seams water-tight. If joints to side members are carefully
made, they may not need caulking.
Bore hole and make plug for draining tub. NOTE: This is shown on side in
drawing but it is better in bottom of tub.
Make and install upright pivot members.
Make and install plunger lever. NOTE: The cross pivot member (round) should be
shouldered or notched at each pivot to prevent side movement.
Make plungers and install (see Figures 2,3 and 4).
-,WTRA HQLFS FDR ADJUSTMENT
Using the Washing Machine
Here are several suggestions for using this washing machine: Fii the washer with
approximately 55 liters (15 gallons) of warm or hot water depending on what is
available. Try to remove stains in clothing before putting it in the wash water.
Rub soap into the areas of garments like cuffs and collars that come in close
contact with the body. Soak very dii clothes before putting them in the washer.
Soap can be dissolved by shaving it into strips and then heating it in a small
quantity of water before adding it to the wash water. A 3kg load of clothes is
the right size load for best cleaning. Wash at a moderate speed, about 50 strokes
a minute, for ten minutes-longer if it seems necessary.
If more than one load of clothes is to be washed, some basic procedures wig help
to simplify the job and conserve w~aier. (Water used for washing and rinsing can
help irrigate a garden plot.)
Fist divide the clothes so that whites and light colors are separate from dark
clothes. Try to keep smaU items together so they won’t get lost. Heavily soiled or
greasy clothes should be washed alone.
352
Wash the white or light-colored things first in the hottest possible water (remember that you will have to handle the wet clothes-don’t get the water too hot!),
then move on through darker clothes. The water will become discolored. Much of
the color is dirt, of course, but some is excess dye. The lightest clothes are
washed in the cleanest water; dark clothes won’t be as noticeably affected by the
coloring matter in the water.
After each load, the wash water can be warmed, if necessary, by adding some
boiing water. A bit more soap may also be needed. Probably at least three loads
of clothes-depending on how duty they are-can be washed before the water
becomes too murky to bc used again.
The clothes, of course, will have to be rinsed thoroughly. Soap or detergent
residues can damage fabrics and may cause allergic reactions. Two rinses are
usually necessary.
Probably the easiest, but most expensive, procedure is to have separate tubs for
rinsing. Tubs can be of either wood or galvanized metal, and may be used for
other purposes provided they are cleaned thoroughly on wash day.
When clothes are ciean, squeeze out as much excess water as possible and put
them into the rinse water. The next load of wash can be soaking while the fist
is rinsed and put to dry. Then the clothes in the machine are washed and the
process repeated.
!f no separate rinse tubs are available, wash up to three loads (if the water stays
clean enough that long) and set each aside. Be sure to keep loads separate, as
dyes from wet clothes may stain tighter colored fabrics. Then drair, and rinse the
washing machine and refill it with clean water. Rinse the clothes,*again starting
with the lightest colored load, and put out to dry. Repeat the whole wash-rinse
process as often as necessary.
Another method is to wash the first load of clothes and squeeze out excess water.
Drain the wash water and refill the machine with clean warm water. Rinse the
clothes, squeeze out excess water, and put to dry. Warm the rinse water with
boiling water and and some soap. Then wash the next load. Repeat the procedure
as often as necessary.
After washing and rinsing the clothes, rinse the washer clean and then replace
the stopper. To keep the wood from drying out and causing the tub to leak, put
about 3cm (1”) of water in the washer when it is not in use.
source:
Petit, V.C. and Holtzclaw, Dr. K. How to Make a Washing Machine. Washington,
D.C.: U.S. Agency for International Development.
~RE~ESS COOKER
Where fuel is scarce, this easy-to-build fueless cooker can be a contribution to
better cooking. It keeps food cooking with a small amount of heat stored in hot
stones; loss of heat is prevented by
a thick layer of insulating material
around the pot.
Fiieless cookers have been successfully used in many countries. Once
the principle of operation, heat
retention through insulation, is
understood, the reader may develop
plans that are better suited to local
resources than those described
here. In some countries, fueless
cookers are built into the ground.
In others, they are built from
surplus tin cans, one can fitted
into another tin can or box but
separated by paper, sawdust, or
other layers of insulation.
Materials
Outside container with lid, 37Scm to 6Ocm (15” to 24”) in diameter
Inside container or well, at least 15cm (6”) smaller in diameter and 15cm (6”)
shorter than outside container
Cooking pot with lid
Cloth for cushion, 1.2 square meters (1 l/2 square yards)
50 sheets newspaper or other insulation
Cardboard
Sand, .95 liter (4 cups)
Cement, .95 liter (4 cups)
Oilcloth for collar (optional), 0.4 square meters (l/2 square yard)
354
The outside container can be a wooden bucket, kerosene cart, garbage can, packing crate, or even a hole in dry ground. The inside container or well can be a
pail or can with a lid. It must allow for 7Scm (3”) of insulation between it and
the outside container and should hold the stone and cooking pot without much
vacant space.
Insulation can be made of shredded newspapers, wool, cotton, sawdust, straw,
rockwoo!, fiberglass, or other material. The insulation should be at least 7Scm
(3”) thick on all sides, top and bottom. Be sure that it is very dry. The bottom
layer of insulation must be strong enough to support the weight of the well,
stone, and cooking pot. A natural stone carved to shape or a piece of concrete
may bc used for the heating stone. The cushion is a cloth sack, 7Scm (3”) thick,
filled with shredded newspapers or other insulation. It should fit snugly in the
outside container. The cooking pot must have a tight lid, and fit nicely into the
well when the stone is in place. Be sure it can be removed easily when full of
hot food.
ing
the Fireless Cooker (gee Figure I)
Wash and dry the containers and lids.
‘~
Cut l&m-wide strips of newspaper several layers thick, RoU each into a cylinder
with a center hole no greater in diameter than a pencil. Pack these on end into
the bottom of the outside container. They will support the well, stone, and pot.
Put the weU in place. Pack insulation around it to within Icm (l/2”) of the top.
Make a cardboard collar covered with oilcloth. Though this is not necessary, it
improves appearance and cleanliness.
Place about 2.5cm (1”) of clean sand in the bottom of the well. This will prevent
the hot stone from scorching the paper rolls and possibly causing a fire.
To make a concrete heating stone, place a Scm-wide cardboard band or collar on
heavy paper or board to form a circle the size of the stone desired. Mii .95 liter
(4 cups) each of cement and sand (the sand should first be washed free of silt);
then mix in enough water (about .35 liter or 1 l/2 cups) to form a stiff mush.
Fii the collar, casting in a wire handle for lifting the hot stone. Let the stone
stand for 48 hours, then remove the collar, place it in cold water, and boil for 30
minutes. Cool it slowly.
Using the Fireless Cooker
It is important to keep the cooking pot and weU carefully washed and open, in
the sunshine if possible, when not in use. The cooker’s lid should be left partly
open and the stone kept clean and dry.
355
It is not necessary to use much water when cooking in a fireless cooker for there
is little loss by evaporation. Most foods should be brought to a boil and cooked
for 4 to 5 minutes on another stove. The heating stone is heated and placed in
the cooker. Then the covered cooking pot is set on the hot stone in the cooker
and the lid is placed on the well. Cereal may be left in the cooker all night. Rice
and cracked or whole wheat are especially good. Beans should be soaked over
night, boiled for 5 minutes and then placed in the cooker for 4 to 5 hours. Dried
fruit should be washed,’ soaked for an hour in 2 parts water to 1 part fruit,
boiled for 5 minutes, then placed in the cooker for 4 hours.
source:
Home Making Around the World Washington, D.C.: U.S. Agency for International
Development, 1963.
CHARCOAL OVEN
This simple charcoal-fired oven is made from two S-gallon oil tin cans. With
practice, all types of baking and roasting can be done effectively.
Tools and Materials
Tin snips
Heavy knife
Nail for scriber and punch
Hammer
Screwdriver
Pliers
Bricks and sand
Metal bar, 2Ocm (7 5/f?) long with
square edge for bending tin
S-gallon cans (2)
Tm (for shelf, top strip, and latch)
Light rod, 5Ocm (19 5/8”) long
Light hinges with bolts (2 pairs)
Stove bolts, 5mm x 13mm (3/16” x
l/2”) (15)
How To Build the Charcoal Oven
Mark the two 5-gallon cans for cutting (see Figure 2), making sure that the
second can is marked the reverse of the lirst. Do not cut the corner that has a
vertical seam: Besides bcmg hard to cut, the seam will strengthen the oven. The
material removed will be easier to make into doors if it is seamless.
356
Cut along the marks with a heavy
knife, keeping the cut-out sections
as undamaged as possible. Fold the
edges of the oven-door openings
back lcm (3/8”) (see Figure 2).
6
smr C/lM~
TDCEwm2
F,~,~REz. CUT 0”~ .%-GALL•
CAN A5 S”OWN ASOY.. TYE
0?-ddE.v CAN IS co?- jTyE
rmvE@SE OF THE ONE u.ce.5
With the nail, punch 5mm (3/16”)
holes around the opening in the
side of the can to be used for the
left hand section of the oven (see
Figure 2). Place the second can
against the one just punched and
mark the holes with the nail. Punch
holes in the second can. Bolt the
cans together, using 10 stove bolts.
Flatten sections cut from cans and mark for doors (see Figure 3). Using the tin
snips, cut doors to size and fold back the lcm (3/g) edge (see Figure 4). Position
doors as shown in Figure 1, butting the edge of each door against the edge of
the opening to which it will be attached. Install hinges.
The door latch (see Figure 1) is made by folding a 6cm x 38cm (2 3/g x 15”)
strip three times lengthwise, forming a piece 2cm (3/4”) wide. An &m (3 l/4”)
piece is cut from the end of the folded strip to form a hook-which is then bolted
(use 2 bolts) to the center of the door on the right. The 3Orm (11 3/4”) piece is
bolted loosely to the center of the door on the left. The unattached end is bent
up to form a handle.
A triangular-shaped hole at the top of the doors where the two cans come
together must be plugged to keep heat from esraping. This can be done by
shaping a small piece of tin to fit the opening, with a tail that is inserted
between the joined cans to hoid it in place.
Construct shelf as shown ;:r: Figure 5 and install (see Figure 1). The shelf should
be bolted in place l&m (5 7/8”) from the floor of the oven (see Figure 5).
357
T h e o v e n should be cleaned
thoroughly and heated at least once
before use to bum out any
remaining oil in the cans.
F/ciUUF.s. sv/LD,NG 4 5HE‘F.
ow to Use the Charcoal Oven
Place lcm (3,W) of sand in the bottom of the oven and place the oven on bricks
as in Figure 1. The oven can be removed until the charcoal starts to burn, then
put in place.
A little time is required before the proper temperature is reached because the
sand must fist absorb and dissipate the heat. For very high bakmg temperatures,
or to brown the top surface of baked goods, additional pieces of charcoal can be
placed on top of the oven. An extra rim can be added to the top edge of cans
for this purpose (see Figure 1).
sources:
V.C. Pettit, United States Agency for International Development
Dale Fritz, VITA Volunteer, Schenectady, New York
PORTABLE METAL COOKSTOVES
Loss of forest cover is a serious problem around the world, particularly in
developing countries. In some of these countries, forest cover has decreased from
over 60 percent to under 2Q percent in just a few decades. One consequence of
this loss of wood supply is that it is becoming increasingly difficult for people in
these areas to obtain fuel to cook their food.
Improving the fuel efftciency of cookstoves is one way to reduce the drain on
forests and the wood supply. Improved stoves can also reduce the cost of cooking
fuel-an expense that consumes up to one third of the income for some families.
Principles of Energy-Effkient Stoves
Traditional stoves are generally of three types. The simplest is the three-stone
design, where the cooking pot rests on stones over an open fue. The second type
is the massive stove, made of clay and sand, that may hold several cook pots, but
which takes a long time and much fuel to heat up. The third type is the ligbtweight portable stove made of sheet metal or ceramic.
358
The traditional portable stove has been studied intensively and modified to
achieve a very high level of efIicieney-40 to SO percent, or more than twice the
efficiency of traditional stoves. In addition, the portable stoves are easily mass
produced by local artisans and find a ready market alongside more traditional
goods.
In a stove, heat is transferred from the fire to the pot by tbe convective heat
process. To get the most convective heat transfer-and hence fuel eff%ency-it is
necessary to pass the hot gases
from the fie over as much of the
surface of the cook pot as possible,
and through as narrow a channel as
possible (see Figure 1).
Figue I. Narrow channel
for cookslove efficiency.
Narrower channels give higher convective beat transfer efficiencies, and thus
reduce the overall size of the tire needed for cooking. But if the channel is too
narrow, the fire may be choked off, and either smoke or die. Experimental work
has shown that a rhannel between 4mm and 8mm wide (about l/4 inch) is best.
If families already have their cock pots, then the stove(s) must be designed and
built to tit the cook pots in order to obtain the narrow channels for the hGt
gases from the fire. This means that one should not design and build the cookstwieies until the sizes of the cook pots have been measured. Ar7 alternative is to
design a cookstove that can be efficient with a variety of pot sizes, using a
selection of inserts provided with the stove so that the channel can be just right
for a variety of pot diameters. It is recommended that a survey be made of the
pot diameters in common use in the local area before the cookstove design is
made fmal.
In order to sell fuel-efficient cookstoves, local artisans mast not only be able to
produce them, bat people must want to bay them and must have the means to do
so. In addition to determining the usual cook pot size in the market area, it is
useful to ask potential custorzers what they want in a cookstove and how much
they think they would be willing to pay. Market surveys in some countries show
most people want a stove that can cook food quickly and use less fuel. The
selling price of the stove described below is approximately USS3.00 (1987) in one
West African country, a price people were willing to pay.
359
Cookstove Design
If you plan to make more than one or two cookstoves, it is best to make templates (patterns) for the stove parts fust. The templates shown in Figures 2, 3,
and 4 will produce stoves suitable for spherical or cylindrical cook pots. Templates may be made of cardboard, plywood, or, better yet, sheet metal.
The stove presented here requires some welding and the use of concrete reinforcing rod (re-rod) as the pot support. Other designs, equally efticient, may use
rivets or hammered seams and pot supports made of the same material as the
stove.
1.
The length of the template is given by
L=C+G+S+T
C is determined by the measure of the pot around its widest circumference.
G is determined by the desired pot-to-wall gap, G = 2pi. For a gap of 4 mm,
6 = 2.5 cm; for 6 mm, G = 3.8; for 8 mm, G = 5.0 cm. A gap of four to six
mm (3/16-l/4”) is preferred. Increase it only if excessive smoke comes out
the door or the heating rate is too slow. S is determined by the amount of
overlap in the seam. It is preferable to weld the stove together end to end
(thus S = 0) to prevent the creation of a small vertical channel by which
the heat can by-pass the pot. If the seam is crosswelded or folded, typical
values for S will bc. 1 cm. T is determined by the thickness of the metal
used. One typic&y uses 1 mm (T = 0.3 cm) or 1.5 mm I;T = 0.47 cm) thick
metal. Thus, for a %I cm circumference pot, a 4 mm gap, an end-to-end
welded seam, and 1 mm thick metal we tin&
E-90+2.5+0.3=928cm
POT SUPPORT
H
AIR INLET
I
Figure 2. Template for a cylindrical metal stove shell
360
2.
For spherical pots, template height H is determined by the sum of the
airhole height (A), the grate-to-pot height (P), and the amount necessary to
extend a few centimeters above the pot’s maximum circumference when in
place on the stove (T).
H=A+P+T
Typicat values for A are 3 cm (1 13/W) and for P 0.4 of the pot diameter.
For cylindrical pots the height T is typically 5 to 10 cm (2 to 4”). The best
height T is determined more precisely by comparing the increased efficiency
and reduced fuel use caused by the additional height versus the increased
cost of the extra metal. Additional height can also be provided at the top
and bottom of the template, typically 1 cm (3,&I”) each, to allow the edge to
be folded over to protect against sharp edges and increase the stove’s
rigidity and strength.
Figure 3. Templates for a
folded pot suppoti, a
welded L-bracket, and a
complete
triangular
support of re-rod. sup
poti should be kept
small so they d o n ? keep
heat away from the pot.
3. Stoves usually have four air holes, about 3 cm by 3 cm (1 13/16” by 1
1,3/W) each (A = 3 cm). Space them symmetrically, but far enough away
from the door and the seams to avoid weakening the stove. Cut the airholes
on two sides only so that when bent upward and inward they can act as
supports for the grate. for larger pots or soft soil where the stove will sink
in, larger airholes may be necessary. Alternatively, for soft soil conditions a
ring-shaped platform can be cut and attached to the stove.
4.
Space pot supports evenly around the stove, but offset from the door and
edges so as not to weaken them. The height P for the pot supports above
the top of the air holes (where the rate till rest) is given roughly by
P = 0.4C/pi or 0.4D
where D is the pot diameter. The best distance will vary somewhat with the
size of wood used locally, its moisture content, and other factors.
5.
The door sire is somewhat arbitrary and is determined by the locally
available wood sire. Typical sires for a %I cm (35”) circumference pot are 12
cm wide by 9 cm high (4 3/4” x 3 l/2”). Place the bottom of the door at the
grate position-the top of the air holes. Make the top of the door several
361
centimeters below the bottom of the pot so that the hot gases are guided up
around the pot rather than out the door. If necessary, decrease the door
height to ensure that it is below the bottom of the pot.
6.
The grate is a circle of sheet
metal cut to fit snugly into
the finished cylinder. Punch
the center diameter with a 30
percent hole density of 1 cm
(3/F) holes.
Figure 4. Template for a grate.
Grate holes are not lo scale.
roducing the Cookstoves
The stoves can be produced in villages in nearly all countries by metal working
artisans with modest skills.
Tools and Materials
Sheet metal shears
Ball-peen hammer
Hole punch
Anvil
Welder
Sheet metal, approx 1 mm (.OV) thick (2 to 3 stoves per sq. meter)
Heavy wire (for handle)
Heat resistant paint (optional)
To produce stoves in quantity:
0
Trace the template on a sheet of metal as many times as desired or as space
permits.
0
Cut each form out in outline. Cut the door, pot support holes, and strips for
the airholes.
0
Roll the metal into a cylinder. The cylinder should be as straight and smooth
as possible.
0
Cut out other components such as pot supports and stabilizers and put them
into place.
0
Cut the grate and punch the holes in it.
0
Weld the stove together. Weld pot supports into place. Alternatively, fold all
seams together. Hammer smooth.
0
Place the grate iu the stove, fold the tabs from the airholes inward and
upward. -
0
Paint it with heat resistant paint where available.
0
Add wire loop if desired to lift stove.
The fmished stoves are shown in Figures 5 and 6.
Figure 5. Cross-section
of the metal stove showing
how the pot jits down inside.
Source: Sam Baldwin, VITA Volunteer, Princeton, New Jersey.
OUTDOOROVEN
An outdoor oven is easy to build and good for baking bread, potatoes, beans,
cereals, cakes, and other foods.
Tools and Materials
Adobe blocks or bricks 35cm x 25cm x 1Oan (14” x 10” x 4”)
Wood or metal for door and smoke hole covers
Clay or cement for plastering
Lay bricks on the ground to make a base, 12ikm x 1Bkm square and 3&m high
(4’ x 4’ x I’), on which to build the oven. after making the base, build the oven
walls in an oval shape as shown in Figures 1 and 2. Lay the bricks flat and
lengthwise starting from each side of the door opening using the center of the
square base as a guide. To form the dome shape and oval door opening, cut the
corners of the bricks as you lay them. The inside space should be about 75cm
(30”) in diameter and 9Ocm (3’) high. Leave a front opening for the oven door and
a small opening at the top to let the smoke escape (see Figure 2).
Now make wooden or metal covers to tit tightly over the door opening and the
smoke-hole (see Figure 3). These should be tight-fitting so that hot air will not
leave the oven when the openings are closed.
Plaster the inside and outside with a clay mixture or cement. The stove should be
re-plastered at least once a year.
With the door and smoke-hole open, build a tire in the oven
When the tire has burned to ashes, sweep out the ashes.
Put the food to be cooked inside the oven. Use trays or be sure the oven floor is
very clean.
Cover the door opening and smokehole tightly.
364
Experience wi!l teach how long food should be cooked. Bread, for example, can be
expected to take an hour to an hour and a half.
This type of oven was used traditionally in many areas of Europe, the southwestern United States, and in villages throughout South Asia.
source:
Home Muking Around the World Washington, D.C.: U.S. Agency for International
Development.
Soap is an essential cleaning agent, helping people to keep themselves and their
surroundmgs clean. When soap is mixed with water, it forms a lather that washes
out dirt and grease far better than water alone.
Soap can be made on a small scale m the home or village cheaply and easily. The
main ingredients are fats and lye, both of which can be made from materials
found throughout the world. Making soap at home is practical when there is waste
fat or oil and when there is no cheap source of soap.
0 BASIC METHODS
The two basic methods for small-scale soap making are:
Method 1. With commercial lye: This method is used when commercially-prepared
lye or caustic soda (sodium hydroxide crystals) is available.
Method 2. With lye leached from ashes (potash): This method is patterned after a
process used by early settlers of North America.
The first method, soap-making with commercial lye, is recommended because it is
simpler and more reliable.
INGREDIENTS FOR SOAP
Fats and Oils
Soap can be made from either animal fat or vegetable oil. Mineral oil cannot be
used. Animal fats commonly used are tallow, mutton, and lard. Vegetable oils used
include coconut, palm nut, maize, olive, cottonseed, soybean, groundnut, safflower,
and castor. Chicken fat, which is not a hard fat, is considered an oil. The best
soap is made from a mixture of fat and oil.
0
If you want a hard soap for use in hot water, use only tallow, made from
m.elting rendered sheep, cattle, or horse fat.
0
If you want a good laundry soap, use 1 part tallow to 1 part lard or cooking
grease from melted hog fat, skin, and bones.
366
If you want a fine toilet soap, use 1 part tallow to 1 part vegetable oil.
0
The best vegetable oils are made from crushing dried coconut meat, palm nut
kernels, or the outer pulp of the palm nut. The last makes a harder soap than the
coconut meat or kernels.
be
Either commercially-prepared lye, also called caustic soda or sodium hydroxide
(NaOH) crystals, or lye leached from ashes, called potash, can be used. Caustic
soda is cheap and is sold in the markets of most countries.
Borax
Borax is not necessary for making soap, but it improves tile soap’s appearance and
increases the amount of suds produced.
Perfume
A&f&l perfumes or essential oils are not necessary ingredients but they can be
used to make a more pleasant soap, particularly if rancid fat is used. If soap is
made from tallow, citrus oil or juice will improve its smell and help preserve it.
Water
The best water to use is soft water. Water that is not too hard can be used, but
if it is very hard it is best to soften it. Hard water contains mineral salts that
hinder the cleansing action of soap. To soften hard water: Add 15ml (1 tablespoon) of lye to 3.8 titers (1 gallon) of hard water, stirring the water as it is
added. Let the mixture stand for several days. Pour off the water from the top.
This is the soft water for soap making. The water and particle mixture at the
bottom of the container can be thrown away. Soft water can also be obtained by
collecting rain water.
SOAP MAKLNG WITH COMMERCIAL LYE
The directions given here will make 4.lkg (9 pounds) of good quality soap. But
the amount can be changed as long as the techniques and proportions are
foilowed.
Equipment and Materials
Bowls, buckets, pots, or tubs made of enamel, iron, or clay. Never use aluminum;
lye destroys it.
Measuring cups of glass or enamel.
Wood or enamel spoons, paddles, or smooth sticks for stirring.
Wood, cardboard, or waxed containers for molding soap. The molds can be of any
size but those that are 5cm to 7.5cm (2” to 3”) deep are best. Gourds or coconut
shells can also be used for molds.
Cotton cloth or waxed paper for lining the molds. Cut the cloth or paper into two
strips: one should be a little wider than the mold and the other should be a little
longer. This lining will make it easier to remove the soap from the molds.
A thermometer that ranges from -18’ to 6S°C (O” to 150°F) is helpful, but not
necessary.
Recipes
For 4.lkg (9 pounds) of soap:
Oil or clean, hard fat: 13 cups (3 titers) or 2.75kg (6 pounds)
Borax (optional): 57ml (l/4 cup)
Lye (sodium hydroxide crystals): 370g (13 ounces)
Water: 1.2 liters (5 cups)*
Perfume (optional), use one of the following;
Oil of sassafras: 2Oml(4 teaspoons)
Oil of wintergreen: 10ml(2 teaspoons)
Oil of citronella: 10ml(2 teaspoons)
Oil of lavender: 10ml(2 teaspoons)
Oil of cloves: 5ml(l teaspoon)
Oil of lemon: Sml(1 teaspoon)
* Note:
Some experienced soap makers prefer to use twice this amount of water
(i.e., 10 cups) and to boil the solution for three hours. Your own
experience and the amount of water and fuel you have available are
your best guide.
368
For one bar of soap:
Oil or clean, hard fat: 23Oml(l cup)
Borax (optional): 5ml(l teaspoon)
Lye (sodium hydroxide crystals): 235g (5 teaspoons)
Water: lL5ml (l/2 cup)
Perfume (optional): a few drops
How to Make the Soap
The fat used in making the soap should be clarified. To do this: put the fat in a
kettle with an equal amount of water; boil this mixture. Remove the kettle from
the fire and strain the mixture through a sieve or a piece of cheesecloth. Add 1
part cold water to 4 parts of hot liquid. Do not stir the mixture; let it stand
until it cools. The clarified fat can then be removed from the top. To kelp in
cleaning the fat, a sliced unpared potato can be added before the mixture is
boiled.
Measure carefully the amount of fat required and mch it down in the kettle to be
used for soap making.
Measure the amount of water required.
Measure the lye required.
To the water previously measured slowly add the measured lye. For safety always
add the lye to the water, never add water to lye. The resulting solution will
become very hot and may spatter. Cool the lye mixture down to a body temperature. To test when the solution has reached body temperature, place your hand
under the vessel holding the lye solution: there should be no noticeable difference
between the temperature of your hand and that of the vessel. DO NOT PDT
YOUR FINGER IN THE? SOLUTION.
Cool the melted fat to body temperature. If borax is used, add it to the fat when
it has cooled.
Then add the lye mixture to the melted fat. The lye mixture should be poured
into the fat very slowly in a small stream. As tkii is beiig done the whole mixture is stirred slowly and evenly in one direction. After the lye solution is added,
the mixture is stirred until the spoon makes a track. This usually takes about 30
minutes. After this let the mixture stand, stirring it once or twice every 15 or 20
minutes for several hours. When the mixture is very thick and honey-like in consistency, pour it into the molds lined with cloth or waxed paper (see Figure 1).
Cover the mold and let it set for 48 hours. Keep it dry and at room temperature.
If it is moved or struck while it is settiug, the ingredients may separate.
At the end of this period, the soap should be fum and cau be removed from the
mold. If it is not fum, let it set longer until it is.
N6ffR.C 3. STACK WE &WL?S 50 %‘AT
P/r? CAN Co?c/AL4r6 ARCWNQ CPND
TyRDc%” ?-/d.EM
If grease is visible on the top of
the soap at the end of the 48-hour
curing period, the soap should
stand a while longer. If there is
liquid at the bottom of the box,
cut the soap into bars and let them
stand a day or two to see if the
liquid will be absorbed.
How to Know Good Soap
The soap should be hard, white, clean smelling, and almost tasteless. It should
shave from the bar in a curl (see Figure 4). It should not be greasy or taste
harsh when touched bv the tongue.
~-
Reclaiming Unsatisfactory Soap
If some of the ingredients are still separated after this curing period, if the soap
is curdled or grainy, or if you want a finer, smoother soap, do this:
Cut the soap into small pieces and put it into a pot with 2.8 liters (12 cups) of
water and any liquid left in the molding box. Avoid touching the soap with your
hands by wearing rubber gloves if possible, as there may be some free lye on the
surfaces of the pieces of soap.
Bring it slowly to a boil and boii for 10 minutes, stirring occasionally. If you
wish, you can add 1Oml (2 teaspoons) of wintergreen, lemon, or other oil at this
stage for perfume. Pour into a mold box, let stand 48 hours, and follow the
procedure below.
Empty the soap from the box and cut it into bars with a string or wire (see
Figure 2). Place the bars in an open stack so that air can circulate around and
through them (see Figure 3). Leave them in a warm, dry place for 2 to 4 weeks.
References:
Bramson, Ann, Smp. New York.: Workman Publishing Co., 1975
Donkor, Peter, Small-&al, Soapmaking. London: fntermediate Technology Development Group, 1956
Francioni, JB, and Cohings, M.L. .!&I~ Making. Extension circular 246. Baton
Rouge, Lo&ana: Louisiana State University, 1943
Making Soclps and Candles. Pownal, Vermont: P.H. Storey Communications Inc.,
1973.
SBFI- SOAP WITH LYE LEACHED FROM ASHES
Tkis method, patterned after one used by the early settlers of North America,
produces soft soap by combining fat and potash (lye obtained by leaching wood or
plant ashes.) The recipe has been tried successfully with waste cooking grease,
olive oil, peanut oil, and cocoa butter.
Leaching the Lye
Teals and Ingredients
Several medium sized rocks
A flat stone with a groove and a
run-off lip chipped into it.
19-liter (S-gallon) wooden bucket
with several small holes in the
bottom. A hollowed log with the
same capacity can be used.
Collection vessels for the lye.
These should be made of iron,
steel, enamel, or clay. An alurnimun
vessel should not be used, since lye
would corrode it.
Small twigs, straw
371
I9 liters (5 gallons) of wood ashes. The ashes may be from all types of woods.
Ashes from hardwoods yield the best lye, but ashes from the burning of plants
and leaves of trees may be used (see Table 1). Ashes of burnt seaweed are
particuiarly useful as Lhese produce a sodium-based lye from which hard soap can
be made. Lye hacked from the ashes of plant life (excepting seaweed) is potask
or potassium carbonate (K2CO3), an alkali. This alkali reacts with fat to form soft
soap. Askes from other materials suck as paper, cloth, or garbage cannot be used.
7.6 liters (2 gailons] of soft or medium-hard water.
Pile the rocks so that the Ilat,
grooved stone rests evenly on top
(see Figure 5). Set the wooden
bucket on this stone.
In the bottom of the bucket, make
a filter to trap the ashes by crisscrossing two layers of small twigs
and placing a iayer of straw on top
(see Figure 6).
F/Lifl/7E 6. nw* L,oYB-RS OF YlrOLL nw65
ARE c.?,.5s- CRasSED 70 FOBS a F/Llzzq
,N 7RE BO7mM of= 7xE .cu*E~. Wl4K~
m. BUCKET 6 F,LLim w-w Aw6S.
WAER /5 FWURED /N &vLT T&s LYE
%xUT/iW, a apow/v .4w,D , s‘owr,’
DR,ps Avm f CoATmNE~.
Fii the bucket with dry ashes. To
keep the lye from beiig leached
accidentally, the ashe; must be
kept dry before tkcy are .it :d.
Dour warm water into the bucket, making the ashes moist and sticky. To make
sure that the water passes through the ashes at the correct rate for leaching the
lye, move the ashes up at the sides of the bucket to form a depression in the
ceecter.
Add all the remaining water in small amounts in the following manner: Fill the
center depression vvitk water; let tke water be absorbed, till the depression again.
When about two-thirds of tke water has been added, the lye or potash, a brown
liquid, will siart to flow from the bottom of the bucket. Use more water, if
necessary? to start this Bow.’ The lye flows over the flat stone into the groove
and then into the collection vessel below the run-off lip. It takes about an hour
to start the Row of lye.
The yield from the atiounts given here is about 1.8 titer (7 3/4 cups) lye. The
rest&s vary according to the amount of water loss from evaporation and the kind
of ashes used.
If the lye is of the correct strength, an egg or potato should float in it. A
chicken feather dipped in the solution should be coated, but not eaten away. If
372
tke solution is weak, pour it
t h r o u g h t h e b a r r e l agaiu, o r
through a new barrel of ashes, or
concentrate it by boiig. ThirtyIive liters of ashes is about the
r@tt amount for 2 kilograms of fat
(a bushel of ashes for 4 pounds of
fat). This proportica is cited in
soap-making recipes of the cok&l
period in tke United States, but
many of the recipes of that era
differ on the proportion of ashes
to fat.
Here is a list of tropical plants whose leaf ashes yield lye for soap making:
SdentiGc Name
Common Name
E%odne,ntIocation
Arthrocnemum indicum
Atripkx repers
Aviccnnio nitida
Cocos mrcifem
mangrove
salt bush
mangrove
coconut palm
Indian coast
Indian coast
Pkilippino swamps
Coasts of all tropical
regions
Indian coast
Indian coast
Indian coast
Indian coast
Indiae coast
Indian coast
Indian coast
Indian coast
Indian coast
Indian coast
Indian coast
HoIocha~% violocea
HaloqIon recurs
Haloqlon muliijlomm
Haloqlon solicomicum
Kochia indica
Salicomia brachiata
Salsolo foetida
Suaeda fruticoso
Suaedo monoica
Suoedo maritime
Suaeda nudiflora
ng
camel food
Aden balsam
the Soap
Equipment and Materials
Iron kettle
Wooden spoon or stick for stirring
Measuring vessels
Wooden, steel, iron, glass, or clay vessels for storing the soap
Clarified fat (see the entry on Soap Making with Commercial Lye for cleaning
pro==)
373
Lye that floats an egg or potato (see Figure 7)
Put 115ml (l/2 cup) of lye in the kettle for every 23Oml(l cup) of fats or &.
Add the measured amount of fat.
Boil the lye and fat together until the mixture becomes thick, rubbery, and foamy.
Remove t\e kettle from the tire and let it cool.
The soap is a thick jelly substance that ranges in color from tan to dark brown
depending on the fats or oils used and the length of boiling time.
Upon strong mixing in water, the soap till lather up into wbite~$uds and serve as
an effective cleaning agent. This soap greatiy improves with age. Store it in a
container for at least a month before using it.
23Oml(l cup) of fat yields 23Om: (1 cup) of soft soap.
Sources:
Marietta Ellis, VITA Volunteer, Bedford, Massachusetts
Dr. S. K. Barat, VITA Volunteer, Adyar, Madras, India
Earl, Alice Morse. Home Life in Colonid Days. New York: MacMillan Company.
Your Own Soup. Washington, D.C: Federal Extension Service, U.S. Department of Agriculture.
Muke
LARGER-SCALE SOAP PRO
In many areas in developing countries soap-making can be an important small business, providing a needed product and earning income with minimal investment.
The Intermediate Technology Development Group, for example, has worked with
the University of Science and Technology in Ghana to develop equipment for
small manufacturing operations. One such set up uses specially made tanks heated
by wood Tues. The diagrams below show the parts for the tank. Soap-making
processes are the same as those described above. Recipe quantities change
according to the amount of soap produced. For example, one small manufacturer
%t Brazil supplied the following recipe for 45 kgs (100 Ibs):
10 kgs tallow
2 kgs lye
2 kgs rosin
36 liters water
..
WOOD FIRED SOAP TANK
1 & L-views uf soap tank cm stand
3-cover of scq? tank (iswle1lic)
4-so;lp tank (isometric)
.S-soap tank stand (iscmebic)
6-sw.p ti stirrer (ianctric)
A-m%4 nip nn. 112 inch diameter
I&mild steel plate. 3/16 inch thick
C-steel rod 314 inch diameler
D-galvanixd steel gauge 16
Donkor, Peter, Srnolf-Scale S~opmaking. London: Intermediate Technology Development Group, 19%
Rezende Iriner, VITA correspondent, Recife, Brazil
ing
A NEST OF LOW-COST BEDS
Tbis nest of three beds will save space in a small room during the daytime
because it takes up only the space needed for one bed. The beds are low in cost
and easy to make from local materiak Dimensions suggested here are approximate. The exact dimensions depend on the kind of wood used.
Tools and Materials
Carpenter’s tools
Wooden boards 25cm x 7Scm (1” x 3”), of varying lengths
Wooden posts km x km (2” x 2”), of varying lengths
Nails
Paint
Baling wire, burlap strips, rope, or wood for the “spring” of the beds.
Au of the beds are the same width but the length and height of each bed varies
so they fit under each other. The nest of beds can then be used as a sofa in the
daytime (Figure 1).
376
The wood used in the largest bed is:
2 boards, 2.5cm x 7.5cm x l&m (1” x 3” x 72”)
2 boards, 2.5cm x 7.5cm x 91.5cm (1” x 3” x 36”)
41egs,5cmx5cmx51cm(ZxZx20”)
0
0
0
Nail the legs to the ends of each of the 91.5cm (36”) boards. Then join these
boards by nailing the 183cm (72”) boards to them as in Figure 1. This completes
the framework, which is now ready for the spring to be. attached.
The spring can be made by nailing baling wire, burlap strips used as webbii or
wood tu the frame. Another method is to bore holes in the framework and pass
rope through the holes as shown in the middle-size bed in Figure 2.
The other hvo beds are made the same way. They use the following materials:
Middle-size bed:
0
0
0
2 boards, 2Scm x 7Scm x 16&m (1” x T x 66”)
2 boards, 2.5cm x 7Scm x 9lScm (1” x 3” x 36”)
4legs,5anx5cmx3&3cm(2”x2”x15*)
Smallest bed:
0
0
0
2 boards, 2Scm x 7Scm x 152cm (1” x 3” x 60”)
2 boards, 2Scm x 7Scm x 91.5cm (1” x T x 36”)
4 legs, 5cm x 5cm x 25cm (Z x 2” x lo”)
37-I
HOW TO MAKE A MA’ITRESS
This low-cost mattress is made from materials available in most areas. It can be
used as a bed at night and as a sofa by day. The mattresses are widely used.
Tools and Materials
cotton
Corn shucks, rice or wheat straw, hay, banana or palm leaves
Smooth, heavy cloth (ticking)
Strong ,ieedles
Waxed cord
Oil felt or double-thickness ticking cut in a round shape, for tufts
Hand paddle with small nails
Sharp knife
aking the Mattress
The fust step is to dip the corn shucks in boiling water and, while they are still
moist, shred them into small strip; with a hand paddle that has small nails in it.
The tough top part of the shuck is thea cut off with a sharp knife. When dry,
the shredded corn shucks are ready for use.
.
378
Cut six pieces of cloth as follows:
0
two pieces the size of the bed, to make the top and bottom of the mattress.
0
two pieces 15cm (6”) wide and the length of the bed for the mattress sides.
0
two pieces IScm (6”) wide and slightly longer than the width of the bed, for
the ends of the mattress.
Sew the pieces together to form a box with rounded comers. Attsh the bot!om
piece on just one side, leaving the bottom open for fig the mattress. Twelve
feed sacks full of tightly-packed corn shucks are eoougb for a double-bed
mattress. A singIe bed mattress needs less.
Pack the fdlii material into the cloth cover in evea layers. Otherwise the
mattress will be lumpy. After each layer, pull the bottom piece over the fdliog
material and beat the mattress gently to distribute the material evenly. Then pull
the bottom piece back and continue faing the mattress. When the mattress is
filled, sew the bottom piece in place. If there are stiU hii and low spots in the
mattress, beat it gently agaim hitting the high spots to drive the faer into the
low spots. Only a few strokes should be needed.
Making a Rolled Edge
A rolled edge will keep the cotton in place and help the mattress to bold its
s h a p e . M a r k a faint line 6cm (2 l/4”) in from the edge seam all around the
mattress top. Mark another faint line l&m (l/2”) below the seam. Sew the two
hues together with stitches about l&m (l/2”) apart, working enough flier into
the roll with each stitch to make the roll firm. Fii the roll evenly. In rounding
the comers, make the stitches closer and take shorter stztches on top of the roll
than on the bottom.
Turn the mattress over and make a roU edge on the other side.
Use a strong needle and waxed cord to sew the round pieces of oil felt or
doubled ticking for simple tufts that will hold the ftimg in place.
More detailed instructions are given in: Making o Cofton Motttws, Federal
Extension Service, U.S. Department of Agriculture.
e
te
Ceramic kilns that burn waste oil from automobiles and other industries have been
operating in Tanzania, Haiti, and several other developing countries for several
years. These k&s offer the advantages of good operational control that is easily
achieved with fuel oil, but at lower fuel cost because waste oil is used.
The waste cil fired system presented here (Figure 1) was designed by Ali Sheriff
and his assistant, Bashii Lalji, in Tanzania for Mr. Sherriffs pottery plant. Mr.
Sherriff also helped entrepreneur,= in Djibouti build and operate kilns for use in
their brick making and pottery businesses.
0ZSt
vantage of
ste Oil
Originally, waste oiJ was collected free from auto service stations and industries,
but by 1983 S535 (US) per liter was charged. At these rates, it cost Mr. Sheriff
US0105 for each fuing of his six-burner kiln, compared with 3165 for fresh oil.
Some alternative fuels such as electricity are too expensive in developing couotries to be e~conomicatly feasible for kilns. One alternative, wood, may be less
costly than waste oil in some countries, but wood supplies are being reduced
rapidly and costs are rising.
The kiln sb~wn iu Fiie 1 is a down draft type with three tireboxes on each
s,ide. The height of the chimney is determined by the intensity of the heat
required. The hotter
have more or fewer fii
fire, the higher the chimney. Other kin designs may
depending on the size.
e,r are peered by gate valves connected to the distribution pipes
A ratio of about 75 percent waste oil and 25 percent
Preheated splash plates serve as a grate to ignite the oil-water mixture. Tbe
grates, made of pieces of sheet steel (Figure 21, slope down so that any fuel not
burned on the upper grate will spilt
off onto the lower grates for
combustion.
The waste oil must be treated
before it can be used as fuel. Tbe
oil is fust filtered througb a
s c r e e n o f 6 0 m e s h o r fmer to
remove solid particles. It is then
allowed to stand in a drum for a
few minutes to let the water settle
to the bottom. A tap at the bottom
of the drum allows water to be
removed.
eheat the splash plates using a wood or charcoal fire. This
If hour. The vents on top of the kiln are then closed
oil and water valves are opened and the mixture should
ly check the fuel-water flows. For ceramics, the fuel
rc~lated to provide a temperature rise in the kiln of
hour. A steady riie prevents the pottery from cracking.
383
In Mr. Sherift’s kiln,
all entrances to
ailowed to cd s
temperature is reached in about t8 hours. At this time,
including the chimney, arc closed and the kiln is
Sheriff, A. and La@, 5. B&e Oil Fired Kiln. VfTA Technical Bulletin. Arlington,
Viginia: V&n:cers in Technical Assistance, 1983
“Ceramic Kitn Burns Waste Oil,” MT.4 News, April 1983, pp. 3-6.
LAR KILN
The $~~I~ r~t~~~~ k&t was designed for both bisque and glaze tiring of small
pottery pieces. Pn bisque tiring, pottery is cured but not glazed. It can be glared
either in the first firing or in subsequent fuings. The kiln can be larger or
smallc~r than the di~e~io~ given here. Its capacity depends on the sire of the
base.
Materials
Common (pressed) brick
Firebrick (Note: Sandstone blocks were used before the invention of tirebrick)
Clay or mortar
The dimensions shown in Figures 4 to 8 are based on the 23cm x 1lScm x 6Scm
(9 x 4 l/r x 2 l/2”) straight brick commonly found in the United States. The
dimensions can be changed to suit the size of locally available brick.
The joints in tbe kihr, except for those in the loading area, should be mortared.
Tbe preferable mortar is a refractory cement; that is, one that is highly resistant
to the action of heat. If there is a
brick plant in the area, find out
what material is used there. If
refractory cement is not available,
make it by mixing crushed firebrick
with your purest clay, which will
be white or light in color. As a
last resort, use clay alone. Iu any
case, have the mortar till as much
of the joint as possible. Each time
the temporary door for loading is
rebuilt it should be mortared with
the purest clay available.
‘384
I
2
!
J
j 2
l-f-y---
i /
I
I
I
I
- I
T-
iiI
I
I ___-- _I
/ d-
I
I
I
- i
/
’ Goouuo
LEVEL.
i
.--7.---
-.
388
In laying the brickwork, stagger the joints in each layer to cut beat loss.
Dig a hole 76cm x 12.6cm and 19cm deep (30” x 49 l/2” x 7 1/2”)-ur whatever
base size is needed for available brick-in level ground. Note in Figures 4, 5, and
7 that the fust three horizontal courses are: first, gravel or common brick;
second, common brick, and third, fuebrick. This foundation is under the fuebox.
The fuebox, with its end open for loadmp; is built with firebrick. If charcoal,
coke, or coal are used as a fueI, the firebox should have grates.
The firebox is a long rectangular chamber, fued from both ends so that the hot
gases flow inward and upward (see Figure 1). Between and above the fires is the
kiln chamber in which the pottery is placed. The hot gases rise through the
chamber and go out the chimney opening at the top. Both the chamber and the
firebox are surrounded by a layer of common brick. Figures 4 through 8 show how
the bricks should bc arranged. Note the staggering of joints in alternate courses.
When the kiln is built, its sides should bc insulated with dry loose sand and/or
crushed brick (see Figures 3 and 4).
If the kiln is outdoors, cover the loose insulation and brickwork to keep it from
getting wet. Sheet metal is suitable. If large pieces are not available, use
flattened tin cans to build a shingle-type cover.
in building up the temporary door after the kiln is loaded (see Figures 3 and 4),
be sure to leave a peephole to watch the inside of the kiln.
Firing
The first time the kiln is fired, heat-up wiU take longer and require more fuel
than usual because the kiln must be dried out.
Sunbake the pottery before tiring it, to bc sure that it is completely dry. Load
the sun-dried pottery on the shelves of the kiln, leaving enough space for
adequate ventilation.
After the kiin has heated up somewhat, you can save fuel by cutting dowa on the
draft. Do this by partly covering the top flue openings with bricks. The pottery
begins to shrink at about 870°C (16@F). To measure temperature, the ceramic
industry uses pyrometric cones.
If no temperature-measuring devices are available, the color of the glow in the
inner mass of the kiln can indicate the approximate temperature of the kiln. See
Table 1.
The kiln should be heated slowly to 870°C (16W°F). This proce& should take
about eight hours. Chemical and physical changes caused during the heating of the
389
TABLE 1
CGLOR/TEWPERATUREGUDE
475 C...Lowest visible red
475 - 650 C...Lowest visible red io'd$ &d : : :
650 - 750 C...Dark red to cherry ,-ed . .
750 - 815 C...Cherry red to bright cherry'red' : :
815- 9OOC . ..Bright cherry red to orange . . . .
900 - 1095 C...Orange to yellow
1095 - 1315 C...Yellow to light y;lioi : : : : : : :
0
: : '~86'~ lzi$ F'
1200 - 13W F'
: : ,380 _ 15000 F'
. , ,600 _ 16500 F:
1650 - 2000" F. ~'.
: : 2000 _ 24000 F.
The glow of the inner mass of the kii gives a rough indication of temperature
kiln can destroy the pottery if they take place too quickly. For example, dehydration of clay and other minerals takes place throughout the whole temperature
range, but particularly between 480°C (9OOoF) and 81s°C (1500°F); organics and
sulfides are oxidized between 595’C (1lOOoF) and 980’ (lSOO°F).
Several hours at 870°C (1600°F) and higher are needed to complete the ftig.
When the fuing is completed and the fire is out, block the flue and tirebox
openings so that the kiln will cool slowly. Let the kiln stand this way overnight.
When the temperature of the kiln has dropped, open the flue and fuebox openings. This slow cooiii keeps the pottery from being cracked by thermal stresses.
Slow cooling through the dark red heat range is most critical.
The time and temperature required to fire an unknown clay can be learned only
be experimenting. Heating and fuing times may vary from those given here.
source:
Irwin M. La&man, VITA Volunteer, Coming, New York
Suppliers of temperature cones are:
The Edward Orton (Jr.) Ceramic Foundation
144 Summit Street, Columbus, Ohio USA
Beil Research, Inc
Box 757, East Liverpool, Ohio USA
Bell Clay Co.
Gleason, Tennessee USA
390
SALT GLAZE FOR POTTERY
This method can be used for applying a very thii transparent glaze to pottery
such as clayware and stoneware. Examples are: brick, sewer-pipe, stoneware
shapes, and containers.
Open pieces, such as bowls, wig become glared inside and out. Narrow-necked
pieces must be glazed inside by a slip-glaze method in which the pottery is dipped
into the glaze.
Considerations
Some ceramic articles will take a salt glaze. Others, under certain conditions, will
not. Experimentation is the best way to discover how to glaze an unknown day.
Common salt (NaCI) may be used atone, and this is common practice. Boric acid or
borax may be added to the salt to improve the glaze and lower the ftirrg
temperature.
Salt glazing can be done in a wide range of temperatures, 670°C to 1360°C
(1230°F to 2470°F); the more usual range is 1200°C to 1300°C (2185OF to 2375OF).
How to Fire the Pottery
Place the pottery on the shelves of the kiln. The pieces should not touch so that
there is plenty of rcmm for ventilation.
Mu 9 parts salt with 1 part borax or boric acid. Thii mixture can be dampened
with water: 5 to 10 percent by weight of the mixture. For ordinary fue-clay
pottery, about 285 to 57Ogm (10 to 20 ounces) of salt is needed for 0.028 cubic
meter (1 cubic foot) of kiln capacity.
When the kiIn is as hot as it wiU get, throw the mixture into the fire heating
the kihx.
This step may be repeated several times when the temperature gets back up to
the hottest point. The kiln is then gradually cooled.
The sodium (Na) separates from the heated salt and combines with the clay body
to form a very thin, uniform glaz.e that shows the colors of the ceramic body.
Dr. Louis Navias, VITA Volunteer, Schenectady, New York
Parmaiee, Cullen W. Cerumic Glazes. Chicago: Cahners Publishing Company.
and
ermaking
In many areas of developing countries paper is scarce. Rural schools may not have
enough paper for their students and market goods may be wrapped in old newspapers if at all. Often this is because resources are not available to invest in
modern papermaking factories, which require large amounts of energy and raw
materials if they are to be economical.
But paper can be made in small shops in small quantities. Access to electricity
makes some of the steps easier, but is not absolutely necessary. (Indeed, paper
was made this way for many years before electricity was discovered.) In a situation where paper is scarce and expensive, it may be worthwhile to consider
small-scale papermakmg as a source of school supplies or as a small business.
Such a business might produce heavy coarse paper for packaging or even thick
paper egg cartons, plaot pots, and so on.
PAPERMAKING PROCESSES
Whether paper is made in a home or school workshop or a small factory, the
production processes for making paper by hand are quite similar. The scale of the
equipment changes with the volume of production and the raw materials vary with
what is available and the quality of paper to be produced.
Pre-processing
Cotton or other rags and waste paper to be recycled are sorted thoroughly to
remove all non-fibrous materials such as staples, paper clips, cellophane, nails,
buttons, zippers, etc. Both rags and paper are cut or shredded into smail pieces.
Pulping
The cleaned and shredded raw materials are brought to the boiling point and
cooked for two to six hours. They are rinsed thoroughly to remove impurities that
might have separated out during the cooking process.
The beater-this can range from a kitchen blender to a specially made tank-is
ffied with the required quantity of water, and the cooked, chopped rags or paper
are added gradually with high speed agitation. Bleaching powder or liquid bleach
(1 percent) is then added. The pulp is washed thoroughly, a process that may take
another six to eight hours. Additives used may include titanium dioxide or other
392
filters, dyes (for colored paper), or optical bleaching agents (for white paper).
Rosin soap and alum are added later.
Lifting, Couching, and Stacking
When the pulp process is complete, the pulp is transferred to storage containiers
or vats. Depending on the scale of the operation, the pulp is then mixed with a
sufficient quantity of water to dilute it to form a uniform suspension, free of
lumps. In the home workshop, the pulp is mixed in quantities to make one sheet
at a tune. In the small factory, a larger quantity may be mixed at one time. The
diluted pulp is then lifted from the water OQ wire screens, and the resulting
sheets are covered by felt or other absorbent cloth. With the cloth is place, the
still wet pulp layer is carefuity lifted from the screen. This process is called
couching (pronounced coochiig). The couching cloth, paper side down, is placed
on a felt covered board and smoothed to remove wrinkles or air bubbles. Each
succeeding sheet is placed in a stack over the first.
ressing and Drying
When a sufticient number of sheets have been formed, they are put under a press
to remove the water. The sheets are then separated and, to avoid shrinkage,
placed under absorbent boards and pressed again. The sheets are hung to dry in
bunches of three to six, according to thickness, or dried in a warm oven.
Sizing
Sig gives paper a harder finish so that water based paints and inks will not
bleed or run. Paper may be sized internally, by adding the sizing agents to the
pulp, or externally, by painting or dipping the dried sheets. For internal sizing,
alum, rosin, gelatin, cornstarch, or linseed oil may be added in very small
quantities at the end of the pulping stage. For external sizing, the dried sheets
are dipped in a dilute glue or starch solution, pressed to remove the excess, and
bung up to dry again. In the home workshop, the individual sheets may be painted
with the dilute solution.
Blotting paper, filter paper, toilet tissue, grey board, and some art papers may be
require very little, if any, sizing.
Calendering
The dried sheets are placed alternately between metal plates into a stack or
“post.” The stack is passed between calender rollers to obtain the desired
smoothness. This can be done in the home workshop by pressing the paper sheets
between sheets of aluminum foil with a hot iron.
393
Sorting and Cutting
After calendering, the sheets are carefully sorted and cut to size for packing,
storage, and/or shipment.
ER IN THE SMALL WORKSHOP
Papermaking at this scale can be done as hobby, for gifts, or to supply schools.
The necessary equipment may already be available in some kitchens, but the
markets should be considered carefully before any investment is made.
Tbii process assmnes that waste paper or cotton cloth will be used to make the
paper. Approximately 50 sheets of 21.5~11 x 28cm (8 l/2” x 11”) paper can be
made from a half kilo (about a pound) of waste paper. Household bleach, alum,
gelatin, cornstarch, and animal glue may also he needed. And ordinary fabric dyes
can bc used to produce tinted or colored papers. As described here, the availability of adequate water and electrical or other power supplies is also assumed.
Equipment and Materials
The following equipment is needed:
De&e box and mold, made of oiled wood (fwre 1)
Power food mixer or blender
Stainless steel or enamel pot (not almuinum)
Steam iron
Stove with oven
Sink, tub or wash basin
Couchmg cloth (e.g., cotton sheeting), cut to sire
Felt or absorbent terry cloth, cut to sire
Thin metal sheet
Fiat “rec.%@ board, lcm (l/4”) plywood or other board
Pulping
Choose paper with minimal printing. Old envelopes are good for this reason; the
glue on the flap won’t matter. Colored paper is acceptable; the dye usually comes
out when it is boded. Avoid paper that has “wet strength” such as paper towels.
Be careful how many brown paper bags you use. Unbleached kraft paper lowers
the brightness or whiteness of the pulp, but it is strong and will give your papetoughness.
Newsprint alone makes a weak pulp, grey in color. It adds little but bulk. Cotton
or other cloth or yarns may also be used. They must be cut or shredded into very
small pieces to avoid jamming the mixer.
394
Cut or tear the paper into small
pieces, about 5cm x Scm (r x r).
w---“:‘-~-- 7:~ Shred any cloth that may be used.
Put the pieces in the pot, cover
with water, and add a few tablespoonfuls of household bleach. Turn
6
on the heat, cover the pot, and
i
bring to a gentle boil. Stir
f occasionally for a couple of hours
to ensure that the bleach is mixed
and all the paper is wetted do~xn
we& then cool.
; ., /
_ * . ” . w.c~, ., 2.. ,.
/to 6
After the batch has cooled, try to
t-- ,,~L.---&
break up the lumps and any
7 fl
r e m a i n i i g p i e c e s o f p a p e r still
ai.i FWD cul*I%I,D(
holding together. The smaller the
@H-g=-en
TOTA PIECES REQ’D.
pieces in the beginning, the easier
ZizGror 101 m.11
. .,LCII mm yho nw
this step is now. (The pulp can
i,
3 .!cEI ,i.- WWL “OG
& f CII‘“.U
then be drained and stored in
ML.plastic bags in a refrigerator, if
you have one, until you are ready
mafRE I
to make the sheets. It will keep for
weeks without any change.)
MI c-u”-
Making the Sheets
Take a lump of the semi-moist pulp you have prepared. Press as much moisture
out of it as possible to leave a ball about the size of a pigeon egg (7g--l/4 oz-dry weight). This is enough pulp to make one 21.5cm x 2Scm sheet. Make the
sheets, one at a time, as follows:
1. Blend and mix pulp in blender 3/4 full of water. Add additives.
2. Put mold in box, screen side up and immerse in sink.
Rap box to get rid of air bubbles.
3. Pour pulp into box.
4. Holdii box down, agitate the water in the box with fingers so that the
pulp spreads evenly over the mesh.
5. Grasp box and mold fumly and lift quickly and evenly to surface (feel
suction).
6. Hold for 10 seconds or so to drain.
395
7. Lift up out of water and hold vertically to drain. If sheet looks okay,
proceed, if flawed, put box and mold back into sink. Repeat steps 4 to 7.
8. Set box on Rat surface and carefully remove box. Note: Water drops on
wet web will make marks!
9. CarefuMy lay cotton couching cloth over web and smooth gently.
IO. Place absorbent felt over couching cloth. Smooth and press down from
center out.
11. Remove felt and wring out water.
12. Repeat IQ and 11 until no more water comes out.
13. Couch off sheet, starting at corner and peeling back quickly.
14. Place couched sheet, paper side up or down on Rat absorbent surface..
Smooth and press dounl to remove trapped air.
15. Repeat for each sheet until a neat stack is built up.
ressing and Drying
The sheets can be dried quickly by pressing them with a hot iron and an aluminum sheet or slowly (2-3 hours) by placing them in a 120°C (2&I”P) oven, with
the couching sheets tacked down to the receiving board at1 along the edges of the
paper she&s. The first method gives a smooth surface on one side, embossing
with cloth marks on the other; the second gives embossing on both sides.
A very stick surface can be obtained by smoothing the couching cloth, paper side
down, against an aluminum or oiled galvanized sheet. A squeegee can be used to
get rid of all the air. Dry in air or in a 120°C (2SOoP) degree oven.
Sizing and Coating
A simple method of internal siring uses a combination of pure gelatin and comstarch (either laundry or cooking type). The gelatin is dissolved in boiig water
and cornstarch is added to make a clear, thick mixture to add to the pulp. Use
about one teaspoon of this per 21Scm x2&m sheet.
Another simple internal siring procedure is to add about l/4 teaspoon of linseed
and/or a teaspoon of cornstarch solution while the pulp is being mixed at step 1.
The oil is dispersed in the water and precipitates on the fiber. The starch will be
caught on the tibers and during the drying stage will set to give a stiffer sheet.
External siring is done when the sheet is coated with a water based solution
394
after the paper has been dried. With an ordinary 4cm (1 l/2) paint brush, coat
ea& sheet with a 7 percent straight corn starch solution. One tablespoonful of
cornstarch added to a cup of water will be enough for 20 to 25 sheets (both
sides). Animal @re czut be added to the starch to improve the water resistance.
Modern glues can be added also.
When the coated sheets are nearly dry to the touch, place them in a neat stack.
They should be somew!rat Iimp but not wet. Put a metal sheet or smooth board on
top. AIIOW the stack to dry overnight. The sheets can then be trimmed if
rwxssary and packaged fo: sale.
NG
IN THE MICRO FACTORY
On a somewhat larger scale, but still in an essentially hand process, paper can be
made in a micro factory capable of producing about 24Okg (l/4 ton) of paper per
day. Such small factories are fairly common in India, and VITA has assisted at
least one such operation in Tanzania. Tbis process uses wastepaper or rags to
make pulp, or pulp purchased from a pulp mill. It can produce good quality bond
or drawing paper, card stock, school tablets, filter paper, to&t tissue, grey
board, and album or blotting paper. It can also turn out such articles as egg
cartons, flower m seed flats, hospital trays, and so on.
In addition to an identified, reliable market, the small factory requires a steady,
reliable supply of raw materials, water, and power. Suggested facihdes include a
building of about 300 square meters for operations and a shed of about 185 square
meters for coIlecting and sorting the materials. Six administrative staff and as
many as 1CtCt laborers working in two or three shifts are needed.
The U.N. Industrial Development Organization (UNIDO) estimates an investment of
approximately USS26,tXXl (1984) for the total cost of installation. Production may
be increased by in&hag one or two more beaters and operating the vats in
three shifts. (Beyond tbis capacity, however, economies of scaIe decline, and
production moves up to small-scale mechanized plants.)
sonrces
VogIer, JGT and Sarjeant, Peter. Understanding Small-Scale Pape~aking. Arlington, Virginia: Volunteers in Technical Assistance, 1986.
Appmptiate Industrial Technology for Paper Products and Small Pulp Mills. Vienna
Austria: United Nations Industrial Development Organization (UNIDO), 1979
Sheriff Dewji and Sons, Arusha, Tanzania
American Paper Institute, 260 Madison Avenue, New York, New York
397
In areas without electricity, lanterns, candles, and cookmg hearths often provide
the only source of hght at night. Candles are easy to make at home for home
use. With attention io quality control, they can be made in a small workshop for
sale in the shops and markets.
The directioos given here are for dipped candles, which are made by repeatedly
dipping a length of wick into melted wax until the candle is the desired sire.
Dipped candles often cost more in the shops than other kinds, but they usually
burn longer and with less smoke. This system, developed by the Environmental
and Development Agency in South Africa, uses a special jig that holds up to four
candles at a time.
Tools and Materials
Paraffin wax (you may wish to experiment with bee’s wax if it is available)
Stearic acid
Candle wicking (the string inside the candle)
Container to melt the wax (this has to be as deep as the candles are tall)
Wiie for the jig
Thermometer, in a brass case
Rod or rope to hang the candles on while they cool
A gas or kerosene stove
It is suggested that a small business or candle making cooperative would likely
need to make an initial investment in 4Okg.s (88 Ibs.) of wax, stearic acid in
quantity to make a ratio of 10 parts wax to 1 part stearic acid, and 20 wire jigs.
KINGTHEJIGS
A jig is the hanger that holds the wicking while you dip it into the melted wax.
Make 20 or so jii for your business. Even working at home it is convenient to
have a half dozen.
To make the jig, hammer 5 nails
into a ptece of wood as shown and
~~~
c u t
o f f
t h e
h e a d s .
Cut one piece of wire &km long and one piece 5Ocm long.
398
Take the shorter piece of wire and wrap it around the nails as shown in Figure 1.
Start at nail 1, bend the wire around nail 2 and then up around nail 3. Then bend
it back to nail 4 and up around
nail 5. Take the wire off the
frame. This is the bottom of the
jig.
Make the top of the jii with the
longer piece of wire. Bend the wire
around the nails as described
above. You will have some left
over. Bend this part into a hook to
hang up the jig with. Take the
wire off the frame and bend down
the corners as Shown in Figure 3.
Take 4 pieces of ticking as long
as you want your candles plus a
little bit. Tie one end of each piece
to the top part of the jig and the
other end to the bottom part
(Figure 4). Fii as many jigs as you
think you will need at one time.
PREPARFNG THE WAX
Cut the wax into small p i e c e s .
Make sure no diit gets mixed up
with it. Melt enough wax and
stearic acid to fill the contz+iner
almost full. Use I part stearic acid
to 10 parts wax.
Heat the wax to 70°C (158OF). Use
the thermometer to check the temperature. This is very important. If
the was is too hot it won’t stay on
the candle and if it is too cool the
candle will be lumpy.
399
The safest way to melt the wax is to set the container with the wax into a pot
of water so that the wax is not directly over the flame. It is very dangerous to
let the wax get too hot. Wax catches liue easily, and a wax fue is difficult to
put out. In case of fue, cover the container and turn off the stove as quickly as
possible. Be careful not to splash the hot wax. It will cat& fne if it falls into
the flame and it will burn your skin if it touches you.
DIPPING THE CANDLES
Take one of the jigs you bave put the v&king on and dip it into the melted wax.
Hang the jig on the rod to cool. Dip another jig with wicking into the melted
wax and hang it on the rod. When you have dipped all the jii you have prepared, start with the first one and dip again. Each time you dip the jig a little more
wax will stick to the -wick and the candle will get thicker. Continue dipping until
candles are the sire you want.
5:
zv?rtnQt---
Don’t handle the candles until they are cool and hard. Then, cut them off the
jigs. Trim the wicks to an even length. Store candles out of the sun and away
from heat.
Put a wide board or plastic sheet under the rod where you are hanging the jigs.
Any excess wax will drip onto them and you can scrape it off and melt it down
again. Be sure to keep thii area clean; any dirt that gets in the wax will get into
your candles. The wax that sticks to the metal jigs can also be scraped off and
used again.
Do not dispose of excess melted wax by pouring it down a drain, When it cools
and hardens it will clog the drain. Besides, any extra wax can be melted down
,,
,’
and used again. If you find that you have to get rid of a batch of wax, let ii
harden and then throw it away.
If the market if, good and you can get the materials, you may want to try scent,
ing your candles with essential oils lie vanilla or sandalwood. Or you might tr]
making colored candles. These oils and pigments must be specially made for use it
candles, however, and are not always available.
SOlUUX
Berold, Robert, and Caine, Collette (eds.). People’s Workbook. Johannesburg, Soutl
Africa: Environmental and Development Agency, 1981.
Simple Melhods of Candle ManufacrUre. London: Intermediate Technology Publica
tions, Inc., 1985.
ic
s
amboo or
ed Writing Pens
This low-cost, easy-to-make pen has been in use in Jordan since 3GOO B.C. Pens
of different sizes can be made for work ranging from fme writing to large block
letters. Siiilar pens have also been used iu Thailand.
Tools and Materials
Dry bamboo, l5cm x Ian x 0.5~~
(6" x 3/8" x 3 / 1 6 )
Small rubber baud or fine wire
Sharp knife
Fine sandpaper
Whittle one end of the bamboo to
the desired width, and then shave
it down to make it flexible (see
Figure 2). Be sure that the writing
tip is made from the more durable
material near the outside of the
bamboo.
Cut the writing end straight across with a sharp knife. Use sandpaper to make
the end smooth. The point of the pen can be shaped to the proper writing angle
for your hand by gently writing on the
sandpaper with the dry pen.
To make a retaining hole for ink, place
the tip of the knife on the pen, at least
3mm (l/S”) up from the point of the
pen, and then rotate the knife to drii a
hole about 2mm (3j32”) in diameter.
The pen can now be. used for writing,
but it will need to be reinked frequently. To make a reservoir pen, attach a
thin bamboo cover plate to the pen as
shown in Figure 3. Attach the cover
plate by wrapping a small rubber band
or a piece of fine w i r e a r o u n d t h e
not&es provided for this.
404
The MufripIier, Vol. 3, No. 10. Washington, D.C.: U.S. Department of State, Agency
for International Development, l%o.
Screen
Silk screen printing is a simple, inexpensive method of producing multiple copies
of attractive visual aids, posters, and other materials, including typewritten pages.
A squeegee forces very thick paint through those parts of the silk screen that
are exposed by the stencil onto paper placed underneath the screen. The silkscreen process presented here is used for educators and trainers who must
prepare their own training materials. It would require considerable upgrading of
equipment and materials to be appropriate for commercial painting operations.
~~~~ING THE SILK SCREEN PRINTER
Tools and Materials
Winges, abut 2Scm x 75cm (1” x 3”)
Wig or regular nuts
Squeegee
Trigger support
Wood for frame
Baseboard or smooth table top
Silk or other sheer cloth
Thumbtacks
Sii screen paint
Paper for copies
Water-soluble paint, e.g., finger paint
(Oil-soluble paint also works well,
but a solvent is needed to clean it off the screen.)
1.
Build a frame (see Figures 1 and 2), using 1.9cm x 5cm (3/4” x 2”) plywood
or other wood. The frame should be big enoulg for the largest prints to be
made. Average inside frame dimensions would be 38.lcm x 50.8cm (18” x 24”).
Make sure that the corners are square and the frame lies flat against a flat
baseboard or table top. The baseboard can also be made of 1.9cm (3/4”)
plywood. A few coats of shellac on the wooden frame wig make it longer
lasting and less apt to warp.
2.
Stretch the silk very tightly over the underside of the frame, using tacks
every 2.&m (I”). Make sure that the threads of the silk run parallel with
the edges of the frame, pull the silk over the outside bottom edges and tack
the silk around the outside of the frame (see Figure 2).
-
3.
Make a saueegee (see Piie 3).
PRINTING
1.
Cut the stencil and attach it to the screen (see “Preparing a Paper Stencil”).
2.
Place the paper or cardboard to be printed under the screen and stencil.
Draw about ltlml (2 teaspoons) of water-soluble paint (for example, finger
paint) in a line along the edge of the silk just inside one end of the frame.
The paint should be thick, about like auto transmission grease, so that it
will not just fag through the screen without being pushed by the squeegee.
3.
Using an edge of the squeegee, pull the paint across the surface of the silk.
This squeezes the paint through all the open areas of the paper stencil. Lii
the screen and remove the print, replacing it with the next piece to be
printed. Pug the paint back in the opposite direction for this print. The
correct technique is to put an amount of paint on the screen that will,
combined with the right pressure on the squeegee, produce a good print with
one stroke of the squeegee.
407
Make sure that the paint
contains n o d r i e d p a i n t
particles. They could damage
the screen.
4.
When a printing is completed,
pull the stencil oflY the screen.
Remove the wing nuts and
wash the frame under running
water.
The pieces to be printed can be registered (lined up so that the printed
image appears in exactly the same place on each piece). Registration guides
can be made of thin cardboard or several layers of tape (see Figure 2).
Thicker guides could break the silk when the squeegee presses the screen
against them. The guides should be taped on the baseboard at the edges of
three sides of the sheets to be printed.
6.
7.
If more than one color is to be printed, registration becomes very important.
The procedure to follow is this:
0
Print the fust color, using
0
Wash the screen as in Step 4 above, and attach the next stencil.
0
Place a piece of waxed paper or thin translucent paper under the
second screen to be printed, and tape this paper on one edge.
0
Print an image of the second screen on this paper.
0
Raise the screen.
0
Slide a sample of the fust printing into position beneath the taped
paper. Adjust the sample so that the second image will appear in the
right place on the pieces already printed.
0
When the sample is lined up, carefully hold the fust printing sample in
position and remove the wax paper.
0
Tape new registration guides on three sides of the sample.
0
More colors can be print
goides.
L, returning to Step 6.
Several colors can be printed over one another if transparent paints are
used.
408
8.
A drying rack (see Figure 5) is helpful when many prints are to be dried.
source:
John Tomlirron, VITA Vohmteer, Rochester, New York
ARING A PAPER STENCIL
This method of preparing a stencil for silk screen printing is more versatile for
some effects than the usual stencil technique: for example, the letter “0” can be
formed without connecting tines to hold the center in place. But the method has
these tiitations: Images must be bold and simple designs. The stencil will last for
only a few hundred impressions; will not hold up with water-base paint; and
cannot be stored.
Tools and Materials
Stencil papersomewhat-transparent white bond paper works well. Commercial
stencil paper can be used, but the edge of the printing may be fuzzy. Thick paper
leaves a thick layer of paint when the squeegee draws the paint across the
screen.
Mimeograph stencils can be used to reproduce typing.
Stencil kniie
A small-blade knife with a handle about as thick as a pencil.
To prepare and use the paper stencil, follow these steps:
0
Place the stencil paper over the image to be reproduced and fasten both to
a hard level surface, like the baseboard of the silk screen.
0
Trace the design and then cut around the areas where one color is to be
printed. Press just hard enough to cut through the stencil paper without
cutting the original. Do not strip the cut-out parts away yet; leave the
stencil intact.
409
0
Put a pad of newspaper on the baseboard of the silk screen so that whea
the screea is lowered it will hit the stencil fumly.
0
Place the stencil oa this pad in the position desired. Slip several pieces of
tape, sticky side up, under the edges of the stendl, this will tape the stencil
to the screen when the screen is lowered. Mask the open areas of the
scxeen beyond the edges of the stencil
0
To make the stencil stick to the screen, draw paint across the screen with
the squeegee.
0
Remove the cut-out parts of the stencil.
0
At the end of the printing run, peel the paper stencil and masking from the
srreen. Clean the screen.
A mimeograph stencil is prepared as it would be for a mimeograph machine.
Attach it to the screen the same way a paper stencil is attached.
::,
Mrs. Renjamin P. Coe, VITA Volunteer, Schenectady, New York
MAKING SILK SCREEN PAINT
The paints described here for silk screen printing should have a shelf life of
several months when they are stored in jars with tight-fitting lids. The recipes
have been tried successfuUy in a temperate climate. Paints colored with powdered
tempera are more brilliant than those colored with food colors or ink. Other
water-soluble dyes can probably be used also.
Materials
Starch or cornstarch
Soap Plakes
Gelatin (optional)
Coloring matter (food color, tempera powder, ink, or a dye of some sort that is
water soluble)
Recipe #l
Lid starch (not instant) 115 ml (l/2 cup)
Roiling water 345ml(l l/2 cup)
Soap Rakes 1lSml (l/2 cup)
Mi starch with enough cold water to make a smooth paste. Add boiing water
and cool until glossy. Stir in soap flakes while mixture is warm. When cool, add
COlOdg.
Recipe #2
Cornstarch 575mI (l/4 cup)
Water 46&111(2 cups)
Soap ftakes 29ml (l/8 cup)
Bring water to a boil. Mix comstarcb with a small amount of cold water and stir
the two together. Bring to a boii and stir until thickened. Add soap flakes while
warm. Color.
This recipe produces paint that seems quite hrmpy but this does not affect the
printing quality.
Dissolve 115mi (l/2 cup) cornstarch in 172Sml(3/4 cup) cold water
Dissolve 1 envelope gelatin (l5ml or 1 tablespoon, unflavored) in 57Sml (l/4 cup)
cold water
Heat 46Oml (2 cups) of water, porn in cornstarch. Add dissolved gelatin. Boil, and
stir until thiskened. Cool and add 115ml (l/2 cup) soap flakes. Color.
NOTE: Adding 5 to 1Oml (1 to 2 teaspoons) of glycerine to any of these recipes
will make the paint easier to use.
Never let dried particles of paint get mixed into the paint or fall onto the screen
because they may puncture the silk during the printing. A small hole in the silk
can be :epaired with a small drop of shellac
Mrs. Benjamin P. Coe, VITA Volunteer, Schenectady, New York
ensive
Inexpensive rubber cement can be made easily with ordinary gasoline and raw
sheet rubber.
Imported pastes are often expensive. Many of these are not good for mounting
pictures and similar materials, they soak through the paper and wrinkle both the
picture and the mount.
Rubber cement does not wrinkle the pieces to be joined. It has another advantage:
if it smears, it can be rubbed off with the fingers when it is dry.
Tools and Materials
Ordinary gasohne: 25lkc (16 ounces)
Raw sheet rubber in one piece:
Sgm (l/5 ounce)
Jar with lid
Stirring rod
Brown bottle
*Tin can
*Charcoal
‘Small pieces of cloth
* Needed only if gasoline is colored.
The rubber to be used should be a translucent, light-brown sheet. Any brand of
gasoline can be used. Some gasolines are highly colored. Thii coloring should be
removed so that the rubber cement will not stain when it is used. To remove the
coloring, pour the gasoline over common charcoal several times (see Figure 2).
Use a clean tin can with a hole in
the bottom. Pi;t a small piece of
cloth in the bottom of the can to
keep the charcoal from falling into
the filtered gasoline. You may have
to change the charcoal several
times before the gasofme is clear.
Put the 5 grams (11.5 ounce) of raw
sheet rubber in a jar and pour in
the Z4kc (16 ounces) of ordinary
gasoline (see figure 1). Cover the
jar.
It takes about three days for the rubber to dissolve completely in the gasoline.
Stir the mixture several times during this period, especially when the mixture
becomes thick. If some of the rubber does not dissolve, more stirring will break it
up. When the rubber is dissolved, you wilt have a smooth, milky-colored cement.
To store the rubber cement, it is best to use a brown bottle because the cement
will become thin if it is exposed to sunlight for a long time.
Mark the bottle:
DANGER EXTREMXY PEAllLE,
HARMPUL OR FATAL IF SWALLOWED
The cement should be kept in a ventilated cupboard when it is not being used.
To make a handy dispenser for the
cement: Cut a hole in the cover of
the jar, large enough for the
handle of a 2.5cm (1”) brush (see
Figure 3). Push the handle through
the hole and leave the brush in the
jar. Tbis should be airtight because
the cement hardens quickly when
exposed to air.
Bunyard, Robert J. “Rubber Cement in a Tropical Climate,” %3te Multiplier, Vol. 2,
No. 6, July 1956.
41s
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Bird, H.R. Undopondig Pa&y Mea oo4 Egg Frod&on. Arfit@oa, Virginia: Volunteers in Technical
Assistance, 1984.
Bradcnbu& N.R. Bibfiogqhy of Jfawnbag and Pnxesiq Fonage Se& 1949-1464. U.8. Depattmcnt of
Agriculture, Apicultutal Research SC&x, AR.5 42-135, Washington: USDA, 1968.
Branch, Diana S. (cd.). Twls for ff-& Chvdmm, and Small-Sca& Formen, @mmau.s. Patttsylada, 1978.
Cmwt, Jamcs. B&c Soil Impmwment for Ewpte. Ariin8too, Virginia: Volunteers in Technical
Assistance. 1983.
I?nsminger, ME, and Olentine, CO., Jr. Fredr and Nutrition. Clovis, California: Ensmingcr Publishing
co.. 1978.
Fitts, J.W.. and Fltts. J.B. UndersIonding Camp&g. Arlington, Virginia: Volunteers in Technical
Asiitann. 1984
Freeman, John A. SunivpI Gmdenin~ Enough Nuuidon J?om Z,wO Square Feet To L.iw Gn..Just in
Case.’ Rock Hill, South Carolina: John’s Press, 1983.
Hu8hes. H.D. Fomges. Attes, !%: Iowa State Univenity Press. 1966.
Hunt. Marjorie, and Bat& Brenda. High Yifd Cordming. Emmaus, Penasylvanis: Rodalc Press, Inc.,
1986.
National Academy of Sciences. NuDimr ReguiremmLs of Pot&y. Washington, D.C: National Academy
F=rcss, 1977.
North, M.O. Commcrciol Chicken Roductin Mom&. Second Edition. Westport. Conncxticut: AVI Publishing Co.. Inc., 1978.
Orr, H.L tick and Goose R&&g. Publication 532. Ontario, Canada: Ministry of Agriculture and Food.
Pilian& W.G.; Bird, H.R; Sunde, M.L; and Ptinglc, DJ. ‘Rice Bran as the Major Energy Source for
Laying Hens.’ Pot&v Science. 61 (1982): 357.
Ready, R.R, Khalcel. R, and Ovcrcash, M.R *Behavior and Transport of Microbial Pathogens and Indicator Organisms in Soils Ttcatcd with Organic Wastes.’ Joumol of Envimnmenml Qua&y. Madison,
Winsin: American Society of Agronomy. 1981.
Rcdalc. J., td. 77te Complete Boofc of Composdng. Emmaus, Pennsylvania: Rodale Press, Inc., 1969.
Rossel, F. W. Soil Condiabnr and Plant Growth London, Et&ma: Logmans Gtccn and Co., Ltd., l%l.
Stem, Peter. SmaU SC& 6rigorioo. Lwdon: Intermediate Technology Publications, 1979.
Yam& JA.. Evans. RA. & Body, J.D. Vmientondbzg Seed Co/&c&t and Handling. Arlington, Virginia:
Volunteers in Technical As&awe, 1986.
FUOD PRUXX5SNG AND PRESERVKIYON
Anders~tt, Jean. The Grit thumb prrvrving Guide. New York: William Marmw 81 Cornpay, Inc., 1976.
419
Burch, Joan, and Butch, Monk Home Canning and Rrsaving. Restott, Virginia: Restott Publishing
cmpany. Inc., 1977.
Carmthets, R.T. UndmtMdig Fisk Resew&m and Racessing. Atiiqtott, Virginia: Volunteers in
Technical Asiitance. 1985.
Central Food Teehttological Rescarrb Institute. ‘Home-Scale Processing and Prcservatioa of Fruits and
Vegetables.” Mysore, India: ‘Ihe Wesley Press, 1981.
Etchells, John L, and Jones, Ivan D. ‘Ptesetvation of Vegetsblg by SaItiqf or Brining.’ Fanners’
Bulletin No. 1932. Washington, D-C: U.S. Ikpanment c Agriculture, 1944.
Groppe, Ckistiae C, and York, George K “PicWes, ReIiis,and Cbuttteys: Quick E!asy, and Safe
Recipes.’ Leafkt No. 2275. Berkeley, California: Univwsity of California, Diiicm of Agricultural
scicnns, 197.5.
Hertzberg, Ruth; Vaughan. Beatrice; and Gtwte, Janet. puctlrg Food @v. Bnttkbom, Vermont: The
Stephen Greene Prcg
Islam, Mehemnnesa. Fond Resow&n in Banglad& Dacca. Bangladesh: Women’s Development Pm
gramnu, IJNICBF/DACcA. 1977.
Kluger, Marilyn. F2txn*g summa‘s Rounty. New York M. Evans and Cmnpany, Inc., 1978.
Lcviwm, Leonard Louis. 77r.c Conpfcti? Book oJPicklu and R&ha. New YorL: Hawthorn Books, Inc..
196.
Lindblad, Carl. and Drub-a. Laurel. Small Fmm Grain Storage. Arlington, Virginia: Volutttcers in Technical Assistance, 1976.
Muny, Sue T. Home Cuing Fish Washington, D.C: Agsiculturc and Rutal Development Sewicq Agency
for International Development, 1967.
Schukr, Stanley, and Sehulcr. Eli&&h Meriwcther. Rezntig a? Fruits of& Each NEW YorL:
The Dial Press, 1973.
Stiebeling, Jazz+ K ‘Solar Food Presrvation.’ Chicago, Illinois: Illinois Institute of Technology, 1981.
Stoner, Cad Hupping, Editor. Stocking Up: How To Resow tJte Fwdr You Grow, Natundly, Emmaw,
Pennsyhania: Rod&e Pros. 197X
U.S. Department of Agriculture. Hutian Nutrition Rcscarrh Division. “Home Canning of Fruits and
Vegetables.” Washington, D.C: U.S. Department of Agriculture, 1963.
Weber. Fred, with Stoney, Carol. R@estsdon in Arid Lands. ArIington, Virginia: Volunteers in Technical As&awe, 19%.
Worgan, J.T. ‘Cantting and Bottling as Methods of Food Preservation in Developing Cotmtries.” ~ppopiate Teciuwlqy. 4 (November 1977): 15-16.
CONSIWJCIlON
Action Peace G?tPs. Handbook for Buikfing Homes oJEmth Washington, D.C: Depstment of Housing
and urban Dewlop ment, (undated).
Ahrats. C. Manual for Supenising Sel~Help Home Co-don witk Stabilized Eank Hocks Made in
the CfhKA-Ram Ma&ne. Kanawba County, Weal Virginia, 1965.
420
American Concrete Insfihrte. Handbook oJConcmc En-g. ACISZ Manual of Practice. Detroit,
Michigan America Gmcrete Institute, 19f2.
Buchanan. W. Hami Moukied Bwm Ckay m Lobour I- Production. Mslawi Ministry of Trade,
Industry, and Tourism (United Nations Industrial Dcwlopment Otganizatio”, Projert DP/MLW/78ILXIJ),
undated.
I*rildig w&h A&be a& .%a&&& Eonit B&k Washington, D.C: United States Department of Agriculture, 1972.
Bush, Alfred. UnderaMding Srob*lsd Eunh COWJUUC~~~IZ Arlbtgton, Virginia: Volunteers in Technical
Assistance. 1984.
Grobe”, E W. Adobe Archlucdm: Its &sign ad Conmucdon Seattle, Washington: ?he Shorty Book
stosq 1975.
Iotanational Iwtitute of Housing Technology. ?iu ManuJacture oJAspkak EmuLdnn Stabilized Soil
l%ch and &ick Makrr’s Monuol. Pres”o, California: California State University, 19?2.
Lunt, M.G. Stobiii.?ed Soil B&arks fa Building. Gsrston, Watford, Bnglsnd: EuiWing Research Establishment, 1930.
‘Stabilized Soil Blocks for Building.* Overseas Building Notes No. 184. Garston, England:
Building &search Establishment. February 1980.
Making Building Blockr with the CAXA-lbm Block Rex. Arlington, Virginia: Valunteers in Technical
Assistance, 1975.
Metalibec Ltd. CINKAA-Rnm Bkxk Cemer~ Soil in Loge Scak Homing Conrmrcdon in East Punjab,
Bombay. India: Government of India Press, 1948.
~~th@ds for Cbacrerizing Adobe Building hfnrerinlr Washington, DC:. National Bureau of Standards,
1978.
Parry, J.P. Brickmak&g in Developing Couwies. Prepared for Owxas Division, Building Research
Ertablishmcnt. UK Garston, Watford, United Kingdom: Building IQsearch Establishment, 1979.
Salvadorea” Foundation for Development and Iaw Cost Housing Research Unit. Stabilized Adobe. Washington, D.C: Organization of America” States, (undated)
Sidibe, B. Undenrnnding Adobe. Arlington. Virginia: Volunteers in Technical Assistance (VITA), 1985.
U.S. Agency for International Development. Handbook for Building Homes oJEmh Action Pamphlet
No. 42fD.X. By Lyle A. Wolfskifl, Wayne A. Dunlop, and Bob M. Callaway. Washington. D.C: Peace
Corps, December 1979.
U. S. Dept of the Amy. Concrete, Mororvy and Brickw~ A Practical Hamibmk for tk.e Home Owner
and Small Buikim. New Yorkz Dover Publications, Inc., 1975.
BaIti”, S. Biomoa SWKS: Enginnring LA&g”, &~&pme”t, and &se&&on. Arlington, Vir$“ia:
Volunteers in Technical Assitance. 1986.
BNF~~. John. Cou”“y Comfom: nte Nov Hont&e& Handbo& New Yorft: Sterling Publishing Co.,
1°C.. 1979.
Brdmr~n, A”“. Soap. New Yorlc Work”tan Publishing Co., 1975.
Clark R (cd.). WOOASm Diswminadon: Ihmd& oft& Confmce Held (I) Worfhtre. lh
Nerherlandr. London: Intemtcdiate Technology PublicationF, Ltd., 1985.
421
de Siha, D. *A Chareosl Stove From Sri Lanke,“Appqprinrc Tecitnbgv, Vol. 7, No. 4.1981. pp. 2224.
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1986.
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CRAPI AND VILUGE INJXISIRY
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Cardew, M. Pimew Potmy. Near Yotk, New York: St. Martin’s press, 1976.
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1968.
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Troy, J. Clara
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Vogler, Jon, and Setjeent. Peter. IJndemMding Smufl-Scafe Pcpmmkhg. Arlington. Virginia: Vohmteem in Technical Assistance, 1986.
422
Weeps, A.G. The M&g
of Tad. lUcw Y&c
Van Nostrand Reinhold Company, 1973.
Young, Jean (cd.). W- CX+sman3 MCMUOL New YorL: Pnegcr Publisbet& 1!?72.
coNMuNl~ll0~AND GENERAL RppeRwcB
Bcmld, Robert, and Caine, lI.Uettc (eds.).
td and Development Agency, 1981.
Pqk’s
W- Jo~~M&uI’&
South
Africa: Enrimnmen-
Darrcw, Ken, end !Axcnian, Mike. Apvxopnhrr TrrhMbgy SoMcboat Stanford, Califontis: Vobmteers
in Asia, 19%.
Mclaren. 1.7% Sm-Scmn: Making and Using a .!mv-Cm Printing Recur lmndcm Intermediate
Technology Publications, Inc.. 1983.
Seymour, John. 7%~ Complete Ba& of Self Su~ietq Loodon: Cm@ Books dii. Transwa rid Publiiers.
Ltd., 1981
nversion Tables
CONVERSION TABLES
MUllIPLY
BCPeY
acres
acres
acres
acres
atmospheres
atmospheres
atmospheres
atmospheres
British thermal units
TO OBlAiN
BY
43,560
4,047
1.562 X 1T3
0.004047
4840
76.0
29.92
10,333
14.70
0.2530
B.t.u.
R.L.".
5.t.u.
centimeters/second
centimeters/second
cubic centlaeters
cubic centimeters
cubic
cubic
centimeters
centimeters
cubic
cubic
cubic
cubic
cubic
feet
feet
feet
feet
cubic Feet
cubic
cubic
cubic
cubic
cubic
feetiminute
feet/minute
feet/minute
Ceet/minute
inches
inches
cubic inches
cubic
meters
meters
cubic
meters
yards
yards
yards
yarda
yards
yards
cubic
cubic
cubic
cubic
cubic
cubic
cubic
cubic yards/min.
meters
square miles
square kilometers
square yards
cm of mercury
inches of mercury
k&square meter
pounds/square inch
kilogram-calories
foot-pounds
horsepower-hours
joules
kilogram-meters
kilowatt-hours
hOC3l?pOWel-
B.t..u.
f3.t.u.
B.t .u./min.
B.t .u./mrn.
B.t .u./min.
CalfJriS
CalClEieS
calories
cent imeters
centimeters
centimeters of mercury
centimeters/second
zent imeters/second
square feet
square
3.08596
1.1622 X 10-6
0.3937
0.01
0.1934
1.969
0.036
0.6
G.02237
10-6
0.102 x
3.531 x
1.308 x
1,728
0.02832
2.832 X
7.481
28.32
472.0
0.1247
0.4720
62.4
5.787 x
1,639 X
2.143 X
35.31
264.2
kilowatts
watts
e.t .U.
foot-pounds
kilowatt-hours
inches
meters
pounds/square
feet/minute
inch
kilometer/hour
10-2
10-5
10-6
IO4
meters/minute
miles/hour
cubic meters
cubic inches
cubic
Feet
cubic yards
cubic inches
cubic meters
cubic centimeters
gallons
liters
cubic ems/second
gallons/second
liters/second
10-4
1O-5
IO-'
103
7.646 X lo5
27.0
46,656
0.7646
202.0
764.6
0.45
pounds
water/min
cubic feet
cubic meters
cubic yards
cubic feet
CJallons
liters
cubic cent imetsrs
cubic Feet
cubic inches
cubic met.ers
gellons
liters
cubic feet/second
TO
MULTIPLY
cubic
yards/min.
cubic yards/min.
degrees (angle)
degrees
degrees
dynes
(angIeI
(angle)
dynes
ergs
ergs
ergs
3.367
12.74
60
0.01745
3,600
1 .a20 x 1 o-!
2.248 x 10-b
9.486 X IO-"
:.376 X lO-8
ergs
ergs
ergs
ergs/second
ergs/second
Feet
feet
feet/second
foot-pounds
foot-pounds
Foot-pounda
foot-pounds
foot-pounds
foot-pounds
foot-pounds/minute
foot-pounds/minute
Foot-pounds/minute
foot-pounds/minute
f
oat-pounds/second
Foot-pounds/second
Foot-pounds/second
foot-pounds/second
gallons
g*llOnS
gallons
gal I o n s
gallons/minute
gelloos/minute
grams
gr *nis
grams
gr ml4
grams/cubic centimeter
grams cent imet.ers
horsepower
horseporier
aorsepoker
horsnpower
horsepower
horsepower
horsepower
horsepower-hours
horsepower-hours
horsepower-hours
horsepower-hours
horsepower-hours
horsepower-hours
inches
inches
OBTAIN
gallons/second
liters/second
minutes
radians
seconds
grams
pounds
e.t.u.
dyne-centimeters
foot-pounds
joules
kilogram-calories
kilogram-meters
horsepower
lo-‘*
30.48
0.3048
18.29
I.286 x 10-3
1.356 X lo7
5.050 x 10-7
3.241 X lO-4
0.1383
3.766 X lO-7
1.286 X lO-3
0.01667
3.241 X lO-4
2.260 X lO-5
7.172 X IO-2
1.818 x 10-3
1.945 x 10-2
1.356 X lO-3
0.1337
231
3.785 X IO-3
3.785
2.228 X 10-3
0.06308
10-3
103
0.03527
0.03215
62.43
9.291 x 10-8
42.44
33,000
550
10.70
0.7457
745.7
1.014
2547
1.98 x 106
641.7
2.737 X lo5
0.7457
2.684 x 106
2.540
254.0
kilowatts
cent imeters
meters
meters/minute
B.t .u.
ergs
horsepower-hours
kilogram-calories
kilogram-meters
kilowatt-hours
8.t .u./minute
Foot-pounds/second
kg-calories/min
kilowatts
B.t.u./minute
horsepower
kg-celcries/min
kilowatts
cubic feet
cubic inches
cubic meters
liters
cubic feet/second
liters/second
kilograms
miligrams
OUnCes
troy o”nces
pounds/cubic feet
B.t.u.
B.t.u./minute
foot-pounds/minute
Foot-pounds/second
kg-calories/aio
kilowatts
watts
horsepower(metric)
6.t.u.
foot-pounds
kilogram-calories
kilogram-meters
kilowatt-hours
joules
cent imeters
millimeters
MULTlPLY
inches
of
mercury
inches
of
water
inches of mercury
inches of mercury
inches of mercury
inches of mercury
inches of water
inches of water
inches of water
inches of water
inches of water
jOtIlE+
joules
~ioules
Joules
kilograms
kilograms
kilograms
kilograms
kilogram-calories
kilogram-calories
kilogram-calories
kilogram-calories
kilogram-calories
kilogram-calories/min.
kilogram-ca?ories/min.
kilogram-calories/min.
kliograms/hectare
kilometers
kilometers
kilometers
kilometers
kilometers
kilometers/hour
kilometers/hour
kilometers/hour
kilometers/hour
kilometers/hour
kilometers/hour
kilowatts
kilowatts
kilowatts
kilowatts
kilowatts
kilowatts
kilowatts-hours
kilowatts-hours
kilowatts-hours
kilowatts-hours
kilowatts-hours
kilowatts-hours
meters
meters
meters
meters
meters
meters
meter-kilograms
BY
TO
0.03342
1.133
345.3
10.13
0.4912
0.002458
0.07355
25.40
0.5781
5.204
0.03613
0.0009458
0.73756
0.0002778
atmosphex=as
feet of water
kgs/sq meter
pounds/sq foot
pounds/sq inch
atmospheres
inches of mercury
kgs/square meter
ounces/square inch
pounds/square foot
pounds/square inch
B.t.u.
foot-pounds
103
2.2046
1.102 x 10-J
3.968
3,066
1.558 x 10-3
4,183
426.6
51.43
0.09351
0.06972
.I393
105
616214
3,281
1,000
1093.6
27.70
54.60
0.9113
0.5396
16.67
0.6214
56.92
4.425 X lo4
737.6
1.341
14.34
grams
pounds
short tons
6.t.u.
foot-pounds
horsepower-hours
103
3,412
2.655 X lo6
1.341
3.6 X lo6
860.5
3.671 X lo5
100
3.2808
39.37
10-J
3
PO936
9.807 x 107
OBTAIN
watt-hours
watt-seconds
dynes
joules
kilogram-meters
foot-oounds/second
horsepower
kilowatts
pounds/acre
imeters
miles
cent
feet
meters
yards
centimeters/set
feet/minute
feet/second
knot s/hour
meters/hour
miles/hour
B.t .u./minute
foot-pound&minute
foot-pounds/second
horsepower
kg-calories/min
watts
B.t.u.
foot-pounds
horsepower-hours
joules
kilogram-calories
kilogram-meters
centimeters
feet
inches
kilometers
millimeters
yards
centimeter-dynes
MULTIPLY
BY
TO
meter-kilograms
105
7.233
1.667
3.281
0.05468
1.06
I. 53728
196.8
3.281
3.6
0.06
2.231
0.03728
1.609 X IO5
5,280
1.6093
1,760
88.0
1.6093
0.8684
8.0
437.5
28.35
0.625
0.0625
centimeter-grams
pound-feet
centimeters/second
feet/minute
meter-kilograms
meters/minute
meters/minute
meters/minute
meters/minute
meters/minute
meters/second
meters/second
meters/second
meters/second
meters/second
meters/second
miles
miles
miles
miles
miles/min
miles/mi"
miles/min
ounces
ounces
Ounces
O”“COS
ounces/square inch
pints (dry)
pints (liquid)
pounds
pounds
pounds
pounds
pounds of water
pounds of water
pounds of water
pounds of water/min.
pounds/cubic
foot
pounds/cubic foot
pounds/cubic
foot
pounds/square foot
pounds/square
foot
pounds/square inch
pounds/square
inch
pounds/square inch
quarts (dry)
quarts (liquid)
quadrants
(angle)
quadrants (angle)
quadrants
(angle)
radians
radians
radians/second
raidens/second
revolutions
revolutions
revolutions
revolutions/minute
square centimeters
square centimeters
square
centimeters
33.60
28.87
444,823
7,000
453.6
0.45
0.01602
27.68
0.1198
2.669 X
0.01602
16.02
5.787 x
4.882
6.944 X
0.06304
703.1
144.0
67.20
57.75
90
5.400
1:571
57.30
3,438
57.30
0.1592
360.0
4.0
6.283
6.0
1.076 X
0.1550
10-6
OBTAIN
feet/second
kilometers/hour
miles/hour
feet/minute
feet/second
kilometers/hour
kilometers/minute
miles/hour
miles/minute
centimeters
feet
kilometers
yards
feet/second
kilometers/minute
knots/minute
drams
grains
grems
pounds
pounds/square
cubic inches
cubic inches
dynes
grains
grams
inch
kilograms
cubic
cubic
1O-4
10-4
1O-3
feet
inches
gallons
cubic feet/second
grams/cubic ems.
kgs/cubic meter
pounds/cubic
inch
kgs/sq meter
pounds/square inch
atmospheres
kgs/square meter
pounds/square foot
cubic inches
cubic inches
degrees
minutes
radians
degrees
minutes
degrees/second
revolutions/second
degrees
quadrants
radians
1O-3
degrees/second
square feet
square inches
square
meters
MULTIPLY
BY
square centimeters
square feet
square feet
square feet
square feet
square feet
square feet
square inches
square
inches
square
meters
square meters
square
meters
square meters
square miles
square miles
square miles
square miles
square yards
square yards
square yards
square yards
temp (degs C) + 237
temp !degs C) + 17.8
temp (degs F) - 32
tons !long)
tons (long)
tons (metric)
100
2.296 X
929.0
144.0
0.09290
3.587 x
0.1111
6.452
645.2
2.471 X
10.764
3.861 X
1.196
tons (metric)
tons
tons
tons
tons
tons
tons
yards
(short)
(short)
(short)/sq.
(short)/sq.
(shortf/sq.
(shortjisq.
foot
foot
inch
inch
TO
10-5
10-e
1O-4
lO-7
640.0
2.7878 X IO7
2.590
3.098 x 106
2.066 X 1O-4
9.0
0.8361
3.228 X 1O-7
1.0
1.8
5/9
1,016
2 40
1093
2,205
907.2
2,000
9.765
13.89
1.406 X lo6
2.000
0: 9144
OBTAIN
square
BCPBS
millimeters
squere
square
square
squere
miles
square
square
centimeters
millimeters
square
acres
centimeters
inches
meters
yards
square feet
square miles
squere yards
scres
square feet
square kilometers
square yards
acres
square feet
square meters
square miles
abs temp (degs K)
temp (degs F)
temp (degs C)
kilogrsms
pounds
kilograms
pound?
kilog~rsms
pounds
kgs/squsre meter
pounds/square inch
kgs/square meter
pounds/square inch
meters
FIGURE 1
TEMPERATURE CONUERSION
The chart in Figure 1 is useful for
uick conversion from degrees Celsius
9 Centlqrade) to degrees Fahrenheit and
vice versa. Although the chart is fast
and handy, you must use the equations
below if your answer must be accurate
to within one degree.
Equations:
Degrees Celsius = 5/9 x (Degrees
Fahrenheit -32)
Degrees Fahrenheit = 1.8 x (Degrees
Celsius) +32
Example:
This example my help to clarify the
use of the equations; 72F equals how
many degrees Celsius?
72F = 5/q (Degrees F -32)
72F = 5/9 (72 -32)
72F = 5/9 (40)
72F = 22.2C
Notice that the chart reads ZZC, an
error of about 0.2C.
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