Tubes Interchange

Interchangeability of Gas
Detection Tubes and Hand
Pumps
Werner R. Haag, Ph.D.
American Industrial Hygiene
Association Journal
Vol. 62, pp 65-69, 2001
Gas Detection Tubes
Question:
Can RAE tubes be used in Gastec
or Draeger hand pumps and vice
versa?
Answer:
Gastec - Yes
Draeger - No
Milestones in better Tube Accuracy




Sliding Scale vs precalibrated printed
scale
Early squeeze bulb pumps lacked
accuracy
Introduction of piston style pumps
Flow limiting device moves from orifices to
the tube itself
Modern Tube Types
Low-Vacuum Bellows
 ~7 mm tube o.d.
 Larger particles
 Examples:
• Draeger Accuro
• MSA Kwik-Draw
High-Vacuum Piston
 ~5 mm tube o.d.
 Smaller particles
 Examples:
• RAE LP-1200
• Gastec GV/100
• MathesonKitagawa 8014400A
Pump Designs
MSA
DRAEGER
RAE
GASTEC
KITAGAWA
Piston Pump Design
Shaft
Piston
Volume
Notch
Pump Flow Characteristics
Internal Vacuum (cm Hg)
70
RAE LP-1200
60
Gastec GV/100
50
Piston Pumps
Kitagawa 8014-400A
40
Draeger Accuro
30
MSA Kwik-Draw
20
10
Bellows Pumps
0
0
20
40
60
80
Time (Seconds)
100
120
System Flow Characteristics
Piston
Pumps
Flow Control
Tube
Pump Vacuum High
Tube Diameter 5 mm
Bellows
Pumps
Pump
Low
7 mm
System Flow Characteristics
Flow rate can affect stain length
because enough time is needed to:
 Allow color reaction to occur
(High flow = stain too long)
 Allow pre-tube reactions to occur
(High flow = stain too short)
Summary of Interchangeability Tests
Pumps
Tube
Test Gas
RAE Gastec Kitagawa
RAE 100-10
10 ppm NH3
11
11
10 (0.5 min)
Gastec 3La
50 ppm NH3
51
52
50
RAE 100-20
300 ppm NH3 290
310
300
RAE 101-05
5 ppm Benz
5.8
5.6
6.0 (10 min)
RAE 101-20
50 ppm Benz 43
45
44
RAE 102-30
250 ppm CO
230
230
240 (2 min)
RAE 103-40
0.5% H2S
0.42% 0.43% 0.43%
RAE 103-10* 25 ppm H2S* 29
29
29
Gastec 4LL* 25 ppm H2S* 26
27
26
Kitagawa 120SD*25 ppm H2S* 29
29
29
*Tests Conducted at Stanford University
Summary of Interchangeability Tests
Pumps
Tube
Test Gas
RAE Gastec Kitagawa
RAE 103-10** 10 ppm H2S** 10
10
10
20 ppm H2S** 20
20
19
50 ppm H2S** 46
47
46
RAE 103-20
100 ppm H2S 97
104
107
RAE 103-30
1000 ppm H2S 1070 1070 1090
RAE 104-50* 10% CO2*
9.2
9.8
9.6
Gastec 2H*
10% CO2*
9.2
9.6
9.1
Kitagawa 126SH*10% CO2*
9.5
9.9
9.8
**Tests Conducted at San Francisco City College
*Tests Conducted at Stanford University
Piston Pump Interchangeability






58 Different mixed tube-pump combinations
11 Different chemicals
Average deviation between pumps: 3.2%
Max deviation between pumps: 14%
Average deviation from standard: 6.7%
Max deviation from standard:
24%
RAE Interchangeability Statement
Interchangeable Piston Pumps:
 RAE LP-1200
 Gastec GV/100
 Matheson-Kitagawa 8014-400A
Pumps Must Have Same:
 Volume Accuracy
 Flow Characteristics
 Tube Fit (5 mm = 5 mm)
RAE Interchangeability Statement
=
MSA Interchangeability Statement
Interchangeable Bellows Pumps:
 MSA Kwik-Draw
 Auer Gas-Tester II H
 Draeger Model 31
 Draeger Accuro
Pumps Must Have Same:
 Volume Accuracy
 Flow Characteristics
 Tube Fit (7mm= 7mm)
Summary of Interchangeability Tests
Tube
RAE 100-10
RAE 100-20
RAE 102-30
Gastec 4LL
Dräger H2S 2/b
MSA H2S-1
RAE 104-50
Kitagawa 126SH
RAE 107-20
RAE 109-20*
Test Gas
10 ppm NH3
300 ppm NH3
250 ppm CO
25 ppm H2S
25 ppm H2S
25 ppm H2S
10% CO2
10% CO2
50 ppm SO2
25 ppm NO
Dräger
ppm
11
230
180
25
31
24
9.2
9.1
49
8.7
MSA
ppm
10
240
200
25
29
26
9.3
9.2
50
9.2
*Combination pre-tube & measurement tube.
min
1
2.5
7
2.5
0.5
0.5
6
3.5
5
7
Piston Avg
ppm
min
11
0.5
300
1
230
2
26
1
34
0.4
28
0.4
9.5
1
9.7
1
50
2
24
2
MSA Interchangeability Statement
=
RAE Interchangeability Statement
=
Agency Approval
Why do several government agencies have
statements against interchangeability?
All seem to be based on old 1974 study* using
pumps of different design and flow
characteristics and mostly are no longer used:
 Four orifice limited pumps
 one bellows pump
 one piston pump
* Cohen, F.H., A study of the interchangeability of gas
detector tubes and pumps, AIHA Journal 35, 686 (1974).
Conclusions



Tubes and pumps are interchangeable if
design/performance criteria are the same
and appropriate leak checks are performed
Interchangeability should be guided by
pump specifications, not by brand name.
Because the piston pumps tested are
equivalent, any new tube designed to work
on the Gastec pump will also work on the
RAE or Kitagawa pumps, and vice versa.
Thank you for reading this data sheet.
For pricing or for further information, please contact us at our UK Office, using the details
below.
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Keison Products,
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Tel: +44 (0)1245 600560
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Email: sales@keison.co.uk
Please note - Product designs and specifications are subject to change without notice. The user is responsible for determining the
suitability of this product.