district of columbia construction codes supplement of 2008 dcmr 12e

district of columbia construction codes supplement of 2008 dcmr 12e
DISTRICT OF COLUMBIA
CONSTRUCTION CODES SUPPLEMENT OF 2008
DCMR 12E MECHANICAL CODE SUPPLEMENT
CHAPTER 4E VENTILATION
SECTION M-401E GENERAL
Add new Section M-401.4.1.1 to the Mechanical Code to read as follows:
M-401.4.1.1 Height Above Grade. The bottom of outside air intake openings
shall be a minimum of 2 feet (610 mm) above the adjacent grade or above the
bottom of adjacent areaways. Where alleys, parking lots, loading docks, and
other areas with vehicular access are located less than 10 feet (3048 mm)
horizontally from the outside air intake opening, such opening shall be located a
minimum of 10 feet (3048 mm) above the surface of those areas.
Add new Section M-401.4.2.1 to the Mechanical Code to read as follows:
M-401.4.2.1 Garage Exhaust. Exhaust openings serving public garages shall be
a minimum of 25 feet (7620 mm) from any operable window, door, or outside air
intake opening. The bottom of exhaust openings serving public garages shall be a
minimum of 15 feet (4572 mm) above streets alleys or other walkways. When
exhaust is directed upwards, the code official is authorized to approve garage
exhaust openings less than 15 feet (4572 mm) above streets, alleys, or other
walkways, in accordance with Section 105.
CHAPTER 5E EXHAUST SYSTEMS
SECTION M-506E COMMERCIAL KITCHEN HOOD VENTILATION SYSTEM
DUCTS AND EXHAUST EQUIPMENT
Delete Section 506.3.12 of the Mechanical Code in its entirety and add new Section M-506.3.12
to read as follows:
M-506.3.12 Type I Exhaust Duct Termination. Ducts shall run as directly to the roof as
practical. The system termination shall be a minimum of 2 feet (610 mm) above the roof
or any part of structures within 10 feet (3048 mm) of the termination, and not less than 25
feet (7620 mm) from any operable windows, intakes, doors or lot lines
Exceptions:
1.
On narrow lots where a 25 foot distance from any operable windows,
intakes, doors, or lot lines cannot be achieved, the code official is
authorized to approve a smaller distance.
2.
When an approved odor and grease removal system is installed,
termination is permitted in accordance with the requirements of Sections
401.5 and 501.2 of the Mechanical Code.
Add new Section M-515 to read as follows:
SECTION M-515E LABORATORY HOODS
M-515.1 Laboratory Hoods. Laboratory hoods and ventilation system shall comply with NFPA
45-2004 listed in Chapter 15.
CHAPTER 6E DUCT SYSTEMS
SECTION M-607E DUCT AND TRANSFER OPENINGS
Delete Exceptions under Section 607.5.5 of the Mechanical Code and add new Exceptions to
read as follows:
M-607.5.5 Shaft enclosures. Shaft enclosures that are permitted to be penetrated by
ducts and air transfer openings shall be protected with listed fire and smoke dampers
installed in accordance with their listing.
Exceptions:
1.
Fire and smoke dampers are not required where steel exhaust sub-ducts
extend at least 22 inches (559 mm) vertically in exhaust shafts provided
there is a continuous airflow upward to the outside and the fan is wired to
the buildings emergency system.
2.
Fire dampers are not required where penetrations are tested in accordance
with ASTM E119 as part of the fire resistance rated assembly.
3.
Fire and smoke dampers are not required where ducts are used as part of
an approved smoke-control system in accordance with Section 909.
4.
Fire and smoke dampers are not required where the penetrations are in
parking garage exhaust or supply shafts that are separated from other
building shafts by not less than 2-hour fire-resistance rated construction.
5.
Smoke dampers are not required where the building is protected
throughout with an automatic sprinkler system in accordance with Section
903.3.1 of the Building Code.
CHAPTER 8E CHIMNEYS AND VENTS
SECTION M-801E GENERAL
Add new Section M-801.21 to the Mechanical Code to read as follows:
M-801.21 Smoke Test. Before a new appliance is put into use, a new or existing chimney shall
either be proved tight by a scented smoke test or provided with a certification of tightness by a
licensed contractor.
CHAPTER 9E SPECIFIC APPLIANCES, FIREPLACES AND SOLID
FUEL-BURNING EQUIPMENT
SECTION M-922E KEROSENE AND OIL-FIRED STOVES
Delete Section 922 of the Mechanical Code in its entirety.
CHAPTER 10E BOILERS, WATER HEATERS AND PRESSURE VESSELS
SECTION M-1004E BOILERS
Delete Section 1004.1 of the Mechanical Code in its entirety and add new Section M-1004.1 to
read as follows.
M-1004.1 Standards. Boilers and their control systems shall be designed and constructed in
accordance with the requirements of one or more of the following standards; ASME Boiler and
Pressure Vessel Code Sections I to XI (2001 Edition), ASME CSD-1 (2002), NFPA 8501, NFPA
8502, NFPA 8504, UL 726, and the National Board Inspection Code (NBIC) 2001 ANSI/NB-23.
Add new Sections M-1012 to M-1020 to the Mechanical Code to read as follows.
SECTION M-1012E INSPECTION CRITERIA
M-1012.1 New Construction. The inspection of the design, construction, installation and
operation of steam or hot water boilers and pressure vessels, and unfired pressure vessel in the
District of Columbia, shall be performed in accordance with the requirements of the ASME
Boiler and Pressure Vessel Code, the NBIC and Safety Control Device Standards as specified by
the manufacturer's inspection instructions. Inspections for compliance with the D.C. local safety
requirements shall be performed in accordance with the District of Columbia Municipal
Regulations Criteria.
M-1012.2 Equipment Replacement. The inspection of boiler and pressure vessel equipment
installed to replace inoperable equipment shall be performed in accordance with the inspection
requirements for new construction as specified in Section M-1012.1.
M-1012.3 Existing Equipment. The inspection of boilers and pressure vessels installed and
operating in existing facilities shall be performed at a frequency in accordance with the
requirements in the NBIC, and the District of Columbia Municipal Regulations
SECTION M-1013E ADDITIONAL GENERAL & SPECIFIC REQUIREMENTS FOR
BOILERS, WATER HEATERS AND PRESSURE VESSELS
M-1013.0 General. The intent of Sections M-1013.0 through M-1020.0 is to provide general
and specific guidance to the code official and the consumer regarding the installation,
maintenance and inspection of new and existing boilers, water heaters, and pressure vessels.
M-1013.1 Inspection of Boilers And Unfired Pressure Vessels
M-1013.1.1 Permit Requirement. A permit shall be obtained for each boiler or unfired
pressure vessel installed, erected, or moved and reinstalled, or re-erected in a new
location in the District of Columbia before any work in connection with the equipment is
performed.
M-1013.1.2 Inspection of Boilers. No person shall operate, or cause to be operated, any
new boiler or unfired pressure vessel which has been installed or erected, or any used
boiler or unfired pressure vessel which has been reinstalled or re-erected in the District
until it has been inspected by the boiler Inspector and a certificate of inspection has been
issued. The certificate must be displayed in the boiler or engine room.
M-1013.1.3 Certificate of Inspection. No person shall operate or cause to be operated
any boiler or unfired pressure vessel requiring inspection under this title without a current
certificate of inspection.
M-1013.1.4 Owner's Responsibility. The owner or user of each boiler or unfired
pressure vessel which is not covered by a current certificate of inspection shall notify the
code official in writing of the following information.
1.
The location of each boiler or unfired pressure vessel not covered by a current
certificate of inspection;
2.
The date of the last inspection, if any;
3.
Whether or not that equipment is insured and inspected by an insurance company;
and
4.
The name of the company insuring it.
M-1013.1.5 Operator's License Suspension/Revocation. The license of any engineer
licensed by the District of Columbia shall be subject to suspension or revocation if he/she
shall operate, or cause to be operated any boiler or unfired pressure vessel under his or
her supervision without a certificate of inspection or with a certificate which has expired.
M-1013.1.6 Operating Pressure. No person shall operate or cause to be operated any
boiler or unfired pressure vessel at a pressure in excess of the allowable pressure as stated
on the certificate of inspection.
M-1013.1.7 Safety Devices. Boilers and unfired pressure vessels shall be equipped with
all safety appliances and piping as prescribed in the ASME Code. No person shall operate
or cause a boiler or unfired pressure vessel to be operated unless equipped with the
prescribed safety appliances and piping, and no person shall remove or tamper with any
safety appliance or piping, except for the purpose of making repairs. Any adjustments to
safety valves shall be made only by direction of an inspector.
M-1013.1.7.1 Tests. When in the judgment of the boiler Inspector it is
considered necessary to demonstrate the proper operation of the boiler safeties
and controls, or to demonstrate the licensed engineer’s ability to properly operate
the boiler, the safety-valve capacity of a boiler and/or the low water cutout shall
be tested. An accumulation test shall be made by shutting off all other steamdischarge outlets from the boiler, and operating the fuel-burning equipment to
produce the maximum steaming capacity of the boiler. An evaporation test shall
be performed to demonstrate proper operation of the low water cutout.
M-1013.1.7.2 Safety-Valve. The safety-valve equipment shall be sufficient to
prevent the pressure from rising more than (a) six (6) percent above the maximum
allowable working pressures for power boilers, and (b) five (5) pounds per square
inch (psi) above the maximum allowable working pressures for heating boilers.
Provision shall be made for piping the safety valve discharge out of the boiler
room during a test pursuant to Section M-1013.1.7.1.
M-1013.1.8 Portable Boiler/Unfired Pressure Vessel. No portable temporary boiler or
unfired pressure vessel shall be used until it has been inspected by an authorized boiler
Inspector and a certificate of inspection issued. Each owner or user of portable boilers or
unfired pressure vessels shall furnish in writing to the code official, on or before the
effective date of this title and yearly thereafter, the following information.
1.
A list of his or her portable boilers and unfired pressure vessels;
2.
A list of the location of each portable boiler and unfired pressure vessel; and
3.
A statement indicating whether the portable boiler and unfired pressure vessel is
insured and inspected by an insurance company.
M-1013.2 Annual Boiler Inspection Requirements
M-1013.2.1 Annual Inspection. All steam boilers including hot water boilers shall be
inspected annually by the boiler Inspector, an assistant boiler Inspector, or by an
Inspector of an insurance company.
M-1013.2.1.1 Steel Steam and Hot Water Boilers. The annual inspection of
steel steam and hot water boilers shall consist of an internal inspection.
M-1013.2.1.2 Internal Inspection. The internal inspection shall consist of a
thorough examination of all tubes, seams, rivets, drums, stay bolts, and other parts
to insure that the boiler is in safe operating condition and able to carry the
pressure allowed.
M-1013.2.1.3 External Inspection. The external inspection to determine the
general condition of the boiler and its appurtenances as well as the adequacy of
safety valves, pressure gages, apparatus for determining water level, and other
appliances shall be made under normal operating conditions at which time the
steam pressure carried shall be observed and the operation of all valves, gages,
safety devices, or other appliances shall be checked to insure that they are in
proper working order.
M-1013.2.1.4 Hydrostatic Test. A hydrostatic test shall be required when, in the
judgment of the Inspector, it is considered necessary in the interest of safety.
M-1013.3 Preparation of Boiler for Inspection
M-1013.3.1 Boiler Preparation. A steam or hot water boiler shall be prepared for
internal inspection by the owner or user on a date specified by the inspector. Insofar as
practicable the internal inspection shall he made within fifteen (15) days prior to the
expiration of the certificate of inspection. In no case shall the internal inspection be
deferred more than thirty (30) days after date of expiration of the current certificate of
inspection. A steam boiler (or hot water) may be ordered discontinued from service until
the inspection is made.
M-1013.3.2 Inspection Procedure. Preparation for internal inspection shall be made in
the following manner.
1.
Water shall be drawn off and the boiler thoroughly washed out;
2.
All manhole and handhole plates, washout plugs and the water column connection
plugs shall he removed and the furnace and combustion chambers thoroughly
cooled and cleaned;
3.
All grates or stoker dead plates of internally-fired boilers shall be removed; and
4.
All leaks of steam or hot water into the boiler shall be stopped. The Inspector may
also require the removal of brickwork and of insulation covering the seams of
shell, drums or domes, sufficient to determine the size and pitch or rivets, their
condition, and any other information as may be necessary to definitely determine
the condition of the boiler and its fitness for safe operation.
M-1013.3.2.1 Hydrostatic Test. A steam or hot water boiler shall be prepared
for hydrostatic test by the owner or user, when required by the Inspector, by
filling the boiler with water to the stop valve and blanking off the connections of
the boiler to other boilers when that boiler is connected to other boilers that are
under steam pressure. Arrangements shall be made with the Inspector for the
protection of the safety valve and under no circumstances shall the safety valve
spring be screwed down for making hydrostatic tests.
M-1013.4 Unfired Pressure Vessels Requiring Annual Inspection
M-1013.4.1 General. Each unfired pressure vessel operating at a pressure in excess of
sixty (60) pounds per square inch and having a capacity in excess of fifteen (15) gallons
shall be inspected annually by the boiler Inspector, an assistant boiler Inspector, or by an
insurance company Inspector. Any unfired pressure vessel as described herein shall be
subjected to inspection if it is connected to a source of supply.
M-1013.4.2 Type of Inspection. The annual inspection of unfired pressure vessels shall
consist of an external inspection including safety devices, and other appurtenances. When
a vessel is provided with manholes an internal inspection shall also be made.
M-1013.4.2.1 Hydrostatic Test. A hydrostatic test may be required when, in the
judgment of the Inspector, it is considered necessary in the interest of safety. This
test shall consist of applying a pressure of one and one-half times the allowable
pressure to the vessel to be prepared for inspection by the owner or user as
directed by the Inspector.
M-1013.5 Annual Inspection by Insurance Companies
M-1013.5.1 General. Any steam or hot water boiler or unfired pressure vessel which is
insured and inspected at least once annually by an insurance company licensed to operate
in the District shall be exempt from inspection by the Department if the requirements of
this section are satisfied.
M-1013.5.1.1 ASME Code. The insurance company shall apply the inspection
provisions in Section I, Part PG, paragraph PG-90, “Inspection and Tests General” in the ASME Boiler and pressure vessel code.
M-1013.5.1.2 Qualifications. Insurance company inspectors shall hold
certificates of competency issued by the District of Columbia.
M-1013.5.2 Reports. Reports of inspections and other data relating to an insured boiler
or unfired pressure vessel as may be required shall be filed with the Department within
thirty (30) days after the inspection on the standard forms and in the manner as required;
provided, that the internal-inspection report shall be filed in time to prevent the certificate
of inspection from becoming more than thirty (30) days overdue. Each report shall be
typewritten and signed in ink, and shall state definitely whether or not the certificate of
inspection shall be issued, and the pressure allowed.
M-1013.5.2.1 Internal Inspection. Each annual internal-inspection report shall
state the nature of all changes or repairs ordered or recommended. If the
certificate of inspection is withheld because changes or repairs have been ordered
or recommended, an additional report shall he filed within thirty (30) days stating
whether the changes or repairs have been completed.
M-1013.5.3 Insurance Company Report. The insurance company shall immediately
report to the Department the name of the owner or user and the location of every boiler
and unfired pressure vessel on which insurance is refused, canceled, or discontinued and
the reason therefore and also for each new object upon which the coverage is taken. Each
insurance company report shall state the names of the licensed engineers working on all
watches. The report shall state the grade of license held, and if there is none, the reports
shall so state.
M-1013.5.4 Fees. The fee of fifty dollars ($50.00) required to be paid by the owner or
user for the issuance of a certificate of inspection shall be forwarded with the inspection
report to the Department with a check made payable to the D.C. Treasurer.
M-1013.5.5 Licensed Engineer. The Inspector shall inform the owner or operator that
licensed engineers are required by law and that the licenses must be posted under glass in
the boiler or engine room with a daily log book of plant operations with all boiler safeties
and controls tested daily for each tour of duty.
M-1013.6 Certificates or Competency For Insurance Company Inspectors
M-1013.6.1 Certificate of Competency. Inspectors of insurance companies authorized
by the code official to inspect and insure steam boilers, hot water boilers unfired pressure
vessels shall hold a Certificate of Competency issued by the Chief Boiler Inspector. The
Certificate of Competency shall be for a period of two (2) years and may be renewed
without further examination for an additional two (2) year period upon request. The fee
for each period shall be two hundred dollars ($200.00).
M-1013.6.1.1 Application. Application for examination of insurance company
inspectors for Certificates of Competency shall be made by the insurance
company in writing to the Chief Boiler Inspector. The application shall state the
name, age, qualifications, experience, and local address of each of the Inspectors
proposed to be employed by the company in the inspection of steam boilers and
unfired pressure vessels in the District of Columbia.
M-1013.6.1.2 National Board of Boiler and Pressure Vessel. A certificate
issued by the National Board of Boiler and Pressure Vessel Inspectors may be
accepted upon proper substantiation and a Certificate of Competency issued
therefore.
M-1013.6.1.3 Cancellation. Whenever an Inspector holding a Certificate of
Competency from the District shall leave the employ of an insurance company,
the company shall give prompt written notice of the facts and the reasons for the
Inspector leaving, to the Chief Boiler Inspector, who shall cause the Inspector's
Certificate of Competency to be canceled.
M-1013.7 Certificates of Inspection
M-1013.7.1 General. No person shall use or cause to be used any steam boiler or unfired
pressure vessel until a certificate of inspection has been issued and posted as required in
this title.
M-1013.7.2 Certificate of Inspection. The certificate of inspection shall not be issued
until it is determined that the boiler or unfired pressure vessel is in condition and in
conformity with the boiler code of the American Society of Mechanical Engineers, and
this title, the Rules and Regulations Governing the Installation of Fuel Burning
Equipment, and the Rules and Regulations Governing the Operation of Engines and
Steam Boilers and the Machinery in and for the District of Columbia. A separate
certificate of inspection shall be issued for each object inspected. Each certificate shall
be enclosed in a glass covered frame to be supplied by the owner and shall be
prominently displayed in the boiler or engine room near the equipment to which it
pertains. Certificates for portable equipment shall be kept with the equipment at all
times.
M-1013.7.2.1 Internal Inspection. In the case of boilers which can be internally
inspected, certificates shall not be issued until after that inspection has been made.
M-1013.7.3 Installations. On all installations for which a permit has been issued, the
contractor or person making the installation shall be responsible for notifying the Chief
Boiler Inspector, in sufficient time so that the necessary inspections can be made.
M-1013.7.4 Operation. The contractor or person making the installation shall be
responsible that no boiler or unfired pressure vessel shall be operated until final
inspection has been made and permission given to operate the equipment. A licensed
engineer shall be in-charge of the boiler if it is operated prior to being turned over to the
owner.
M-1013.8 Notice to Make Repairs or Alterations
M-1013.8.1 General. If upon inspection it is found that repairs, alterations, or cleaning
are necessary to insure the safe operation of a steam boiler or unfired pressure vessel, and
its conformity to the ASME Code and this title, a written notice stating the work required
to be done and time of completion shall be sent to the owner or user.
M-1013.8.1.1 Repairs, Alterations, or Cleaning. Any repairs, alterations, or
cleaning, shall be made as directed. Upon completion of the work ordered, the
Chief Boiler Inspector, shall be notified. If the work has not been completed
within the time allowed, operation of the equipment may be ordered discontinued.
M-1013.9 Condemnation of Defective or Unsafe Equipment
M-1013.9.1 General. Whenever the boiler inspector finds that a boiler or unfired
pressure vessel, or its necessary appurtenances, is in such a defective or unsafe condition
that life or property is endangered, he or she shall immediately order its further use and
operation discontinued. If, in his or her opinion, it cannot be repaired and made safe, he
or she shall condemn it.
M-1013.9.2 Revocation/Suspension. The boiler inspector shall revoke or suspend the
certificate of inspection pertaining to any boiler or unfired pressure vessel discontinued or
condemned pursuant to Section M-1013.9.1, making a written report of the action taken
with the reasons therefore to the Chief Boiler Inspector. The report shall contain a
detailed description of the unsafe condition of the boiler or unfired pressure vessel.
M-1013.9.3 Notification. A written notice of the revocation or suspension of certificate
of inspection and the reasons therefore shall be served on the owner or user. In the case of
an insured boiler or unfired pressure vessel where the certificate of inspection was issued
on the certification of an insurance company, the notice shall be sent to the company.
M-1013.9.4 Unsafe Conditions. No person shall again operate or cause to be operated
any boiler or unfired pressure vessel which is known to be unsafe or which has been
condemned by the boiler inspector, nor shall any person operate or cause to be operated,
any boiler or unfired pressure vessel, the further use and operation of which has been
ordered discontinued by the boiler inspector, or where the certificate of inspection has
been suspended, until the defective or unsafe condition which was the reason for that
action has been corrected and a new certificate of inspection issued. A boiler or unfired
pressure vessel which has been condemned by an inspector shall be distinctly labeled by
the D.C. Boiler Inspector's Office. Numbers on condemned boilers shall not be
reassigned.
M-1013.10 Numbering Boilers and Unfired Pressure Vessels
M-1013.10.1 General. Every boiler and unfired pressure vessel shall be given a District
of Columbia number. Numbers assigned to cast-iron boilers shall be of metal not less
than one inch (1") in height and shall be securely attached to a metal plate which in turn
shall be securely attached to the front of the boiler. Miniature boilers shall have sufficient
space provided so that the District of Columbia numbers can be stamped on the shell and
be clearly visible when the insulating jacket is in place.
SECTION M-1014E CONSTRUCTION, INSTALLATION, AND OPERATION OF
BOILERS AND UNFIRED PRESSURE VESSELS
M-1014.1 General Provisions. All steam boilers, except boilers which are exempted by Section
8 of the Boiler Inspection Act of June 25, 1936, shall bear the following information.
1.
The ASME symbol;
2.
The name of the manufacturer;
3.
The maximum allowable working pressure;
4.
The serial number and National Board Number;
5.
The year built; and
6.
Any other required data to indicate that it has been built in accordance with the ASME
Boiler and Pressure Vessel Code.
M-1014.1.1 Identification Number. All boilers, except Low Pressure Heating Boilers
and unfired pressure vessels as described in Section M-1014.1 shall bear a National
Board Number to indicate that it has been inspected by an inspector holding a National
Board Commission.
M-1014.1.2 Operating Pressure and Capacity. All unfired pressure vessel operated at a
pressure in excess of sixty (60) pounds per square inch and having a capacity in excess of
fifteen (15) gallons, shall bear the following information.
1.
The ASME symbol;
2.
The name of the manufacturer;
3.
The maximum allowable working pressure;
4.
The serial number and National Board Numbers;
5.
The year built; and
6.
Any other required data to indicate that it has been built in accordance with the
provisions of Section VIII in the ASME Boiler and Pressure Vessel Code.
M-1014.2 Permits Required for Installation
M-1014.2.1 General. No person shall erect, install, re-erect, or reinstall or cause to be
erected, installed, re-erected or any steam or hot water boiler or unfired pressure vessel
until he or she shall have made application on the form provided and obtained an
installation permit.
M-1014.2.2 Permit Applications. Applications for permits shall be accompanied by a
form known as "Manufacturer's Data Report," properly filled out and signed by an
Inspector licensed to insure Vessel Inspectors, showing that the boiler or unfired
pressures vessel has been constructed and inspected in accordance with the requirements
of the American Society of Mechanical Engineers Boiler and Unfired Pressure Vessel
Code. When an application is made to install a used boiler or unfired pressure vessel
definite information shall be furnished showing that the boiler or unfired pressure vessel
has been built in accordance with all the requirements of the ASME Code and is so
stamped. Upon approval of the application and the accompanying data a Permit for the
installation, erection, reinstallation, or re-erection shall be issued by the Permit Branch,
Licenses and Permit Division, after payment of the required fee to the D.C. Treasurer.
M-1014.2.3 Installation Permit. Before an installation permit for a used boiler or
unfired pressure vessel shall be issued, the boiler Inspector shall carefully inspect the
boiler or unfired pressure vessel in order to determine whether it is safe to operate, and
any repairs or changes that may be necessary. The fee for that inspection shall be the
same as called for under annual inspection.
M-1014.2.4 Notification. When notification has been given to prepare a boiler or
unfired pressure vessel for inspection or hydrostatic test on a definite date, or when a
definite appointment for an inspection cannot be made by reason of the boiler or unfired
pressure vessel not being properly prepared for inspection, so that an additional call or
calls are thereby made necessary; or when additional inspections are required in order to
secure compliance with orders previously issued, each additional call or inspection may
be charged for at the same fee as prescribed under Annual Inspection Fees.
M-1014.2.5 Unscheduled Inspection. For an inspection made upon request or to
determine the safety of an object not regularly inspected, the fee shall be as prescribed
under Annual Inspection Fees.
M-1014.2.6 Inspection Fees. For the inspection of a boiler being retubed in a shop, the
fee shall be the same as for the annual inspection. For an inspection to determine
whether the condition of a boiler or unfired pressure vessel is such that it can be installed
in the District, the fee shall be the same as prescribed under Annual Inspection Fees.
M-1014.2.7 Welding Fee. Fee for welding qualification test shall be one-hundred dollars
($100.00). For the inspection of pipe or boiler welding the fee shall be one-hundred
dollars ($100.00) per day. If a welder license has expired for less than a period of six (6)
months from its expiration date, a late fee shall be applied of fifty dollars ($50.00).
Welding license renewal fees shall be the amount of one-hundred dollars ($100.00) for 2
years. If a welder license has expired for a period of six (6) months or more, the person
must be retested.
M-1014.2.8 Certification Fee. The fee for certificate of competency for insurance
company Inspectors for a two (2) year period shall be two hundred dollars ($200.00).
M-1014.3 Payment of Fees
M-1014.3.1 General. All fees shall be paid to the D.C. Treasurer, who shall issue a
receipt for the payment of the following fees.
1.
Fees for the installation permit and subsequent inspection of a boiler or unfired
pressure vessel shall be paid prior to the issuance of a permit and before any work
is started.
2.
All fees for the inspection of boilers or unfired pressure vessels shall become due
and payable immediately upon the making of the inspection and the certificate of
inspection shall not be issued while there are any unpaid fees outstanding.
M-1014.4 Requirements for Power Boilers
M-1014.4.1 Steel Platform. On the top of every power boiler setting, a steel platform
reached by means of a stationary steel stairway or ladder shall be provided. The platform
shall be provided with a four inch (4") toe guard, a steel railing not less than thirty-six
inches (36") inches in height, and shall have a runway made of steel grating not less than
thirty inches (30") in width.
M-1014.4.2 Platform Access. The stairway or ladder shall not be less than sixteen (16")
inches in width and shall provide easy access to and from the platform. Where there is
more than one boiler or where otherwise necessary a second stairway or ladder remote
from the other shall be provided.
M-1014.4.2.1 Means of Egress. Two unobstructed and accessible exits remote
from each other shall be provided in every room housing power boilers of
seventy-five (75) horsepower total capacity and over and heating boilers having a
total capacity of 2,400,000 BTU and over. Blow off pits, ash pits, alleyways,
steam pipe tunnels, and other places where there would be danger of men being
trapped shall have adequate ventilation, lighting, and a sufficient number of
adequate means of egress.
M-1014.4.3 Blow-off Pits. Blow-off piping from power boilers shall not discharge
directly into a sewer. A blow-off tank or sump shall be used where conditions do not
provide an adequate and safe open discharge.
M-1014.4.4 Blow-off Tanks. Blow-off tanks shall be designed for at least fifty percent
(50%) of the working steam pressure of the boiler to which it is connected and shall be
built in accordance with the Unfired Pressure Vessel Code. The tanks shall have a
discharge connection at least six inches (6”) above the maximum water level with a water
seal, a vent from the top of the tank, and a cold-water connection to the top of the tank.
The vent shall be routed to a safe point of discharge which shall be above the roof of the
building of which it is a part or any adjoining building to which it may not constitute a
hazard or nuisance, and shall be substantially supported and drained. The design of each
tank and piping shall be submitted to the Department for approval. Sizes shall not be less
than indicated in Table M-1014-1.
M-1014.5 Installation of Low Pressure Heating Boilers
M-1014.5.1 General. The return water connection to every low pressure steam or hot
water heating boiler shall be arranged to form what is known as the "Hartford Loop" so
that the water cannot be forced out of the boiler below the safe water level. This
connection shall be installed on each boiler, with the inside bottom of the return pipe
close nipple where it enters the equalizing loop being at the same level as the top of the
bottom nut of the water gage glass.
M-1014.5.2 Equalizer Pipe. Each boiler shall have a separate equalizer pipe installed
between the bottom opening of the boiler and the boiler stop valve, when used. The
equalizer pipe shall not have a valve in it at any point and shall not be used as a means to
connect two or more boilers together below the water line. Equalizer pipe sizes shall not
be less than the schedules indicated in Table M-1014-2.
M-1014.5.3 Stop Valve. When a stop valve is used in the return line of the loop it shall
be located within six (6) feet of the floor. A drain valve shall be provided at the lower
point of the return line. Galvanized pipe and fittings shall not be used in any part of the
equalizer pipe or return.
M-1014.5.4 City Water Feed. Each boiler shall be provided with a city water feed line
which shall not discharge directly into any part of a boiler exposed to the direct radiant
heat from the fire. It shall be connected into the equalizing line between the boiler and
the condensate return connection and shall have a check valve in the line as close to the
boiler as possible.
M-1014.5.5 Boiler Feed Line. The boiler feed line shall be adequate to take care of the
maximum demand of the boiler.
M-1014.5.6 City Water Shut-off Valve. All connections from the city water shut-off
valve shall be made of brass pipe with screwed fittings. Tubing shall not be used.
M-1014.5.7 Condensate Return Pump. A condensate return pump shall have capacity
to supply the boiler or boilers with sufficient water to maintain a normal water level when
the boilers are operating at maximum capacity. When more than one boiler is installed
the condensate return line shall be arranged to supply all boilers equally.
M-1014.5.8 Stop Valve. A stop valve shall be installed in each supply and return
connection of two or more boilers connected to a common system. When a stop valve is
used in the supply pipe connection of a single boiler, there shall be one used in the return
pipe connection or vice versa. If there are multiple branch connections each one shall be
valved. When stop valves over two inches (2") in size are used they shall be of the
outside screw-and-yoke type.
M-1014.5.8.1 Stop Valve Location. Stop valves shall be located as close to the
boiler as possible and when over seven feet (7’) above the floor shall be made
accessible for operation by means of a permanent steel ladder and platform or by
a chain or motor operated mechanism.
M-1014.5.9 Blow-off Connections. Each boiler shall have one or more blow-off
connections fitted with straightway valves connected directly with the lowest water
space. Plug or bob cocks shall not be used. A discharge pipe shall be run to the floor full
size with an ell at the bottom to direct the water away from the operator or to a blow-off
tank. A “tee” fitting shall be used at the boiler in order to provide for cleaning the line.
Blow-off valves shall not be smaller than the schedule indicated in Table M-1014-3. If a
surface blow down is used, it shall be run full size to the floor with an ell at the bottom or
to a common drain.
M-1014.5.10 Wash-out and Hand-hole Openings. All wash-out and hand-hole
openings shall be accessible and shall not be obstructed or blocked by pipe or other
obstacle. Capped pipe nipples and plugs shall be installed in wash-out openings.
M-1014.5.11 Cross Connections. There shall be no cross connection below the water
line for any purpose between two or more boilers.
M-1014.6 Boiler Controls
M-1014.6.1 Steam Limit Control. Every steam boiler, when mechanically fired, shall
be provided with a steam limit control (pressure regulator) which shall operate to prevent
the steam pressure from rising above the allowable working pressure of the boiler. All
connections shall be on non-ferrous pipe with screwed fittings. There shall not be any
valve between the boiler and the control.
M-1014.6.2 Master Limit Control. When two or more boilers are connected to a
common header, a master limit control connected into the main steam header shall be
provided to control all boilers simultaneously.
M-1014.6.3 Low-Water Fuel Cut-Off. Each steam boiler, when mechanically fired,
shall be equipped with an approved low-water fuel cut-off, so located as to automatically
cut off the fuel supply in case the water-gage glass indicates low-water level.
M-1014.6.3.1 Cut-Off Operational Independence. The operation of the lowwater fuel cut-off shall not be dependent upon the functioning of another device.
M-1014.6.3.2 Burner Cut-Off Location. When an oil burner is manually
operated, the cut-off valve shall be located in the oil line close to the burner and
shall have a manual re-set.
M-1014.6.3.3 Valve Location Restriction. No valves shall be permitted between
the low-water fuel cut-off and the boiler.
M-1014.6.4 Water-Gage Glass Controls. Each steam boiler shall have one or more
water-gage glasses attached to the water column or directly to the boiler by means of
valved fittings, with the lower fitting provided with a drain valve of the straightway type
with opening not less than one quarter inch (1/4”) diameter. The gage glass shall be
visible from the operating floor and without the removal of any cover or casing. There
shall be no obstruction to interfere with visibility of the gage glass.
M-1014.6.5 Operating Elevated Gage Glass Controls. When gage cocks or gage glass
shut off cocks are located seventy-eight inches (78”) or more above the operating floor,
they shall be of the quick opening type with chains or rods attached for operation from
the floor. The gage glass and pressure gage shall be illuminated by a light with an
approved type of reflector so that they can be easily read.
M-1014.6.6 Automatic Water Feeder. An automatic water feeder shall be installed on
each mechanically fired steam heating boiler. It shall have sufficient capacity to take
care of the maximum boiler output.
M-1014.6.7 Feed Pump Capacity. A boiler feed pump, when used, shall have capacity
to supply sufficient water to all boilers to maintain a normal water level when the boiler
or boilers are operating at maximum capacity.
M-1014.6.8 City Water By-Pass. A city water by-pass valve, with the valve accessible
from the floor, shall be installed around a feeder and shall have valved drain run to within
six inches (6") of the floor. A mechanical city water feeder shall be installed with a
bypass valve, inlet and outlet valves accessible from the floor with cross tees for
inspection with the drain valve piping run to within six (6) inches of the floor.
M-1014.6.9 Feed-Water Level. A water feeder shall be installed so that it will not
maintain the water level above the normal operating level as specified by the
manufacturer of the boiler.
M-1014.6.10 Minimum Boiler Water Level. On low-pressure steam heating boilers, the
water gage glass shall be located so that the lowest permissible water level in the glass
shall be as follows.
M-1014.6.10.1 Multiple Fire-Tube Boilers. For multiple fire-tube boilers at
least one half inch (½”) of water shall be maintained over the top row of tubes or
the fusible plug, if issued, whichever is higher.
M-1014.6.10.2 Scotch Marine Boilers. For package type Scotch Marine boilers
at least one half inch (½”) of water shall be maintained over the top row of tubes
or the fusible plug, if used, whichever is the higher.
M-1014.6.10.3 Horizontal Tube Boilers. For fire-box, horizontal water tube
boilers at least one inch (1”) of water shall be maintained over the highest point of
the crown sheet.
M-1014.6.10.4 Miscellaneous Boilers. For any other type boiler the minimum
water level shall be maintained in accordance with the manufacturers’
recommendations.
M-1014.6.11 Multiple Boiler Water Level. Two or more boilers shall be arranged so
that the low water line of all boilers are at the same level; provided, that when each boiler
is provided with an individual pump control and an automatically operated feed water
control valve they may be approved for operation with different water levels.
M-1014.6.12 Boiler Pressure Gage. Every boiler shall have a pressure gage connected
to its steam space, or to its water column, or to its steam connection by means of a siphon
or equivalent device exterior to the boiler, and of sufficient capacity to keep the gage tube
filled with water. The pressure gage shall be arranged so that the gage cannot be shut off
from the boiler except by a cock with a “tee” or lever handle installed in the pipe near the
gage.
M-1014.6.13 Cock Handle Position. The handle of the cock for the pressure gage shall
be parallel to the pipe in which it is located when the cock is open.
M-1014.6.14 Gage Scale Graduations. The scale on the dial of a gage on a low
pressure boiler shall be graduated to not less than thirty (30 psi) in five (5 psi)
graduations. Connections to steam gage siphons shall be of non-ferrous pipe. The gage
shall be visible at all times without the removal of any cover or casing, and shall be of
such size and so located as to be easily readable from the operating floor.
M-1014.6.15 Independent Controls. When two or more mechanically fired steam
boilers are connected to the same system, each boiler shall have independent low-water
fuel cut-offs, pressure controls, pressure gages and water feeders.
M-1014.6.16 Non-Ferrous Pipe and Fittings. All of the connections for the water
column, water feeder, low-water fuel cut-out and make up water line to the boiler, shall
be of non-ferrous pipe and screwed fittings, with a cross at each right angle turn and with
a check valve in the fed line as close to the boiler as possible. High pressure boilers shall
have a valve between the boiler and the check valve. Tubing shall not be permitted on
boiler piping or fittings. All piping shall be firmly braced and supported.
M-1014.6.17 Drain Locations. Drains shall be located so that the discharge will not
impinge on the boiler setting or electrical equipment. Water column, water feeder and
low-water fuel cut-out shall have separate full size straight-way valve drains run to within
six inches (6”) from the floor or to a common visible drain, with the valves located to be
conveniently accessible for operation. Plug cocks shall not be used.
M-1014.7 Safety Valves
M-1014.7.1 General. Each steam boiler shall be provided with one or more safety valves
of the spring-pop type and having side outlet discharge, adjusted and sealed to discharge
at a pressure not to exceed fifteen (15) pounds per square inch. Seals shall be attached in
a manner to prevent the valve from being taken apart or re-set to relieve at a higher
pressure without breaking the seal.
M-1014.7.2 Lever-Lifting Device. Each valve shall have a substantial lever-lifting
device which will positively lift the disk from its seat at least one-sixteenth inch (1/16")
when there is no pressure on the boiler. Where the lever is more than seventy-eight inches
(78") from the floor, a flexible chain or cable operating over a pulley shall be provided so
that the valve can be tested.
M-1014.7.3 Identification. Each steam safety valve shall bear the ASME symbol to
indicate that it complies with the requirements of the ASME Boiler Code in regard to
construction, testing and rating, and shall be plainly and permanently marked by the
manufacturer in such a way that the marking will be readable when the valve is installed
and will not be obliterated in service.
M-1014.7.3.1 Marking. The marking shall include the following information.
1.
The manufacturer's name;
2.
The type and catalog number;
3.
The pressure at which it is set to blow; and
4.
The capacity in pounds of steam per hour as certified by the National
Board of Boiler and Pressure Vessel Inspectors.
M-1014.7.4 Operating Capacity. The steam safety valve capacity for each steam boiler
shall be such that with the fuel burning equipment installed and operating at maximum
capacity, the pressure cannot rise more than five (5) psi above the maximum allowable
working pressure of the boiler.
M-1014.7.5 Operating Conditions. When operating conditions are changed, such as
when there is no stamping on a valve or it is not legible, or when a safety valve does not
function properly, then a new safety valve or valves as required in this section shall be
installed.
M-1014.7.6 Installation. It shall be the responsibility of the contractor making the
installation or the changes, to provide and install the necessary safety valves.
M-1014.7.7 Test. In case of dispute over the safety valve capacity or when, in judgment
of the Inspector, it is considered advisable to test the capacity of the safety valves, an
accumulation test shall be made by the contractor or owner in the presence of the
Inspector.
M-1014.7.7.1 Test Procedure. This test shall be made by closing off all other
discharge outlets from the boiler and operating the fuel burning equipment at
maximum capacity. The safety valves shall be sufficient to prevent the pressure
from rising more than five (5) psi above the maximum allowable working
pressure of the boiler. Provision shall be made for piping the steam discharge
from the boiler room during the test.
M-1014.7.8 Minimum Capacity. The minimum capacity of the safety valve or valves in
pounds of steam per hour shall be determined as follows:
1.
2.
For steel or cast iron boilers, multiply the square feet of heating surface, if
available, by five (5) or use the maximum rating output of the boiler as given by
the manufacturer, whichever is greater.
If the fuel burning equipment installed will produce a greater output than the
minimum specified in Section M-1014.7.8(1), the capacity of the safety valve or
valves shall be based on the maximum output obtainable. In any event the
requirements of Section M-1014.7 shall be met.
M-1014.7.9 Safety Valves Connection. Safety valves shall be connected to boilers with
the spindle in a vertical position in any one of the following ways:
1.
Either directly to a tapped or flanged opening in the boiler;
2.
To a fitting connected to the boiler by a close nipple;
3.
To a Y-base;
4.
To a valveless steam pipe between the adjacent boilers; or
5.
To a valveless header connecting steam outlets on the same boiler.
M-1014.7.9.1 Y-base Connection. When a Y-base is used pursuant to paragraph
M-1014.7.9(3) above, the inlet area shall not be less than the combined outlet
areas.
M-1014.7.9.2 Clearance. There shall be sufficient clearance above and around
safety valves so that they can be removed and replaced without dismantling. The
identification plate shall be located so as to be readable.
M-1014.7.10 Shut-off. No shut-off or connection of any description shall be placed
between a safety valve and the boiler, nor on the discharge pipe between such valve and
the atmosphere. A safety valve shall not be connected to an internal pipe in the boiler.
Tubing or galvanized pipe shall not be used between the valve and boiler.
M-1014.7.11 Discharge Pipe. A discharge pipe shall not be used on safety valves on
low pressure except where a boiler is located in a restricted space or where the discharge
from the valve might constitute a hazard to persons or to equipment. A discharge opening
of a single valve or the aggregate area of all valves based on the nominal diameter of the
discharge openings of the valves with which it connects.
M-1014.7.11.1 Discharge Pipe Installation. The discharge pipe shall be fitted
with an open drain to prevent water from lodging in the upper part of the valve or
in the pipe. When an elbow is placed on a safety valve discharge pipe, it shall be
located close to valve outlet. The pipe shall be supported so that no strain is
placed on valve body. The discharge shall be arranged so there will be no danger
of scalding attendants. A safety valve shall not be installed to discharge inside the
casing of a self-contained boiler.
M-1014.7.11.2 Discharge Pipe Location. The safety valve or valves of each
high-pressure boiler shall be provided with a full size discharge pipe leading to a
safe point of discharge which shall be above the roof of the building of which it is
a part, or any adjoining building to which it may constitute a hazard or nuisance.
Any discharge pipe shall be braced and supported so that there is no weight or
strain on the safety valve body. The area of the discharge pipe shall be equal to
the area of all of the safety valves discharging into it and forty-five (45) degree
turns, shall be used. Visible, non-valved drains shall be provided for that piping.
M-1014.7.11.3 Discharge Pipes not Required. Boilers of twenty-five (25)
horsepower or less shall not be required to have discharge pipes if the discharge
from the safety valve will not constitute a hazard.
M-1014.7.12 Connection of Two or More Boilers. When two or more boilers which
are allowed different pressures are connected to a common steam main, all safety valves
shall be set at a pressure exceeding the lowest pressure allowed, provided that when two
or more boilers which are allowed different pressures are connected to a common steam
main and all safety valves are set at a pressure not exceeding the lowest pressure allowed,
the boiler allowed the lowest pressure shall be protected by a safety valve or valves
placed on the connecting pipe to the steam main.
M-1014.7.12.1 Connecting Pipe. The area or combined area of the safety valve
or valves placed on the connecting pipe to the steam main shall not be less than
the area of the connecting pipe, except when the steam main is smaller than the
connecting pipe the area of the safety valve or valves placed in the connecting
pipe shall not be less than the area of the steam main. Each safety valve placed on
the connecting pipe shall be set at the lowest allowable pressure of any of the
boilers.
M-1014.8 Explosion Doors
M-1014.8.1 General. Each boiler burning fuel in suspended or gaseous form shall have
one or more self-closing explosion doors located in the boiler setting and breeching as
required. This shall apply not only to new installations but existing installations, if
changed to burn such fuel.
M-1014.8.2 Explosion Doors. Explosion doors, when located in the walls of the boiler
setting within seven feet (7') of the firing floor or of any platform or walkway, shall be
provided with substantial deflectors to divert the blast of exploding gas so that it will not
constitute a hazard.
M-1014.9 Installation of Miniature Boilers
M-1014.9.1 Miniature Boilers. The classification "miniature" shall apply to fired
pressure vessels, and fired and unfired boilers which do not exceed the following limits.
1.
Sixteen(16") inches inside diameter of shell;
2.
Five (5) cu. ft. gross volume, exclusive of casing and insulation;
3.
Twenty (20) square feet water heating surface;
4.
One-Hundred (100) pounds per square inch maximum allowable working
pressure.
M-1014.9.1.1 Limitation. Where any one of the limits specified in Section M1014.9.1 is exceeded, the rules for power boilers shall apply.
M-1014.9.2 Clearance. Each boiler shall be located so that adequate space will be
provided for the proper operation of the boiler and appurtenances and for the inspection
of all surfaces and their necessary maintenance and repair. Each boiler shall have the
following minimum clearances.
1.
At least eighteen inches (18") on all sides;
2.
At least three feet (3') clearance from electric meters and main-line switches; and
3.
At least eighteen inches (18") clearance from all other switches and fuse boxes.
4.
A boiler shall not be located closer than three feet (3') horizontally from any gas
meter.
M-1014.9.3 Feed Pump. Each boiler operating at a pressure in excess of twenty-five
(25) pounds per square inch shall be provided with at least one feed pump or other
approved feeding device except where the steam generator is operated with no extraction
of steam (closed system).
M-1014.9.4 Blow-off Connection. Each boiler shall be provided with a blow-off
connection which shall not be reduced in size and shall be led to a safe point of discharge.
Whenever, in the judgment of the boiler inspector a safe place of discharge cannot be
provided, a blow-down tank shall be installed, and a one inch (1") vent leading to a safe
point of discharge shall be provided on each of those tanks. The blow-off shall be fitted
with a valve or cock in direct connection with the lowest water space practicable.
M-1014.9.5 Mechanically Fired Boilers. All boilers mechanically fired shall be
provided with an automatic low-water fuel cut-out so located as to automatically cut off
the fuel supply in case the water level falls to a point not lower than the bottom of the
water glass.
M-1014.9.6 Gas-Fired Boilers. Where boilers are gas-fired, the burners used shall
conform to the requirements of the Fuel Gas Code. The burner shall be equipped with a
fuel-regulating governor which shall be automatic and regulated by the steam pressure.
This governor shall be so constructed that in the event of its failure, there shall be no
possibility of steam from the boiler entering the gas chamber or supply pipe. A manual
stop or throttle valve shall be located in the inlet pipe ahead of the fuel-regulating
governor. All requirements of the Fuel Gas Code shall be satisfied.
M-1014.9.7 Boiler Vent Installations. Each gas-fired boiler shall be connected to a vent
or flue, or to a chimney, extended to an approved location outside of the building, all to
be of approved design, and in accordance with the boiler manufacturers’ installation
instructions.
M-1014.10 Installation of Unfired Pressure Vessels
M-1014.10.1 General. Each unfired pressure vessel shall be installed so that it is
available for complete external inspection of shell and heads and shall be located so that
wherever possible, there will be not less than twelve inches (12”) between any floor,
wall, ceiling, or other obstruction. There shall be no piping or other obstructions to
prevent proper access; any manhole or inspection opening shall be located so that it is
readily accessible. All stamping and longitudinal welded or riveted joints shall be located
in a position as to be readily visible to the inspector. Where necessary to install a vessel
underground, it shall be enclosed in a concrete or brick pit with a removable cover so that
inspection of the entire shell and heads of the vessel can be made.
M-1014.10.2 Structural Supports. Each unfired pressure vessel shall be supported by
masonry or structural supports of sufficient strength and rigidity to safely support the
vessel and its contents. There shall be no vibration in either the vessel or its connecting
piping.
M-1014.10.3 Piping and Connections. All piping and connections to an unfired
pressure vessel shall be supported in a substantial and safe manner so that there is no
strain placed upon the vessel. Provision shall be made for expansion, contraction, and
drainage.
M-1014.10.4 Protection. Each unfired pressure vessel shall be painted with two coats of
approved paint, so that it is protected from rust or corrosion. It shall not be in contact
with any corrosive material or moisture.
M-1014.10.5 Drip Pipe. Each unfired pressure vessel shall have bottom drip pipe fitted
with a valve or cock in direct connection with the lowest space practicable. The
minimum size of pipe and fittings shall be three quarters of an inch (3/4") except for
tanks twenty inches (20") in diameter or less in which the minimum of the pipe and
fitting shall be one-quarter inch (1/4"). If a plug cock is used, the plug shall be held in
place with a guard or gland. Globe valves and cocks shall not be used.
M-1014.10.6 Pressure Gage. Each unfired pressure vessel shall have a pressure gage
connected in a manner that the gage cannot be shut off from the vessel, except by a cock
with a “T” or lever handle which shall be placed on the pipe near the gage. Connections
to gages shall be placed on the pipe near the gage. Connections to gages shall be made of
non-ferrous pipe and fittings from the tank to the gage. Tubing shall not be used. The dial
of the gage shall be graduated to not less than one and one-half times the maximum
pressures allowed for the vessel. A one-quarter inch (1/4") test gage connection shall be
provided for attaching the inspector's test gage.
M-1014.11 Safety Valves for Unfired Pressure Vessels
M-1014.11.1 General. Each unfired pressure vessel shall be protected by safety and
relief valves and indicating and controlling devices to insure its safe operation. These
valves and devices shall be so constructed, located, and installed that they cannot readily
be rendered inoperative.
M-1014.11.2 Safety Valves. The relieving capacity of safety valves shall be such as to
prevent a rise of pressure in the vessel of more than ten (10) percent above the maximum
allowable working pressure, taking into account the effect of static head. Safety valve
discharge shall be carried to a safe place.
M-1014.11.3 Type of Safety Valve. Each safety valve shall be of the direct springloaded type having a substantial lever-lifting device so that the disk can be lifted from its
seat by the spindle not less than one-eighth (1/8th) the diameter of the valve when the
pressure of the vessel is seventy-five percent (75%) of that at which the safety valve is set
to blow.
M-1014.11.4 Marking. Every such valve shall be marked "ASME or National Board
Standard," and shall give the following information.
1.
The name or identifying mark of the manufacturer;
2.
The pipe size of valve inlet;
3.
The pressures of which the valve is set to blow; and
4.
The relieving capacity.
M-1014.11.5 Prohibit & Safety Valves. Safety valves having either the seat or disk of
cast iron shall not be used.
M-1014.11.6 Multiple Safety Valves. If more than one safety valve is used, the
discharge capacity shall be taken as the combined capacity of all valves.
M-1014.11.7 Pressure Relief in Unfired Pressure Vessels. For vessels in which
pressure is not generated but is derived from an outside source, each safety valve shall be
so connected to the vessel, vessels, or system which it protects as to prevent a rise in
pressures beyond the maximum allowable pressure in any vessel protected by the safety
valve.
M-1014.11.8 Pressure Relief In. For vessels in which pressure may be generated, the
safety valve or valves shall be connected directly to the vessel which is to be protected or
to a pipe line leading to the vessel. The internal cross-sectional area of the pipe line shall
be not less than the nominal area of the safety valve or valves used, and without any
intervening valve between the vessel and the safety valve or valves protecting it.
M-1014.11.9 Pressure Relief Escape Pipe. When an escape pipe is used, it shall be full-
sized and fitted with an open drain to prevent liquid from lodging in the upper part of thesafety valve, and no valve of any description shall be placed on the escape pipe between
the safety valve and the atmosphere.
M-1014.11.10 Escape Pipe Fittings. When an elbow is placed on an escape pipe, it
shall be located close to the safety valve outlet or the escape pipe shall be securely
anchored and supported. When two or more safety valves are placed on one connection,
this connection shall have a cross-sectional area at least equal to the combined area of
these safety valves.
M-1014.11.11 Freeze Protection. Each safety valve which is exposed to a temperature
of thirty-two (32) degree F. or less shall have a drain at least three-eighths inch (3/8") in
diameter at the lowest point where water can collect; provided, that safety valves threequarters inch (3/4") in size and less may have drain holes as large as possible but not less
than three-eighths inch (3/8") diameter.
M-1014.11.12 Spring Adjustment. Safety-valve springs shall not be adjusted to carry
more than ten (10) percent greater pressure than that for which the springs were made.
M-1014.11.13 Valve Testing. Each safety valve shall be tested once every day or more
often by raising the disk from its seat.
M-1014.11.14 Valve Sizing. Safety valves for compressed air tanks shall not exceed
three inches (3") in diameter and shall be proportioned for the maximum number of cubic
feet of free air that can be supplied per minute as determined in Section VIII, Division 1,
Part UG, paragraph UG-133, “Determination of Pressure Relief Requirements” in the
ASME Code.
M-1014.11.15 Use of Rupture Disks. Rupture disks or heads may be used for additional
protection of pressure vessels but they shall be designed to fail at a pressure above the
safety or relief valve setting.
M-1014.11.16 Multiple Vessels. When two or more unfired pressure vessels which are
allowed different pressures are connected to a common source of pressure, all safety
valves shall be set at pressure not exceeding the lowest pressure allowed.
M-1014.12 Penalties for Code Violations. Any person who violates or fails to comply with any
one or more of the provisions of this chapter, shall upon conviction thereof in the District of
Columbia Superior Court, on information filed by the Office of the Attorney General, be subject
to a fine of not to exceed two thousand dollars ($2000.00) or to imprisonment for not more than
90 days, or both, for each and every violation thereof and each violation shall constitute a
separate offense.
TABLE M-1014-1
REQUIREMENTS FOR POWER BOILERS
(see M-1014.4.4)
BOILER RATING
SIZE TANK
OUTLET
VENT
2 to 25 horsepower
26 to 75 horsepower
76 to 150 horsepower
151 to 250 horsepower
24 in. diameter by 36 in. deep
30 in. diameter by 48 in. deep
36 in. diameter by 54 in. deep
36 in. diameter by 60 in. deep
2
3
5
5
2
3
4
5
251 to 600 horsepower
601 to 1,000 horsepower
42 in. diameter by 66 in. deep
48 in. diameter by 72 in. deep
5
6
6
6
TABLE M-1014-2
EQUALIZER PIPE SIZES
(see M-1014.5.2)
GRATE AREA
(square feet)
S.V.R.C.
(pounds per hour)
PIPE SIZE
(inches)
Under 4
250 or less
1½
4 to 15
Over 15
251 or 2000
2001 or over
2½
4
*Note. Safety Valve Relieving Capacity for this purpose shall be the capacity as stamped on a
steel boiler or on the name plate of a cast iron boiler.
TABLE M-1014-3
BLOW-OFF VALVES
(see M-1014.5.9)
BOILER RATING
(square feet E.D.R.)
Pipe Size
(inches)
Under 1000
1001 to 3500
3501 to 8500
¾
1
1½
8501 to over
2
SECTION M-1015E WATER STORAGE TANKS, WATER HEATERS, HYDROPNEUMATIC TANKS
M-1015.1 General. Each hot water storage tank, range boiler, or automatic storage water heater,
having a nominal water-containing capacity of one-hundred twenty (120) gallons or less shall be
built for a minimum working pressure of one-hundred twenty-five (125) pounds per square inch
and shall be tested hydrostatically to three-hundred (300) pounds per square inch. Each tank
shall have clearly and indelibly stamped or stenciled thereon the name of the manufacturer, the
maximum allowable working pressure for which it is built, and the test pressure.
M-1015.1.1 Tank Label. Each hot water tank shall be stamped with the ASME symbol
to indicate that it is constructed in accordance with the Unfired Pressure Vessel Code of
the American Society of Mechanical Engineers. It shall also be stamped with the name of
the manufacturer, the maximum allowable working pressure, the year built, and the
identifying number of the National Board of Boiler and Pressure Vessel Inspectors.
M-1015.1.2 Permit Application. Applications for permits for hot water storage tanks as
described in Section M-1015.1 shall be accompanied by the Manufacturers’ Data Report
which shall be signed by an Inspector licensed to inspect boilers and pressure vessels by
the National Board.
M-1015.1.3 Gas-fired Automatic Storage Water Heaters. Gas fired automatic storage
water heaters shall bear a label indicating approval and listing in accordance with the
Fuel Gas Code.
M-1015.1.4 Oil Fired or Electrically Heated Water Heaters. Oil fired or electrically
heated automatic storage water heaters shall bear the U.L. label to indicate listing by
Underwriters Laboratories, Inc.
M-1015.1.5 Storage Water Heater Label. Each storage water heater shall bear the
manufacturer's trade name, if any, the catalog number, the firing rate (input), the output
in gallons per hour at one-hundred degrees Fahrenheit (100 deg F.) rise in temperature,
and the nominal capacity in gallons of the storage tank.
M-1015.1.6 Storage Tank Construction. Storage tanks shall be supported upon metal
supports of pipe or structural steel resting upon the floor, or they may be hung from
supports attached to structural steel or concrete beams, provided the beams have been
determined to be of sufficient strength to support the additional weight; or they may be
installed upon concrete saddles. Provision shall be made to take care of expansion. Tanks
shall not be supported by their piping system. Manhole openings shall be kept clear of all
walls, pipes, or other obstructions.
M-1015.1.7 Installation-Gas-Fired Water Heaters. Each gas-fired water heater shall be
provided with an approved draft diverter installed in accordance with the manufacturer's
design, and shall be connected to an effective chimney shall be above the entrance of
other vent connectors or breechings.
M-1015.1.8 Commercial and Industrial Installation. In commercial and industrial
establishments when a connection to a chimney is impracticable, the installation of an
automatic water heater may be approved by the Director if the following requirements are
met. The maximum flow of gas shall be limited by fixed orifices to values in relation to
the net cubical contents of the space in which the heater is located as specified in Table
M-1015. In no case shall the maximum input rate exceed 10,000 BTU per hour; and the
heater shall otherwise conform to these regulations.
M-1015.1.9 Prohibited Use. No water from a hot water supply boiler, automatic water
heater coil or tank shall be used for building heating, except that water to be used for
auxiliary space heating may be by-passed from any such boiler or heater, provided there
is no actual withdrawal or possible leakage of water from the unit, and that all surfaces
and connections in contact with the water are of copper or other approved corrosion
resistant material.
M-1015.1.10 Existing Tanks. A tank currently in use shall not be painted, lined or
repaired on the inside with any material or in any manner that will affect either the color
or taste of the water supply after the tank is put into service. Any material intended for
use as a lining or protective coating for the interior of tanks shall be submitted for
approval.
M-1015.1.11 Tank Maintenance and Repair. The water supply connections to and
from the tank shall be disconnected or plugged while the tank is being cleaned, painted,
lined or repaired, to prevent any foreign fluid or substance from entering the distribution
piping. Adequate measures shall be taken for the protection of workmen in the tank.
M-1015.1.12 Welding Repair. Any repair by welding on a tank shall be done by a
welder qualified and licensed by the Department and the work shall be done under the
supervision of a D.C. Boiler Inspector or an insurance company.
M-1015.1.13 Modification or Additions. When any changes or additions are made to
an existing hot water supply system or when a storage tank is replaced or moved,
compliance with this title shall be required; provided, that when there is no available
opening in the top of an automatic storage water heater having a nominal water
containing capacity of one-hundred twenty (120) gallons or less, the valve shall be
installed in the outlet header from the heater with only one fitting between the relief valve
and the tank.
M-1015.2 Hydro-pneumatic Tanks
M-1015.2.1 Construction. Each hydro-pneumatic tank shall be constructed for a
minimum working pressure of one-hundred fifty (150) pounds per square inch.
M-1015.2.2 Label. Each hydro-pneumatic tank shall be stamped with the following
information.
The ASME symbol to indicate that it is constructed in accordance with the Unfired
Pressure Vessel Code of the American Society of Mechanical Engineers;
1.
The name of the manufacturer;
2.
The maximum allowable working pressure;
3.
The year built; and
4.
The identifying number of the National Board of Boiler and Pressure
Vessel Inspector.
M-1015.2.3 Permit Applications. Applications for permits shall be accompanied by the
Manufacturers Data Report which shall be signed by an Inspector licensed to inspect
boilers and pressure vessels by the National Board.
M-1015.2.4 Gage-Glass. Each hydro-pneumatic tank shall be provided with a gage-glass
to show the level of the water in the upper section of the tank and a pressure gage. It shall
also be provided with an eleven inch (11") manhole opening which shall be kept clear of
all walls, pipes, or other obstructions.
M-1015.2.5 Safety Valves. Each hydro-pneumatic shall be equipped with a lever lifting
safety valve bearing the ASME symbol suitable for use with air, installed in a vertical
position on the top of the tank and set to relieve at or below the maximum allowable
working pressure of the tank. The valve shall be sealed to prevent tampering and there
shall be no shut-off valve between the tank and the relief valve.
M-1015.2.6 Pressure Gage. Each tank shall be provided with a pressure gage not less
than four inches (4”) in diameter connected directly to the tank by means of non-ferrous
pipe. A cock with a tee handle shall be placed in the pipe near the gage. The gage shall be
graduated to not less than one and one-half (1.5) times the maximum allowable working
pressure of the tank.
M-1015.2.7 Valve By-Pass. Each hydro-pneumatic tank shall be piped to include a fullsize valved by-pass so that city water can be used in the building when the tank is not in
service.
M-1015.2.8 Vacuum Relieving Device. Each hydro-pneumatic tank shall be provided
with a vacuum relieving device located on the top of the tank and a horizontal swing
check valve in the water supply line from the pump to the tank, and in the District water
supply by-pass line to the tank. A valved sludge drain pipe shall be installed at the
bottom of the tank and shall discharge through an open connection into the drainage
system of the building.
M-1015.3 Relief Valves, Gages, and Safety Controls
M-1015.3.1 General. Each hot water storage tank and automatic water heater shall be
equipped with safety controls, which shall prevent the temperature of the water in the
tank from exceeding two-hundred degrees Fahrenheit (200 deg F.) and the pressure from
exceeding the maximum allowable working pressure for which the tank is built. Each
such unit shall be equipped with the following.
1.
A pressure relief valve and a separate temperature relief valve of the spillage type;
2.
A combined temperature-pressure relief valve of the spillage type; or
3.
In the case of automatic water heaters manufactured as a unit, a thermostat and
pressure relief valve.
M-1015.3.2 Pressure Relief Valve. Each pressure relief valve shall be of the lever
lifting, spring-loaded type without disk on the pressure side of the valve. The valves shall
be set to relieve at a pressure at or below the maximum allowable working pressure of the
tank and shall be so arranged that they cannot be reset to relieve at a higher pressure than
stamped thereon.
M-1015.3.3 Relief Valve Capacity. The valve or valves shall have sufficient capacity to
prevent the pressure in the tank from rising more than ten percent (10%) above the
maximum allowable working pressure. The rate capacity of the valve, or valves shall be
equal to the maximum gross output of the heating unit installed. The gross output shall be
determined from the data supplied on the manufacturer's name plate, catalog data, or
from the fuel input.
M-1015.3.4 Label. Pressure relief valves shall bear the ASME symbol to indicate that
they comply with the requirements of the ASME Low Pressure Heating Boiler Code in
regard to construction, testing, and rating, and shall be plainly and permanently marked
by the manufacturer in a way that the marking will be readable when the valve is installed
and will not be obliterated in service. Pressure relief valves used on non-ASME
approved, gas-fired equipment shall bear the symbol to indicate listing under the
requirements of an approved testing agency, and shall bear the ASME symbol for
equipment using other fuels. The marking on pressure relief valves shall include the
following information:
1.
The manufacturer's name;
2.
The type and catalog number;
3.
The pressure at which it is set to blow; and
4.
The capacity in pounds of steam or BTU per hour as certified by the National
Board of Boiler and Pressure Vessel Inspectors.
M-1015.3.5 Valve Size. No pressure relief valve shall be less than three-quarter inch
(3/4") standard pipe size.
M-1015.3.6 Installation. Each pressure relief valve shall be installed in a vertical
position directly on the top of the tank, or if there is no opening available, to a fitting in
the hot water service line within two inches (2") from the tank. Each pressure relief valve
shall have a full size discharge pipe of non-ferrous metal, with an unthreaded open end,
run to an approved plumbing fixture or if none is available to within six inches (6") of the
floor. When the discharge pipe is over one inch (1") in diameter it shall be supported and
braced to prevent any strain being placed on the valve.
M-1015.3.7 Multiple Valve Use. If more than one valve is used, they may be connected
to a manifold whose inlet pipe area shall be equal to the area of the inlet openings of all
the valves. There shall be no restriction in size on either the inlet or discharge side of the
valve or valves, and there shall be no shut-off valve or check valve between the relief
valve and the tank.
M-1015.3.8 Temperature Relief Valve. Each temperature relief valve shall bear a label
indicating approval and listing by ASME, and shall be submitted for approval to the
Department.
M-1015.3.8.1 Valve Type and Design. Each temperature relief valve shall be of
the automatic self-closing type with a test lever and shall be designed to open at
two-hundred degrees Fahrenheit (200 degrees F.) or lower and be of sufficient
capacity to limit the temperature to not over two-hundred degrees Fahrenheit (200
degrees F.). The valve shall be non-adjustable and shall not be less than threequarter inch (3/4") standard pipe size.
M-1015.3.8.2. Label. Each temperature relief valve shall bear a plate
permanently attached, giving the following information.
1.
The name of the manufacturer;
2.
The model or type number of the valve;
3.
The temperature at which the valve will deliver its rated capacity; and
4.
The rated capacity in BTU.
M-1015.3.8.3 Installation. Each temperature relief valve shall be installed in a
vertical position on the top of the tank. Valves shall be screwed directly into the
tank without intervening fittings unless the dip tube extension type is used, in
which case the tube shall project into the tank. If a fitting is used, it shall be of
non-ferrous material. Each valve shall have a full size discharge pipe with an
unthreaded open end, run to within six inches (6") of the floor or to a suitable
fixture. There shall be no restrictions in size on either the inlet or discharge side
of the valve, and there shall be no shut-off or check valve between the relief valve
and the tank.
M-1015.3.9 Combined Temperature and Pressure Valve. When a combination
temperature-pressure relief valve is used, it shall conform with and be installed similarly
to the requirements for pressure relief valves and for temperature relief valves. It shall
bear both the ASME symbol and required stamping in addition to the symbol of the AGA
for the temperature relief element.
M-1015.3.10 Aquastat. Each aquastat used on an automatic gas water heater unless
provided as part of a complete AGA approved unit, shall be listed by AGA and shall
operate to shut off the gas supply to limit the temperature of the heated water to not over
two-hundred ten degrees Fahrenheit (210 deg F.).
M-1015.3.11 Hot Water Heating Systems. Hot water supply boilers, tankless heaters,
electric heaters, immersion heating coils in boilers and any other type of heater shall be
protected against excessive pressure, as provided herein.
M-1015.3.11.1 Pressure Gage. Each hot water supply boiler and hot water
storage tank shall be provided with a pressure gage connected directly to the
boiler or tank by means of non-ferrous pipe. A cock with a tee handle shall be
placed in the pipe near the gage. The gage shall have a dial not less than four
inches (4") in diameter and be so located that it can be easily read from the floor.
It shall be graduated to not less than one and one-half (1.5) times the maximum
allowable working pressure of the boiler or tank. Gages shall not be required for
range boilers and domestic type water heaters.
M-1015.3.11.2 Thermometer. Each hot water supply boiler, hot water storage
tank, tankless heater, immersion type heater or any other type of heater shall be
provided with a thermometer reading up to three-hundred degrees Fahrenheit (300
degrees F.), of a size and so located that it can be easily read from the floor. It
shall be located in a well so that it will indicate the temperature of the water at or
near the outlet and shall be accurate within two percent (2%). Thermometers shall
not be required for range boilers or domestic type water heaters.
M-1015.3.11.3 Water Mixing Valve. When hot water is used by the general
public or by persons not in control of the heating equipment, an approved water
mixing valve shall be installed to limit the temperature of the water at the fixture
to not over one-hundred forty degrees Fahrenheit (140 degrees F.). A
thermometer shall be installed on the discharge side of the mixing valve and be of
a size and so located as to be easily read.
TABLE M-1015
MAXIMUM PERMISSIBLE FLOW FOR UNVENTED COMMERCIAL AND
INDUSTRIAL WATER HEATERS
(see M-1015.1.8)
Net Cubical
Contents of Room
or Space
(in cubic feet)
PERMISSIBLE MAXIMUM GAS FLOW IN
CUBIC FEET PER HOUR
COLUMN NO. 1
(a)
COLUMN NO. 2
(b)
1000 to 1500
1500 to 2000
2
3
3
4
2000 to 2500
2500 to 3000
3000 to 3500
3500 to 4000
Over 4000
4
5
6
7
8
5
6
7
8
8
Note a.
Column No.1 applies to appliances when located in areas, which do not
have openings to other areas.
Note b.
Column No. 2 applies to appliances when located in areas, which have
permanent openings of at least 15 sq. ft. leading to another area of equal
or greater cubical content.
SECTION M-1016E WELDING ON BOILERS AND UNFIRED PRESSURE VESSELS
M-1016.1 General Rules for Welding. The construction, installation, repair or alteration of a
boiler or unfired pressure vessel by welding shall be made in accordance with Section IX, Part
QW, “Welding” in the ASME Code governing the particular kind of vessel or work to be done.
M-1016.1.1 Welding Procedure. A contractor desiring to make repairs shall have a
written welding procedure specification that shall be prepared and qualified in
accordance with the Welding Qualification of Section IX, Article II, “Welding Procedure
Qualifications” in the ASME Code, or the contractor may use the standard D.C. welding
procedure specification. This procedure shall then be used for qualifying each welders
and shall be strictly adhered to in making repairs under this chapter. A welder shall be
limited to the type of steel and thickness of plate for which he or she was qualified.
M-1016.1.2 Qualification Test. Each welder shall pass satisfactory qualification tests as
required by Section IX, Article III, “Welding Performance Qualifications” in the ASME
Code, NBIC and the D.C. Welding Standard. The qualification test for individual
welders shall be made in accordance with the ASME Code. The test shall be made in the
presence of the boiler inspector or an assistant boiler inspector who shall stamp the
specimens with a D.C. identifying number. A welder may be accepted without further
examination provided that he submits a satisfactory welding procedure and operator
qualification test, made in accordance with the ASME Code and these regulations, for
approval prior to any welding. The qualification test does qualify a welder to do welding
on pressure piping.
M-1016.1.3 Test Specimens. After the specimens have been prepared as required by
Section IX, Part QW, paragraph QW-310, “Qualification Test Coupons” in the ASME
Code, they shall be tested by the D.C. Boiler Inspector, or they may be submitted to the
National Institute of Standards and Technology (NIST) for test. The test shall be made in
accordance with the guided-bend jig test as described Section IX, Part QW, paragraph
QW-160, “Guided-Bend Tests” in the ASME Code. A report shall be made on a form
similar to data recording forms in Section IX, Appendix-B, “Non-mandatory Welding
and Brazing Forms” in the ASME Code. If the report indicates that the welder has
passed the test, a card authorizing him or her to do welding on boilers or unfired pressure
vessels in the District of Columbia for a period of two (2) years from the date of the test,
shall be issued.
M-1016.1.4 Fees. The fee for witnessing the welding and making the tests shall be sixtyfive dollars ($65.00). The fee for the NIST test is additional. All fees are payable in
advance.
M-1016.2 Qualification Retest. A welder who fails to meet the requirements for one or more of
the test specimens may be retested under the following conditions.
1.
When an immediate retest is made, the welder shall make two test welds of each type for
each position on which he has failed, all of which shall pass the test examination; or
2.
If, in the judgment of the inspector, the welder requires further training or practice, a
complete retest of the welder shall be made after he has completed his additional training
or practice.
M-1016.3 Inspector's Authority. Notwithstanding the issuance of a qualification card, the
inspector may request a new test under the following circumstances.
1.
When a welder has not welded under the procedure specification for a period of three (3)
months or more;
2.
When there is a specific reason to question his ability to make welds that meet the
specification; and
3.
At the expiration of his two (2) year qualification period.
M-1016.3.1 Welding Defects. If any question should arise as to the quality of a weld,
the inspector may call for test specimens to be trepanned from the welds. Preparation of
the specimens and examination shall be done by the NIST and the contractor shall stand
all expense incidental to this testing.
M-1016.3.2 Welding Inspection. No welding on any boiler or unfired pressure vessel
shall be done before an inspection has been made by the boiler Inspector, an assistant
boiler Inspector, or an insurance company Inspector, and the method of welding
sanctioned by that Inspector. If, in the opinion of the Inspector, a hydrostatic test is
necessary, that test shall be applied after the repairs have been completed.
M-1016.4 Repairs of Boilers or Unfired Pressure Vessels. Before repairs are started, it shall
be the duty of the Inspector to satisfy himself or herself, by examination of the written welding
procedure and records of qualification tests, that procedures and welders have been properly
tested and qualified. Welding repairs or alterations on boilers or unfired pressure vessels and
connections by unqualified contractors or welding operators will not be accepted for either new
or existing installations.
M-1016.4.1 Inspector’s Report. A report shall be made of every welded repair by the
Inspector who authorized and witnessed the repair.
M-1016.5 Rules for Welding on Boilers and Unfired Pressure Vessels
M-1016.5.1 Welding Rule. The construction, installation, repair or alteration of a boiler
or unfired pressure vessel by welding shall be made in accordance with the section of the
ASME Code governing the particular kind of vessel or work to be done or by the specific
requirements in this section for welded repairs.
M-1016.5.2 Qualified Welding Procedure. A contractor desiring to make repairs shall
have a written welding procedure specification that shall be prepared and qualified in
accordance with the Welding Qualification in Section IX of the ASME code, or the
contractor may use the standard D.C. welding procedure specification. This procedure
shall then be used for qualifying each welders and shall be strictly adhered to in making
repairs under this chapter. A welder shall be limited to the type of steel and thickness of
plate for which he or she was qualified.
M-1016.5.3 Welder Qualifications. Each welder shall pass satisfactory qualification
tests as required by the ASME Code.
M-1016.5.4 Qualification Standard. The qualification test for individual welders shall
be made in accordance with the ASME Code. The test shall be made in the presence of
the boiler inspector or an assistant boiler inspector who shall stamp the specimens with a
D.C. identifying number. A welder may be accepted without further examination
provided that he submits a satisfactory welding procedure and operator qualification test,
made in accordance with the ASME Code and these regulations for approval prior to any
welding.
M-1016.5.5 Specimen Test. After the specimens have been prepared as required by the
ASME Code, they shall be tested by the D.C. Boiler Inspector or they may be submitted
to the NIST for test. The test shall be made in accordance with the guided-bend jig test
as described in the ASME Code. A report shall be made on a form similar to the data
recording forms in Section IX, Appendix-B in the ASME Code.
M-1016.5.6 Welding Fees. The fee for witnessing the welding and making the tests
shall be one-hundred dollars ($100.00). The fee for the NIST test is additional. All fees
are payable in advance.
M-1016.5.7 Authorization Card. If the report indicates that the welder has passed the
test, a card authorizing him or her to do welding on boilers or unfired pressure vessels in
the District of Columbia for a period of two (2) years from the date of the test, shall be
issued.
M-1016.5.8 Welder Qualification Limit. The qualification test does not qualify a
welder to do welding on pressure piping.
M-1016.5.9 Welder Re-Test. A welder who fails to meet the requirements for one or
more of the test specimens may be retested under the following conditions.
1.
When an immediate retest is made, the welder shall make two test welds of each
type for each position on which he has failed, all of which shall pass the test
examination; or
2.
If, in the judgment of the inspector, the welder requires further training or
practice, a complete retest of the welder shall be made after he has completed this
additional training or practice.
M-1016.5.10 Welder Re-Test Performance. Notwithstanding the issuance of a
qualification card, the inspector may request a new test under the following
circumstances.
1.
2.
3.
When a welder has not welded under the procedure specification for a period of
three (3) months or more;
When there is a specific reason to question his ability to make welds that meet the
specification; and
At the expiration of the two (2) year qualification period.
M-1016.5.11 Trepanned Specimen. If any question should arise as to the quality of a
weld, the inspector may call for test specimens to be trepanned from the welds.
Preparation of the specimens and examination shall be done by the NIST and the
contractor shall stand all expense incidental to this testing.
M-1016.5.12 Inspection Requirements. No welding on any boiler or unfired pressure
vessel shall be done before an inspection has been made by the boiler inspector, an
assistant boiler inspector, or an insurance company inspector, and the method of welding
sanctioned by that inspector. If, in the opinion of the inspector, a hydrostatic test is
necessary, that test shall be applied after the repairs have been completed.
M-1016.5.13 Inspector Examination. Before repairs are started, it shall be the duty of
the inspector to satisfy himself or herself, by examination of the written welding
procedures and records of qualification tests, that procedures and welders have been
properly tested and qualified.
M-1016.5.14 Weld Rejection. Welding repairs or alterations on boilers or unfired
pressure vessels and connections by unqualified contractors or welding operators will not
be accepted for either new or existing installations.
M-1016.5.15 Inspector’s Report. A report shall be made on every welded repair by the
inspector who authorized and witnessed the repair.
M-1016.6 Method of Conducting Tests
M-1016.6.1 Welder Qualification Tests. The qualification tests described shall be
specially devised tests to determine a welder’s ability to produce sound wells. In order to
determine the welder’s ability to make groove wells in various positions in plate, the
following three positions for tests are required.
1.
Test Position I – Plates placed in a vertical position with the welding groove in a
horizontal plane. This test shall qualify the welder to make flat and horizontal
welds.
2.
Test Position II – Plates placed in a vertical position with the axis of the weld
vertical. The test shall qualify the welder to make flat and vertical welds.
3.
Test Position III – Plates placed in a horizontal position with the weld metal
deposited form the underside of the plate. This test shall qualify the welder to
make flat welds in the overhead position.
M-1016.6.2 Weld Plate Specifications. The base material of the plates to be welded
shall be of flange or firebox steel quality three-eights inch (3/8”) thick and having a
tensile strength of not less than fifty-five thousand (55,000) pounds per square inch. The
plates shall be five inches (5”) long by six inches (6”) wide, and shall be prepared for a
single “V” groove butt joint.
M-1016.6.3 Preparing Test Specimens. The method of preparing test specimens shall
be as follows:
1.
When the welding has been completed, specimens shall be removed as directed
by machine or flame cutting. They shall be approximately one and one-half
inches (1.5”) wide.
2.
The weld reinforcement shall be removed by machine or grinding, flush with the
surface or the base metal.
3.
The corners of the edges of all test specimens shall be rounded to a radius of not
more than one-fifteenth inch (1/15”).
In addition to (1), (2) and (3) above, the test specimens shall be prepared as specified in
Section IX, paragraph QW-462, “Test Specimens” in the ASME Code.
M-1016.6.4 Specimen Testing Methods. The method of testing specimens shall be as
follows:
Specimens shall be bent in a bending jig called the “guided bend test”, until the curvature
of the specimen is such that a one-thirty-second inch (1/32”) wire cannot be passed
between the curve portion of the plunger and the specimen. Face bend specimens shall
be placed with the face of the weld toward the gap in the jig; root bend specimens shall
be placed with the root of the weld toward the gap.
After removal from the jig, the convex surface of the specimens shall be examined for the
appearance of cracks or other open defects. Any specimen in which a crack or other open
defect is present after the bending exceeding one-eight inch (1/8”) measured in any
direction, shall be cause for failure to pass the test.
M-1016.7 Repairs by Welding
M-1016.7.1 Repairs Limited to Steels. The repairs that may be made under these rules
are limited to steels having known weldable quality and are further limited to carbon
steels having a carbon content of not more than thirty-five hundredths percent (0.35%)
and low alloy steels having a carbon content of not more than twenty-five hundredths
(0.25%) percent. A welder shall not make repairs in a plate thickness in excess of that
permitted under the qualification tests in the ASME Code, or on a material, or in a
thickness of plate that is not permitted within the welder’s qualification tests.
M-1016.7.2 Groove Welding. Groove welds shall completely penetrate the material
being welded. If possible, welding shall be applied from both sides of the plate, or a
backing strip or ring may be used to insure complete penetration. Welds shall have a
convex surface on both sides if applied on both sides of the plates being joined; or on one
side if welding is applied from one side only. No valleys or undercutting at edges or
welded joints shall be permitted. The reinforcement may be chipped, ground or
machined off flush with the base metal, if so desired, after the welding has been
completed.
M-1016.7.3 Defective Weld Repair. In making a repair to a weld that has failed in
service, the defective weld material shall be removed by chipping or grinding until sound
metal is reached on all sides. The resulting groove shall be filled as required by the
applicable welding procedure.
M-1016.7.4 Carbon Steel Stress-Relieving. In the repair of carbon or low alloy steels,
when required by these rules and when considered necessary by the authorized inspector,
thermal stress-relieving shall be applied to the completed work. The heat may be applied
by any means that will raise the temperature of the material gradually and uniformly to
approximate twelve-hundred degrees Fahrenheit (1200 deg. F.). In the absence of more
accurate means of determining temperature, a dull “red glow” in daylight will suffice.
This temperature shall be maintained for a period of one hour per inch of thickness of
material.
M-1016.7.4.1 Circumferential Joints. For circumferential joints, the area heated
shall comprise a band extending completely around the cylinder and having a
width on each side of the center line of the weld not less than three times the
greatest width of the finished weld.
M-1016.7.4.2 Nozzles. For nozzles, the heated area shall comprise a
circumferential band extending around the entire vessel, including the nozzle of
welded attachment, and shall extend at least six times the plate thickness beyond
the welding which connects the nozzle or other attachment to the vessel.
M-1016.7.5 Stress-Relieve Cooldown Procedure. Upon completion of the stressrelieving operation, the plate shall be allowed to cool at a rate not greater than fivehundred degrees Fahrenheit (500 deg. F.) per hour divided by the maximum thickness of
the welded part in inches, but in no case more than five-hundred degrees Fahrenheit (500
deg. F.) is reached, after which normal cooling by exposure in a still atmosphere may be
permitted.
M-1016.7.6 Thermal Stress-Relief Alternatives. It should be noted that under certain
conditions, thermal stress relieving as outlined above may be inadvisable. In such cases
any other method of stress-relieving acceptable to the authorized inspector may be used.
Under certain conditions preheating may be necessary.
M-1016.8 Welded Repairs on Boilers and Unfired Pressure Vessels
M-1016.8.1 Crack Repair in Stayed Areas. Cracks in stayed areas may be repaired by
welding, provided that no multiple or star cracks radiating from rivet or stay bolt holes
shall be welded.
M-1016.8.2 Crack Repair in Unstayed Shells. Cracks in unstayed shells, drums or
headers of boilers or pressure vessels may be repaired by welding, provided that the
cracks do not extend between rivet holes in a longitude seam or parallel to a longitudinal
riveted seam within eight inches (8”), measured from the nearest caulking edge. The
total length of any one such crack shall not exceed eight inches (8”). A crack of greater
length may be welded provided the complete repair is radiographed and stress-relieved.
Any crack that may be welded shall be properly prepared to permit fusion through the
entire plate.
M-1016.8.3 Crack Repair in Unstayed Furnaces. Cracks of any length in unstayed
furnaces may be welded, provided that the welds are thermally stress relieved. Welds
shall be applied from both sides of the plate wherever possible. Welds applied from one
side only may be used if expressly permitted by the inspector. Repair of cracks at the
knuckle or turn of flange of furnace openings shall be prohibited except upon special
approval by the Inspector.
M-1016.8.4 Corrosion Repair in Stayed Furnaces. Corroded areas in stayed furnaces
may be built up by welding, provided that the remaining plate has an average thickness of
not less that fifty percent (50%) of the original thickness, and further provided that the
areas so affected are not sufficiently extensive to impair the safety of the object. In those
cased the stays and stay bolts shall come completely through the reinforcing metal and
the original ends of the stay bolts shall be plainly visible to the Inspector.
M-1016.8.5 Corrosion Repair Around Manholes. Corroded areas around manholes or
handhole openings, in either stayed or unstayed plates, may be built up by welding,
provided that the average loss of thickness does not exceed fifty percent (50%) of the
original plate thickness and the area to be repaired does not extend more than three inches
(3”) from the edge of the hole.
M-1016.8.6 Corrosion Repair in Unstayed Shells. Corroded areas in unstayed shells,
drums or of the object has not been impaired.
M-1016.8.7 Repairing Connector Areas. Edges of butt straps, of plate laps and
nozzles, or of connections, attached by riveting may be restored to their original thickness
by welding. No seal welding shall be used except upon special approval of the Inspector,
and in no case where cracks are present in riveted areas.
M-1016.8.8 Welding Tube Ends. The ends of tubes in fire-tube and water-tube boilers
may be welded, provided that they have not been reduced more than ten percent (10%)
percent in thickness and comply with the requirements of paragraphs PWT-11 and PFT12 in Section I, Parts PWT and PFT in the ASME Power Boiler Code.
M-1016.8.9 Re-ending Tubes, Pipes. Re-ending of piecing tubes or pipes in either firetube or water-tube boilers shall be permitted, provided that the thickness of the tube or
pipe has not been reduced by more than ten percent (10%) from the thickness required by
the ASME Code for the pressure approved. In all cases they shall comply with the
requirements in Section I, Part PWT, paragraph PWT-10, “Tube Wall Thickness” in the
ASME Power Boiler Code.
M-1016.8.10 Patch Material. The material used for patches shall be of the same general
quality and have at least the minimum physical properties of the plate to be patched. The
thickness of any patch shall be at least equal to, but not more than one-third inch (1/3”)
greater than the plate being patched.
M-1016.8.11 Patches Permitted. Flush or butt-welded patches or new sections may be
applied to stayed plates without limitation of size or plate thickness. Lapped or filletwelded patches may be applied to stayed plates, provided that they are not exposed to
radiant heat. Lapped and fillet-welded patches may be applied on the pressure side of the
sheet in unstayed areas, provided that the maximum diameter of the opening so repaired
does not exceed sixteen (16) times the thickness of the plate, but in no case larger than
eight inches (8”) in diameter.
M-1016.8.12 Patches Not Permitted. No flush or butt-welded patches in unstayed
shells, drums or headers shall be permitted.
M-1016.8.13 Threaded to Weld-in Stays. Threaded stays may be replaced by weldedin stays, provided that in the judgment of the Inspector, the plate adjacent to the stay bolt
has not been materially weakened by deterioration or wastage. All requirements of the
applicable sections of the ASME Code governing welded-in stays, including Section I,
Part PW, paragraph PW-19, “Welded-in Stays” shall be complied with.
SECTION M-1017E EXISTING INSTALLATIONS. POWER BOILERS
M-1017.1 Maximum Allowable Working Pressure. The maximum allowable working pressure
on the shell or drum of a power boiler shall be determined by the strength of the weakest section
of the structure, computed from the following information.
1.
The thickness of the plate;
2.
The tensile strength of the plate;
3.
The efficiency of the longitudinal joint, or tube ligaments (whichever is least);
4.
The inside diameter of the course; and
5.
The factor of safety allowed by this chapter.
M-1017.1.1 Computation. The maximum allowable working pressure computation shall
be as follows:
TS x t x E
R x FS
=
Maximum allowable working pressure
in pounds per square inch
TS
=
ultimate tensile strength of shell plates, pound per square inch
t
=
minimum thickness of shell plate in weakest course in inches
E
=
R
=
efficiency of longitudinal joint. (See Section VIII, Division 1, Part UW,
paragraph UW-12 in ASME Code)
inside radius of the weakest course of the shell or drum in inches.
FS
=
factor of safety allowed by these rules.
M-1017.2 Factors of Safety. The factor of safety for boilers of nonstandard construction, the
longitudinal joints of which are of butt and double strap construction, shall be not less than the
following:
1.
Four and one-half (4.5) for boilers not over 20 years old;
2.
Five (5) for boilers over 20, but not more than 25 years old;
3.
Five and one-half (5.5) for boilers over 25, but not more than 30 years old;
At the beginning of each five (5) year period thereafter, the factor of safety shall be increased by
not less than five-tenths (0.5).
M-1017.2.1 Maximum Allowable Working Pressure Limit. In no case shall the
maximum allowable working pressure on old boilers be increased unless they are being
operated at a lesser pressure than would be allowable for new boilers, in which case the
changed pressure shall not exceed that allowable for new boilers of the same
construction.
M-1017.2.2 Conditional Factor of Safety Limits. The factor of safety for all standard
boilers, the longitudinal joints of which are of butt and double strap construction shall be
five (5) for boilers not more than twenty-five (25) years old, and at the beginning of each
five (5) year period thereafter, the factor of safety shall be increased by not less than fivetenths (0.5), provided that after a thorough internal and external inspection and a
hydrostatic pressure test to one and one-half times the pressure allowed during which no
distress or leakage develops, the pressure allowed may be continued at a factor of safety
of five (5).
M-1017.2.3 Lowest Factor of Safety. The lowest factor of safety for boilers of the
water-tube type of nonstandard construction, the longitudinal joints of which are of lap
riveted construction shall be not less than the following:
1.
Five (5) for boilers not over 20 years old.
2.
Five and one-half (5.5) for boilers over 20, but not over 25 years old.
3.
Six (6) for boilers over 25, but not over 30 years old.
4.
At the beginning of each five (5) year period thereafter, the factor of safety for
boilers of the water-tube type of nonstandard construction, the longitudinal joints
of which are of lap riveted construction, shall be increased by not less than fivetenths (0.5).
M-1017.2.3.1 Lowest Factor of Safety. The lowest factor of safety for all fire
tube, flue and cylinder boilers of nonstandard construction, the shells of which are
exposed to the products of combustion and which have continuous longitudinal
joints of lap-riveted construction exceeding twelve feet (12ft) in length, shall be
not less than the following:
1.
Six (6) for boilers not over 10 years old.
2.
Six and one-half (6.5) for boilers over 10, but not over 15 years old.
3.
Seven (7) for boilers over 15, but not over 20 years old.
4.
At the beginning of each five (5) year period thereafter, the factor of safety
for boilers as specified in 1, 2 and 3 above, shall be increased by not less
than five-tenths (0.5). This type of boiler when removed from an existing
setting shall not be reinstalled for a pressure in excess of fifteen (15)
pounds.
M-1017.3 Cast-Iron Headers and Mud Drum. The maximum allowable working pressure on
water-tube boilers, the tubes of which are secured to cast-iron or malleable-iron headers, or
which have cast-iron mud drums, shall not exceed one-hundred sixty (160) pounds per square
inch.
M-1017.4 Tensile Strength. When the tensile strength of steel or wrought iron shell plates is not
known, it shall be taken as fifty-five thousand (55,000) pounds per square inch for steel and
forty-five thousand (45,000) pounds per square inch for wrought iron.
M-1017.5 Crushing Strength of Mild Steel. The resistance to crushing of mild steel shall be
taken at ninety-five thousand (95,000) pounds per square inch of cross-sectional area.
M-1017.6 Rivets. In computing the ultimate strength of rivets in shear the cross-sectional area
of the rivet shank shall be used for the values in pounds per square inch based upon the
requirements in Section I of the ASME Code.
M-1017.6.1 Size of Rivets. When the diameter of the rivet holes in the longitudinal joints
on a boiler is not known, the diameter and cross-sectional area of rivets, after driving,
may be selected from Table M-1017 or ascertained by cutting out one rivet in the body of
the joint.
M-1017.7 Inspection of Inaccessible Parts. The heads of water tube boiler mud drums or
headers which are not accessible for inspection shall have the brick work removed after the
boiler has been in service for ten (10) years and at not less than every five (5) years period
thereafter. All seams and parts of fire-tube boilers that are not accessible for inspection shall be
exposed whenever, in the discretion of the inspector, the general condition of the boiler appears
to be such that further examination is desirable.
M-1017.8 Safety Valves. Each boiler shall be equipped with one or more safety valves of the
spring-pop type with a lifting device, placed as close to the boiler as possible. No valve of any
description shall be placed between the safety valve and the boiler nor on the escape pipe
between the safety valve and the atmosphere. When an elbow is placed on a safety valve escape
pipe, it shall be located close to the safety valve outlet or the escape pipe shall be securely
anchored and supported. When an escape pipe is used, it shall be full sized and fitted with an
open drain to prevent water lodging in the upper part of the safety valve or escape pipe. Safety
valves having either the seat or disk of cast iron shall not be used. Dead weight and lever weight
safety valves shall be prohibited.
M-1017.8.1 Safety Valves Capacity. The safety-valve capacity of each boiler shall be
such that the safety valve or valves will discharge all the steam that can be generated by
the boiler without allowing the pressure to rise more than six percent (6%) above the
maximum allowable working pressure, or more than six percent (6%) percent above the
highest pressure to which any valve is set.
M-1017.8.2 Safety Valves Setting. One or more safety valves on every boiler shall be
set at or below the maximum allowable working pressure. The remaining valves may be
set within a range of three percent (3%) above the maximum allowable working pressure,
but the range of setting of all the safety valves on a boiler shall not exceed ten percent
(10%) of the highest pressures to which any valve is set.
M-1017.9 Parts and Equipment for existing installations – Power Boilers.
M-1017.9.1 Fire-Actuated Fusible Plugs. Fire-actuated fusible plugs when used shall
conform to the rules and regulations of the ASME Code for new construction.
M-1017.9.2 Water Glass. Each steam boiler shall have at least one water glass, the
lowest visible part of which shall be as called for under the ASME Code for new
construction.
M-1017.9.3 Gage Cock. Each boiler shall have three or more gage cocks located within
the range of the visible length of the water glass when the maximum allowable working
pressure exceeds fifteen (15) pounds per square inch except when such boiler has two
water glasses with independent connections to the boiler, located on the same horizontal
line and not less than two feet (2') apart.
M-1017.9.4 Outlet Connections. No outlet connections except for damper regulator,
feed water regulator, low water fuel cut-out, drains or steam gage shall be placed on the
pipes connecting a water column to a boiler. Each water column shall have a valved
drain run to within six inches (6") of the floor.
M-1017.9.5 Steam Gage. Each steam boiler shall have a steam gage connected to the
steam space or to the steam connection to the water column. The steam gage shall be
connected to a siphon or equivalent device of sufficient capacity to keep the gage tube
filled with water and so arranged that the gage cannot be shut off from the boiler except
by a cock placed near the gage and provided with a “T” or level handle arranged to be
parallel to the pipe in which it is located when the cock is open.
M-1017.9.6 Low-Water Cut-Off. Each steam boiler when mechanically fired shall be
equipped with a low-water cut-off so located as to automatically cut off the fuel supply
when the water level falls to a point not lower than the top of the bottom nut of the water
glass. Each cut-off shall have a drain run to within six inches (6") of the floor. When two
or more mechanically fired boilers are connected to the same system, each boiler shall
have independent low-water cut-offs, controls, and gages.
M-1017.9.7 Stop Valve. Each steam outlet from a high-pressure boiler (except safetyvalve connections) shall be fitted with a stop valve located as close as practicable to the
boiler.
M-1017.9.8 Blow Drains. When a stop valve is so located that water can accumulate,
free blow drains shall be provided, the discharge of which shall be visible to the operator
while manipulating the valve.
M-1017.10 Blow-Off Connection. Each boiler shall have a full-size blow-off fitted with a valve
or cock in direct connection with the lowest water space practicable. When cocks are used they
shall be of the gland or guard type and suitable for the pressure allowed. Globe valves are not
permitted.
M-1017.10.1 Maximum Pressure. When the maximum allowable working pressure
exceeds one-hundred (100) pounds per square inch, the blow-off shall be extra heavy
from boiler to valve or valves, and shall run full size without reducers or bushings. Blowoff piping shall be of black wrought iron or black steel (not galvanized) and shall be extra
heavy pipe.
M-1017.10.2 Fittings. All fittings, between the boiler and valve shall be steel or extra
heavy fittings of bronze, brass, or malleable iron. In case of renewal of pipe or fittings in
the blow-off lines, as specified in this paragraph, they shall be installed in accordance
with the ASME Code for new installations.
M-1017.10.3 Blow-off Pipe. When the maximum allowable working pressure exceeds
one-hundred (100) pounds per square inch, each bottom blow-off pipe shall be fitted with
two valves or a valve and cock such valves and cocks to be of the extra heavy type. A
bottom blow-off pipe when exposed to direct furnace heat shall be protected by fire-brick
or other heat-resisting material, so arranged that the pipe may be inspected. An opening
in the boiler setting for a blow-off pipe shall be arranged to provide for free expansion
and contraction.
M-1017.11 Feed-Water Connections. The feed pipe of a steam boiler shall be provided with a
check valve near the boiler and a valve or cock between the check valve and the boiler, and when
two or more boilers are fed from a common source, there shall also be a globe valve on the
branch to each boiler between the check valve and the source of supply. When a globe valve is
used on a feed pipe, the inlet shall be under the disk from the valve. In all cases where the safety
valve is set above twenty-five (25) pounds, there shall be an additional means of feeding water
against the maximum approved pressure.
M-1017.12 Test Pressure. When a hydrostatic test is applied, test pressure shall be not more
than one and one-half times the maximum allowable working pressure. During a hydrostatic test
of a boiler, suitable provisions shall be made so that it will not be necessary to screw down the
compression screw upon the spring of the safety valve.
M-1017.13 Repair and Replacements. Where repairs or replacements are made or fittings or
appliances renewed or attached to a boiler, they must comply with the ASME Code for new
installations.
M-1017.14 Conditions not Covered by These Rules. If any condition not definitely covered by
this chapter, the ASME Code for new installations shall apply.
TABLE M-1017
SIZES OF RIVETS BASED ON PLATE THICKNESS
(see M-1017.6.1)
Inch
Inch
Inch
Inch
Inch
Inch
1/4
9/32
5/16
11/32
3/8
13/32
Diameter of rivet
after driving
11/15
11/16
3/4
3/4
13/16
13/16
Thickness of plate
7/16
15/32
2
9/16
5/8
-
Diameter of rivet
after driving
15/16
15/16
15/16
11/16
11/16
-
Thickness of plate
SECTION M-1018E EXISTING INSTALLATIONS - HEATING BOILERS
M-1018.1 Maximum Allowable Working Pressure. Maximum allowable working pressure of
heating boilers shall be as follows.
1.
Riveted Heating Boilers. The maximum allowable working pressures on the shell or
drum of riveted heating boiler shall be determined in accordance with Section M-1017.0,
except that in no case shall the maximum allowable working pressure of a steam-heating
boiler exceed fifteen (15) pounds per square inch.
2.
Cast Iron Heating Boilers. The maximum allowable working pressure of a boiler
composed principally of cast iron shall not exceed fifteen pounds (15 psi) unless such
boiler complies with all other requirements of the rules and regulations for power boilers.
The maximum allowable working pressure of a boiler having cast-iron shell or heads and
steel or wrought-iron tubes shall not exceed fifteen (15 psi).
M-1018.1.1 Low Pressure Boiler. A radiator in which steam pressure is generated at a
pressure of fifteen (15 psi) or less shall be considered a low pressure boiler.
M-1018.1.2 Manufacturers Specification and Identification. The maximum allowable
working pressure shall in no case exceed the pressure indicated by the manufacturer's
identification stenciled or cast upon the boiler or upon a plate secured to it. In the absence
of a manufacturer's identification stencil or plate the maximum allowable working
pressure shall not exceed that guaranteed in the manufacturer's specification or catalogs.
M-1018.1.3 Safe Operating Pressure. If in the judgment of an inspector, a steamheating boiler is not safe for operation at the pressure previously approved, the pressure
shall be reduced to the safe amount or proper repair shall be made or the boiler retired
from service.
M-1018.2 Safety Valves. Each steam-heating boiler shall be provided with one or more safety
valves with a total area of not less than one square inch (1 sq. in.) for each five square feet (5 sq.
ft) of grate area or equivalent, if grates are not used. The steam-relieving capacity of the safety
valve or valves on any boiler shall be sufficient to prevent the boiler pressure from rising more
than five (5 psi) above the maximum allowable working pressure of the boiler.
M-1018.2.1 Capacity. If there is any doubt as to the capacity of the safety valve, an
accumulation test shall be run. No safety valve shall be smaller than three-quarter inch
(3/4") in diameter or larger than four and one-half inches (4.5") in diameter.
M-1018.2.2 Stop Valve. No stop valve of any description shall be located between a
boiler and its safety valve, nor in the safety valve discharge pipe.
M-1018.3 Parts and Equipment. Each steam boiler shall be equipped with the following parts
and equipment in accordance with each specified conditions.
M-1018.3.1 Steam Gage Pressure. Each steam boiler shall have a steam pressure gage
connected to the steam space of the boiler itself or on steam pipe near the boiler. The
graduations of the steam gage shall not be less than fifteen (15 psi) nor more than thirty
(30 psi).
M-1018.3.2 Water Gage Glass. Each boiler shall have at least one water gage glass
with the lowest visible part above the heating surfaces in the primary combustion
chamber. When, in the judgment of an Inspector, the heating surfaces above the lowwater line may be injured by contact with gases of high temperature, the water gages
shall be raised until the lowest visible part of the glass gage is above the testing surface.
M-1018.3.3 Gage Cocks. Each steam boiler shall have two or more gage cocks located
within the visible length of the water gage glass except when such boiler is provided with
two water gage glasses.
M-1018.3.4 Steam Stop Valve. If a boiler may be closed off from the heating system
by closing a steam stop valve, there shall be a check valve in the condensate return line
between the boiler and the system. If any part of a heating system may be closed off
from the remainder of the system by closing a steam stop valve, there shall be a check
valve in the condensate return pipe from that part of the system.
M-1018.3.5 Feed-Water Connections. Feed-water connections shall be independent of
any water gage connections and it is recommended that the connections be made to the
condensate return pipe of reservoir of the condensate return pump. There shall be a check
valve in the feed-water line close to the boiler.
M-1018.3.6 Low-Water Cut-Off Mechanical Fired Boilers. Each mechanically fired
boiler shall be equipped with a low-water cut-off so located as to automatically cut off
the fuel supply in case the water level falls to a point not lower than the tip of the bottom
nut of the water glass. Each cut-off shall have a drain run to within six inches (6") of the
floor. When two or more mechanically fired boilers are connected to the same system,
each boiler shall have independent low-water cut-offs, controls, and gages.
M-1018.3.7 Low-Water Cut-Off Electrically Operated Boilers. If a low-water fuel
cut-out device is electrically operated, it shall be so connected that it will assume the
"cut-out" position when the electric current is off.
M-1018.3.8 Condensate Return Pump. Each condensate return pump shall be provided
with an automatic water level control set to maintain the water level within the limits of
two gage cocks.
M-1018.4 Repairs or Replacements. When repairs or replacement of parts or piping are made
or fittings or appliances renewed or attached to a boiler, the rules applying to new installations
shall be followed as nearly as practicable.
M-1018.4.1 Safety Valve. When a safety valve is replaced the requirements of Section
M-1014.0 and Section M-1015.0 shall be complied with, no valve being less than threequarter inch (3/4") in diameter or larger than four and one-half inches (4.5") in diameter.
SECTION M-1019E EXISTING INSTALLATIONS - MINIATURE BOILERS
M-1019.1 Maximum Allowable Working Pressure. The maximum allowable working
pressure on the shell of a boiler or drum shall be determined by the formula.
TS x t x E
R x FS
=
Maximum allowable working pressure
in pounds per square inch
Where:
TS
=
ultimate tensile strength of shell plates, pound per square inch
t
=
minimum thickness of shell plate in weakest course in inches
E
=
E
=
R
=
efficiency of longitudinal joint. (See Section VIII, Division 1, Part UW,
paragraph UW-12 in ASME Code)
efficiency for tube ligaments between openings as calculated in Section I, Part
PG, paragraphs PG-52 and PG-53 in the ASME Code.
inside radius of the weakest course of the shell or drum in inches.
FS
=
factor of safety allowed by these rules.
N.B. To be used as given for longitudinal joints, riveted construction, or if for fusion welded joints, E shall be taken
as specified in Section VIII, Division 1, Part UW, paragraph UW-12, “Joint Efficiencies” in the ASME Code. In
any case where there are both riveted joints and tube ligaments to consider, the weaker of these shall be used for E.
M-1019.2 Parts and Equipment. Each miniature boiler shall be equipped with the following
parts and equipment in accordance with each specified conditions.
M-1019.2.1 Feed Pump. Each miniature boiler operating at a pressure in excess of
twenty-five (25) pounds per square inch shall be provided with at least one feed pump or
other approved feeding device except where the steam generator is operated with no
extraction of steam (closed system). In the latter case, in lieu of a feeding device, a
suitable connection or opening, not less than one-half inch (½") pipe size, shall be
provided to fill the generator when cold.
M-1019.2.2 Feed Water and Blow-Off Connections. Each miniature boiler shall be
fitted with feed water and blow-off connections which shall not be less than one-half inch
(½") iron pipe size unless operated on a closed system. The feed pipe shall be provided
with a check valve and stop valve. The blow-off shall be fitted with a valve or cock in
direct connection with the lowest water space practicable. When the boiler is under
pressure, feed water shall not be introduced through the openings or connections used for
the column, the water gage glass or gage cocks. All valves, pipe fittings, and appliances
shall be at least one-hundred twenty-five (125 psi) standard pressure.
M-1019.2.3 Water Gage Glass and Gage Cocks. Each miniature boiler shall be
equipped with a water gage glass and one or more gage cocks. The lowest permissible
water level shall be at a point one-third of the height of the shell except where the boiler
is equipped with internal furnace, when it shall be not less than one-third of the length of
the tube above the top of the furnace. In the case of small generating units operated on the
closed system, where there is insufficient space for the usual water gage, water-level
indicators of the glass bull's eye type may be used.
M-1019.2.4 Steam Gage. Each miniature boiler shall be equipped with a steam gage
having its dial graduated to not less than one and one-half times the maximum allowable
working pressure. The gage shall he connected to the steam space or to the steam
connection to the water column by a brass or bronze composition siphon tube or
equivalent device that will keep the gage tube filled with water.
M-1019.2.5 Safety Valve. Each boiler shall be equipped with a sealed, spring loaded
“pop” safety valve not less than one-half inch (½") diameter connected directly to the
boiler. To insure the safety valve being free each valve shall have a substantially lifting
device by which the valve disk may be lifted from its seat when there is at least seventyfive percent (75%) of full working pressure in the boiler. All safety valves shall be
mounted with their spindles vertical and freely accessible.
1.
Safety Valve Identification. The safety valve shall be plainly marked by the
manufacturer with the following information.
(a)
Manufacturer name or identifying trademark;
(b)
The nominal diameter;
(c)
The steam pressure at which it is set to blow; and
(d)
The capacity in pounds and ASME Standard.
2.
Minimum Relieving Capacity. The minimum relieving capacity for the safety
valve shall be determined on the basis of three (3) pounds of steam per hour per
square foot of heating surface and shall be sufficient to discharge all the steam
that can be generated by the boiler without allowing the pressures to rise more
than six percent (6%) above the maximum allowable working pressure.
M-1019.2.6 Standard Stop Valve. Each steam line from a boiler shall be provided with
a one-hundred twenty-five (125 psi) standard stop valve located as close to the boiler
shell or drum as is practicable.
M-1019.2.7 Blow-Off Connections. Each boiler shall be provided with a blow-off
connection which shall not be reduced in size and shall be led to a safe point of discharge.
Whenever, in the judgment of the boiler inspector, such a place cannot be provided, a
blow-down tank shall be provided on all such tanks. The blow-off shall be fitted with a
valve or cock in direct connection with the lowest water space practicable.
M-1019.2.8 Automatic Low-Water Fuel Cut-Off. Each boiler mechanically fired other
than by gas shall be provided with an automatic low-water fuel cut-off so located as to
automatically cut off the fuel supply in case the water level falls to a point not lower than
the bottom of the water glass.
M-1019.2.9 Exception. Where boilers are gas-fired, the burners used shall conform to
the requirements of the American Gas Association. The burner shall in those cases be
equipped with a fuel-regulating governor which shall be automatic and regulated by the
steam pressure. The governor shall be so constructed that in the event of its failure, there
can be no possibility of steam from, the boiler entering the gas chamber or supply pipe. A
manual stop cock or throttle valve shall in all cases be located in the inlet pipe ahead of
the fuel-regulating governor. Each gas-fired boiler shall be equipped with a four inch
(4") vent or flue extended to an approved location outside of the building or connected to
a chimney, all to be in accordance with the Building Code. Where the horizontal run is
more than ten feet (10'), the vent shall be increased to six inches (6").
M-1019.2.10 Replacement. All boiler replacements shall conform to the rules and
regulations governing new installations.
M-1019.2.11 Retubed Boilers. Each retubed boiler must be inspected and passed by the
boiler inspector before the boiler is again put in service. The annual inspection fee will be
charged for this inspection.
M-1019.2.12 Used Boilers. Each used boiler brought into the District of Columbia shall
be inspected by the boiler inspector before being installed.
M-1019.2.13 Installation Permit. Moving a boiler and reinstating it in the same or
another building shall require an installation permit.
SECTION M-1020E EXISTING INSTALLATIONS - UNFIRED PRESSURE VESSELS
M-1020.1 Maximum Allowable Internal Working Pressures. For internal pressure, the
maximum allowable working pressure for the shell of a pressure vessel shall be determined by
the strength of the weakest course computed for the thickness of the plate, the tensile strength of
the plate, the efficiency of the longitudinal joint, the inside diameter of the course (see R below)
and the factor of safety allowed by the rules.
TS x t x E
R x FS
Maximum allowable working pressure
in pounds per square inch
=
Where:
TS
=
ultimate tensile strength of shell plates, pound per square inch
t
=
minimum thickness of shell plate in weakest course in inches
E
=
efficiency of longitudinal joint depending upon construction. Use values
as follows:
For riveted
joints
For fusion
welded joint
=
calculated riveted efficiency.
=
Single “V” weld, fifty (50) percent.
Double “V” weld, seventy (70) percent.
Forge weld, eighty (80) percent.
Brazed, eighty (80) percent.
Brazed copper, ninety (90) percent.
E
=
R
=
FS
=
efficiency for tube ligaments between openings as calculated in Section
I, Part PG, paragraphs PG-52 and PG-53 in the ASME Code.
Inside radius of the weakest course of the shell, inches, provided the
thickness of the shell does not exceed ten (10) percent of the radius. If
the thickness is over ten (10) percent of radius, the outer radius shall be
used.
factor of safety allowed by these rules.
M-1020.2 Maximum Allowable External Working Pressure. The maximum allowable
working pressure for cylindrical vessels subjected to external or collapsing pressure shall be
determined by methods in Section 1, Part PG, paragraph PG-28 in the ASME Code, except that
the factor of safety used to calculate the working pressure shall be in accordance with the
requirements of Section 1020.3.
M-1020.3 Existing Pressure Vessels. The maximum permissible working pressure on pressure
vessels of other than lap-seam construction shall have a factor of safety of not less than four and
one-half (4.5).
M-1020.3.1 Exception. The maximum permissible working pressure on pressure vessels
(PVs) with longitudinal lap joints shall be calculated in accordance with the age of the
vessel and the following factors of safety.
1.
Not less than four (4) for PVs up to and including ten (10) years of age.
2.
Not less than four and one-half (4.5) for PVs from ten (10) years of age to twenty
(20) years of age.
3.
Not less than five (5) for PVs from twenty (20) years of age to twenty-five (25)
years of age.
4.
Not less than five and one-half (5.5) for PVs from twenty-five (25) years of age to
thirty (30) years of age.
M-1020.4 Maximum Allowable Working Pressure Limit. In no case shall the maximum
allowable working pressure be increased unless such vessels are being operated at a lesser
pressure than would be allowable for new vessels, in which case the changed pressure shall not
exceed that allowable for new vessels of the same construction.
M-1020.4.1 Stress Limits. In checking the conformity of existing vessels with the
limiting stresses for use in the design of pressure vessels, it is necessary to take account
of the effect of static head that may be produced in any part in order that such stress
limits be not exceeded.
M-1020.4.2 Age Limit. The age limit of a pressure vessel having a longitudinal lap joint
and carrying over fifty (50) pounds pressure per square inch, shall be thirty (30) years.
M-1020.5 Inspection of Inaccessible Parts. Where, in the opinion of the inspector, as the result
of the conditions disclosed at the regulator inspection, it is deemed advisable to remove interior
or exterior lining, covering or brick work to expose certain parts of the vessel not visible at time
of regular inspection, the inspector shall require the removal of such material to permit proper
inspection and drilling of same to ascertain thickness if necessary.
M-1020.6 Lap-Seam Cracks. The shell or drum of a pressure vessel in which a lap seam crack
is discovered along a longitudinal riveted joint, either butt or lap construction, shall be
immediately discontinued from use. If the vessel is not more than fifteen (15) years of age, a
complete new course of the original thickness may be installed at the discretion of the inspector
(and after approval by the boiler inspector). Patching shall be prohibited. (By "lap-seam crack" is
meant the typical crack frequently found in lap seams, extending parallel to the longitudinal
joints and located either between or adjacent to rivet holes).
M-1020.7 Tensile Strength. When the tensile strength of steel shell plates is not known, it shall
be taken as fifty-five thousand (55,000) pounds per square inch for temperatures not exceeding
seven-hundred degrees Fahrenheit (700 degrees F.).
M-1020.8 Crushing Strength of Mild Steel. The resistance to crushing of mild steel shall be
taken at ninety-five thousand (95,000) pounds per square inch of cross-sectional area.
M-1020.9 Rivets. In computing the ultimate strength of rivets in shear the following values of
the cross-sectional area of the rivet shank shall be used.
POUNDS PER SQUARE INCH
Steel rivets in single shear
44,000
Steel rivets in double shear
88,000
M-1020.9.1 Cross-Sectional Area. The cross-sectional area used in the computations
shall be that of the rivet shank after driving.
M-1020.9.2 Diameter. When the diameter of the rivet holes in the longitudinal joints of
a pressure vessel is not known, the diameter and cross-sectional area of rivet after
driving, may be ascertained from Table M-1017.0 or by cutting out one rivet in the body
of the joint.
M-1020.10 Safety Appliances. Each unfired pressure vessel shall be protected by such safety
and relief valves and indicating and controlling devices as will insure its safe operation. These
valves and devices shall be so constructed, located, and installed such that they cannot readily be
rendered inoperative. The relieving capacity of safety valves shall be such as to prevent a rise of
pressure in the vessel of more than ten percent (10%) percent above the maximum allowable
working pressure, taking into account the effect of a static head. Safety valve discharges shall be
carried to a safe place.
CHAPTER 11E REFRIGERATION
SECTION M-1101E GENERAL
Add new Sections M-1101.4.1 through M-1101.4.3 to the Mechanical Code to read as follows:
M-1101.4.1 Condenser Cooling Water. Water used for condenser cooling purposes
without recirculation shall at all times be regulated by automatic controls designed to
produce a minimum water temperature rise of 15 degrees Fahrenheit (8.3 degrees
Celsius), and to stop the flow of water when cooling is not required.
M-1101.4.2 Refrigeration Systems. No permit shall be issued for the installation of a
refrigeration system requiring water from the public water mains, quantity of which
exceeds 15 gallons per minute, until an application signed by the owner or owners of the
premises where the system is to be installed has been filed with and approved by the
Water and Sewer Authority.
M-1101.4.3 Water for Refrigeration. Water supplied from the public water mains shall
not be used for refrigeration purposes to the extent that the use might be detrimental to
the proper service of consumers in the distribution area, as determined by the director of
the Water and Sewer Authority.
SECTION M-1105E MACHINERY ROOM, GENERAL REQUIREMENTS
Add new Section M-1105.7.1 to the Mechanical Code to read as follows:
M-1105.7.1 Discharge Pipe Sizing. Discharge piping shall be in accordance with
ASHRAE 15.
CHAPTER 15E REFERENCED STANDARDS
Add the following Referenced Standards to the Mechanical Code:
ANSI
Standard
Reference
number
American National Standards Institute
25 West 43rd Street
Fourth Floor
New York, NY 10036
Title
Referenced in
code section
number
721.13
ASHRAE
Standard
Reference
number
American Society of Heating, Refrigerating
And Air-Conditioning Engineers, Inc.
1791 Tullie Circle, NE
Atlanta, GA 30329-2305
Title
Referenced in
code section
number
15-2004
ASME
Standard
Reference
number
ASME 98
I through XI
American Society of Mechanical Engineers
Three Park Avenue
New York, NY 10016-5990
Title
Referenced in
code section
number
NBIC
Standard
Reference
number
NFPA
Standard
Reference
number
National Board Inspection Code
National Board of Boiler and Pressure Vessel Inspectors
1055 Crupper Avenue
Columbus, OH 43229
Title
National Fire Protection Association
Batterymarch Park
Quincy, MA 02269
Title
NFPA 45-2004
Fire Protection for Laboratories using Chemicals
UL
Underwriters Laboratories, Inc.
333 Pfingsten Road
Northbrook, IL 60062-2096
Standard
Reference
number
835
Referenced in
code section
number
Title
Referenced in
code section
number
Referenced in
code section
number
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement