TITLE 16. LABOR AND EMPLOYMENT
Title of Regulation: 16VAC25-50. Boiler and Pressure
Vessel Regulations (amending 16VAC25-50-10, 16VAC25-50-20,
16VAC25-50-30, 16VAC25-50-260, 16VAC25-50-280, 16VAC25-50-300, 16VAC25-50-330,
16VAC25-50-360, 16VAC25-50-370, 16VAC25-50-380, 16VAC25-50-430, 16VAC25-50-460,
16VAC25-50-540).
Statutory Authority: § 40.1-51.6 of the Code of
Virginia.
Effective Date: November 1, 2018.
Agency Contact: Ed Hilton, Director, Boiler Safety
Compliance, Department of Labor and Industry, Main Street Centre, 600 East Main
Street, Richmond, VA 23219, telephone (804) 786-3169, FAX (804) 371-2324, or
email ed.hilton@doli.virginia.gov.
Summary:
The regulatory action incorporates the most recent editions
of nationally recognized model codes and forms produced by the American Society
of Mechanical Engineers, the National Board of Boiler and Pressure Vessel
Inspectors, and other standard-writing groups into the safety and inspection
regulations for boilers and pressure vessels.
Summary of Public Comments and Agency's Response: No
public comments were received by the promulgating agency.
Part I
Definitions
16VAC25-50-10. Definitions.
The following words and terms when used in this chapter shall
have the following meanings, unless the context clearly indicates otherwise:
"Act" means the Boiler and Pressure Vessel Safety
Act, Chapter 3.1 (§ 40.1-51.5 et seq.) of Title 40.1 of the Code of Virginia.
"Alteration" means any change in the item described
on the original Manufacturers' Data Report which affects the pressure
containing capability of the boiler or pressure vessel. Non-physical changes,
such as an increase in the maximum allowable working pressure (internal or
external) or design temperature of a boiler or pressure vessel, shall be
considered an alteration. A reduction in minimum temperature such that
additional mechanical tests are required shall also be considered an
alteration.
"ANSI/ASME CSD-1" means ASME CSD-1-2012,
Controls and Safety Devices for Automatically Fired Boilers, 2012 Edition,
American Society of Mechanical Engineers.
"API-510" means API-510, Pressure Vessel
Inspection Code: In-Service Inspection, Rating, Repair, and Alteration, Tenth
Edition, May 2014, American Petroleum Institute.
"Approved" means acceptable to the board,
commissioner or chief inspector as applicable.
"ASME B31" means ASME B31.1-2014, Power Piping,
an International Piping Code, The American Society of Mechanical Engineers.
"ASME Code" means the Boiler and Pressure Vessel
Code of the American Society of Mechanical Engineers approved and adopted by
the governing council of such society and approved and adopted by the board.
"Authorized inspection agency" means one of the
following:
a. A department or division established by a state,
commonwealth or municipality of the United States, or a province of Canada,
which has adopted one or more sections of the Boiler and Pressure Vessel
Code of the ASME Code and whose inspectors hold valid commissions
with the National Board of Boiler and Pressure Vessel Inspectors; or equivalent
qualifications as defined and set forth in 16VAC25-50-50 and 16VAC25-50-70;
b. An inspection agency of an insurance company which is
authorized (licensed) to write boiler and pressure vessel insurance in those
jurisdictions which have examined the agency's inspectors to represent such
jurisdictions as is evident by the issuance of a valid certificate of
competency to the inspector;
c. An owner-user inspection agency as defined in this section;
or
d. A contract fee inspector.
"Board" means the Virginia Safety and Health Codes
Board.
"Boiler" means a closed vessel in which water is
heated, steam is generated, steam is superheated, or any combination of them,
under pressure or vacuum for use externally to itself by the direct application
of heat. The term "boiler" shall include fired units for heating or
vaporizing liquids other than water where these units are separate from
processing systems and are complete within themselves.
[ "BTU" means British thermal unit. ]
"Certificate of competency" means a certificate
issued by the commissioner to a person who has passed the prescribed examination
as provided in 16VAC25-50-50. See §§ 40.1-51.9 and 40.1-51:9:1 40.1-51.9:1
of the Act.
"Certificate inspection" means an inspection, the
report of which is used by the chief inspector to decide whether or not a
certificate, as provided for in § 40.1-51.10 of the Act may be issued. This
certificate inspection shall be an internal inspection when required;
otherwise, it shall be as complete an inspection as possible.
"Chief inspector" means the chief boiler and
pressure vessel inspector of the Commonwealth.
"Commission, National Board" means the commission
issued by the National Board to a holder of a Certificate of Competency for the
purpose of conducting inspections in the Commonwealth in accordance with
the National Board Bylaws and this chapter. The employer must submit the
inspector's application to the National Board for a commission.
"Commissioner" means the Commissioner of the
Department of Labor and Industry.
"Commonwealth inspector" means any agent appointed
by the commissioner under the provisions of § 40.1-51.9 of the Act.
"Condemned boiler or pressure vessel" means a
boiler or pressure vessel that has been inspected and declared unsafe for use
or disqualified by legal requirements and to which a stamping or marking
designating its condemnation has been applied by the chief or commonwealth
inspector.
"Current edition of the ASME Code" means the
2015 Edition of the ASME Code, which has been adopted by the Safety and Health
Codes Board.
"Department" means the Department of Labor and
Industry.
"Division" means the Boiler Safety Enforcement
Division of the Department of Labor and Industry.
"Electric boiler" means a boiler in which the
source of heat is electricity.
"Examining board" means persons appointed by the
chief inspector to monitor examinations of inspectors.
"Existing installation" means and includes any
boiler or pressure vessel constructed, installed, placed in operation or
contracted for before July 1, 1974.
"External inspection" means an inspection of the
exterior of the boiler or pressure vessel and its appliances when the item is
in operation.
"Heating boiler" means a steam or vapor boiler
operating at pressures not exceeding 15 psig, or a hot water boiler operating
at pressures not exceeding 160 psig or temperature not exceeding 250°F at or
near the boiler outlet.
"High-pressure, high-temperature water boiler"
means a water boiler operating at pressures exceeding 160 psig or temperatures
exceeding 250°F at or near the boiler outlet.
"Hobby boiler" means a steam boiler which serves no
commercial purpose and is used solely for hobby or display and operated solely
for the enjoyment of the owner.
"Hot water supply boiler" means a boiler furnishing
hot water to be used externally to itself at pressures not exceeding 160 psig
or temperatures not exceeding 250°F at or near the boiler outlet, with the
exception of boilers which are directly fired by oil, gas or electricity where
none of the following limitations are is exceeded:
a. Heat input of 200,000 BTU per hour;
b. Water temperature of 210°F; or
c. Nominal water containing capacity of 120 gallons.
"Hot water supply storage tanks" means those heated
by steam or any other indirect means where any one of the following limitations
are is exceeded:
a. Heat input of 200,000 BTU per hour;
b. Water temperature of 210°F; or
c. Nominal water containing capacity of 120 gallons.
"Inspection certificate" means a certificate issued
by the chief inspector for the operation of a boiler or pressure vessel.
"Inspector" means the chief inspector, commonwealth
inspector or special inspector.
"Internal inspection" means a complete examination
of the internal and external surfaces of a boiler or pressure vessel and its
appliances while it is shut down and manhole plates, handhole plates or other
inspection openings removed.
"Lap seam crack" means a failure in a lap joint
extending parallel to the longitudinal joint and located either between or
adjacent to rivet holes.
"Miniature boiler" means any boiler which does not
exceed any one of the following limits:
a. 16 inches inside diameter of shell;
b. 20 square feet heating surface;
c. 5 cubic feet gross volume, exclusive of casing and
insulation; or
d. 100 psig maximum allowable working pressure.
"National Board" means the National Board of Boiler
and Pressure Vessel Inspectors, 1055 Crupper Avenue, Columbus, OH 43229, whose
membership is composed of the chief inspectors of government jurisdictions who
are charged with the enforcement of the provisions of the ASME Code.
"National Board Inspection Code" means the
manual for boiler and pressure vessel inspectors published by the National
Board. Copies of this code may be obtained from the National Board NB-23,
the National Board Inspection Code, 2015 Edition, The National Board of Boiler
Pressure Vessel Inspectors.
"National Fire Protection Association No. 85"
means the NFPA® 85, Boiler and Combustion Systems Hazards Code, 2015
Edition, National Fire Protection Association.
"New boiler or pressure vessel installation" means
all boilers or pressure vessels constructed, installed, placed in operation or
contracted for after July 1, 1974.
"NFPA" means the National Fire Protection
Association.
"Nonstandard boiler or pressure vessel" means a
boiler or pressure vessel that does not bear the stamp of Commonwealth of
Virginia, the ASME stamp or the National Board stamp when applicable.
"Owner or user" means any person, partnership, firm
or corporation who is legally responsible for the safe operation of a boiler or
pressure vessel within the Commonwealth.
"Owner-user inspection agency" means any person,
partnership, firm or corporation registered with the chief inspector and
approved by the board as being legally responsible for inspecting pressure
vessels which they operate in this Commonwealth.
"Portable boiler" means an internally fired boiler
which is primarily intended for temporary location and whose construction and
usage permit it to be readily moved from one location to another.
"Power boiler" means a boiler in which steam or
other vapor is generated at a pressure of more than 15 psig.
"Pressure vessel" means a vessel in which the
pressure is obtained from an external source, or by the application of heat
from an indirect source, or from a direct source, other than those boilers
defined in Part I (16VAC25-50-10 et seq.) of this chapter.
"PSIG" means pounds per square inch gauge.
"R Certificate of Authorization" means an
authorization issued by the National Board for the repair and alteration of
boilers and pressure vessels.
"Reinstalled boiler or pressure vessel" means a
boiler or pressure vessel removed from its original setting and reinstalled at
the same location or at a new location.
"Repair" means work necessary to return a boiler or
pressure vessel to a safe and satisfactory operating condition, provided there
is no deviation from the original design.
"Secondhand boiler or pressure vessel" means a
boiler or pressure vessel which has changed both location and ownership since
the last certificate inspection.
"Special inspector" means an inspector holding a
Virginia Certificate of Competency, and who is regularly employed by an
insurance company authorized (licensed) to write boiler and pressure vessel
insurance in this Commonwealth, an inspector continuously employed by any
company operating pressure vessels in this Commonwealth used or to be used by
the company, or a contract fee inspector.
"Standard boiler or pressure vessel" means a boiler
or pressure vessel which bears the stamp of the Commonwealth of Virginia, the
ASME Code stamp and the National Board stamp when applicable.
"Underwriters' Laboratories" means Underwriters'
Laboratories, Inc., 333 Pfingsten Road, Northbrook, Illinois 60062, which is a
nonprofit, independent organization testing for public safety. It maintains and
operates laboratories for the examination and testing of devices, systems, and
materials to determine their relation to life, fire, casualty hazards and crime
prevention.
"VR Certificate of Authorization" means an
authorization issued by the National Board for the repair of pressure relief
valves.
"Water heater" means a vessel used to supply: (i)
potable hot water; or (ii) both space heat and potable water in combination
which is directly heated by the combustion of fuels, electricity, or any other
source and withdrawn for use external to the system at pressures not to exceed
160 psi or temperatures of 210°F. This term also includes fired storage water
heaters defined by the Virginia Uniform Statewide Building Code as a
"water heater."
Part II
Administration
16VAC25-50-20. Minimum construction standards for boilers and
pressure vessels.
A. Boilers and pressure vessels to be installed for operation
in this Commonwealth shall be designed, constructed, inspected, stamped and
installed in accordance with the applicable ASME Boiler and Pressure Vessel
Code including all addenda and applicable code case(s) cases,
other international construction standards which are acceptable to the chief
inspector, and this chapter.
B. Boilers and pressure vessels shall bear the National Board
stamping, except cast iron boilers and UM vessels. A copy of the Manufacturers'
Data Report, signed by the manufacturer's representative and the National Board
commissioned inspector, shall be filed by the owner or user with the chief
inspector prior to its operation in the Commonwealth.
C. Pressure piping -- (including welded piping) -- Piping
external to power boilers extending from the boiler to the first stop valve of
a single boiler [ , ] and to the second stop valve in a
battery of two or more boilers is subject to the requirements of the current
edition of the ASME Power Boiler Code, Section I and the design,
fabrication, installation and testing of the valves and piping shall be in
conformity with the applicable paragraphs of the current edition of the
ASME Code, Section I. Applicable ASME data report forms for this piping
shall be furnished by the owner to the chief inspector. Construction rules for
materials, design, fabrication, installation and testing both for the boiler
external piping and the power piping beyond the valve or valves required by the
current edition of the ASME Power Boiler Code, Section I, are
referenced in ANSI ASME B31.1, Power piping, and the code ASME
Code.
D. Boilers and pressure vessels brought into the Commonwealth
and not meeting code ASME Code requirements shall not be operated
unless the [ owner/user owner or user ] is granted a
variance in accordance with § 40.1-51.19 of the Act.
The request for variance shall include all documentation
related to the boiler or pressure vessel that will provide evidence of
equivalent fabrication standards, i.e., design specification, calculations,
material specifications, detailed construction drawings, fabrication and
inspection procedures and qualification records, examination, inspection and
test records, and any available manufacturers' data report.
In order to facilitate such a variance approval, the
submission of documentation, in the English language and in current U.S.
standard units of measure would be helpful. The following list of documents,
while not all inclusive, would be useful in providing evidence of safety
equivalent to ASME Code construction:
1. List of materials used for each pressure part;
2. The design calculations to determine the maximum allowable
working pressure in accordance with the ASME Boiler and Pressure Vessel
Code, applicable section, edition and addenda;
3. The design code used and the source of stress values for
the materials used in the design calculations;
4. The welding procedures used and the qualification records
for each procedure;
5. The material identification for each type of welding
material used;
6. The performance qualification records for each welder or
welding operator used in the construction of the boiler or pressure vessel;
7. The extent of any nondestructive examination (NDE)
performed and the qualification records of NDE operators;
8. Record of final pressure test signed by a third party
inspector;
9. Name and organization of the third party inspection agency;
10. A certification from a licensed professional engineer
stating that the boiler or pressure vessel has been constructed to a standard
providing equivalent safety to that of the ASME Boiler and Pressure Vessel
Code. A signature, date and seal of the certifying engineer is are
required;
11. Where applicable, a matrix of differences between the
actual construction of the boiler or pressure vessel for which a variance is
requested and a similar boiler or pressure vessel that is code ASME
Code stamped; and
12. Where applicable, a letter from an insurance company
stating that it will insure the boiler or pressure vessel.
After notification of a violation of these rules and
regulations this chapter, an [ owner/user owner or
user ] desiring a variance shall submit a request for variance within
30 days.
The chief inspector shall respond to any request for a
variance within 30 days of receipt of all required documentation, and
shall submit a recommendation to the commissioner, who will make the decision
on the variance.
E. Before secondhand equipment is installed, application for
permission to install shall be filed by the owner or user with the chief
inspector and approval obtained.
F. Electric boilers, subject to the requirements of the Act
and this chapter, shall bear the Underwriters' Laboratories label on the
completed unit or assembly by the manufacturer. This label shall be in addition
to the code symbol stamping requirements of the ASME Code and the
National Board.
16VAC25-50-30. Frequency of inspections of boilers and pressure
vessels.
A. Power boilers and high-pressure, high-temperature water
boilers shall receive an annual internal inspection for certification. Such
boilers shall also receive, where possible, an annual external inspection,
given while under representative operating conditions.
B. Heating boilers shall receive a certificate inspection
biennially.
1. Steam boilers shall receive an internal inspection where
construction permits.
2. Water boilers shall receive an external inspection with an
internal inspection at the discretion of the inspector where construction
permits.
C. Except as provided for in subsection E of this section,
pressure vessels subject to internal corrosion shall receive a certificate
inspection biennially. This inspection shall be an internal inspection
conducted at the discretion of the inspector where construction permits.
D. Except as provided for in subsection E of this section,
pressure vessels not subject to internal corrosion shall receive a certificate
inspection biennially. This inspection shall be an external inspection, with an
internal inspection conducted at the discretion of the inspector where
construction permits.
E. Pressure vessels that are under the supervision of an
authorized owner-user inspection agency shall be inspected at intervals in a
manner as agreed upon between the [ Commissioner commissioner ]
and that agency.
F. Boiler and pressure vessel components of nuclear power
plants, that are included in the Act, shall be inspected as
provided by Section XI of the ASME Boiler and Pressure Vessel
Code, Section XI.
G. Based upon documentation of such actual service conditions
by the owner or user of the operating equipment, the [ Commissioner
commissioner ] may permit variations in the inspection requirements
as provided in the Act.
16VAC25-50-260. Removal of safety appliances.
A. No person shall attempt to remove or do any work on any
safety appliance prescribed by this chapter while a boiler or pressure vessel
is in operation, except as provided in applicable sections of the current
edition of the ASME Code. Should any of these appliances be removed for
repair during an outage of a boiler or pressure vessel, they must be
reinstalled and in proper working order before the object is again placed in
service.
B. No person shall load the safety valve or valves in any
manner to maintain a working pressure in excess of that stated on the
inspection certificate.
16VAC25-50-280. Requirements for new installations.
A. No boiler or pressure vessel shall be installed in this
Commonwealth unless it has been constructed, inspected and stamped as provided
in Part II, 16VAC25-50-20 except:
1. Those exempt by the Act;
2. Those outlined in Part II, 16VAC25-50-20 D; and
3. Those existing boilers and pressure vessels which that
are to be reinstalled.
B. All new boiler and pressure vessel installations,
including reinstalled and secondhand boilers and pressure vessels, shall be
installed in accordance with the requirements of the current edition of the
ASME Code and this chapter.
C. A boiler or pressure vessel constructed equivalent to ASME
Code standards, or having the standard stamping of another state that
has adopted a standard of construction equivalent to the standard of this
Commonwealth, may be accepted by the chief inspector. The person desiring to
install the boiler or pressure vessel shall make application for the
installation prior to construction and shall file the Manufacturers' Data
Report for the boiler or pressure vessel with the chief inspector following
construction and prior to installation.
D. The stamping shall not be concealed by insulation or paint
and shall be exposed at all times unless a suitable record is kept of the
location of the stamping so that it may be readily uncovered at any time this
may be desired.
16VAC25-50-300. Return loop connection.
The return water connections to all low-pressure, steam
heating boilers supplying a gravity return heating system shall be arranged to
form a loop so that the water cannot be forced out of the boiler below the safe
water level. This connection, known as a "return pipe loop
connection," is shown in Section IV, the current edition of the
ASME Heating Boiler Code, Section IV.
16VAC25-50-330. Operation.
The current edition of the ASME Code, Section VII,
Recommended Rules for Care of Power Boilers, Section VII, and the current
edition of the ASME Code, Section VI, Recommended Rules for Care of Heating
Boilers, Section VI, of the ASME Code, shall be used as a guide for
proper and safe operating practices.
Part III
Existing Installations
16VAC25-50-360. Power and high-pressure, high-temperature water
boilers.
A. Age limit of existing boilers.
1. The age limit of any boiler of nonstandard construction,
installed before July 1, 1974, other than one having a riveted, longitudinal
lap joint, shall be 30 years; however, any boiler passing a thorough internal
and external inspection, and not displaying any leakage or distress
under a hydrostatic pressure test of 1-1/2 times the allowable working pressure
held for at least 30 minutes, may be continued in operation without
reduction in working pressure. The age limit of any boiler having riveted,
longitudinal, lap joints and operating at a pressure in excess of 50
psig shall be 20 years. This type of boiler, when removed from an existing
setting, shall not be reinstalled for a pressure in excess of 15 psig. A
reasonable time for replacement, not to exceed one year, may be given at the
discretion of the chief inspector.
2. The shell or drum of a boiler in which a typical lap seam
crack is discovered along a longitudinal riveted joint for either butt or lap
joints shall be permanently removed from service.
3. The age limit of boilers of standard construction,
installed before July 1, 1974, shall be determined from the results of a
thorough internal and external inspection by an authorized inspector and the
application of an appropriate pressure test. Hydrostatic test pressure shall be
1-1/2 times the allowable working pressure and maintained for 30 minutes. The
boiler may be continued in service at the same working pressure provided there
is no evidence of leakage or distress under these test conditions.
4. The minimum temperature of the water used for the
hydrostatic test of low-pressure boilers and pressure vessels shall be 60°F.
The minimum temperature of the water used for the hydrostatic test of power
boilers shall be 70°F or ambient whichever is greater.
B. The maximum allowable working pressure for standard
boilers shall be determined in accordance with the applicable provisions of the
edition of the ASME Code under which they were constructed and stamped.
C. 1. The maximum allowable working pressure on the shell of
a nonstandard boiler shall be determined by the strength of the weakest section
of the structure, computed from the thickness of the plate, the tensile
strength of the plate, the efficiency of the longitudinal joint or tube
ligaments, the inside diameter of the weakest course and the factor of safety
allowed by this chapter.
|
TStE
|
=
|
Maximum allowable working
pressure, psi
|
|
RFS
|
where:
TS = ultimate tensile strength of shell plates, psi
t = minimum thickness of shell plate, in weakest course,
inches
E = efficiency of longitudinal joint:
For tube ligaments, E shall be determined by the rules in the
ASME Code, Section I of the ASME Code for Power Boilers. For riveted
joints, E shall be determined by the rules in the applicable edition of the
ASME Code. For seamless construction, E shall be considered 100%.
R = inside radius of the weakest course of the shell, in
inches
FS = factor of safety permitted.
2. Tensile strength. When the tensile strength of steel or
wrought iron shell plates is not known, it shall be taken as 55,000 psi.
3. Crushing strength of mild steel. The resistance to crushing
of mild steel shall be taken at 95,000 psi of cross-sectional area.
4. Strength of rivets in shear. When computing the ultimate
strength of rivets in shear, the following values, in pounds per square inch,
of the cross-sectional area of the rivet shank shall be used.
|
PSI
|
Iron rivets in single shear
|
38,000
|
Iron rivets in double shear
|
76,000
|
Steel rivets in single shear
|
44,000
|
Steel rivets in double shear
|
88,000
|
When the diameter of the rivet holes in the longitudinal
joints of a boiler is not known, the diameter and cross-sectional area of
rivets, after driving, may be selected from Table 1, or as ascertained by
cutting out one rivet in the body of the joint.
TABLE 1
SIZES OF RIVETS BASED ON PLATE THICKNESS
(in inches)
|
Plate of Thickness
|
Rivet Diameter after Driving
|
1/4
|
11/16
|
9/32
|
11/16
|
5/16
|
3/4
|
11/32
|
3/4
|
3/8
|
13/16
|
13/32
|
13/16
|
7/16
|
15/16
|
15/32
|
15/16
|
1/2
|
15/16
|
9/16
|
1-1/16
|
5/8
|
1-1/16
|
5. Factors of safety. The following factors of safety shall be
increased by the inspector if the condition and safety of the boiler demand it:
a. The lowest factor of safety permissible on existing
installations shall be 4.5 for vessels built prior to January 1, 1999. For
vessels built on or after January 1, 1999, the factor of safety may be 4.0.
Horizontal-return-tubular boilers having continuous longitudinal lap seams more
than 12 feet in length, shall have a factor of safety of eight. When
this type of boiler is removed from its existing setting, it shall not be
reinstalled for pressures in excess of 15 psig.
b. Reinstalled or secondhand boilers shall have a minimum
factor of safety of six when the longitudinal seams are of lap-riveted
construction, and a minimum factor of safety of five when the longitudinal
seams are of butt-strap and double-strap construction.
D. Cast-iron headers and mud drums. The maximum allowable
working pressure on a water tube boiler, the tubes of which are secured to cast
iron or malleable-iron headers, or which have cast iron mud drums, shall not
exceed 160 psig.
E. Pressure on cast iron boilers. The maximum allowable
working pressure for any cast iron boiler, except hot water boilers, shall be
15 psig.
F. Safety valves.
1. The use of weighted-lever safety valves, or safety valves
having either the seat or disk of cast iron, shall be prohibited. Valves of
this type shall be replaced by direct, spring-loaded, pop-type valves that
conform to the requirements of the current edition of the ASME Code,
Section I.
2. Each boiler shall have at least one safety valve,
and, if it has more than 500 square feet of water-heating surface or an
electric power input of more than 500 kilowatts, it shall have two or more
safety valves.
3. The valve or valves shall be connected to the boiler,
independent of any other steam connection, and attached as close as possible to
the boiler without unnecessary intervening pipe or fittings. Where alteration
is required to conform to this requirement, the chief inspector shall allow the
owner or user reasonable time in which to complete the work.
4. No valves of any description shall be placed between the
safety valve and the boiler nor on the escape pipe, if used, between the safety
valve and the atmosphere, except as provided by applicable sections of the current
edition of the ASME Code. When an escape pipe is used, it shall be at least
full size of the safety-valve discharge and fitted with an open drain to
prevent water lodging in the upper part of the safety valve or escape pipe.
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 anchored and
supported securely. All safety valve discharges shall be located or piped as
not to endanger persons working in the area.
5. The safety-valve capacity of each boiler shall be so 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 6.0% above the
highest pressure to which any valve is set, and in no case to more than 6.0%
above the maximum allowable working pressure.
6. 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 3.0% above the maximum allowable working pressure, but
the range of setting of all the safety valves on a boiler shall not exceed 10%
of the highest pressure to which any valve is set.
7. When two or more boilers, operating at different pressures
and safety valve settings, are interconnected, the lower pressure boilers or
interconnected piping shall be equipped with safety valves of sufficient
capacity to prevent overpressure, considering the maximum generating capacity
of all boilers.
8. In those cases where the boiler is supplied with feedwater
directly from water mains without the use of feeding apparatus (not to include
return traps), no safety valve shall be set at a pressure higher than 94% of
the lowest pressure obtained in the supply main feeding the boiler.
9. The relieving capacity of the safety valves on any boiler
shall be checked by one of the three following methods and, if found to be
insufficient, additional valves shall be provided:
a. By making an accumulation test, which consists of shutting
off all other steam-discharge outlets from the boiler and forcing the fires to
the maximum. The safety-valve capacity shall be sufficient to prevent a rise of
pressure in excess of 6.0% of the maximum allowable working pressure. This
method shall not be used on a boiler with a superheater or reheater.
b. By measuring the maximum amount of fuel that can be burned
and computing the corresponding evaporative capacity (steam-generating
capacity) upon the basis of the heating value of this fuel. These computations
shall be made as outlined in the appendix of the current edition of the
ASME Code, Section I.
c. By measuring the maximum amount of feedwater that can be
evaporated.
When either of the methods (b or c) outlined in this
subdivision is employed, the sum of the safety-valve capacities shall be equal
to or greater than the maximum evaporative capacity (maximum steam-generating
capacity) of the boiler.
10. The relieving capacity of safety valves for forced-flow steam
generators shall be in accordance with the requirements of Section I the
current edition of the ASME Boiler Code, Section I.
11. Safety valves and safety relief valves requiring repair
shall be replaced with a new valve or repaired by the original manufacturer,
its authorized representative or the holder of a "VR" Stamp.
G. Boiler feeding.
1. Each boiler shall have a feed supply which that
will permit it to be fed at any time while under pressure.
2. A boiler having more than 500 square feet of water-heating
surface shall have at least two means of feeding, one of which shall be an
approved feed pump or injector. A source of feed directly from water mains at a
pressure 6.0% greater than the set pressure of the safety valve with the
highest setting may be considered one of the means. As provided in the current
edition of the ASME Power Boiler Code, Section I, boilers fired by
gaseous, liquid or solid fuel in suspension may be equipped with a single means
of feeding water provided means are furnished for the immediate shutoff of heat
input if the water feed is interrupted.
3. The feedwater shall be introduced into the boiler in a
manner so that it will not be discharged close to riveted joints of shell or
furnace sheets, or directly against surfaces exposed to products of combustion,
or to direct radiation from the fire.
4. The feed piping to the boiler shall be provided with a
check valve near the boiler and a valve or cock between the check valve and the
boiler. When two or more boilers are fed from a common source, there shall also
be a valve on the branch to each boiler between the check valve and source of
supply. Whenever a globe valve is used on feed piping, the inlet shall be under
the disk of the valve.
5. In all cases where returns are fed back to the boiler by
gravity, there shall be a check valve and stop valve in each return line, the
stop valve to be placed between the boiler and the check valve, and both shall
be located as close to the boiler as is practicable. No stop valves shall be placed
in the supply and return pipe connections of a single boiler installation.
6. Where deaerating heaters are not employed, the temperature
of the feedwater shall not be less than 120°F to avoid the possibility of
setting up localized stress. Where deaerating heaters are employed, the minimum
feedwater temperature shall not be less than 215°F so that dissolved gases may
be thoroughly released.
H. Water level indicators.
1. Each boiler shall have at least one water gauge glass
installed and located so that the lowest visible part of the water glass shall
be at least two inches above the lowest permissible water level, at which level
there will be no danger of overheating any part of the boiler when in operation
at that level; except as provided by the current edition of the ASME
Code.
2. No outlet connections (except for damper regulator,
feedwater regulator, low-water fuel cutout, drain, steam gauges, or such
apparatus that does not permit the escape of an appreciable amount of steam or
water from it) shall be placed on the piping that connects the water column to
the boiler. The water column shall be provided with a valved drain of at least
3/4 inch pipe size; the drain is to be piped to a safe location.
3. When the direct reading of gauge glass water level is not
readily visible to the operator in his working area dependable indirect
indications shall be provided utilizing remote level indicators or equipment to
transmit the gauge glass image. When remote level indication is provided for
the operator instead of the gauge glass, the minimum level reference shall be
clearly marked.
I. Steam gauges.
1. Each steam boiler shall have a steam gauge, with dial range
not less than 1-1/2 times the maximum allowable working pressure, connected to
the steam space or to the steam connection to the water column. The steam gauge
shall be connected to a siphon or equivalent device of sufficient capacity to
keep the gauge tube filled with water and arranged so that the gauge cannot be
shut off from the boiler except by a cock with a tee or lever handle placed in
the pipe near the gauge. The handle of the cock shall be parallel to the pipe
in which it is located when the cock is open.
2. When a steam gauge connection longer than eight feet
becomes necessary, a shutoff valve may be used near the boiler provided the
valve is of the outside-screw-and-yoke type and is locked open. The line shall
be of ample size with provision for free blowing.
3. Each boiler shall be provided with a test gauge connection
and suitable valving for the exclusive purpose of attaching a test gauge so
that the accuracy of the boiler steam gauge may be ascertained while the boiler
is in operation.
J. Stop valves.
1. Except for a single-boiler, prime-mover installation, each
steam outlet from a boiler (except safety valve and water column connections)
shall be fitted with a stop valve located as close as practicable to the
boiler.
2. In a single-boiler, prime-mover installation the steam stop
valve may be omitted provided the prime-mover throttle valve is equipped with
an indicator to show whether the valve is open or closed and is designed to
withstand the required hydrostatic pressure test of the boiler.
3. When a stop valve is so located that water can accumulate,
ample drains shall be provided. The drainage shall be piped to a safe location
and shall not be discharged on the top of the boiler or its setting.
4. When boilers provided with manholes are connected to a
common steam main, the steam connection from each boiler shall be fitted with
two stop valves having an ample free-blow drain between them. The discharge of
the drain shall be visible to the operator and shall be piped clear of the
boiler setting. The stop valves shall consist preferably of one automatic
nonreturn valve (set next to the boiler) and a second valve of the
outside-screw-and-yoke type.
K. Blowoff connection.
1. The construction of the setting around each blowoff pipe
shall permit free expansion and contraction. Careful attention shall be given
to the problem of sealing these setting openings without restricting the
movement of the blowoff piping.
2. All blowoff piping, when exposed to furnace heat, shall be
protected by firebrick or other heat-resisting material constructed so that the
piping may be inspected.
3. Each boiler shall have a blowoff pipe, fitted with a valve
or cock, in direct connection with the lowest water space. Cocks shall be of
the gland or guard type and suitable for the pressure allowed. The use of globe
valves shall not be permitted. Where the maximum allowable working pressure
exceeds 100 psig, each blowoff pipe shall be provided with two valves or a
valve and cock; however only one valve need be provided for forced-flow steam
generators with no fixed steam and waterline;, high-temperature
water boilers, and those used for traction or portable purposes with
less than 100 gallons normal water content.
4. Blowoff piping shall comply with the requirements of the current
edition of the ASME Code, Section I, and ANSI ASME
B31.1, from the boiler to the valve or valves, and shall be run full size
without use of reducers or bushings. All piping shall be steel. Galvanized
steel pipe and fittings shall not be used for blowoff piping.
5. All fittings between the boiler and blowoff valve shall be
of steel. In case of renewal of blowoff pipe or fittings, they shall be
installed in accordance with this chapter for new installations.
L. Repairs and renewals of boiler fittings and appliances.
Whenever repairs are made to fittings or appliances or it becomes necessary to
replace them, such repairs or replacements shall comply with the requirements
for new installations.
M. Each automatically fired steam boiler or system of
commonly connected steam boilers shall have at least one steam pressure control
device that will shut off the fuel supply to each boiler or system of commonly
connected boilers when the steam pressure reaches a preset maximum operating
pressure. In addition, each individual automatically fired steam boiler shall
have a high steam pressure limit control that will prevent generation of steam
pressure in excess of the maximum allowable working pressure.
N. Conditions not covered by this chapter. All cases not
specifically covered by this chapter shall be treated as new installations
pursuant to 16VAC25-50-280 or may be referred to the chief inspector for
instructions concerning the requirements.
16VAC25-50-370. Heating boilers.
A. Standard boilers. The maximum allowable working pressure
of standard boilers shall in no case exceed the pressure indicated by the
manufacturer's identification stamped or cast on the boiler or on a plate
secured to it.
B. Nonstandard riveted boilers. The maximum allowable working
pressure on the shell of a nonstandard riveted heating boiler shall be
determined in accordance with 16VAC25-50-360 C covering existing installations,
power boilers, except that in no case shall the maximum allowable working
pressure of a steam heating boiler exceed 15 psig, or a hot water boiler exceed
160 psig or 250°F temperature.
C. Nonstandard welded boilers. The maximum allowable working
pressure of a nonstandard steel or wrought iron heating boiler of welded
construction shall not exceed 15 psig for steam. For other than steam service,
the maximum allowable working pressure shall be calculated in accordance with Section
IV of the ASME Code, Section IV.
D. Nonstandard cast iron boilers.
1. The maximum allowable working pressure of a nonstandard
boiler composed principally of cast iron shall not exceed 15 psig for steam
service or 30 psig for hot water service.
2. The maximum allowable working pressure of a nonstandard
boiler having cast iron shell or heads and steel or wrought iron tubes shall
not exceed 15 psig for steam service or 30 psig for hot water service.
E. Safety valves.
1. Each steam boiler must have one or more officially rated
(ASME Code stamped and National Board rated) safety valves of the spring
pop type adjusted to discharge at a pressure not to exceed 15 psig. Seals shall
be attached in a manner to prevent the valve from being taken apart without
breaking the seal. The safety valves shall be arranged so that they cannot be
reset to relieve at a higher pressure than the maximum allowable working
pressure of the boiler. A body drain connection below seat level shall be
provided by the manufacturer, and this drain shall not be plugged during
or after field installation. For valves exceeding two inch pipe size, the drain
hole or holes shall be tapped not less than 3/8 inch pipe size. For valves less
than two inches, the drain hole shall not be less than ¼ 1/4 inch
in diameter.
2. No safety valve for a steam boiler shall be smaller than
3/4 inch unless the boiler and radiating surfaces consist of a self-contained
unit. No safety valve shall be larger than 4-1/2 inches. The inlet opening
shall have an inside diameter equal to, or greater than, the seat diameter.
3. The minimum relieving capacity of the valve or valves shall
be governed by the capacity marking on the boiler.
4. The minimum valve capacity in pounds per hour shall be the
greater of that determined by dividing the maximum BTU output at the boiler nozzle
obtained by the firing of any fuel for which the unit is installed by 1,000;
or shall be determined on the basis of the pounds of steam generated per hour
per square foot of boiler heating surface as given in Table 2. When operating
conditions require it a greater relieving capacity shall be provided. In every
case, the requirements of subdivision 5 of this subsection shall be met.
TABLE 2
Minimum Pounds of Steam Per Hour Per Square Foot of Heating Surface
|
|
Fire Tube Boilers
|
Water Tube Boilers
|
Boiler Heating Surface:
|
Hand fired
|
5
|
6
|
Stoker fired
|
7
|
8
|
Oil, gas, or pulverized fuel fired
|
8
|
10
|
Waterwall Heating Surface:
|
Hand fired
|
8
|
8
|
Stoker fired
|
10
|
12
|
Oil, gas, or pulverized fuel fired
|
14
|
16
|
NOTES: When a boiler is fired only by a gas giving a heat
value of not in excess of 200 BTU per cubic foot, the minimum safety valve or
safety relief valve relieving capacity may be based on the value given for
handfired boilers above in Table 2.
The minimum safety valve or safety relief valve relieving
capacity for electric boilers shall be 3-1/2 pounds per hour per kilowatt
input.
For heating surface determination, see the current
edition of the ASME Code, Section IV.
|
5. The safety valve capacity for each steam boiler shall be
such that with the fuel burning equipment operating at maximum capacity, the
pressure cannot rise more than five psig above the maximum allowable working
pressure.
6. When operating conditions are changed, or additional boiler
surface is installed, the valve capacity shall be increased, if necessary, to
meet the new conditions and be in accordance with subdivisions 4 and 5 of this
subsection. When additional valves are required, they may be installed on the
outlet piping provided there is no intervening valve.
7. If there is any doubt as to the capacity of the safety
valve, an accumulation test shall be run (see the current edition of the
ASME Code, Section VI, Care of Heating Boilers) VI).
8. No valve of any description shall be placed between the
safety valve and the boiler, nor on the discharge pipe between the safety valve
and the atmosphere. The discharge pipe shall be at least full size and be
fitted with an open drain to prevent water lodging in the upper part of the
safety valve or in the discharge pipe. When an elbow is placed on the safety
valve discharge pipe, it shall be located close to the safety valve outlet,
or the discharge pipe shall be securely anchored and supported. All safety
valve discharges shall be so located or piped as not to endanger persons
working in the area.
F. Safety relief valve requirements for hot water boilers.
1. Each hot water boiler shall have one or more officially
rated (ASME Code stamped and National Board rated) safety relief valves
set to relieve at or below the maximum allowable working pressure of the
boiler. Safety relief valves officially rated as to capacity shall have pop
action when tested by steam. When more than one safety relief valve is used on
hot water boilers, the additional valve or valves shall be officially rated and
shall be set within a range not to exceed six psig above the maximum allowable
working pressure of the boiler up to and including 60 psig and 5.0% for those
having a maximum allowable working pressure exceeding 60 psig. Safety relief
valves shall be spring loaded. Safety relief valves shall be so arranged that
they cannot be reset at a higher pressure than the maximum permitted by this
paragraph.
2. No materials liable to fail due to deterioration or
vulcanization when subject to saturated steam temperature corresponding to
capacity test pressure shall be used for any part.
3. No safety relief valve shall be smaller than 3/4 inch nor
larger than 4-1/2 inches standard pipe size, except that boilers having a heat
input not greater than 15,000 BTU per hour may be equipped with a safety relief
valve of 1/2 inch standard pipe size. The inlet opening shall have an inside
diameter approximately equal to, or greater than, the seat diameter. In no case
shall the minimum opening through any part of the valve be less than 1/2 inch
diameter or its equivalent area.
4. The required steam relieving capacity, in pounds per hour,
of the pressure relieving device or devices on a boiler shall be the greater of
that determined by dividing the maximum output in BTU at the boiler outlet
obtained by the firing of any fuel for which the unit is installed by 1,000, or
on the basis of pounds of steam generated per hour per square foot of boiler
heating surface as given in Table 2. When necessary a greater relieving
capacity of valves shall be provided. In every case, the requirements of subsection
subdivision F 6 of this section shall be met.
5. When operating conditions are changed, or additional boiler
heating surface is installed, the valve capacity shall be increased, if
necessary, to meet the new conditions and shall be in accordance with
subdivision F 6 of this section. The additional valves required, on account of
changed conditions, may be installed on the outlet piping provided there is no
intervening valve.
6. Safety relief valve capacity for each boiler shall be so
that, with the fuel burning equipment installed and operated at maximum
capacity the pressure cannot rise more than 6 six psig above the
maximum allowable working pressure for pressure up to and including 60 psig and
5.0% of maximum allowable working pressures over 60 psig.
7. If there is any doubt as to the capacity of the safety
relief valve, an accumulation test shall be run (see the current edition of
the ASME Code, Section VI, Care of Heating Boilers) VI).
8. No valve of any description shall be placed between the
safety relief valve and the boiler, nor on the discharge pipe between the
safety relief valve and the atmosphere. The discharge pipe shall be at least
full size and fitted with an open drain to prevent water lodging in the upper
part of the safety relief valve or in the discharge pipe. When an elbow is placed
on the safety relief valve discharge pipe, it shall be located close to the
safety relief valve outlet or the discharge pipe shall be securely anchored and
supported. All safety relief valve discharges shall be so located or piped as
not to endanger persons working in the area.
G. Valve replacement and repair. Safety valves and safety
relief valves requiring repair shall be replaced with a new valve or repaired
by the original manufacturer, its authorized representative, or the holder of a
"VR" Stamp.
H. Pressure relieving devices. Boilers and fired storage
water heaters except those exempted by the Act shall be equipped with pressure
relieving devices in accordance with the requirements of Section IV the
current edition of the of the ASME Boiler and Pressure Vessel Code,
Section IV.
I. Instruments, fittings and control requirements.
Instruments, fittings and controls for each boiler installation shall comply
with the requirements of the current edition of the ASME Heating
Boiler Code, Section IV.
J. Low water fuel cutoff.
1. Each automatically fired hot water heating boiler with heat
input greater than 400,000 BTU's BTUs per hour shall have an
automatic low water fuel cutoff which that has been designed for
hot water service, located so as to stop the fuel supply automatically when the
surface of the water falls to the level established in subdivision 2 of this
subsection (also see ASME Heating Boiler Code, Section IV).
2. As there is no normal waterline to be maintained in a hot
water heating boiler, any location of the low water fuel cutoff above the
lowest safe permissible water level established by the boiler manufacturer is
satisfactory.
3. A coil type boiler or a water tube boiler with heat input
greater than 400,000 BTU's BTUs per hour requiring forced
circulation, to prevent overheating of the coils or tubes, shall have a flow
sensing device installed in the outlet piping, instead of the low water fuel
cutoff required in subdivision 1 of this subsection to stop the fuel supply
automatically when the circulating flow is interrupted.
K. Steam gauges.
1. Each steam boiler shall have a steam gauge connected to its
steam space, its water column, or its steam connection, by means of a siphon or
equivalent device exterior to the boiler. The siphon shall be of sufficient
capacity to keep the gauge tube filled with water and arranged so that the
gauge cannot be shut off from the boiler except by a cock.
2. The range of the scale on the dial of a steam boiler
pressure gauge shall be not less than 30 psig nor more than 60 psig. The gauge
shall be provided with effective stops for the indicating pointer at the zero
point and at the maximum pressure point. The travel of the pointer from 0
zero to full scale 30 psig shall be at least three inches.
L. Pressure or altitude gauges.
1. Each hot water boiler shall have a pressure or altitude
gauge connected to it or to its flow connection in a manner so that it cannot
be shut off from the boiler except by a cock with tee or lever handle placed on
the pipe near the gauge. The handle of the cock shall be parallel to the pipe
in which it is located when the cock is open.
2. The range of the scale on the dial of the pressure or
altitude gauge shall be not less than 1-1/2 times nor more than three times the
maximum allowable working pressure. The gauge shall be provided with effective
stops for the indicating pointer at the 0 zero point and at the
maximum pressure point.
3. Piping or tubing for pressure or altitude gauge connections
shall be of nonferrous metal when smaller than one inch pipe size.
M. Thermometers. Each hot water boiler shall have a
thermometer located and connected so that it shall be easily readable when
observing the water pressure or altitude gauge. The thermometer shall be
located so that it will at all times indicate the temperature in degrees
Fahrenheit of the water in the boiler at or near the outlet.
N. Water gauge glasses.
1. Each steam boiler shall have one or more water gauge
glasses attached to the water column or boiler by means of valved fittings. The
lower fitting shall be provided with a drain valve of the straightaway type
with opening not less than 1/4 inch diameter to facilitate cleaning. Gauge
glass replacement shall be possible while the boiler is under pressure.
2. Transparent material, other than glass, may be used for the
water gauge provided that the material has proved suitable for the pressure,
temperature and corrosive conditions encountered in service.
O. Stop valves and check valves.
1. If a boiler can 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.
2. If any part of a heating system can 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.
P. Feedwater connections.
1. Feedwater, make-up water, or water treatment shall be
introduced into a boiler through the return piping system or through an independent
feedwater connection which that does not discharge against parts
of the boiler exposed to direct radiant heat from the fire. Feedwater, make-up water,
or water treatment shall not be introduced through openings or connections
provided for inspection or cleaning, safety valve, safety relief valve, surface
blowoff, water column, water gauge glass, pressure gauge or temperature gauge.
2. Feedwater piping shall be provided with a check valve near
the boiler and a stop valve or cock between the check valve and the boiler or
return pipe system.
Q. Return pump. Each boiler equipped with a condensate return
pump, where practicable, shall be provided with a water level control arranged
to maintain the water level in the boiler automatically within the range of the
gauge glass.
R. Repairs and renewals of boiler fittings and appliances.
Whenever repairs are made to fittings or appliances, or it becomes necessary to
replace them, the repairs or replacements shall comply with the requirements
for new installations.
S. Conditions not covered by this chapter. Any case not
specifically covered by this chapter shall be treated as a new boiler or
pressure vessel installation pursuant to 16VAC25-50-280 or may be referred to
the chief inspector for instructions concerning the requirements.
16VAC25-50-380. Pressure vessels.
A. Maximum allowable working pressure for standard pressure
vessels. The maximum allowable working pressure for standard pressure vessels
shall be determined in accordance with the applicable provisions of the edition
of the ASME Code or API-ASME code under which they were constructed and
stamped. The maximum allowable working pressure shall not be increased to a
greater pressure than shown on the manufacturers nameplate stamping and data
report.
B. Maximum allowable working pressure for nonstandard
pressure vessels.
1. For internal pressure. The maximum allowable working
pressure on the shell of a nonstandard pressure vessel shall be determined by
the strength of the weakest course computed from the thickness of the plate,
the tensile strength of the plate, the efficiency of the longitudinal joint,
the inside diameter of the weakest course and the factor set by this chapter.
TStE
|
=
|
maximum allowable working pressure, psi
|
RFS
|
where:
TS = ultimate tensile strength of shell plate, psi. When the
tensile strength of the steel plate is not known, it shall be taken as 55,000
psi for temperatures not exceeding 700°F.
t = minimum thickness of shell plate of weakest course, inches
E = efficiency of longitudinal joint depending upon
construction. Use the following values:
For riveted joints -- calculated riveted efficiency;
For fusion-welded joints:
Single lap weld
|
40%
|
Double lap weld
|
50%
|
Single butt weld
|
60%
|
Double butt weld
|
70%
|
Forge weld
|
70%
|
Brazed steel
|
80%
|
R = inside radius of weakest course of shell, inches, provided
the thickness does not exceed 10% of the radius. If the thickness is over 10%
of the radius, the outer radius shall be used.
FS = factor of safety allowed by this chapter.
2. For external pressure. The maximum allowable working
pressure for cylindrical nonstandard pressure vessels subjected to external or
collapsing pressure shall be determined by the rules in the ASME Code,
Section VIII, Division 1, of the ASME Code.
3. Factors of safety. The minimum factor of safety shall in no
case be less than 3.5 for vessels built on or after January 1, 1999. For
vessels built prior to January 1, 1999, the minimum factor of safety shall in
no case be less than 4.0. The factor of safety may be increased when deemed
necessary by the inspector to insure the operation of the vessel within safe
limits. The condition of the vessel and the particular service of which it is
subject will be the determining factors.
4. The maximum allowable working pressure permitted for formed
heads under pressure shall be determined by using the appropriate formulas from
the ASME Code, Section VIII, Division 1, ASME Code and the
tensile strength and factors of safety given in subdivisions 1 and 3 of this
subsection.
C. Inspection of inaccessible parts. Where in the opinion of
the inspector, as the result of conditions disclosed at the time of inspection,
it is advisable to remove the interior or exterior lining, covering, or
brickwork to expose certain parts of the vessel not normally visible, the owner
or user shall remove the materials to permit proper inspection and to establish
construction details. Metal thickness shall be determined utilizing appropriate
equipment including drilling if necessary.
D. Pressure relief devices. Pressure relief devices for each
pressure vessel installation, not exempt by the Act, shall comply with the
requirements of the ASME Pressure Vessel Code, Section VIII.
E. Safety appliances.
1. Each pressure vessel shall be protected by safety and
relief valves and indicating and controlling devices which will insure its safe
operation. These valves and devices shall be constructed, located and installed
so that they cannot readily be rendered inoperative. The relieving capacity of
the safety valves shall prevent a rise of pressure in the vessel of more than
10% above the maximum allowable working pressure, taking into account the
effect of static head. Safety valve discharges shall be located or piped so as
not to endanger persons working in the area.
2. Safety valves and safety relief valves requiring repair
shall be replaced with a new valve or repairs shall be performed by the
original manufacturer, its authorized representative, or the holder of a
"VR" stamp.
F. Repairs and renewals of fittings and appliances. Whenever
repairs are made to fittings or appliances, or it becomes necessary to replace
them, the repairs or replacements shall comply with requirements for new
installations.
G. Conditions not covered by this chapter. All cases not
specifically covered by this chapter shall be treated as new installations or
may be referred to the chief inspector for instructions concerning the requirements.
16VAC25-50-430. Hydrostatic pressure tests.
A. A hydrostatic pressure test, when applied to boilers or
pressure vessels, shall not exceed 1.25 times the maximum allowable working
pressure, except as provided by the current edition of the ASME Code.
The pressure shall be under proper control so that in no case shall the
required test pressure be exceeded by more than 2.0%.
B. See 16VAC25-50-360 A 4 for temperature limitations on
particular power boiler installations.
C. When a hydrostatic test is to be applied to existing
installations, the pressure shall be as follows:
1. For all cases involving the question of tightness, the
pressure shall be equal to the working pressure.
2. For all cases involving the question of safety, the test
pressure shall not exceed 1.25 times the maximum allowable working pressure for
temperature. During such test the safety valve or valves shall be removed or
each valve disk shall be held to its seat by means of a testing clamp and not
by screwing down the compression screw upon the spring.
16VAC25-50-460. Blowoff equipment.
A. The blowdown from a boiler or boilers that enters a sewer
system or blowdown which is considered a hazard to life or property shall pass
through blowoff equipment that will reduce pressure and temperature as required
below.
B. The temperature of the water leaving the blowoff equipment
shall not exceed 140°F.
C. The pressure of the blowdown leaving any type of blowoff
equipment shall not exceed 5.0 five psig.
D. The blowoff piping and fittings between the boiler and the
blowoff tank shall comply with Section I of the current edition of
the ASME code Code, Section I and ANSI ASME
B31.1.
E. All materials used in the fabrication of boiler blowoff
equipment shall comply with Section II of the current edition of the
ASME code Code, Section II.
F. All blowoff equipment shall be fitted with openings to
facilitate cleaning and inspection.
G. Blowoff equipment which conforms to the provisions set
forth in the National Board publication, "Boiler Blowoff Equipment",
shall meet the requirements of this section.
16VAC25-50-540. Jacketed kettles and miniatures boilers.
Jacketed kettles and miniature boilers are acceptable for
installation if constructed and stamped in accordance with Section I, IV, or VIII,
Division 1, of the current edition of the ASME code Code
and registered with the National Board.
NOTICE: The following
forms used in administering the regulation were filed by the agency. The forms
are not being published; however, online users of this issue of the Virginia
Register of Regulations may click on the name of a form with a hyperlink to
access it. The forms are also available from the agency contact or may be
viewed at the Office of the Registrar of Regulations, 900 East Main Street,
11th Floor, Richmond, Virginia 23219.
FORMS (16VAC25-50)
R 1 Form, Report of Welded __ Repair or __ Alteration, CVR1
Rev 1.0.
Form R-1, Report of Repair, National Board Inspection
Code, NB-66 (rev. 2012).
Form R-2, Report of Alteration, National Board Inspection
Code (eff. 1/1/99).
Form R-3, Report of Parts Fabricated By Welding, National
Board Inspection Code (eff. 1/1/99).
Form R-4, Report Supplementary Sheet, National Board
Inspection Code (eff. 1/1/99).
Form
R-1, Report of Repair, NB-66, Rev. 13 (rev. 6/25/2015)
Form
R-2, Report of Alteration, NB-229, Rev. 7 (rev.11/12/2015)
Form
R-3, Report of Parts Fabricated by Welding, NB-230, Rev. 3 (rev. 9/24/2015)
Form
R-4, Report Supplement Sheet, NB-231, Rev. 2, (rev. 9/23/2015)
BPV-5, Boiler or Pressure Vessel Data Report- First Internal
Inspection (eff. 1/1/99).
BPV-6, Boiler - Fired Pressure Vessel - Report of Inspection
(eff. 1/1/99).
DOCUMENTS INCORPORATED BY REFERENCE (16VAC25-50)
2007 Boiler and Pressure Vessel Code, ASME Code, American
Society of Mechanical Engineers.
National Board Bylaws, National Board of Boiler and
Pressure Vessel Inspectors, August 8, 1996.
ANSI/NB 23, 2007 National Board Inspection Code, National
Board of Boiler and Pressure Vessel Inspectors.
ASME B31.1, ASME Code for Power Piping, American National
Standards Institute, 2007.
NFPA 85 Boiler and Combustion Systems Hazards, 2001
Edition, National Fire Protection Association.
Part CG (General), Part CW (Steam and Waterside Control)
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