[Code of Federal Regulations]
[Title 29, Volume 5]
[Revised as of January 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 29CFR1910.110]
[Page 297-333]
TITLE 29--LABOR
CHAPTER XVII--OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT
OF LABOR
PART 1910_OCCUPATIONAL SAFETY AND HEALTH STANDARDS--Table of Contents
Subpart H_Hazardous Materials
Sec. 1910.110 Storage and handling of liquefied petroleum gases.
(a) Definitions applicable to this section. As used in this section:
(1) API-ASME container--A container constructed in accordance with
the requirements of paragraph (b)(3)(iii) of this section.
(2) ASME container--A container constructed in accordance with the
requirements of paragraph (b)(3)(i) of this section.
(3) Container assembly--An assembly consisting essentially of the
container and fittings for all container openings, including shutoff
valves, excess flow valves, liquid-level gaging devices, safety relief
devices, and protective housing.
(4) Containers--All vessels, such as tanks, cylinders, or drums,
used for transportation or storing liquefied petroleum gases.
(5) DOT--Department of Transportation.
(6) DOT container--A container constructed in accordance with the
applicable requirements of 49 CFR chapter 1.
(7) ``Liquified petroleum gases''--``LPG'' and ``LP-Gas''--Any
material which is composed predominantly of any of the following
hydrocarbons, or mixtures of them; propane, propylene, butanes (normal
butane or iso-butane), and butylenes.
(8) Movable fuel storage tenders or farm carts--Containers not in
excess of 1,200 gallons water capacity, equipped with wheels to be towed
from one location of usage to another. They are basically nonhighway
vehicles, but may occasionally be moved over public roads or highways.
They are used as a fuel
[[Page 298]]
supply for farm tractors, construction machinery and similar equipment.
(9) P.S.I.G.--pounds per square inch gauge.
(10) P.S.I.A.--pounds per square inch absolute.
(11) Systems--an assembly of equipment consisting essentially of the
container or containers, major devices such as vaporizers, safety relief
valves, excess flow valves, regulators, and piping connecting such
parts.
(12) Vaporizer-burner--an integral vaporizer-burner unit, dependent
upon the heat generated by the burner as the source of heat to vaporize
the liquid used for dehydrators or dryers.
(13) Ventilation, adequate--when specified for the prevention of
fire during normal operation, ventilation shall be considered adequate
when the concentration of the gas in a gas-air mixture does not exceed
25 percent of the lower flammable limit.
(14) Approved--unless otherwise indicated, listing or approval by a
nationally recognized testing laboratory. Refer to Sec. 1910.7 for
definition of nationally recognized testing laboratory.
(15) Listed--see ``approved'' in Sec. 1910.110(14).
(16) DOT Specifications--regulations of the Department of
Transportation published in 49 CFR chapter I.
(17)-(18) [Reserved]
(19) DOT cylinders--cylinders meeting the requirements of 49 CFR
chapter I.
(b) Basic rules--(1) Odorizing gases. (i) All liquefied petroleum
gases shall be effectively odorized by an approved agent of such
character as to indicate positively, by distinct odor, the presence of
gas down to concentration in air of not over one-fifth the lower limit
of flammability. Odorization, however, is not required if harmful in the
use of further processing of the liquefied petroleum gas, or if
odorization will serve no useful purpose as a warning agent in such use
or further processing.
(ii) The odorization requirement of paragraph (b)(1)(i) of this
section shall be considered to be met by the use of 1.0 pounds of ethyl
mercaptan, 1.0 pounds of thiophane or 1.4 pounds of amyl mercaptan per
10,000 gallons of LP-Gas. However, this listing of odorants and
quantities shall not exclude the use of other odorants that meet the
odorization requirements of paragraph (b)(1)(i) of this section.
(2) Approval of equipment and systems. (i) Each system utilizing DOT
containers in accordance with 49 CFR part 178 shall have its container
valves, connectors, manifold valve assemblies, and regulators approved.
(ii) Each system for domestic or commercial use utilizing containers
of 2,000 gallons or less water capacity, other than those constructed in
accordance with 49 CFR part 178, shall consist of a container assembly
and one or more regulators, and may include other parts. The system as a
unit or the container assembly as a unit, and the regulator or
regulators, shall be individually listed.
(iii) In systems utilizing containers of over 2,000 gallons water
capacity, each regulator, container valve, excess flow valve, gaging
device, and relief valve installed on or at the container, shall have
its correctness as to design, construction, and performance determined
by listing by a nationally recognized testing laboratory. Refer to Sec.
1910.7 for definition of nationally recognized testing laboratory.
(3) Requirements for construction and original test of containers.
(i) Containers used with systems embodied in paragraphs (d), (e), (g),
and (h) of this section, except as provided in paragraphs (e)(3)(iii)
and (g)(2)(i) of this section, shall be designed, constructed, and
tested in accordance with the Rules for Construction of Unfired Pressure
Vessels, section VIII, Division 1, American Society of Mechanical
Engineers (ASME) Boiler and Pressure Vessel Code, 1968 edition, which is
incorporated by reference as specified in Sec. 1910.6.
(ii) Containers constructed according to the 1949 and earlier
editions of the ASME Code do not have to comply with paragraphs U-2
through U-10 and U-19 thereof. Containers constructed according to
paragraph U-70 in the 1949 and earlier editions are not authorized.
(iii) Containers designed, constructed, and tested prior to July 1,
1961, according to the Code for Unfired Pressure Vessels for Petroleum
Liquids
[[Page 299]]
and Gases, 1951 edition with 1954 Addenda, of the American Petroleum
Institute and the American Society of Mechanical Engineers, which is
incorporated by reference as specified in Sec. 1910.6, shall be
considered in conformance. Containers constructed according to API-ASME
Code do not have to comply with section I or with appendix to section I.
Paragraphs W-601 to W-606 inclusive in the 1943 and earlier editions do
not apply.
(iv) The provisions of paragraph (b)(3)(i) of this section shall not
be construed as prohibiting the continued use or reinstallation of
containers constructed and maintained in accordance with the standard
for the Storage and Handling of Liquefied Petroleum Gases NFPA No. 58 in
effect at the time of fabrication.
(v) Containers used with systems embodied in paragraph (b),
(d)(3)(iii), and (f) of this section, shall be constructed, tested, and
stamped in accordance with DOT specifications effective at the date of
their manufacture.
(4) Welding of containers. (i) Welding to the shell, head, or any
other part of the container subject to internal pressure, shall be done
in compliance with the code under which the tank was fabricated. Other
welding is permitted only on saddle plates, lugs, or brackets attached
to the container by the tank manufacturer.
(ii) Where repair or modification involving welding of DOT
containers is required, the container shall be returned to a qualified
manufacturer making containers of the same type, and the repair or
modification made in compliance with DOT regulations.
(5) Markings on containers. (i) Each container covered in paragraph
(b)(3)(i) of this section, except as provided in paragraph (b)(3)(iv) of
this section shall be marked as specified in the following:
(a) With a marking identifying compliance with, and other markings
required by, the rules of the reference under which the container is
constructed; or with the stamp and other markings required by the
National Board of Boiler and Pressure Vessel Inspectors.
(b) With notation as to whether the container is designed for
underground or aboveground installation or both. If intended for both
and different style hoods are provided, the marking shall indicate the
proper hood for each type of installation.
(c) With the name and address of the supplier of the container, or
with the trade name of the container.
(d) With the water capacity of the container in pounds or gallons,
U.S. Standard.
(e) With the pressure in p.s.i.g., for which the container is
designed.
(f) With the wording ``This container shall not contain a product
having a vapor pressure in excess of ---- p.s.i.g. at 100 [deg]F.,'' see
subparagraph (14)(viii) of this paragraph.
(g) With the tare weight in pounds or other identified unit of
weight for containers with a water capacity of 300 pounds or less.
(h) With marking indicating the maximum level to which the container
may be filled with liquid at temperatures between 20 [deg]F. and 130
[deg]F., except on containers provided with fixed maximum level
indicators or which are filled by weighing. Markings shall be increments
of not more than 20 [deg]F. This marking may be located on the liquid
level gaging device.
(i) With the outside surface area in square feet.
(ii) Markings specified shall be on a metal nameplate attached to
the container and located in such a manner as to remain visible after
the container is installed.
(iii) When LP-Gas and one or more other gases are stored or used in
the same area, the containers shall be marked to identify their content.
Marking shall be in compliance with American National Standard Z48.1-
1954, ``Method of Marking Portable Compressed Gas Containers To Identify
the Material Contained'', which is incorporated by reference as
specified in Sec. 1910.6.
(6) Location of containers and regulating equipment. (i) Containers,
and first stage regulating equipment if used, shall be located outside
of buildings, except under one or more of the following:
(a) In buildings used exclusively for container charging,
vaporization pressure reduction, gas mixing, gas manufacturing, or
distribution.
[[Page 300]]
(b) When portable use is necessary and in accordance with paragraph
(c)(5) of this section.
(c) LP-Gas fueled stationary or portable engines in accordance with
paragraph (e) (11) or (12) of this section.
(d) LP-Gas fueled industrial trucks used in accordance with
paragraph (e)(13) of this section.
(e) LP-Gas fueled vehicles garaged in accordance with paragraph
(e)(14) of this section.
(f) Containers awaiting use or resale when stored in accordance with
paragraph (f) of this section.
(ii) Each individual container shall be located with respect to the
nearest important building or group of buildings in accordance with
Table H-23.
Table H-23
----------------------------------------------------------------------------------------------------------------
Minimum distances
--------------------------------------------------------------------------
Water capacity per container Containers
-------------------------------------------------- Between aboveground
Underground Aboveground containers
----------------------------------------------------------------------------------------------------------------
Less than 125 gals.\1\............... 10 feet................ None................... None.
125 to 250 gals...................... 10 feet................ 10 feet................ None.
251 to 500 gals...................... 10 feet................ 10 feet................ 3 feet.
501 to 2,000 gals.................... 25 feet \2\............ 25 feet \2\............ 3 feet.
2,001 to 30,000 gals................. 50 feet................ 50 feet................ 5 feet.
30,001 to 70,000 gals................ 50 feet................ 75 feet.\3\............
70,001 to 90,000 gals................ 50 feet................ 100 feet.\3\...........
----------------------------------------------------------------------------------------------------------------
\1\ If the aggregate water capacity of a multi-container installation at a consumer site is 501 gallons or
greater, the minimum distance shall comply with the appropriate portion of this table, applying the aggregate
capacity rather than the capacity per container. If more than one installation is made, each installation
shall be separated from another installation by at least 25 feet. Do not apply the MINIMUM DISTANCES BETWEEN
ABOVE-GROUND CONTAINERS to such installations.
\2\ The above distance requirements may be reduced to not less than 10 feet for a single container of 1,200
gallons water capacity or less, providing such a container is at least 25 feet from any other LP-Gas container
of more than 125 gallons water capacity.
\3\ \1/4\ of sum of diameters of adjacent containers.
(iii) Containers installed for use shall not be stacked one above
the other.
(iv) [Reserved]
(v) In the case of buildings devoted exclusively to gas
manufacturing and distributing operations, the distances required by
Table H-23 may be reduced provided that in no case shall containers of
water capacity exceeding 500 gallons be located closer than 10 feet to
such gas manufacturing and distributing buildings.
(vi) Readily ignitible material such as weeds and long dry grass
shall be removed within 10 feet of any container.
(vii) The minimum separation between liquefied petroleum gas
containers and flammable liquid tanks shall be 20 feet, and the minimum
separation between a container and the centerline of the dike shall be
10 feet. The foregoing provision shall not apply when LP-Gas containers
of 125 gallons or less capacity are installed adjacent to Class III
flammable liquid tanks of 275 gallons or less capacity.
(viii) Suitable means shall be taken to prevent the accumulation of
flammable liquids under adjacent liquified petroleum gas containers,
such as by diking, diversion curbs, or grading.
(ix) When dikes are used with flammable liquid tanks, no liquefied
petroleum gas containers shall be located within the diked area.
(7) Container valves and container accessories. (i) Valves,
fittings, and accessories connected directly to the container including
primary shutoff valves, shall have a rated working pressure of at least
250 p.s.i.g. and shall be of material and design suitable for LP-Gas
service. Cast iron shall not be used for container valves, fittings, and
accessories. This does not prohibit the use of container valves made of
malleable or nodular iron.
(ii) Connections to containers, except safety relief connections,
liquid level gaging devices, and plugged openings, shall have shutoff
valves located as close to the container as practicable.
(iii) Excess flow valves, where required shall close automatically
at the rated flows of vapor or liquid as specified by the manufacturer.
The connections or line including valves, fittings, etc., being
protected by an excess flow valve shall have a greater capacity than the
rated flow of the excess flow valve.
(iv) Liquid level gaging devices which are so constructed that
outward flow of container contents shall not exceed that passed by a No.
54 drill size opening, need not be equipped with excess flow valves.
(v) Openings from container or through fittings attached directly on
container to which pressure gage connection is made, need not be
equipped with shutoff or excess flow valves if such openings are
restricted to not larger than No. 54 drill size opening.
[[Page 301]]
(vi) Except as provided in paragraph (c)(5)(i)(b) of this section,
excess flow and back pressure check valves where required by this
section shall be located inside of the container or at a point outside
where the line enters the container; in the latter case, installation
shall be made in such manner that any undue strain beyond the excess
flow or back pressure check valve will not cause breakage between the
container and such valve.
(vii) Excess flow valves shall be designed with a bypass, not to
exceed a No. 60 drill size opening to allow equalization of pressures.
(viii) Containers of more than 30 gallons water capacity and less
than 2,000 gallons water capacity, filled on a volumetric basis, and
manufactured after December 1, 1963, shall be equipped for filling into
the vapor space.
(8) Piping--including pipe, tubing, and fittings. (i) Pipe, except
as provided in paragraphs (e)(6)(i) and (g)(10)(iii), of this section
shall be wrought iron or steel (black or galvanized), brass, copper, or
aluminum alloy. Aluminum alloy pipe shall be at least Schedule 40 in
accordance with the specifications for Aluminum Alloy Pipe, American
National Standards Institute (ANSI) H38.7-1969 (ASTM, B241-69), which is
incorporated by reference as specified in Sec. 1910.6, except that the
use of alloy 5456 is prohibited and shall be suitably marked at each end
of each length indicating compliance with American National Standard
Institute Specifications. Aluminum Alloy pipe shall be protected against
external corrosion when it is in contact with dissimilar metals other
than galvanized steel, or its location is subject to repeated wetting by
such liquids as water (except rain water), detergents, sewage, or
leaking from other piping, or it passes through flooring, plaster,
masonry, or insulation. Galvanized sheet steel or pipe, galvanized
inside and out, may be considered suitable protection. The maximum
nominal pipe size for aluminum pipe shall be three-fourths inch and
shall not be used for pressures exceeding 20 p.s.i.g. Aluminum alloy
pipe shall not be installed within 6 inches of the ground.
(a) Vapor piping with operating pressures not exceeding 125 p.s.i.g.
shall be suitable for a working pressure of at least 125 p.s.i.g. Pipe
shall be at least Schedule 40 (ASTM A-53-69, Grade B Electric Resistance
Welded and Electric Flash Welded Pipe, which is incorporated by
reference as specified in Sec. 1910.6, or equal).
(b) Vapor piping with operating pressures over 125 p.s.i.g. and all
liquid piping shall be suitable for a working pressure of at least 250
p.s.i.g. Pipe shall be at least Schedule 80 if joints are threaded or
threaded and back welded. At least Schedule 40 (ASTM A-53-69 Grade B
Electric Resistance Welded and Electric Flash Welded Pipe or equal)
shall be used if joints are welded, or welded and flanged.
(ii) Tubing shall be seamless and of copper, brass, steel, or
aluminum alloy. Copper tubing shall be of type K or L or equivalent as
covered in the Specification for Seamless Copper Water Tube, ANSI H23.1-
1970 (ASTM B88-69), which is incorporated by reference as specified in
Sec. 1910.6. Aluminum alloy tubing shall be of Type A or B or
equivalent as covered in Specification ASTM B210-68 (which is
incorporated by reference as specified in Sec. 1910.6) and shall be
suitably marked every 18 inches indicating compliance with ASTM
Specifications. The minimum nominal wall thickness of copper tubing and
aluminum alloy tubing shall be as specified in Table H-24 and Table H-
25.
Aluminum alloy tubing shall be protected against external corrosion when
it is in contact with dissimilar metals other than galvanized steel, or
its location is subject to repeated wetting by liquids such as water
(except rainwater), detergents, sewage, or leakage from other piping, or
it passes through flooring, plaster, masonry, or insulation. Galvanized
sheet steel or pipe, galvanized inside and out, may be considered
suitable protection. The maximum outside diameter for aluminum alloy
tubing shall be three-fourths inch and shall not be used for pressures
exceeding 20 p.s.i.g. Aluminum alloy tubing shall not be installed
within 6 inches of the ground.
[[Page 302]]
Table H-24--Wall Thickness of Copper Tubing \1\
------------------------------------------------------------------------
Nominal wall thickness (inches)
Standard size Nominal outside ---------------------------------
(inches) diameter (inches) Type K Type L
------------------------------------------------------------------------
\1/4\ 0.375 0.035 0.030
\3/8\ 0.500 0.049 0.035
\1/2\ 0.625 0.049 0.040
\5/8\ 0.750 0.049 0.042
\3/4\ 0.875 0.065 0.045
1 1.125 0.065 0.050
1\1/4\ 1.375 0.065 0.055
1\1/2\ 1.625 0.072 0.060
2 2.125 0.083 0.070
------------------------------------------------------------------------
\1\ Based on data in Specification for Seamless Copper Water Tube, ANSI
H23.1-1970 (ASTM B-88-69).
Note: The standard size by which tube is designated is \1/8\ inch
smaller than its nominal outside diameter.
Table H-25--Wall Thickness of Aluminum Alloy Tubing \1\
------------------------------------------------------------------------
Nominal wall thickness (inches)
Outside diameter -----------------------------------------------
(inches) Type A Type B
------------------------------------------------------------------------
\3/8\ 0.035 0.049
\1/2\ 0.035 0.049
\5/8\ 0.042 0.049
\3/4\ 0.049 0.058
------------------------------------------------------------------------
\1\ Based on data in Standard Specification for Aluminum-Alloy Drawn
Seamless Coiled Tubes for Special Purpose Applications, ASTM B210-68.
(iii) In systems where the gas in liquid form without pressure
reduction enters the building, only heavy walled seamless brass or
copper tubing with an internal diameter not greater than three thirty-
seconds inch, and a wall thickness of not less than three sixty-fourths
inch shall be used. This requirement shall not apply to research and
experimental laboratories, buildings, or separate fire divisions of
buildings used exclusively for housing internal combustion engines, and
to commercial gas plants or bulk stations where containers are charged,
nor to industrial vaporizer buildings, nor to buildings, structures, or
equipment under construction or undergoing major renovation.
(iv) Pipe joints may be screwed, flanged, welded, soldered, or
brazed with a material having a melting point exceeding 1,000 [deg]F.
Joints on seamless copper, brass, steel, or aluminum alloy gas tubing
shall be made by means of approved gas tubing fittings, or soldered or
brazed with a material having a melting point exceeding 1,000 [deg]F.
(v) For operating pressures of 125 p.s.i.g. or less, fittings shall
be designed for a pressure of at least 125 p.s.i.g. For operating
pressures above 125 p.s.i.g., fittings shall be designed for a minimum
of 250 p.s.i.g.
(vi) The use of threaded cast iron pipe fittings such as ells, tees,
crosses, couplings, and unions is prohibited. Aluminum alloy fittings
shall be used with aluminum alloy pipe and tubing. Insulated fittings
shall be used where aluminum alloy pipe or tubing connects with a
dissimilar metal.
(vii) Strainers, regulators, meters, compressors, pumps, etc., are
not to be considered as pipe fittings. This does not prohibit the use of
malleable, nodular, or higher strength gray iron for such equipment.
(viii) All materials such as valve seats, packing, gaskets,
diaphragms, etc., shall be of such quality as to be resistant to the
action of liquefied petroleum gas under the service conditions to which
they are subjected.
(ix) All piping, tubing, or hose shall be tested after assembly and
proved free from leaks at not less than normal operating pressures.
After installation, piping and tubing of all domestic and commercial
systems shall be tested and proved free of leaks using a manometer or
equivalent device that will indicate a drop in pressure. Test shall not
be made with a flame.
(x) Provision shall be made to compensate for expansion,
contraction, jarring, and vibration, and for settling. This may be
accomplished by flexible connections.
(xi) Piping outside buildings may be buried, above ground, or both,
but shall be well supported and protected against physical damage. Where
soil conditions warrant, all piping shall be protected against
corrosion. Where condensation may occur, the piping shall be pitched
back to the container, or suitable means shall be provided for
revaporization of the condensate.
(9) Hose specifications. (i) Hose shall be fabricated of materials
that are resistant to the action of LP-Gas in the liquid and vapor
phases. If wire braid is used for reinforcing the hose, it shall be of
corrosion-resistant material such as stainless steel.
(ii) Hose subject to container pressure shall be marked ``LP-Gas''
or
[[Page 303]]
``LPG'' at not greater than 10-foot intervals.
(iii) Hose subject to container pressure shall be designed for a
bursting pressure of not less than 1,250 p.s.i.g.
(iv) Hose subject to container pressure shall have its correctness
as to design construction and performance determined by being listed
(see Sec. 1910.110(a)(15)).
(v) Hose connections subject to container pressure shall be capable
of withstanding, without leakage, a test pressure of not less than 500
p.s.i.g.
(vi) Hose and hose connections on the low-pressure side of the
regulator or reducing valve shall be designed for a bursting pressure of
not less than 125 p.s.i.g. or five times the set pressure of the relief
devices protecting that portion of the system, whichever is higher.
(vii) Hose may be used on the low-pressure side of regulators to
connect to other than domestic and commercial gas appliances under the
following conditions:
(a) The appliances connected with hose shall be portable and need a
flexible connection.
(b) For use inside buildings the hose shall be of minimum practical
length, but shall not exceed 6 feet except as provided in paragraph
(c)(5)(i)(g) of this section and shall not extend from one room to
another, nor pass through any walls, partitions, ceilings, or floors.
Such hose shall not be concealed from view or used in a concealed
location. For use outside of buildings, the hose may exceed this length
but shall be kept as short as practical.
(c) The hose shall be approved and shall not be used where it is
likely to be subjected to temperatures above 125 [deg]F. The hose shall
be securely connected to the appliance and the use of rubber slip ends
shall not be permitted.
(d) The shutoff valve for an appliance connected by hose shall be in
the metal pipe or tubing and not at the appliance end of the hose. When
shutoff valves are installed close to each other, precautions shall be
taken to prevent operation of the wrong valve.
(e) Hose used for connecting to wall outlets shall be protected from
physical damage.
(10) Safety devices. (i) Every container except those constructed in
accordance with DOT specifications and every vaporizer (except motor
fuel vaporizers and except vaporizers described in paragraph
(b)(11)(ii)(c) of this section and paragraph (d)(4)(v)(a) of this
section) whether heated by artificial means or not, shall be provided
with one or more safety relief valves of spring-loaded or equivalent
type. These valves shall be arranged to afford free vent to the outer
air with discharge not less than 5 feet horizontally away from any
opening into the building which is below such discharge. The rate of
discharge shall be in accordance with the requirements of paragraph
(b)(10)(ii) or (b)(10)(iii) of this section in the case of vaporizers.
(ii) Minimum required rate of discharge in cubic feet per minute of
air at 120 percent of the maximum permitted start to discharge pressure
for safety relief valves to be used on containers other than those
constructed in accordance with DOT specification shall be as follows:
------------------------------------------------------------------------
Flow rate
Surface area (sq. ft.) CFM air
------------------------------------------------------------------------
20 or less.................................................. 626
25.......................................................... 751
30.......................................................... 872
35.......................................................... 990
40.......................................................... 1,100
45.......................................................... 1,220
50.......................................................... 1,330
55.......................................................... 1,430
60.......................................................... 1,540
65.......................................................... 1,640
70.......................................................... 1,750
75.......................................................... 1,850
80.......................................................... 1,950
85.......................................................... 2,050
90.......................................................... 2,150
95.......................................................... 2,240
100......................................................... 2,340
105......................................................... 2,440
110......................................................... 2,530
115......................................................... 2,630
120......................................................... 2,720
125......................................................... 2,810
130......................................................... 2,900
135......................................................... 2,990
140......................................................... 3,080
145......................................................... 3,170
150......................................................... 3,260
155......................................................... 3,350
160......................................................... 3,440
165......................................................... 3,530
170......................................................... 3,620
175......................................................... 3,700
180......................................................... 3,790
185......................................................... 3,880
190......................................................... 3,960
195......................................................... 4,050
200......................................................... 4,130
210......................................................... 4,300
220......................................................... 4,470
[[Page 304]]
230......................................................... 4,630
240......................................................... 4,800
250......................................................... 4,960
260......................................................... 5,130
270......................................................... 5,290
280......................................................... 5,450
290......................................................... 5,610
300......................................................... 5,760
310......................................................... 5,920
320......................................................... 6,080
330......................................................... 6,230
340......................................................... 6,390
350......................................................... 6,540
360......................................................... 6,690
370......................................................... 6,840
380......................................................... 7,000
390......................................................... 7,150
400......................................................... 7,300
450......................................................... 8,040
500......................................................... 8,760
550......................................................... 9,470
600......................................................... 10,170
650......................................................... 10,860
700......................................................... 11,550
750......................................................... 12,220
800......................................................... 12,880
850......................................................... 13,540
900......................................................... 14,190
950......................................................... 14,830
1,000....................................................... 15,470
1,050....................................................... 16,100
1,100....................................................... 16,720
1,150....................................................... 17,350
1,200....................................................... 17,960
1,250....................................................... 18,570
1,300....................................................... 19,180
1,350....................................................... 19,780
1,400....................................................... 20,380
1,450....................................................... 20,980
1,500....................................................... 21,570
1,550....................................................... 22,160
1,600....................................................... 22,740
1,650....................................................... 23,320
1,700....................................................... 23,900
1,750....................................................... 24,470
1,800....................................................... 25,050
1,850....................................................... 25,620
1,900....................................................... 26,180
1,950....................................................... 26,750
2,000....................................................... 27,310
------------------------------------------------------------------------
Surface area=total outside surface area of container in square feet.
When the surface area is not stamped on the nameplate or when the
marking is not legible, the area can be calculated by using one of the
following formulas:
(1) Cylindrical container with hemispherical heads:
Area=Overall lengthxoutside diameterx 3.1416.
(2) Cylindrical container with other than hemispherical heads:
Area=(Overall length+0.3 outside diameter) xoutside diameterx3.1416.
Note: This formula is not exact, but will give results within the
limits of practical accuracy for the sole purpose of sizing relief
valves.
(3) Spherical container:
Area=Outside diameter squaredx3.1416.
Flow Rate-CFM Air=Required flow capacity in cubic feet per minute of air
at standard conditions, 60 F. and atmospheric pressure (14.7 p.s.i.a.).
The rate of discharge may be interpolated for intermediate values of
surface area. For containers with total outside surface area greater
than 2,000 square feet, the required flow rate can be calculated using
the formula, Flow Rate-CFM Air=53.632 A0.82.
A=total outside surface area of the container in square feet.
Valves not marked ``Air'' have flow rate marking in cubic feet per
minute of liquefied petroleum gas. These can be converted to ratings in
cubic feet per minute of air by multiplying the liquefied petroleum gas
ratings by factors listed below. Air flow ratings can be converted to
ratings in cubic feet per minute of liquefied petroleum gas by dividing
the air ratings by the factors listed below.
Air Conversion Factors
Container type.................. 100 125 150 175 200
Air conversion factor........... 1.162 1.142 1.113 1.078 1.010
(iii) Minimum Required Rate of Discharge for Safety Relief Valves
for Liquefied Petroleum Gas Vaporizers (Steam Heated, Water Heated, and
Direct Fired).
The minimum required rate of discharge for safety relief valves shall be
determined as follows:
(a) Obtain the total surface area by adding the surface area of
vaporizer shell in square feet directly in contact with LP-Gas and the
heat exchanged surface area in square feet directly in contact with LP-
Gas.
(b) Obtain the minimum required rate of discharge in cubic feet of
air per minute, at 60 [deg]F. and 14.7 p.s.i.a. from paragraph
(b)(10)(ii) of this section, for this total surface area.
(iv) Container and vaporizer safety relief valves shall be set to
start-to-discharge, with relation to the design pressure of the
container, in accordance with Table H-26.
(v) Safety relief devices used with systems employing containers
other than those constructed according to DOT specifications shall be so
constructed as to discharge at not less than the rates shown in
paragraph (b)(10)(ii) of this section, before the pressure is in excess
of 120 percent of
[[Page 305]]
the maximum (not including the 10 percent referred to in paragraph
(b)(10)(iv) of this section) permitted start to discharge pressure
setting of the device.
Table H-26
------------------------------------------------------------------------
Minimum Maximum
Containers (percent) (percent)
------------------------------------------------------------------------
ASME Code; Par. U-68, U-69--1949 and earlier 110 \1\ 25
editions.......................................
ASME Code; Par. U-200, U-201--1949 edition...... 88 \1\ 100
ASME Code--1950, 1952, 1956, 1959, 1962, 1965 88 \1\ 100
and 1968 (Division I) editions.................
API--ASME Code--all editions.................... 88 \1\ 100
DOT--As prescribed in 49 CFR Chapter I..........
------------------------------------------------------------------------
\1\ Manufacturers of safety relief valves are allowed a plus tolerance
not exceeding 10 percent of the set pressure marked on the valve.
(vi) In certain locations sufficiently sustained high temperatures
prevail which require the use of a lower vapor pressure product to be
stored or the use of a higher designed pressure vessel in order to
prevent the safety valves opening as the result of these temperatures.
As an alternative the tanks may be protected by cooling devices such as
by spraying, by shading, or other effective means.
(vii) Safety relief valves shall be arranged so that the possibility
of tampering will be minimized. If pressure setting or adjustment is
external, the relief valves shall be provided with approved means for
sealing adjustment.
(viii) Shutoff valves shall not be installed between the safety
relief devices and the container, or the equipment or piping to which
the safety relief device is connected except that a shutoff valve may be
used where the arrangement of this valve is such that full required
capacity flow through the safety relief device is always afforded.
(ix) Safety relief valves shall have direct communication with the
vapor space of the container at all times.
(x) Each container safety relief valve used with systems covered by
paragraphs (d), (e), (g), and (h) of this section, except as provided in
paragraph (e)(3)(iii) of this section shall be plainly and permanently
marked with the following: ``Container Type'' of the pressure vessel on
which the valve is designed to be installed; the pressure in p.s.i.g. at
which the valve is set to discharge; the actual rate of discharge of the
valve in cubic feet per minute of air at 60 [deg]F. and 14.7 p.s.i.a.;
and the manufacturer's name and catalog number, for example: T200-250-
4050 AIR--indicating that the valve is suitable for use on a Type 200
container, that it is set to start to discharge at 250 p.s.i.g.; and
that its rate of discharge is 4,050 cubic feet per minute of air as
determined in subdivision (ii) of this subparagraph.
(xi) Safety relief valve assemblies, including their connections,
shall be of sufficient size so as to provide the rate of flow required
for the container on which they are installed.
(xii) A hydrostatic relief valve shall be installed between each
pair of shut-off valves on liquefied petroleum gas liquid piping so as
to relieve into a safe atmosphere. The start-to-discharge pressure
setting of such relief valves shall not be in excess of 500 p.s.i.g. The
minimum setting on relief valves installed in piping connected to other
than DOT containers shall not be lower than 140 percent of the container
relief valve setting and in piping connected to DOT containers not lower
than 400 p.s.i.g. The start-to-discharge pressure setting of such a
relief valve, if installed on the discharge side of a pump, shall be
greater than the maximum pressure permitted by the recirculation device
in the system.
(xiii) The discharge from any safety relief device shall not
terminate in or beneath any building, except relief devices covered by
paragraphs (b)(6)(i) (a) through (e) of this section, or paragraphs (c)
(4)(i) or (5) of this section.
(xiv) Container safety relief devices and regulator relief vents
shall be located not less than five (5) feet in any direction from air
openings into sealed combustion system appliances or mechanical
ventilation air intakes.
(11) Vaporizer and housing. (i) Indirect fired vaporizers utilizing
steam, water, or other heating medium shall be constructed and installed
as follows:
(a) Vaporizers shall be constructed in accordance with the
requirements of paragraph (b)(3) (i)-(iii) of this section and shall be
permanently marked as follows:
(1) With the code marking signifying the specifications to which the
vaporizer is constructed.
[[Page 306]]
(2) With the allowable working pressure and temperature for which
the vaporizer is designed.
(3) With the sum of the outside surface area and the inside heat
exchange surface area expressed in square feet.
(4) With the name or symbol of the manufacturer.
(b) Vaporizers having an inside diameter of 6 inches or less
exempted by the ASME Unfired Pressure Vessel Code, Section VIII of the
ASME Boiler and Pressure Vessel Code--1968 shall have a design pressure
not less than 250 p.s.i.g. and need not be permanently marked.
(c) Heating or cooling coils shall not be installed inside a storage
container.
(d) Vaporizers may be installed in buildings, rooms, sheds, or lean-
tos used exclusively for gas manufacturing or distribution, or in other
structures of light, noncombustible construction or equivalent, well
ventilated near the floor line and roof.
When vaporizing and/or mixing equipment is located in a structure or
building not used exclusively for gas manufacturing or distribution,
either attached to or within such a building, such structure or room
shall be separated from the remainder of the building by a wall designed
to withstand a static pressure of at least 100 pounds per square foot.
This wall shall have no openings or pipe or conduit passing through it.
Such structure or room shall be provided with adequate ventilation and
shall have a roof or at least one exterior wall of lightweight
construction.
(e) Vaporizers shall have, at or near the discharge, a safety relief
valve providing an effective rate of discharge in accordance with
paragraph (b)(10)(iii) of this section, except as provided in paragraph
(d)(4)(v)(a), of this section.
(f) The heating medium lines into and leaving the vaporizer shall be
provided with suitable means for preventing the flow of gas into the
heat systems in the event of tube rupture in the vaporizer. Vaporizers
shall be provided with suitable automatic means to prevent liquid
passing through the vaporizers to the gas discharge piping.
(g) The device that supplies the necessary heat for producing steam,
hot water, or other heating medium may be installed in a building,
compartment, room, or lean-to which shall be ventilated near the
floorline and roof to the outside. The device location shall be
separated from all compartments or rooms containing liquefied petroleum
gas vaporizers, pumps, and central gas mixing devices by a wall designed
to withstand a static pressure of at least 100 pounds per square foot.
This wall shall have no openings or pipes or conduit passing through it.
This requirement does not apply to the domestic water heaters which may
supply heat for a vaporizer in a domestic system.
(h) Gas-fired heating systems supplying heat exclusively for
vaporization purposes shall be equipped with automatic safety devices to
shut off the flow of gas to main burners, if the pilot light should
fail.
(i) Vaporizers may be an integral part of a fuel storage container
directly connected to the liquid section or gas section or both.
(j) Vaporizers shall not be equipped with fusible plugs.
(k) Vaporizer houses shall not have unprotected drains to sewers or
sump pits.
(ii) Atmospheric vaporizers employing heat from the ground or
surrounding air shall be installed as follows:
(a) Buried underground, or
(b) Located inside the building close to a point at which pipe
enters the building provided the capacity of the unit does not exceed 1
quart.
(c) Vaporizers of less than 1 quart capacity heated by the ground or
surrounding air, need not be equipped with safety relief valves provided
that adequate tests demonstrate that the assembly is safe without safety
relief valves.
(iii) Direct gas-fired vaporizers shall be constructed, marked, and
installed as follows:
(a)(1) In accordance with the requirements of the American Society
of Mechanical Engineers Boiler and Pressure Vessel Code--1968 that are
applicable to the maximum working conditions for which the vaporizer is
designed.
(2) With the name of the manufacturer; rated BTU input to the
burner; the area of the heat exchange surface
[[Page 307]]
in square feet; the outside surface of the vaporizer in square feet; and
the maximum vaporizing capacity in gallons per hour.
(b)(1) Vaporizers may be connected to the liquid section or the gas
section of the storage container, or both; but in any case there shall
be at the container a manually operated valve in each connection to
permit completely shutting off when desired, of all flow of gas or
liquid from container to vaporizer.
(2) Vaporizers with capacity not exceeding 35 gallons per hour shall
be located at least 5 feet from container shutoff valves. Vaporizers
having capacity of more than 35 gallons but not exceeding 100 gallons
per hour shall be located at least 10 feet from the container shutoff
valves. Vaporizers having a capacity greater than 100 gallons per hour
shall be located at least 15 feet from container shutoff valves.
(c) Vaporizers may be installed in buildings, rooms, housings,
sheds, or lean-tos used exclusively for vaporizing or mixing of
liquefied petroleum gas. Vaporizing housing structures shall be of
noncombustible construction, well ventilated near the floorline and the
highest point of the roof. When vaporizer and/or mixing equipment is
located in a structure or room attached to or within a building, such
structure or room shall be separated from the remainder of the building
by a wall designed to withstand a static pressure of at least 100 pounds
per square foot. This wall shall have no openings or pipes or conduit
passing through it. Such structure or room shall be provided with
adequate ventilation, and shall have a roof or at least one exterior
wall of lightweight construction.
(d) Vaporizers shall have at or near the discharge, a safety relief
valve providing an effective rate of discharge in accordance with
paragraph (b)(10)(iii) of this section. The relief valve shall be so
located as not to be subjected to temperatures in excess of 140 [deg]F.
(e) Vaporizers shall be provided with suitable automatic means to
prevent liquid passing from the vaporizer to the gas discharge piping of
the vaporizer.
(f) Vaporizers shall be provided with means for manually turning off
the gas to the main burner and pilot.
(g) Vaporizers shall be equipped with automatic safety devices to
shut off the flow of gas to main burners if the pilot light should fail.
When the flow through the pilot exceeds 2,000 B.t.u. per hour, the pilot
also shall be equipped with an automatic safety device to shut off the
flow of gas to the pilot should the pilot flame be extinguished.
(h) Pressure regulating and pressure reducing equipment if located
within 10 feet of a direct fire vaporizer shall be separated from the
open flame by a substantially airtight noncombustible partition or
partitions.
(i) Except as provided in (c) of this subdivision, the following
minimum distances shall be maintained between direct fired vaporizers
and the nearest important building or group of buildings:
Ten feet for vaporizers having a capacity of 15 gallons per hour or less
vaporizing capacity.
Twenty-five feet for vaporizers having a vaporizing capacity of 16 to
100 gallons per hour.
Fifty feet for vaporizers having a vaporizing capacity exceeding 100
gallons per hour.
(j) Direct fired vaporizers shall not raise the product pressure
above the design pressure of the vaporizer equipment nor shall they
raise the product pressure within the storage container above the
pressure shown in the second column of Table H-31.
(k) Vaporizers shall not be provided with fusible plugs.
(l) Vaporizers shall not have unprotected drains to sewers or sump
pits.
(iv) Direct gas-fired tank heaters shall be constructed and
installed as follows:
(a) Direct gas-fired tank heaters, and tanks to which they are
applied, shall only be installed above ground.
(b) Tank heaters shall be permanently marked with the name of the
manufacturer, the rated B.t.u. input to the burner, and the maximum
vaporizing capacity in gallons per hour.
(c) Tank heaters may be an integral part of a fuel storage container
directly connected to the container liquid section, or vapor section, or
both.
(d) Tank heaters shall be provided with a means for manually turning
off the gas to the main burner and pilot.
[[Page 308]]
(e) Tank heaters shall be equipped with an automatic safety device
to shut off the flow of gas to main burners, if the pilot light should
fail. When flow through pilot exceeds 2,000 B.t.u. per hour, the pilot
also shall be equipped with an automatic safety device to shut off the
flow of gas to the pilot should the pilot flame be extinguished.
(f) Pressure regulating and pressure reducing equipment if located
within 10 feet of a direct fired tank heater shall be separated from the
open flame by a substantially airtight noncombustible partition.
(g) The following minimum distances shall be maintained between a
storage tank heated by a direct fired tank heater and the nearest
important building or group of buildings:
Ten feet for storage containers of less than 500 gallons water capacity.
Twenty-five feet for storage containers of 500 to 1,200 gallons water
capacity.
Fifty feet for storage containers of over 1,200 gallons water capacity.
(h) No direct fired tank heater shall raise the product pressure
within the storage container over 75 percent of the pressure set out in
the second column of Table H-31.
(v) The vaporizer section of vaporizer-burners used for dehydrators
or dryers shall be located outside of buildings; they shall be
constructed and installed as follows:
(a) Vaporizer-burners shall have a minimum design pressure of 250
p.s.i.g. with a factor of safety of five.
(b) Manually operated positive shut-off valves shall be located at
the containers to shut off all flow to the vaporizer-burners.
(c) Minimum distances between storage containers and vaporizer-
burners shall be as follows:
------------------------------------------------------------------------
Minimum
Water capacity per container (gallons) distances
(feet)
------------------------------------------------------------------------
Less than 501............................................... 10
501 to 2,000................................................ 25
Over 2,000.................................................. 50
------------------------------------------------------------------------
(d) The vaporizer section of vaporizer-burners shall be protected by
a hydrostatic relief valve. The relief valve shall be located so as not
to be subjected to temperatures in excess of 140 [deg]F. The start-to-
discharge pressure setting shall be such as to protect the components
involved, but not less than 250 p.s.i.g. The discharge shall be directed
upward and away from component parts of the equipment and away from
operating personnel.
(e) Vaporizer-burners shall be provided with means for manually
turning off the gas to the main burner and pilot.
(f) Vaporizer-burners shall be equipped with automatic safety
devices to shut off the flow of gas to the main burner and pilot in the
event the pilot is extinguished.
(g) Pressure regulating and control equipment shall be located or
protected so that the temperatures surrounding this equipment shall not
exceed 140 [deg]F. except that equipment components may be used at
higher temperatures if designed to withstand such temperatures.
(h) Pressure regulating and control equipment when located
downstream of the vaporizer shall be designed to withstand the maximum
discharge temperature of the vapor.
(i) The vaporizer section of vaporizer-burners shall not be provided
with fusible plugs.
(j) Vaporizer coils or jackets shall be made of ferrous metal or
high temperature alloys.
(k) Equipment utilizing vaporizer-burners shall be equipped with
automatic shutoff devices upstream and downstream of the vaporizer
section connected so as to operate in the event of excessive
temperature, flame failure, and, if applicable, insufficient airflow.
(12) Filling densities. (i) The ``filling density'' is defined as
the percent ratio of the weight of the gas in a container to the weight
of water the container will hold at 60 [deg]F. All containers shall be
filled according to the filling densities shown in Table H-27.
Table H-27--Maximum Permitted Filling Density
------------------------------------------------------------------------
Above ground containers
----------------------------------
0 to 1,200 U.S. Over 1,200 U.S.
Specific gravity at gals. (1,000 gals. (1,000 Under ground
60 [deg]F. (15.6 imp. gal., imp. gal., containers, all
[deg]C.) 4,550 liters) 4,550 liters) capacities
total water total water
cap. cap.
------------------------------------------------------------------------
Percent Percent Percent
[[Page 309]]
0 .496-0 .503 41 44 45
.504- .510 42 45 46
.511- .519 43 46 47
.520- .527 44 47 48
.528- .536 45 48 49
.537- .544 46 49 50
.545- .552 47 50 51
.553- .560 48 51 52
.561- .568 49 52 53
.569- .576 50 53 54
.577- .584 51 54 55
.585- .592 52 55 56
.593- .600 53 56 57
------------------------------------------------------------------------
(ii) Except as provided in paragraph (b)(12)(iii) of this section,
any container including mobile cargo tanks and portable tank containers
regardless of size or construction, shipped under DOT jurisdiction or
constructed in accordance with 49 CFR chapter I Specifications shall be
charged according to 49 CFR chapter I requirements.
(iii) Portable containers not subject to DOT jurisdiction (such as,
but not limited to, motor fuel containers on industrial and lift trucks,
and farm tractors covered in paragraph (e) of this section, or
containers recharged at the installation) may be filled either by
weight, or by volume using a fixed length dip tube gaging device.
(13) LP-Gas in buildings. (i) Vapor shall be piped into buildings at
pressures in excess of 20 p.s.i.g. only if the buildings or separate
areas thereof, (a) are constructed in accordance with this section; (b)
are used excusively to house equipment for vaporization, pressure
reduction, gas mixing, gas manufacturing, or distribution, or to house
internal combustion engines, industrial processes, research and
experimental laboratories, or equipment and processes using such gas and
having similar hazard; (c) buildings, structures, or equipment under
construction or undergoing major renovation.
(ii) Liquid may be permitted in buildings as follows:
(a) Buildings, or separate areas of buildings, used exclusively to
house equipment for vaporization, pressure reduction, gas mixing, gas
manufacturing, or distribution, or to house internal combustion engines,
industrial processes, research and experimental laboratories, or
equipment and processes using such gas and having similar hazard; and
when such buildings, or separate areas thereof are constructed in
accordance with this section.
(b) Buildings, structures, or equipment under construction or
undergoing major renovation provided the temporary piping meets the
following conditions:
(1) Liquid piping inside the building shall conform to the
requirements of paragraph (b)(8) of this section, and shall not exceed
three-fourths iron pipe size. Copper tubing with an outside diameter of
three-fourths inch or less may be used provided it conforms to Type K of
Specifications for Seamless Water Tube, ANSI H23.1-1970 (ASTM B88-69)
(see Table H-24). All such piping shall be protected against
construction hazards. Liquid piping inside buildings shall be kept to a
minimum. Such piping shall be securely fastened to walls or other
surfaces so as to provide adequate protection from breakage and so
located as to subject the liquid line to lowest ambient temperatures.
(2) A shutoff valve shall be installed in each intermediate branch
line where it takes off the main line and shall be readily accessible. A
shutoff valve shall also be placed at the appliance end of the
intermediate branch line. Such shutoff valve shall be upstream of any
flexible connector used with the appliance.
(3) Suitable excess flow valves shall be installed in the container
outlet line supplying liquid LP-Gas to the building. A suitable excess
flow valve shall be installed immediately downstream of each shutoff
valve. Suitable excess flow valves shall be installed where piping size
is reduced and shall be sized for the reduced size piping.
(4) Hydrostatic relief valves shall be installed in accordance with
paragraph (b)(10)(xii) of this section.
(5) The use of hose to carry liquid between the container and the
building or at any point in the liquid line, except at the appliance
connector, shall be prohibited.
[[Page 310]]
(6) Where flexible connectors are necessary for appliance
installation, such connectors shall be as short as practicable and shall
comply with paragraph (b)(8)(ii) or (9) of this section.
(7) Release of fuel when any section of piping or appliances is
disconnected shall be minimized by either of the following methods:
(i) Using an approved automatic quick-closing coupling (a type
closing in both directions when coupled in the fuel line), or
(ii) Closing the valve nearest to the appliance and allowing the
appliance to operate until the fuel in the line is consumed.
(iii) Portable containers shall not be taken into buildings except
as provided in paragraph (b)(6)(i) of this section.
(14) Transfer of liquids. The employer shall assure that (i) at
least one attendant shall remain close to the transfer connection from
the time the connections are first made until they are finally
disconnected, during the transfer of the product.
(ii) Containers shall be filled or used only upon authorization of
the owner.
(iii) Containers manufactured in accordance with specifications of
49 CFR part 178 and authorized by 49 CFR chapter 1 as a ``single trip''
or ``nonrefillable container'' shall not be refilled or reused in LP-Gas
service.
(iv) Gas or liquid shall not be vented to the atmosphere to assist
in transferring contents of one container to another, except as provided
in paragraph (e)(5)(iv) of this section and except that this shall not
preclude the use of listed pump utilizing LP-Gas in the vapor phase as a
source of energy and venting such gas to the atmosphere at a rate not to
exceed that from a No. 31 drill size opening and provided that such
venting and liquid transfer shall be located not less than 50 feet from
the nearest important building.
(v) Filling of fuel containers for industrial trucks or motor
vehicles from industrial bulk storage containers shall be performed not
less than 10 feet from the nearest important masonry-walled building or
not less than 25 feet from the nearest important building or other
construction and, in any event, not less than 25 feet from any building
opening.
(vi) Filling of portable containers, containers mounted on skids,
fuel containers on farm tractors, or similar applications, from storage
containers used in domestic or commercial service, shall be performed
not less than 50 feet from the nearest important building.
(vii) The filling connection and the vent from the liquid level
gages in containers, filled at point of installation, shall not be less
than 10 feet in any direction from air openings into sealed combustion
system appliances or mechanical ventilation air intakes.
(viii) Fuel supply containers shall be gaged and charged only in the
open air or in buildings especially provided for that purpose.
(ix) The maximum vapor pressure of the product at 100 [deg]F. which
may be transferred into a container shall be in accordance with
paragraphs (d)(2) and (e)(3) of this section. (For DOT containers use
DOT requirements.)
(x) Marketers and users shall exercise precaution to assure that
only those gases for which the system is designed, examined, and listed,
are employed in its operation, particularly with regard to pressures.
(xi) Pumps or compressors shall be designed for use with LP-Gas.
When compressors are used they shall normally take suction from the
vapor space of the container being filled and discharge to the vapor
space of the container being emptied.
(xii) Pumping systems, when equipped with a positive displacement
pump, shall include a recirculating device which shall limit the
differential pressure on the pump under normal operating conditions to
the maximum differential pressure rating of the pump. The discharge of
the pumping system shall be protected so that pressure does not exceed
350 p.s.i.g. If a recirculation system discharges into the supply tank
and contains a manual shutoff valve, an adequate secondary safety
recirculation system shall be incorporated which shall have no means of
rendering it inoperative. Manual shutoff valves in recirculation systems
shall be kept open except during an emergency or when repairs are being
made to the system.
[[Page 311]]
(xiii) When necessary, unloading piping or hoses shall be provided
with suitable bleeder valves for relieving pressure before
disconnection.
(xiv) Agricultural air moving equipment, including crop dryers,
shall be shut down when supply containers are being filled unless the
air intakes and sources of ignition on the equipment are located 50 feet
or more from the container.
(xv) Agricultural equipment employing open flames or equipment with
integral containers, such as flame cultivators, weed burners, and, in
addition, tractors, shall be shut down during refueling.
(15) Tank car or transport truck loading or unloading points and
operations. (i) The track of tank car siding shall be relatively level.
(ii) A ``Tank Car Connected'' sign, as covered by DOT rules, shall
be installed at the active end or ends of the siding while the tank car
is connected.
(iii) While cars are on sidetrack for loading or unloading, the
wheels at both ends shall be blocked on the rails.
(iv) The employer shall insure that an employee is in attendance at
all times while the tank car, cars, or trucks are being loaded or
unloaded.
(v) A backflow check valve, excess-flow valve, or a shutoff valve
with means of remote closing, to protect against uncontrolled discharge
of LP-Gas from storage tank piping shall be installed close to the point
where the liquid piping and hose or swing joint pipe is connected.
(vi) Where practical, the distance of the unloading or loading point
shall conform to the distances in subparagraph (6)(ii) of this
paragraph.
(16) Instructions. Personnel performing installation, removal,
operation, and maintenance work shall be properly trained in such
function.
(17) Electrical equipment and other sources of ignition. (i)
Electrical equipment and wiring shall be of a type specified by and
shall be installed in accordance with subpart S of this part, for
ordinary locations except that fixed electrical equipment in classified
areas shall comply with subparagraph (18) of this paragraph.
(ii) Open flames or other sources of ignition shall not be permitted
in vaporizer rooms (except those housing direct-fired vaporizers),
pumphouses, container charging rooms or other similar locations. Direct-
fired vaporizers shall not be permitted in pumphouses or container
charging rooms.
(iii) Liquefied petroleum gas storage containers do not require
lightning protection.
(iv) Since liquefied petroleum gas is contained in a closed system
of piping and equipment, the system need not be electrically conductive
or electrically bonded for protection against static electricity.
(v) Open flames (except as provided for in paragraph (b)(11) of this
section), cutting or welding, portable electric tools, and extension
lights capable of igniting LP-Gas, shall not be permitted within
classified areas specified in Table H-28 unless the LP-Gas facilities
have been freed of all liquid and vapor, or special precautions observed
under carefully controlled conditions.
Table H-28
------------------------------------------------------------------------
Equipment shall
Extent of classified area be suitable for
Part Location \1\ Class 1, Group
D \2\
------------------------------------------------------------------------
A Storage Within 15 feet in all Division 2.
containers directions from
other than DOT connections, except
cylinders. connections otherwise
covered in Table H-28.
B Tank vehicle and Within 5 feet in all Division 1.
tank car directions from connections
loading and regularly made or
unloading \3\. disconnected for product
transfer.
Beyond 5 feet but within 15 Division 2.
feet in all directions from
a point where connections
are regularly made or
disconnected and within the
cylindrical volume between
the horizontal equator of
the sphere and grade. (See
Figure H-1).
C Gage vent Within 5 feet in all Division 1.
openings other directions from point of
than those on discharge.
DOT cylinders. Beyond 5 feet but within 15
feet in all directions from
point of discharge.
Division 2.
D Relief valve Within direct path of Division 1.
discharge other discharge.
than those on
DOT cylinders.
Within 5 feet in all Division 1.
directions from point of
discharge.
[[Page 312]]
Beyond 5 feet but within 15 Division 2.
feet in all directions from
point of discharge except
within the direct path of
discharge.
E Pumps, ............................
compressors,
gas-air mixers
and vaporizers
other than
direct fired.
Indoors without Entire room and any adjacent Division 1.
ventilation. room not separated by a
gastight partition.
Within 15 feet of the Division 2.
exterior side of any
exterior wall or roof that
is not vaportight or within
15 feet of any exterior
opening.
Indoors with Entire room and any adjacent Division 2.
adequate room not separated by a
ventilation \4\. gastight partition.
Outdoors in open Within 15 feet in all Division 2.
air at or directions from this
abovegrade. equipment and within the
cylindrical volume between
the horizontal equator of
the sphere and grade. See
Figure H-1.
F Service Station Entire space within Division 1.
Dispensing dispenser enclosure, and 18
Units. inches horizontally from
enclosure exterior up to an
elevation 4 ft. above
dispenser base. Entire pit
or open space beneath
dispenser.
Up to 18 inches abovegrade Division 2.
within 20 ft. horizontally
from any edge of enclosure.
Note: For pits within this
area, see Part F of this
table..
G Pits or trenches ............................
containing or
located beneath
LP-Gas valves,
pumps,
compressors,
regulators, and
similar
equipment.
Without Entire pit or trench........ Division 1.
mechanical
ventilation.
Entire room and any adjacent Division 1.
room not separated by a
gastight partition.
Within 15 feet in all Division 2.
directions from pit or
trench when located
outdoors.
With adequate Entire pit or trench........ Division 2.
mechanical
ventilation.
Entire room and any adjacent Division 2.
room not separated by a
gastight partition.
Within 15 feet in all Division 2.
directions from pit or
trench when located
outdoors.
H Special Entire room................. Division 2.
buildings or
rooms for
storage of
portable
containers.
Pipelines and Within 5 ft. in all Division 1.
connections directions from point of
containing discharge.
operational Beyond 5 ft. from point of
bleeds, drips, discharge, same as Part E
vents or drains. of this table.
J Container
filling:.
Indoors without Entire room................. Division 1.
ventilation.
Indoors with Within 5 feet in all Division 1.
adequate directions from connections
ventilation \4\. regularly made or
disconnected for product
transfer.
Beyond 5 feet and entire Division 2.
room.
Outdoors in open Within 5 feet in all Division 1.
air. directions from connections
regularly made or
disconnected for product
transfer.
Beyond 5 feet but within 15 Division 2.
feet in all directions from
a point where connections
are regularly made or
disconnected and within the
cylindrical volume between
the horizontal equator of
the sphere and grade. (See
Figure H-1).
------------------------------------------------------------------------
\1\ The classified area shall not extend beyond an unpierced wall, roof,
or solid vaportight partition.
\2\ See subpart S of this part.
\3\ When classifying extent of hazardous area, consideration shall be
given to possible variations in the spotting of tank cars and tank
vehicles at the unloading points and the effect these variations of
actual spotting point may have on the point of connection.
\4\ Ventilation, either natural or mechanical, is considered adequate
when the concentration of the gas in a gas-air mixture does not exceed
25 percent of the lower flammable limit under normal operating
conditions.
[[Page 313]]
[GRAPHIC] [TIFF OMITTED] TC27OC91.025
Figure H-1
(18) Fixed electrical equipment in classified areas. Fixed
electrical equipment and wiring installed within classified areas
specified in Table H-28 shall comply with Table H-28 and shall be
installed in accordance with Subpart S of this part. This provision does
not apply to fixed electrical equipment at residential or commercial
installations of LP-Gas systems or to systems covered by paragraph (e)
or (g) of this section.
(19) Liquid-level gaging device. (i) Each container manufactured
after December 31, 1965, and filled on a volumetric basis shall be
equipped with a fixed liquid-level gage to indicate the maximum
permitted filling level as provided in paragraph (b)(19)(v) of this
section. Each container manufactured after December 31, 1969, shall have
permanently attached to the container adjacent to the fixed level gage a
marking showing the percentage full that will be shown by that gage.
When a variable liquid-level gage is also provided, the fixed liquid-
level gage will also serve as a means for checking the variable gage.
These gages shall be used in charging containers as required in
paragraph (b)(12) of this section.
(ii) All variable gaging devices shall be arranged so that the
maximum liquid level for butane, for a 50-50 mixture of butane and
propane, and for propane, to which the container may be charged is
readily determinable. The markings indicating the various liquid levels
from empty to full shall be on the system nameplate or gaging device or
part may be on the system nameplate and part on the gaging device. Dials
of magnetic or rotary gages shall show whether they are for cylindrical
or spherical containers and whether for aboveground or underground
service. The dials of gages intended for use only on aboveground
containers of over 1,200 gallons water capacity shall be so marked.
(iii) Gaging devices that require bleeding of the product to the
atmosphere, such as the rotary tube, fixed tube, and slip tube, shall be
designed so that the bleed valve maximum opening is not larger than a
No. 54 drill size, unless provided with excess flow valve.
(iv) Gaging devices shall have a design working pressure of at least
250 p.s.i.g.
(v) Length of tube or position of fixed liquid-level gage shall be
designed to indicate the maximum level to which the container may be
filled for the product contained. This level shall be based on the
volume of the product at 40 [deg]F. at its maximum permitted filling
density for aboveground containers and at 50 [deg]F. for underground
containers. The employer shall calculate the filling point for which the
fixed liquid level gage shall be designed according to the method in
this subdivision.
(a) It is impossible to set out in a table the length of a fixed dip
tube for various capacity tanks because of the varying tank diameters
and lengths and because the tank may be installed either in a vertical
or horizontal position. Knowing the maximum permitted filling volume in
gallons, however, the length of the fixed tube can be determined by the
use of a strapping table obtained from the container manufacturer. The
length of the fixed tube should be such that when its lower end touches
the surface of the liquid in the container, the contents of the
container will be the maximum permitted volume as determined by the
following formula:
[(Water capacity (gals.) of container*xfilling density**)/(Specific
gravity of LP-Gas*xvolume correction factor x 100)]=Maximum volume
of LP-Gas
*Measured at 60 [deg]F.
**From subparagraph (12) of this paragraph ``Filling Densities.''
For aboveground containers the liquid temperature is assumed to be
40 [deg]F. and for underground containers the liquid temperature is
assumed to be 50 [deg]F. To correct the
[[Page 314]]
liquid volumes at these temperatures to 60 [deg]F. the following factors
shall be used.
(b) Formula for determining maximum volume of liquefied petroleum
gas for which a fixed length of dip tube shall be set:
Table H-29--Volume Correction Factors
------------------------------------------------------------------------
Specific gravity Aboveground Underground
------------------------------------------------------------------------
0.500 1.033 1.017
.510 1.031 1.016
.520 1.029 1.015
.530 1.028 1.014
.540 1.026 1.013
.550 1.025 1.013
.560 1.024 1.012
.570 1.023 1.011
.580 1.021 1.011
.590 1.020 1.010
------------------------------------------------------------------------
(c) The maximum volume of LP-Gas which can be placed in a container
when determining the length of the dip tube expressed as a percentage of
total water content of the container is calculated by the following
formula.
(d) The maximum weight of LP-Gas which may be placed in a container
for determining the length of a fixed dip tube is determined by
multiplying the maximum volume of liquefied petroleum gas obtained by
the formula in paragraph (b)(19)(b) of this section by the pounds of
liquefied petroleum gas in a gallon at 40 [deg]F. for abovegound and at
50 [deg]F. for underground containers. For example, typical pounds per
gallon are specified below:
Example: Assume a 100-gallon total water capacity tank for
aboveground storage of propane having a specific gravity of 0.510 of 60
[deg]F.
[(100 (gals.)x42 (filling density from subparagraph (12) of this
paragraph))/(0.510x1.031 (correction factor from Table H-
29)x100)]=(4200/52.6)
(4200/52.6)=79.8 gallons propane, the maximum amount permitted to be
placed in a 100-gallon total water capacity aboveground container
equipped with a fixed dip tube.
[(Maximum volume of LP-Gas (from formula in subdivision (b) of this
subdivision)x100)/Total water content of container in gallons]=Maximum
percent of LP-Gas
------------------------------------------------------------------------
Aboveground, Underground,
pounds per pounds per
gallon gallon
------------------------------------------------------------------------
Propane..................................... 4.37 4.31
N Butane.................................... 4.97 4.92
------------------------------------------------------------------------
(vi) Fixed liquid-level gages used on containers other than DOT
containers shall be stamped on the exterior of the gage with the letters
``DT'' followed by the vertical distance (expressed in inches and
carried out to one decimal place) from the top of container to the end
of the dip tube or to the centerline of the gage when it is located at
the maximum permitted filling level. For portable containers that may be
filled in the horizontal and/or vertical position the letters ``DT''
shall be followed by ``V'' with the vertical distance from the top of
the container to the end of the dip tube for vertical filling and with
``H'' followed by the proper distance for horizontal filling. For DOT
containers the stamping shall be placed both on the exterior of the gage
and on the container. On above-ground or cargo containers where the
gages are positioned at specific levels, the marking may be specified in
percent of total tank contents and the marking shall be stamped on the
container.
(vii) Gage glasses of the columnar type shall be restricted to
charging plants where the fuel is withdrawn in the liquid phase only.
They shall be equipped with valves having metallic handwheels, with
excess flow valves, and with extra-heavy glass adequately protected with
a metal housing applied by the gage manufacturer. They shall be shielded
against the direct rays of the sun. Gage glasses of the columnar type
are prohibited on tank trucks, and on motor fuel tanks, and on
containers used in domestic, commercial, and industrial installations.
(viii) Gaging devices of the float, or equivalent type which do not
require flow for their operation and having connections extending to a
point outside the container do not have to be equipped with excess flow
valves provided the piping and fittings are adequately designed to
withstand the container pressure and are properly protected against
physical damage and breakage.
(20) Requirements for appliances. (i) Except as provided in
paragraph (b)(20)(ii) of this section, new commercial and industrial gas
consuming appliances shall be approved.
[[Page 315]]
(ii) Any appliance that was originally manufactured for operation
with a gaseous fuel other than LP-Gas and is in good condition may be
used with LP-Gas only after it is properly converted, adapted, and
tested for performance with LP-Gas before the appliance is placed in
use.
(iii) Unattended heaters used inside buildings for the purpose of
animal or poultry production or care shall be equipped with an approved
automatic device designed to shut off the flow of gas to the main
burners, and pilot if used, in the event of flame extinguishment.
(iv) All commercial, industrial, and agricultural appliances or
equipment shall be installed in accordance with the requirements of this
section and in accordance with the following NFPA consensus standards,
which are incorporated by reference as specified in Sec. 1910.6:
(a) Domestic and commercial appliances--NFPA 54-1969, Standard for
the Installation of Gas Appliances and Gas Piping.
(b) Industrial appliances--NFPA 54A-1969, Standard for the
Installation of Gas Piping and Gas Equipment on Industrial Premises and
Certain Other Premises.
(c) Standard for the Installation and Use of Stationary Combustion
Engines and Gas Turbines--NFPA 37-1970.
(d) Standard for the Installation of Equipment for the Removal of
Smoke and Grease-Laden Vapors from Commercial Cooking Equipment, NFPA
96-1970.
(c) Cylinder systems--(1) Application. This paragraph applies
specifically to systems utilizing containers constructed in accordance
with DOT Specifications. All requirements of paragraph (b) of this
section apply to this paragraph unless otherwise noted in paragraph (b)
of this section.
(2) Marking of containers. Containers shall be marked in accordance
with DOT regulations. Additional markings not in conflict with DOT
regulations may be used.
(3) Description of a system. A system shall include the container
base or bracket, containers, container valves, connectors, manifold
valve assembly, regulators, and relief valves.
(4) Containers and regulating equipment installed outside of
buildings or structures. (i) Containers shall not be buried below
ground. However, this shall not prohibit the installation in a
compartment or recess below grade level such as a niche in a slope or
terrace wall which is used for no other purpose, providing that the
container and regulating equipment are not in contact with the ground
and the compartment or recess is drained and ventilated horizontally to
the outside air from its lowest level, with the outlet at least 3 feet
away from any building opening which is below the level of such outlet.
Except as provided in paragraph (b)(10)(xiii) of this section, the
discharge from safety relief devices shall be located not less than 3
feet horizontally away from any building opening which is below the
level of such discharge and shall not terminate beneath any building
unless such space is well ventilated to the outside and is not enclosed
on more than two sides.
(ii) Containers shall be set upon firm foundation or otherwise
firmly secured; the possible effect on the outlet piping of settling
shall be guarded against by a flexible connection or special fitting.
(5) Containers and equipment used inside of buildings or structures.
(i) When operational requirements make portable use of containers
necessary and their location outside of buildings or structure is
impracticable, containers and equipment are permitted to be used inside
of buildings or structures in accordance with (a) through (l) of this
subdivision, and, in addition, such other provisions of this
subparagraph as are applicable to the particular use or occupancy.
(a) Containers in use shall mean connected for use.
(b) Systems utilizing containers having a water capacity greater
than 2\1/2\ pounds (nominal 1 pound LP-Gas capacity) shall be equipped
with excess flow valves. Such excess flow valves shall be either
integral with the container valves or in the connections to the
container valve outlets. In either case, an excess flow valve shall be
installed in such a manner that any undue strain beyond the excess flow
valve will not cause breakage between
[[Page 316]]
the container and the excess flow valve. The installation of excess flow
valves shall take into account the type of valve protection provided.
(c) Regulators, if used, shall be either directly connected to the
container valves or to manifolds connected to the container values. The
regulator shall be suitable for use with LP-Gas. Manifolds and fittings
connecting containers to pressure regulator inlets shall be designed for
at least 250 p.s.i.g. service pressure.
(d) Valves on containers having a water capacity greater than 50
pounds (nominal 20 pounds LP-Gas capacity) shall be protected while in
use.
(e) Containers shall be marked in accordance with paragraph
(b)(5)(iii) of this section and paragraph (c)(2) of this section.
(f) Pipe or tubing shall conform to paragraph (b)(8) of this section
except that aluminum pipe or tubing shall not be used.
(g)(1) Hose shall be designed for a working pressure of at least 250
p.s.i.g. Hose and hose connections shall have their correctness as to
design, construction and performance determined by listing by a
nationally recognized testing laboratory. The hose length may exceed the
length specified in paragraph (b)(9)(vii)(b) of this section, but shall
be as short as practicable. Refer to Sec. 1910.7 for definition of
nationally recognized testing laboratory.
(2) Hose shall be long enough to permit compliance with spacing
provisions of this subparagraph without kinking or straining or causing
hose to be so close to a burner as to be damaged by heat.
(h) Portable heaters, including salamanders, shall be equipped with
an approved automatic device to shut off the flow of gas to the main
burner, and pilot if used, in the event of flame extinguishment. Such
heaters having inputs above 50,000 B.t.u. manufactured on or after May
17, 1967, and such heaters having inputs above 100,000 B.t.u.
manufactured before May 17, 1967, shall be equipped with either.
(1) A pilot which must be lighted and proved before the main burner
can be turned on; or
(2) An electric ignition system.
The provisions of this paragraph (h) do not apply to tar kettle burners,
torches, melting pots, nor do they apply to portable heaters under 7,500
B.t.u.h. input when used with containers having a maximum water capacity
of 2\1/2\ pounds. Container valves, connectors, regulators, manifolds,
piping, and tubing shall not be used as structural supports for heaters.
(i) Containers, regulating equipment, manifolds, pipe, tubing, and
hose shall be located so as to minimize exposure to abnormally high
temperatures (such as may result from exposure to convection or
radiation from heating equipment or installation in confined spaces),
physical damage, or tampering by unauthorized persons.
(j) Heat producing equipment shall be located and used so as to
minimize the possibility of ignition of combustibles.
(k) Containers having a water capacity greater than 2\1/2\ pounds
(nominal 1 pound LP-Gas capacity) connected for use, shall stand on a
firm and substantially level surface and, when necessary, shall be
secured in an upright position.
(l) Containers, including the valve protective devices, shall be
installed so as to minimize the probability of impingement of discharge
of safety relief devices upon containers.
(ii) Containers having a maximum water capacity of 2\1/2\ pounds
(nominal 1 pound LP-Gas capacity) are permitted to be used inside of
buildings as part of approved self-contained hand torch assemblies or
similar appliances.
(iii) Containers having a maximum water capacity of 12 pounds
(nominal 5 pounds LP-Gas capacity) are permitted to be used temporarily
inside of buildings for public exhibition or demonstration purposes,
including use for classroom demonstrations.
(iv) [Reserved]
(v) Containers are permitted to be used in buildings or structures
under construction or undergoing major renovation when such buildings or
structures are not occupied by the public, as follows:
(a) The maximum water capacity of individual containers shall be 245
pounds (nominal 100 pounds LP-Gas capacity).
[[Page 317]]
(b) For temporary heating such as curing concrete, drying plaster
and similar applications, heaters (other than integral heater-container
units) shall be located at least 6 feet from any LP-Gas container. This
shall not prohibit the use of heaters specifically designed for
attachment to the container or to a supporting standard, provided they
are designed and installed so as to prevent direct or radiant heat
application from the heater onto the container. Blower and radiant type
heaters shall not be directed toward any LP-Gas container within 20
feet.
(c) If two or more heater-container units, of either the integral or
nonintegral type, are located in an unpartitioned area on the same
floor, the container or containers of each unit shall be separated from
the container or containers of any other unit by at least 20 feet.
(d) When heaters are connected to containers for use in an
unpartitioned area on the same floor, the total water capacity of
containers manifolded together for connection to a heater or heaters
shall not be greater than 735 pounds (nominal 300 pounds LP-Gas
capacity). Such manifolds shall be separated by at least 20 feet.
(e) On floors on which heaters are not connected for use, containers
are permitted to be manifolded together for connection to a heater or
heaters on another floor, Provided:
(1) The total water capacity of containers connected to any one
manifold is not greater than 2,450 pounds (nominal 1,000 pounds LP-Gas
capacity) and;
(2) Where more than one manifold having a total water capacity
greater than 735 pounds (nominal 300 pounds LP-Gas capacity) are located
in the same unpartitioned area, they shall be separated by at least 50
feet.
(f) Storage of containers awaiting use shall be in accordance with
paragraph (f) of this section.
(vi) Containers are permitted to be used in industrial occupancies
for processing, research, or experimental purposes as follows:
(a) The maximum water capacity of individual containers shall be 245
pounds (nominal 100 pounds LP-Gas capacity).
(b) Containers connected to a manifold shall have a total water
capacity not greater than 735 pounds (nominal 300 pounds LP-Gas
capacity) and not more than one such manifold may be located in the same
room unless separated at least 20 feet from a similar unit.
(c) The amount of LP-Gas in containers for research and experimental
use shall be limited to the smallest practical quantity.
(vii)(a) Containers are permitted to be used in industrial
occupancies with essentially noncombustible contents where portable
equipment for space heating is essential and where a permanent heating
installation is not practical, as follows:
(b) Containers and heaters shall comply with and be used in
accordance with paragraph (c)(5)(v) of this section.
(viii) Containers are permitted to be used in buildings for
temporary emergency heating purposes, if necessary to prevent damage to
the buildings or contents, when the permanent heating system is
temporarily out of service, as follows:
(a) Containers and heaters shall comply with and be used in
accordance with paragraph (c)(5)(v) of this section.
(b) The temporary heating equipment shall not be left unattended.
(ix) Containers are permitted to be used temporarily in buildings
for training purposes related in installation and use of LP-Gas systems,
as follows:
(a) The maximum water capacity of individual containers shall be 245
pounds (nominal 100 pounds LP-Gas capacity), but the maximum quantity of
LP-Gas that may be placed in each container shall be 20 pounds.
(b) If more than one such container is located in the same room, the
containers shall be separated by at least 20 feet.
(6) Container valves and accessories. (i) Valves in the assembly of
multiple container systems shall be arranged so that replacement of
containers can be made without shutting off the flow of gas in the
system.
Note: This provision is not to be construed as requiring an
automatic changeover device.
(ii) Regulators and low-pressure relief devices shall be rigidly
attached to
[[Page 318]]
the cylinder valves, cylinders, supporting standards, the building walls
or otherwise rigidly secured and shall be so installed or protected that
the elements (sleet, snow, or ice) will not affect their operation.
(iii) Valves and connections to the containers shall be protected
while in transit, in storage, and while being moved into final
utilization, as follows:
(a) By setting into the recess of the container to prevent the
possibility of their being struck if the container is dropped upon a
flat surface, or
(b) By ventilated cap or collar, fastened to the container capable
of withstanding a blow from any direction equivalent to that of a 30-
pound weight dropped 4 feet. Construction must be such that a blow will
not be transmitted to the valve or other connection.
(iv) When containers are not connected to the system, the outlet
valves shall be kept tightly closed or plugged, even though containers
are considered empty.
(v) Containers having a water capacity in excess of 50 pounds
(approximately 21 pounds LP-Gas capacity), recharged at the
installation, shall be provided with excess flow or backflow check
valves to prevent the discharge of container contents in case of failure
of the filling or equalizing connection.
(7) Safety devices. (i) Containers shall be provided with safety
devices as required by DOT regulations.
(ii) A final stage regulator of an LP-Gas system (excluding any
appliance regulator) shall be equipped on the low-pressure side with a
relief valve which is set to start to discharge within the limits
specified in Table H-30.
Table H-30
------------------------------------------------------------------------
Relief valve start-to-
discharge pressure
setting (percent of
Regulator delivery pressure regulator delivery
pressure)
-----------------------
Minimum Maximum
------------------------------------------------------------------------
1 p.s.i.g. or less.............................. 200 300
Above 1 p.s.i.g. but not over 3 p.s.i.g......... 140 200
Above 3 p.s.i.g................................. 125 200
------------------------------------------------------------------------
(iii) When a regulator or pressure relief valve is used inside a
building for other than purposes specified in paragraphs (b)(6)(i) (a)-
(g) of this section, the relief valve and the space above the regulator
and relief valve diaphragms shall be vented to the outside air with the
discharge outlet located not less than 3 feet horizontally away from any
building opening which is below such discharge. These provisions do not
apply to individual appliance regulators when protection is otherwise
provided nor to paragraph (c)(5) of this section and paragraph
(b)(10)(xiii) of this section. In buildings devoted exclusively to gas
distribution purposes, the space above the diaphragm need not be vented
to the outside.
(8) Reinstallation of containers. Containers shall not be
reinstalled unless they are requalified in accordance with DOT
regulations.
(9) Permissible product. A product shall not be placed in a
container marked with a service pressure less than four-fifths of the
maximum vapor pressure of product at 130 [deg]F.
(d) Systems utilizing containers other than DOT containers--(1)
Application. This paragraph applies specifically to systems utilizing
storage containers other than those constructed in accordance with DOT
specifications. Paragraph (b) of this section applies to this paragraph
unless otherwise noted in paragraph (b) of this section.
(2) Design pressure and classification of storage containers.
Storage containers shall be designed and classified in accordance with
Table H-31.
Table H-31
------------------------------------------------------------------------
Minimum design pressure of container,
lb. per sq. in. gage
--------------------------------------
For gases with 1949 edition of ASME
vapor press. Code (Par. U-200, U-
Not to exceed 1949 and 201); 1950, 1952,
Container type lb. per sq. in. earlier 1956, 1959, 1962,
gage at 100 editions of 1965, and 1968
[deg]F. (37.8 ASME Code (Par. (Division 1)
[deg]C.) U-68, U-69) editions of ASME
Code; All editions
of API-ASME Code \3\
------------------------------------------------------------------------
\1\ 80 \1\ 80 \1\ 80 \1\ 100
100 100 100 125
125 125 125 156
150 150 150 187
175 175 175 219
\2\ 200 215 200 250
------------------------------------------------------------------------
\1\ New storage containers of the 80 type have not been authorized since
Dec. 31, 1947.
[[Page 319]]
\2\ Container type may be increased by increments of 25. The minimum
design pressure of containers shall be 100% of the container type
designation when constructed under 1949 or earlier editions of the
ASME Code (Par. U-68 and U-69). The minimum design pressure of
containers shall be 125% of the container type designation when
constructed under: (1) the 1949 ASME Code (Par. U-200 and U-201), (2)
1950, 1952, 1956, 1959, 1962, 1965, and 1968 (Division 1) editions of
the ASME Code, and (3) all editions of the API-ASME Code.
\3\ Construction of containers under the API-ASME Code is not authorized
after July 1, 1961.
(3) Container valves and accessories, filler pipes, and discharge
pipes. (i) The filling pipe inlet terminal shall not be located inside a
building. For containers with a water capacity of 125 gallons or more,
such terminals shall be located not less than 10 feet from any building
(see paragraph (b)(6)(ii) of this section), and preferably not less than
5 feet from any driveway, and shall be located in a protective housing
built for the purpose.
(ii) The filling connection shall be fitted with one of the
following:
(a) Combination back-pressure check valve and excess flow valve.
(b) One double or two single back-pressure check valves.
(c) A positive shutoff valve, in conjunction with either:
(1) An internal back-pressure valve, or
(2) An internal excess flow valve.
(iii) All openings in a container shall be equipped with approved
automatic excess flow valves except in the following: Filling
connections as provided in paragraph (d)(3)(ii) of this section; safety
relief connections, liquid-level gaging devices as provided in
paragraphs (b)(7)(iv), (19)(iii), and (19)(viii) of this section;
pressure gage connections as provided in paragraph (b)(7)(v) of this
section, as provided in paragraphs (d) (iv), (vi), and (vii) of this
section.
(iv) An excess flow valve is not required in the withdrawal service
line providing the following are complied with:
(a) Such systems' total water capacity does not exceed 2,000 U.S.
gallons.
(b) The discharge from the service outlet is controlled by a
suitable manually operated shutoff valve which is:
(1) Threaded directly into the service outlet of the container; or
(2) Is an integral part of a substantial fitting threaded into or on
the service outlet of the container; or
(3) Threaded directly into a substantial fitting threaded into or on
the service outlet of the container.
(c) The shutoff valve is equipped with an attached handwheel or the
equivalent.
(d) The controlling orifice between the contents of the container
and the outlet of the shutoff valve does not exceed five-sixteenths inch
in diameter for vapor withdrawal systems and one-eighth inch in diameter
for liquid withdrawal systems.
(e) An approved pressure-reducing regulator is directly attached to
the outlet of the shutoff valve and is rigidly supported, or that an
approved pressure-reducing regulator is attached to the outlet of the
shutoff valve by means of a suitable flexible connection, provided the
regulator is adequately supported and properly protected on or at the
tank.
(v) All inlet and outlet connections except safety relief valves,
liquid level gaging devices and pressure gages on containers of 2,000
gallons water capacity, or more, and on any container used to supply
fuel directly to an internal combustion engine, shall be labeled to
designate whether they communicate with vapor or liquid space. Labels
may be on valves.
(vi) In lieu of an excess flow valve openings may be fitted with a
quick-closing internal valve which, except during operating periods
shall remain closed. The internal mechanism for such valves may be
provided with a secondary control which shall be equipped with a fusible
plug (not over 220 [deg]F. melting point) which will cause the internal
valve to close automatically in case of fire.
(vii) Not more than two plugged openings shall be permitted on a
container of 2,000 gallons or less water capacity.
(viii) Containers of 125 gallons water capacity or more manufactured
after July 1, 1961, shall be provided with an approved device for liquid
evacuation, the size of which shall be three-fourths inch National Pipe
Thread minimum. A plugged opening will not satisfy this requirement.
(4) Safety devices. (i) All safety devices shall comply with the
following:
[[Page 320]]
(a) All container safety relief devices shall be located on the
containers and shall have direct communication with the vapor of space
of the container.
(b) In industrial and gas manufacturing plants, discharge pipe from
safety relief valves on pipe lines within a building shall discharge
vertically upward and shall be piped to a point outside a building.
(c) Safety relief device discharge terminals shall be so located as
to provide protection against physical damage and such discharge pipes
shall be fitted with loose raincaps. Return bends and restrictive
pipefittings shall not be permitted.
(d) If desired, discharge lines from two or more safety relief
devices located on the same unit, or similar lines from two or more
different units, may be run into a common discharge header, provided
that the cross-sectional area of such header be at least equal to the
sum of the cross-sectional area of the individual discharge lines, and
that the setting of safety relief valves are the same.
(e) Each storage container of over 2,000 gallons water capacity
shall be provided with a suitable pressure gage.
(f) A final stage regulator of an LP-Gas system (excluding any
appliance regulator) shall be equipped on the low-pressure side with a
relief valve which is set to start to discharge within the limits
specified in Table H-30.
(g) When a regulator or pressure relief valve is installed inside a
building, the relief valve and the space above the regulator and relief
valve diaphragms shall be vented to the outside air with the discharge
outlet located not less than 3 feet horizontally away from any opening
into the building which is below such discharge. (These provisions do
not apply to individual appliance regulators when protection is
otherwise provided. In buildings devoted exclusively to gas distribution
purposes, the space above the diaphragm need not be vented to the
outside.)
(ii) Safety devices for aboveground containers shall be provided as
follows:
(a) Containers of 1,200 gallons water capacity or less which may
contain liquid fuel when installed above ground shall have the rate of
discharge required by paragraph (b)(10)(ii) of this section provided by
a spring-loaded relief valve or valves. In addition to the required
spring-loaded relief valve(s), suitable fuse plug(s) may be used
provided the total discharge area of the fuse plug(s) for each container
does not exceed 0.25 square inch.
(b) The fusible metal of the fuse plugs shall have a yield
temperature of 208 [deg]F. minimum and 220 [deg]F. maximum. Relief
valves and fuse plugs shall have direct communication with the vapor
space of the container.
(c) On a container having a water capacity greater than 125 gallons,
but not over 2,000 gallons, the discharge from the safety relief valves
shall be vented away from the container vertically upwards and
unobstructed to the open air in such a manner as to prevent any
impingement of escaping gas upon the container; loose-fitting rain caps
shall be used. Suitable provision shall be made for draining condensate
which may accumulate in the relief valve or its discharge pipe.
(d) On containers of 125 gallons water capacity or less, the
discharge from safety relief devices shall be located not less than 5
feet horizontally away from any opening into the building below the
level of such discharge.
(e) On a container having a water capacity greater than 2,000
gallons, the discharge from the safety relief valves shall be vented
away from the container vertically upwards to a point at least 7 feet
above the container, and unobstructed to the open air in such a manner
as to prevent any impingement of escaping gas upon the container; loose-
fitting rain caps shall be used. Suitable provision shall be made so
that any liquid or condensate that may accumulate inside of the safety
relief valve or its discharge pipe will not render the valve
inoperative. If a drain is used, a means shall be provided to protect
the container, adjacent containers, piping, or equipment against
impingement of flame resulting from ignition of product escaping from
the drain.
(iii) On all containers which are installed underground and which
contain no liquid fuel until buried and covered, the rate of discharge
of the spring-loaded relief valve installed thereon may be reduced to a
minimum of 30 percent of
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the rate of discharge specified in paragraph (b)(10)(ii) of this
section. Containers so protected shall not be uncovered after
installation until the liquid fuel has been removed therefrom.
Containers which may contain liquid fuel before being installed under
ground and before being completely covered with earth are to be
considered aboveground containers when determining the rate of discharge
requirement of the relief valves.
(iv) On underground containers of more than 2,000 gallons water
capacity, the discharge from safety relief devices shall be piped
vertically and directly upward to a point at least 7 feet above the
ground.
Where there is a probability of the manhole or housing becoming flooded,
the discharge from regulator vent lines shall be above the highest
probable water level. All manholes or housings shall be provided with
ventilated louvers or their equivalent, the area of such openings
equaling or exceeding the combined discharge areas of the safety relief
valves and other vent lines which discharge their content into the
manhole housing.
(v) Safety devices for vaporizers shall be provided as follows:
(a) Vaporizers of less than 1 quart total capacity, heated by the
ground or the surrounding air, need not be equipped with safety relief
valves provided that adequate tests certified by any of the authorities
referred to in paragraph (b)(2) of this section, demonstrate that the
assembly is safe without safety relief valves.
(b) No vaporizer shall be equipped with fusible plugs.
(c) In industrial and gas manufacturing plants, safety relief valves
on vaporizers within a building shall be piped to a point outside the
building and be discharged upward.
(5) Reinstallation of containers. Containers may be reinstalled if
they do not show any evidence of harmful external corrosion or other
damage. Where containers are reinstalled underground, the corrosion
resistant coating shall be put in good condition (see paragraph
(c)(7)(vi) of this section). Where containers are reinstalled above
ground, the safety devices and gaging devices shall comply with
paragraph (c)(4) of this section and paragraph (b)(19) of this section
respectively for aboveground containers.
(6) Capacity of containers. A storage container shall not exceed
90,000 gallons water capacity.
(7) Installation of storage containers. (i) Containers installed
above ground, except as provided in paragraph (c)(7)(vii) of this
section, shall be provided with substantial masonry or noncombustible
structural supports on firm masonry foundation.
(ii) Aboveground containers shall be supported as follows:
(a) Horizontal containers shall be mounted on saddles in such a
manner as to permit expansion and contraction. Structural metal supports
may be employed when they are protected against fire in an approved
manner. Suitable means of preventing corrosion shall be provided on that
portion of the container in contact with the foundations or saddles.
(b) Containers of 2,000 gallons water capacity or less may be
installed with nonfireproofed ferrous metal supports if mounted on
concrete pads or footings, and if the distance from the outside bottom
of the container shell to the concrete pad, footing, or the ground does
not exceed 24 inches.
(iii) Any container may be installed with nonfireproofed ferrous
metal supports if mounted on concrete pads or footings, and if the
distance from the outside bottom of the container to the ground does not
exceed 5 feet, provided the container is in an isolated location.
(iv) Containers may be partially buried providing the following
requirements are met:
(a) The portion of the container below the surface and for a
vertical distance not less than 3 inches above the surface of the ground
is protected to resist corrosion, and the container is protected against
settling and corrosion as required for fully buried containers.
(b) Spacing requirements shall be as specified for underground tanks
in paragraph (b)(6)(ii) of this section.
(c) Relief valve capacity shall be as required for aboveground
containers.
(d) Container is located so as not to be subject to vehicular
damage, or is
[[Page 322]]
adequately protected against such damage.
(e) Filling densities shall be as required for above-ground
containers.
(v) Containers buried underground shall be placed so that the top of
the container is not less than 6 inches below grade. Where an
underground container might be subject to abrasive action or physical
damage due to vehicular traffic or other causes, then it shall be:
(a) Placed not less than 2 feet below grade, or
(b) Otherwise protected against such physical damage.
It will not be necessary to cover the portion of the container to which
manhole and other connections are affixed; however, where necessary,
protection shall be provided against vehicular damage. When necessary to
prevent floating, containers shall be securely anchored or weighted.
(vi)(a) Containers shall be given a protective coating before being
placed under ground. This coating shall be equivalent to hot-dip
galvanizing or to two coatings of red lead followed by a heavy coating
of coal tar or asphalt. In lowering the container into place, care shall
be exercised to prevent damage to the coating. Any damage to the coating
shall be repaired before backfilling.
(b) Containers shall be set on a firm foundation (firm earth may be
used) and surrounded with earth or sand firmly tamped in place.
(vii) Containers with foundations attached (portable or semiportable
containers with suitable steel ``runners'' or ``skids'' and popularly
known in the industry as ``skid tanks'') shall be designed, installed,
and used in accordance with these rules subject to the following
provisions:
(a) If they are to be used at a given general location for a
temporary period not to exceed 6 months they need not have fire-
resisting foundations or saddles but shall have adequate ferrous metal
supports.
(b) They shall not be located with the outside bottom of the
container shell more than 5 feet above the surface of the ground unless
fire-resisting supports are provided.
(c) The bottom of the skids shall not be less than 2 inches or more
than 12 inches below the outside bottom of the container shell.
(d) Flanges, nozzles, valves, fittings, and the like, having
communication with the interior of the container, shall be protected
against physical damage.
(e) When not permanently located on fire-resisting foundations,
piping connections shall be sufficiently flexible to minimize the
possibility of breakage or leakage of connections if the container
settles, moves, or is otherwise displaced.
(f) Skids, or lugs for attachment of skids, shall be secured to the
container in accordance with the code or rules under which the container
is designed and built (with a minimum factor of safety of four) to
withstand loading in any direction equal to four times the weight of the
container and attachments when filled to the maximum permissible loaded
weight.
(viii) Field welding where necessary shall be made only on saddle
plates or brackets which were applied by the manufacturer of the tank.
(ix) For aboveground containers, secure anchorage or adequate pier
height shall be provided against possible container flotation wherever
sufficiently high floodwater might occur.
(x) When permanently installed containers are interconnected,
provision shall be made to compensate for expansion, contraction,
vibration, and settling of containers, and interconnecting piping. Where
flexible connections are used, they shall be of an approved type and
shall be designed for a bursting pressure of not less than five times
the vapor pressure of the product at 100 [deg]F. The use of nonmetallic
hose is prohibited for permanently interconnecting such containers.
(xi) Container assemblies listed for interchangeable installation
above ground or under ground shall conform to the requirements for
aboveground installations with respect to safety relief capacity and
filling density. For installation above ground all other requirements
for aboveground installations shall apply. For installation under ground
all other requirements for underground installations shall apply.
(8) Protection of container accessories. (i) Valves, regulating,
gaging, and
[[Page 323]]
other container accessory equipment shall be protected against tampering
and physical damage. Such accessories shall also be so protected during
the transit of containers intended for installation underground.
(ii) On underground or combination aboveground-underground
containers, the service valve handwheel, the terminal for connecting the
hose, and the opening through which there can be a flow from safety
relief valves shall be at least 4 inches above the container and this
opening shall be located in the dome or housing. Underground systems
shall be so installed that all the above openings, including the
regulator vent, are located above the normal maximum water table.
(iii) All connections to underground containers shall be located
within a substantial dome, housing, or manhole and with access thereto
protected by a substantial cover.
(9) Drips for condensed gas. Where vaporized gas on the low-pressure
side of the system may condense to a liquid at normal operating
temperatures and pressures, suitable means shall be provided for
revaporization of the condensate.
(10) Damage from vehicles. When damage to LP-Gas systems from
vehicular traffic is a possibility, precautions against such damage
shall be taken.
(11) Drains. No drains or blowoff lines shall be directed into or in
proximity to sewer systems used for other purposes.
(12) General provisions applicable to systems in industrial plants
(of 2,000 gallons water capacity and more) and to bulk filling plants.
(i) When standard watch service is provided, it shall be extended to the
LP-Gas installation and personnel properly trained.
(ii) If loading and unloading are normally done during other than
daylight hours, adequate lights shall be provided to illuminate storage
containers, control valves, and other equipment.
(iii) Suitable roadways or means of access for extinguishing
equipment such as wheeled extinguishers or fire department apparatus
shall be provided.
(iv) To minimize trespassing or tampering, the area which includes
container appurtenances, pumping equipment, loading and unloading
facilities, and cylinder-filling facilities shall be enclosed with at
least a 6-foot-high industrial type fence unless otherwise adequately
protected. There shall be at least two means of emergency access.
(13) Container-charging plants. (i) The container-charging room
shall be located not less than:
(a) Ten feet from bulk storage containers.
(b) [Reserved]
(ii) Tank truck filling station outlets shall be located not less
than:
(a) [Reserved]
