29 Cfr 1910.111

rmajette on DSK29S0YB1PROD with CFR

§ 1910.111

29 CFR Ch. XVII (7–1–10 Edition)

signs shall be not less than 4 inches
high. The motors of all vehicles being
fueled shall be shut off during the fueling operations.
(13) Electrical. Electrical equipment
and installations shall conform to
paragraphs (b) (17) and (18) of this section.
(14) Fire protection. Each service station shall be provided with at least one
approved portable fire extinguisher
having at least an 8–B, C, rating.
(i) Scope—(1) Application. (i) Paragraph (b) of this section applies to installations made in accordance with
the requirements of paragraphs (c), (d),
(e), (g), and (h) of this section, except
as noted in each of those paragraphs.
(ii) Paragraphs (c) through (h) of this
section apply as provided in each of
those paragraphs.
(2) Inapplicability. This section does
not apply to:
(i) Marine and pipeline terminals,
natural gas processing plants, refineries, or tank farms other than those
at industrial sites.
(ii) LP-Gas refrigerated storage systems;
(iii) LP-Gas when used with oxygen.
The requirements of § 1910.253 shall
apply to such use;
(iv) LP-Gas when used in utility gas
plants. The National Fire Protection
Association Standard for the Storage
and Handling of Liquefied Petroleum
Gases at Utility Gas Plants, NFPA No.
59–1968, shall apply to such use;
(v) Low-pressure (not in excess of
one-half pound per square inch or 14
inches water column) LP-Gas piping
systems, and the installation and operation of residential and commercial appliances including their inlet connections, supplied through such systems.
For such systems, the National Fire
Protection Association Standard for
the Installation of Gas Appliances and
Gas Piping, NFPA 54–1969 shall apply.
(3) Retroactivity. Unless otherwise
stated, it is not intended that the provisions of this section be retroactive.
(i) Existing plants, appliances, equipment, buildings, structures, and installations for the storage, handling or use
of LP-Gas, which were in compliance
with the current provisions of the National Fire Protection Association
Standard for the Storage and Handling

of Liquefied Petroleum Gases NFPA
No. 58, at the time of manufacture or
installation may be continued in use, if
such continued use does not constitute
a recognized hazard that is causing or
is likely to cause death or serious
physical harm to employees.
(ii) Stocks of equipment and appliances on hand in such locations as
manufacturers’ storage, distribution
warehouses, and dealers’ storage and
showrooms, which were in compliance
with the current provisions of the National Fire Protection Association
Standard for the Storage and Handling
of Liquefied Petroleum Gases, NFPA
No. 58, at the time of manufacture,
may be placed in service, if such use
does not constitute a recognized hazard
that is causing or is likely to cause
death or serious physical harm to employees.
[39 FR 23502, June 27, 1974, as amended at 43
FR 49747, Oct. 24, 1978; 49 FR 5322, Feb. 10,
1984; 53 FR 12122, Apr. 12, 1988; 55 FR 25094,
June 20, 1990; 55 FR 32015, Aug. 6, 1990; 58 FR
35309, June 30, 1993; 61 FR 9237, 9238, Mar. 7,
1996; 63 FR 33466, June 18, 1998; 72 FR 71069,
Dec. 14, 2007]

§ 1910.111 Storage and handling of anhydrous ammonia.
(a) General—(1) Scope. (i) This standard is intended to apply to the design,
construction, location, installation,
and operation of anhydrous ammonia
systems including refrigerated ammonia storage systems.
(ii) This standard does not apply to:
(a) Ammonia manufacturing plants.
(b) Refrigeration plants where ammonia is used solely as a refrigerant.
(2) Definitions. As used in this section.
(i) Appurtenances. All devices such as
pumps, compressors, safety relief devices, liquid-level gaging devices,
valves and pressure gages.
(ii) Cylinder. A container of 1,000
pounds of water capacity or less constructed in accordance with Department of Transportation specifications.
(iii) Code. The Boiler and Pressure
Vessel Code, Section VIII, Unfired
Pressure Vessels of the American Society of Mechanical Engineers (ASME)—
1968.
(iv) Container. Includes all vessels,
tanks, cylinders, or spheres used for

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Occupational Safety and Health Admin., Labor
transportation, storage, or application
of anhydrous ammonia.
(v) DOT. U.S. Department of Transportation.
(vi) Design pressure is identical to the
term Maximum Allowable Working Pressure used in the Code.
(vii) Farm vehicle (implement of husbandry). A vehicle for use on a farm on
which is mounted a container of not
over 1,200 gallons water capacity.
(viii) Filling density. the percent ratio
of the weight of the gas in a container
to the weight of water at 60 °F. that
the container will hold.
(ix) Gas. Anhydrous ammonia in either the gaseous or liquefied state.
(x) Gas masks. Gas masks must be approved by the National Institute for
Occupational
Safety
and
Health
(NIOSH) under 42 CFR part 84 for use
with anhydrous ammonia.
(xi) Capacity. Total volume of the
container in standard U.S. gallons.
(xii) DOT specifications—Regulations
of the Department of Transportation
published in 49 CFR Chapter I.
(b) Basic rules. This paragraph applies
to all paragraphs of this section unless
otherwise noted.
(1) Approval of equipment and systems.
Each appurtenance shall be approved in
accordance with paragraph (b)(1) (i),
(ii), (iii), or (iv) of this section.
(i) It was installed before February 8,
1973, and was approved, tested, and installed in accordance with either the
provisions of the American National
Standard for the Storage and Handling
of Anhydrous Ammonia, K61.1, or the
Fertilizer Institute Standards for the
Storage and Handling of Agricultural
Anhydrous Ammonia, M–1, (both of
which are incorporated by reference as
specified in § 1910.6) in effect at the
time of installation; or
(ii) It is accepted, or certified, or listed, or labeled, or otherwise determined
to be safe by a nationally recognized
testing laboratory; or
(iii) It is a type which no nationally
recognized testing laboratory does, or
will undertake to, accept, certify, list,
label, or determine to be safe; and such
equipment is inspected or tested by
any Federal, State, municipal, or other
local authority responsible for enforcing occupational safety provisions of a
Federal, State, municipal or other

§ 1910.111

local law, code, or regulation pertaining to the storage, handling, transport, and use of anhydrous ammonia,
and found to be in compliance with either the provisions of the American
National Standard for the Storage and
Handling of Anhydrous Ammonia,
K61.1, or the Fertilizer Institute Standards for the Storage and Handling of
Agricultural Anhydrous Ammonia, M–
1, in effect at the time of installation;
or
(iv) It is a custom-designed and custom-built unit, which no nationally
recognized testing laboratory, or Federal, State, municipal or local authority responsible for the enforcement of a
Federal, State, municipal, or local law,
code or regulation pertaining to the
storage, transportation and use of anhydrous ammonia is willing to undertake to accept, certify, list, label or determine to be safe, and the employer
has on file a document attesting to its
safe condition following the conduct of
appropriate tests. The document shall
be signed by a registered professional
engineer or other person having special
training or experience sufficient to permit him to form an opinion as to safety
of the unit involved. The document
shall set forth the test bases, test data
and results, and also the qualifications
of the certifying person.
(v) For the purposes of this paragraph (b)(1), the word listed means that
equipment is of a kind mentioned in a
list which is published by a nationally
recognized laboratory which makes
periodic inspection of the production of
such equipment, and states such equipment meets nationally recognized
standards or has been tested and found
safe for use in a specified manner. Labeled means there is attached to it a
label, symbol, or other identifying
mark of a nationally recognized testing
laboratory which, makes periodic inspections of the production of such
equipment, and whose labeling indicates compliance with nationally recognized standards or tests to determine
safe use in a specified manner. Certified
means it has been tested and found by
a nationally recognized testing laboratory to meet nationally recognized
standards or to be safe for use in a
specified manner, or is of a kind whose
production is periodically inspected by

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§ 1910.111

29 CFR Ch. XVII (7–1–10 Edition)

a nationally recognized testing laboratory, and it bears a label, tag, or other
record of certification.
(vi) For the purposes of this paragraph (b)(1), refer to § 1910.7 for definition of nationally recognized testing
laboratory.
(2) Requirements for construction, original test and requalification of nonrefrigerated containers. (i) Containers used
with systems covered in paragraphs (c),
(f), (g), and (h) of this section shall be
constructed and tested in accordance
with the Code except that construction
under Table UW12 at a basic joint efficiency of under 80 percent is not authorized.
(ii) Containers built according to the
Code do not have to comply with Paragraphs UG125 to UG128 inclusive, and
Paragraphs UG132 and UG133 of the
Code.
(iii) Containers exceeding 36 inches in
diameter or 250 gallons water capacity
shall be constructed to comply with
one or more of the following:
(a) Containers shall be stress relieved
after fabrication in accordance with
the Code, or
(b) Cold-form heads when used, shall
be stress relieved, or
(c) Hot-formed heads shall be used.
(iv) Welding to the shell, head, or any
other part of the container subject to
internal pressure shall be done in compliance with the Code. Other welding is
permitted only on saddle plates, lugs,
or brackets attached to the container
by the container manufacturer.
(v) Containers used with systems covered in paragraph (e) of this section
shall be constructed and tested in accordance with the DOT specifications.
(vi) The provisions of subdivision (i)
of this subparagraph shall not be construed as prohibiting the continued use
or reinstallation of containers constructed and maintained in accordance
with the 1949, 1950, 1952, 1956, 1959, and
1962 editions of the Code or any revisions thereof in effect at the time of
fabrication.
(3) Marking nonrefrigerated containers.
(i) System nameplates, when required,
shall be permanently attached to the
system so as to be readily accessible
for inspection and shall include markings as prescribed in subdivision (ii) of
this subparagraph.

(ii) Each container or system covered
in paragraphs (c), (f), (g), and (h) of this
section shall be marked as specified in
the following:
(a) With a notation ‘‘Anhydrous Ammonia.’’
(b) With a marking identifying compliance with the rules of the Code
under which the container is constructed.
Under ground: Container and system nameplate.
Above ground: Container.

(c) With a notation whether the system is designed for underground or
aboveground installation or both.
(d) With the name and address of the
supplier of the system or the trade
name of the system and with the date
of fabrication.
Under ground and above ground: System
nameplate.

(e) With the water capacity of the
container in pounds at 60 °F. or gallons, U.S. Standard.
Under ground: Container and system nameplate.
Above ground: Container.

(f) With the design pressure in pounds
per square inch.
Under ground: Container and system nameplate.
Above ground: Container.

(g) With the wall thickness of the
shell and heads.
Under ground: Container and system nameplate.
Above ground: Container.

(h) With marking indicating the
maximum level to which the container
may be filled with liquid anhydrous
ammonia at temperatures between 20
°F. and 130 °F. except on containers
provided with fixed level indicators,
such as fixed length dip tubes, or containers that are filled with weight.
Markings shall be in increments of not
more than 20 °F.
Above ground and under ground: System
nameplate or on liquid-level gaging device.

(i) With the total outside surface area
of the container in square feet.
Under ground: System nameplate.
Above ground: No requirement.

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Occupational Safety and Health Admin., Labor
(j) Marking specified on the container shall be on the container itself
or on a nameplate permanently attached to it.
(4) Marking refrigerated containers.
Each refrigerated container shall be
marked with nameplate on the outer
covering in an accessible place as specified in the following:
(i) With the notation, ‘‘Anhydrous
Ammonia.’’
(ii) With the name and address of the
builder and the date of fabrication.
(iii) With the water capacity of the
container in gallons, U.S. Standard.
(iv) With the design pressure.
(v) With the minimum temperature
in degrees Fahrenheit for which the
container was designed.
(vi) The maximum allowable water
level to which the container may be
filled for test purposes.
(vii) With the density of the product
in pounds per cubic foot for which the
container was designed.
(viii) With the maximum level to
which the container may be filled with
liquid anhydrous ammonia.
(5) Location of containers. (i) Consideration shall be given to the physiological effects of ammonia as well as to
adjacent fire hazards in selecting the
location for a storage container. Containers shall be located outside of
buildings or in buildings or sections
thereof especially provided for this
purpose.
(ii) Permanent storage containers
shall be located at least 50 feet from a
dug well or other sources of potable
water supply, unless the container is a
part of a water-treatment installation.
(iii)–(iv) [Reserved]
(v) Storage areas shall be kept free of
readily ignitible materials such as
waste, weeds, and long dry grass.
(6) Container appurtenances. (i) All appurtenances shall be designed for not
less than the maximum working pressure of that portion of the system on
which they are installed. All appurtenances shall be fabricated from materials proved suitable for anhydrous
ammonia service.
(ii) All connections to containers except safety relief devices, gaging devices, or those fitted with No. 54 drillsize orifice shall have shutoff valves lo-

§ 1910.111

cated as close to the container as practicable.
(iii) Excess flow valves where required by these standards shall close
automatically at the rated flows of
vapor or liquid as specified by the manufacturer. The connections and line including valves and fittings being protected by an excess flow valve shall
have a greater capacity than the rated
flow of the excess flow valve so that
the valve will close in case of failure of
the line or fittings.
(iv) Liquid-level gaging devices that
require bleeding of the product to the
atmosphere and which are so constructed that outward flow will not exceed that passed by a No. 54 drill-size
opening need not be equipped with excess flow valves.
(v) Openings from the container or
through fittings attached directly on
the container to which pressure gage
connections are made need not be
equipped with excess flow valves if
such openings are not larger than No.
54 drill size.
(vi) Excess flow and back pressure
check valves where required by the
standards in this section shall be located inside of the container or at a
point outside as close as practicable to
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
the 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) All excess flow valves shall be
plainly and permanently marked with
the name or trademark of the manufacturer, the catalog number, and the
rated capacity.
(7) Piping, tubing, and fittings. (i) All
piping, tubing, and fittings shall be
made of material suitable for anhydrous ammonia service.
(ii) All piping, tubing, and fittings
shall be designed for a pressure not less
than the maximum pressure to which
they may be subjected in service.
(iii) All refrigerated piping shall conform to the Refrigeration Piping Code,

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§ 1910.111

29 CFR Ch. XVII (7–1–10 Edition)

American National Standards Institute, B31.5–1966 with addenda B31.1a–
1968, which is incorporated by reference
as specified in § 1910.6, as it applies to
ammonia.
(iv) Piping used on non-refrigerated
systems shall be at least American Society for Testing and Materials
(ASTM) A–53–69 Grade B Electric Resistance Welded and Electric Flash
Welded Pipe, which is incorporated by
reference as specified in § 1910.6, or
equal. Such pipe shall be at least
schedule 40 when joints are welded, or
welded and flanged. Such pipe shall be
at least schedule 80 when joints are
threaded. Threaded connections shall
not be back-welded. Brass, copper, or
galvanized steel pipe shall not be used.
(v) Tubing made of brass, copper, or
other material subject to attack by
ammonia shall not be used.
(vi) Cast iron fittings shall not be
used but this shall not prohibit the use
of fittings made specifically for ammonia service of malleable, nodular, or
high strength gray iron meeting American Society for Testing and Materials
(ASTM) A47–68, ASTM 395–68, or ASTM
A126–66 Class B or C all of which are incorporated by reference as specified in
§ 1910.6.
(vii) Joint compounds shall be resistant to ammonia.
(8) Hose specifications. (i) Hose used in
ammonia service shall conform to the
joint Agricultural Ammonia Institute—Rubber Manufacturers Association Specifications for Anhydrous Ammonia Hose.
(ii) Hose subject to container pressure shall be designed for a minimum
working pressure of 350 p.s.i.g. and a
minimum burst pressure of 1,750 p.s.i.g.
Hose assemblies, when made up, shall
be capable of withstanding a test pressure of 500 p.s.i.g.
(iii) Hose and hose connections located on the low-pressure side of flow
control of pressure-reducing valves
shall be designed for a bursting pressure of not less than 5 times the pressure setting of the safety relief devices
protecting that portion of the system
but not less than 125 p.s.i.g. All connections shall be so designed and constructed that there will be no leakage
when connected.

(iv) Where hose is to be used for
transferring liquid from one container
to another, ‘‘wet’’ hose is recommended.
Such
hose
shall
be
equipped with approved shutoff valves
at the discharge end. Provision shall be
made to prevent excessive pressure in
the hose.
(v) On all hose one-half inch outside
diameter and larger, used for the transfer of anhydrous ammonia liquid or
vapor, there shall be etched, cast, or
impressed at 5-foot intervals the following information.
‘‘Anhydrous Ammonia’’ xxx p.s.i.g. (maximum working pressure), manufacturer’s
name or trademark, year of manufacture.

In lieu of this requirement the same information may be contained on a
nameplate permanently attached to
the hose.
TABLE H–36
[Minimum required rate of discharge in cubic feet per minute
of air at 120 percent of the maximum permitted start to discharge pressure of safety relief valves]
Flow rate
CFM air

Surface area (sq. ft.)
20 .........................................................................
25 .........................................................................
30 .........................................................................
35 .........................................................................
40 .........................................................................
45 .........................................................................
50 .........................................................................
55 .........................................................................
60 .........................................................................
65 .........................................................................
70 .........................................................................
75 .........................................................................
80 .........................................................................
85 .........................................................................
90 .........................................................................
95 .........................................................................
100 .......................................................................
105 .......................................................................
110 .......................................................................
115 .......................................................................
120 .......................................................................
125 .......................................................................
130 .......................................................................
135 .......................................................................
140 .......................................................................
145 .......................................................................
150 .......................................................................
155 .......................................................................
160 .......................................................................
165 .......................................................................
170 .......................................................................
175 .......................................................................
180 .......................................................................
185 .......................................................................
190 .......................................................................
195 .......................................................................
200 .......................................................................
210 .......................................................................
220 .......................................................................

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258
310
360
408
455
501
547
591
635
678
720
762
804
845
885
925
965
1,010
1,050
1,090
1,120
1,160
1,200
1,240
1,280
1,310
1,350
1,390
1,420
1,460
1,500
1,530
1,570
1,600
1,640
1,670
1,710
1,780
1,850

Occupational Safety and Health Admin., Labor
TABLE H–36—Continued
[Minimum required rate of discharge in cubic feet per minute
of air at 120 percent of the maximum permitted start to discharge pressure of safety relief valves]
Flow rate
CFM air

Surface area (sq. ft.)

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230 .......................................................................
240 .......................................................................
250 .......................................................................
260 .......................................................................
270 .......................................................................
280 .......................................................................
290 .......................................................................
300 .......................................................................
310 .......................................................................
320 .......................................................................
330 .......................................................................
340 .......................................................................
350 .......................................................................
360 .......................................................................
370 .......................................................................
380 .......................................................................
390 .......................................................................
400 .......................................................................
450 .......................................................................
500 .......................................................................
550 .......................................................................
600 .......................................................................
650 .......................................................................
700 .......................................................................
750 .......................................................................
800 .......................................................................
850 .......................................................................
900 .......................................................................
950 .......................................................................
1,000 ....................................................................
1,050 ....................................................................
1,100 ....................................................................
1,150 ....................................................................
1,200 ....................................................................
1,250 ....................................................................
1,300 ....................................................................
1,350 ....................................................................
1,400 ....................................................................
1,450 ....................................................................
1,500 ....................................................................
1,550 ....................................................................
1,600 ....................................................................
1,650 ....................................................................
1,700 ....................................................................
1,750 ....................................................................
1,800 ....................................................................
1,850 ....................................................................
1,900 ....................................................................
1,950 ....................................................................
2,000 ....................................................................
2,050 ....................................................................
2,100 ....................................................................
2,150 ....................................................................
2,200 ....................................................................
2,250 ....................................................................
2,300 ....................................................................
2,350 ....................................................................
2,400 ....................................................................
2,450 ....................................................................
2,500 ....................................................................

1,920
1,980
2,050
2,120
2,180
2,250
2,320
2,380
2,450
2,510
2,570
2,640
2,700
2,760
2,830
2,890
2,950
3,010
3,320
3,620
3,910
4,200
4,480
4,760
5,040
5,300
5,590
5,850
6,120
6,380
6,640
6,900
7,160
7,410
7,660
7,910
8,160
8,410
8,650
8,900
9,140
9,380
9,620
9,860
10,090
10,330
10,560
10,800
11,030
11,260
11,490
11,720
11,950
12,180
12,400
12,630
12,850
13,080
13,300
13,520

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:

§ 1910.111

(1) Cylindrical container with hemispherical heads:
Area=overall length in feet times outside diameter in feet times 3.1416.
(2) Cylindrical container with other than
hemispherical heads:
Area=(overall length in feet plus 0.3 outside
diameter in feet) times outside diameter in
feet times 3.1416.
(3) Spherical container:
Area=outside diameter in feet squared times
3.1416.
Flow Rate—CFM Air=cubic feet per minute
of air required 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 2,500 square feet, the required
flow rate can be calculated using the formula: Flow Rate CFM Air=22.11 A0 82, where
A=outside surface area of the container in
square feet.

(9) Safety relief devices. (i) Every container used in systems covered by paragraphs (c), (f), (g), and (h) of this section shall be provided with one or more
safety relief valves of the spring-loaded
or equivalent type. The discharge from
safety-relief valves shall be vented
away from the container upward and
unobstructed to the atmosphere. All
relief-valve discharge openings shall
have suitable rain caps that will allow
free discharge of the vapor and prevent
entrance of water. Provision shall be
made for draining condensate which
may accumulate. The rate of the discharge shall be in accordance with the
provisions of Table H–36.
(ii) Container safety-relief valves
shall be set to start-to-discharge as follows, with relation to the design pressure of the container:
Containers
ASME-U–68, U–69 ........................
ASME-U–200, U–201 ....................
ASME 1959, 1956, 1952, or 1962
API-ASME .....................................
U.S. Coast Guard ..........................

Minimum
(percent)
110
95
95
95
95

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125
100
100
100
100

As required by DOT Regulations.
(iii) Safety relief devices used in systems covered by paragraphs (c), (f), (g),
and (h) of this section shall be constructed to discharge at not less than
the rates required in paragraph (b)(9)(i)
of this section before the pressure is in
excess of 120 percent (not including the

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§ 1910.111

29 CFR Ch. XVII (7–1–10 Edition)

10 percent tolerance referred to in
paragraph (b)(9)(ii) of this section) of
the maximum permitted start-to-discharge pressure setting of the device.
(iv) Safety-relief valves shall be so
arranged that the possibility of tampering will be minimized. If the pressure setting adjustment is external,
the relief valves shall be provided with
means for sealing the adjustment.
(v) Shutoff valves shall not be installed between the safety-relief valves
and the container; except, that a shutoff valve may be used where the arrangement of this valve is such as always to afford full required capacity
flow through the relief valves.
(vi) Safety-relief valves shall have direct communication with the vapor
space of the container.
(vii) Each container safety-relief
valve used with systems covered by
paragraphs (c), (f), (g), and (h) of this
section shall be plainly and permanently marked with the symbol ‘‘NH3’’
or ‘‘AA’’; with the pressure in poundsper-square-inch gage at which the
valve is set to start-to-discharge; with
the actual rate of discharge of the
valve at its full open position in cubic
feet per minute of air at 60 °F. and atmospheric pressure; and with the manufacturer’s name and catalog number.
Example: ‘‘NH3 250–4050 Air’’ indicates
that the valve is suitable for use on an
anhydrous ammonia container, is set
to start-to-discharge at a pressure of
250 p.s.i.g., and that its rate of discharge at full open position (subdivisions (ii) and (iii) of this subparagraph)
is 4,050 cubic feet per minute of air.
(viii) The flow capacity of the relief
valve shall not be restricted by any
connection to it on either the upstream
or downstream side.
(ix) A hydrostatic relief valve shall
be installed between each pair of valves
in the liquid ammonia piping or hose
where liquid may be trapped so as to
relieve into the atmosphere at a safe
location.
(10) General.
(i) [Reserved]
(ii) Stationary storage installations
must have at least two suitable gas
masks in readily-accessible locations.
Full-face masks with ammonia canisters that have been approved by
NIOSH under 42 CFR part 84 are suit-

able for emergency action involving
most anhydrous ammonia leaks, particularly leaks that occur outdoors.
For respiratory protection in concentrated ammonia atmospheres, a
self-contained breathing apparatus is
required.
(iii) Stationary storage installations
shall have an easily accessible shower
or a 50-gallon drum of water.
(iv) Each vehicle transporting ammonia in bulk except farm applicator vehicles shall carry a container of at
least 5 gallons of water and shall be
equipped with a full face mask.
(11) Charging of containers. (i) The filling densities for containers that are
not refrigerated shall not exceed the
following:
Type of container

Percent by
weight

Percent by
volume

Aboveground-Uninsulated .............
Aboveground-Uninsulated .............
Aboveground-Insulated .................
Underground-Uninsulated .............
DOT—In accord with DOT regulations..

56
..................
57
58

82
87.5
83.5
85

(ii) Aboveground uninsulated containers may be charged 87.5 percent by
volume provided the temperature of
the anhydrous ammonia being charged
is determined to be not lower than 30
°F. or provided the charging of the container is stopped at the first indication
of frost or ice formation on its outside
surface and is not resumed until such
frost or ice has disappeared.
(12) Transfer of liquids. (i) Anhydrous
ammonia shall always be at a temperature suitable for the material of construction and the design of the receiving container.
(ii) The employer shall require the
continuous presence of an attendant in
the vicinity of the operation during
such time as ammonia is being transferred.
(iii) Containers shall be charged or
used only upon authorization of the
owner.
(iv) Containers shall be gaged and
charged only in the open atmosphere or
in buildings or areas thereof provided
for that purpose.
(v) Pumps used for transferring ammonia shall be those manufactured for
that purpose.
(a) Pumps shall be designed for at
least 250 p.s.i.g. working pressure.

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(b) Positive displacement pumps
shall have, installed off the discharged
port, a constant differential relief
valve discharging into the suction port
of the pump through a line of sufficient
size to carry the full capacity of the
pump at relief valve setting, which setting and installation shall be according
to the pump manufacturer’s recommendations.
(c) On the discharge side of the pump,
before the relief valve line, there shall
be installed a pressure gage graduated
from 0 to 400 p.s.i.
(d) Plant piping shall contain shutoff
valves located as close as practical to
pump connections.
(vi) Compressors used for transferring or refrigerating ammonia shall be
recommended for ammonia service by
the manufacturer.
(a) Compressors shall be designed for
at least 250 p.s.i.g. working pressure.
(b) Plant piping shall contain shutoff
valves located as close as practical to
compressor connections.
(c) A relief valve large enough to discharge the full capacity of the compressor shall be connected to the discharge before any shutoff valve.
(d) Compressors shall have pressure
gages at suction and discharge graduated to at least one and one-half
times the maximum pressure that can
be developed.
(e) Adequate means, such as drainable liquid trap, shall be provided on
the compressor suction to minimize
the entry of liquid into the compressor.
(vii) Loading and unloading systems
shall be protected by suitable devices
to prevent emptying of the storage
container or the container being loaded
or unloaded in the event of severance
of the hose. Backflow check valves or
properly sized excess flow valves shall
be installed where necessary to provide
such protection. In the event that such
valves are not practical, remotely operated shutoff valves may be installed.
(13) Tank car unloading points and operations. (i) Provisions for unloading
tank cars shall conform to the applicable recommendations contained in the
DOT regulations.
(ii) The employer shall insure that
unloading operations are performed by
reliable persons properly instructed
and given the authority to monitor

§ 1910.111

careful compliance with all applicable
procedures.
(iii) Caution signs shall be so placed
on the track or car as to give necessary
warning to persons approaching the car
from open end or ends of siding and
shall be left up until after the car is
unloaded and disconnected from discharge connections. Signs shall be of
metal or other suitable material, at
least 12 by 15 inches in size and bear
the words ‘‘STOP—Tank Car Connected’’ or ‘‘STOP—Men at Work’’ the
word, ‘‘STOP,’’ being in letters at least
4 inches high and the other words in
letters at least 2 inches high.
(iv) The track of a tank car siding
shall be substantially level.
(v) Brakes shall be set and wheels
blocked on all cars being unloaded.
(14) Liquid-level gaging device. (i) Each
container except those filled by weight
shall be equipped with an approved liquid-level gaging device. A thermometer
well shall be provided in all containers
not utilizing a fixed liquid-level gaging
device.
(ii) All gaging devices shall be arranged so that the maximum liquid
level to which the container is filled is
readily determined.
(iii) Gaging devices that require
bleeding of the product to the atmosphere such as the rotary tube, fixed
tube, and slip tube devices shall be designed so that the maximum opening of
the bleed valve is not larger than No.
54 drill size unless provided with an excess flow valve. (This requirement does
not apply to farm vehicles used for the
application of ammonia as covered in
paragraph (h) of this section.)
(iv) Gaging devices shall have a design pressure equal to or greater than
the design pressure of the container on
which they are installed.
(v) Fixed tube liquid-level gages shall
be designed and installed to indicate
that level at which the container is
filled to 85 percent of its water capacity in gallons.
(vi) Gage glasses of the columnar
type shall be restricted to stationary
storage installations. They shall be
equipped with shutoff valves having
metallic handwheels, with excess-flow
valves, and with extra heavy glass adequately protected with a metal housing
applied by the gage manufacturer.

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29 CFR Ch. XVII (7–1–10 Edition)

They shall be shielded against the direct rays of the sun.
(15) [Reserved]
(16) Electrical equipment and wiring. (i)
Electrical equipment and wiring for
use in ammonia installations shall be
general purpose or weather resistant as
appropriate.
(ii) Electrical systems shall be installed and maintained in accordance
with subpart S of this part.
(c) Systems utilizing stationary, nonrefrigerated storage containers. This
paragraph applies to stationary, nonrefrigerated storage installations utilizing containers other than those covered in paragraph (e) of this section.
Paragraph (b) of this section applies to
this paragraph unless otherwise noted.
(1) Design pressure and construction of
containers. The minimum design pressure for nonrefrigerated containers
shall be 250 p.s.i.g.
(2) Container valves and accessories,
filling and discharge connections. (i)
Each filling connection shall be provided with combination back-pressure
check valve and excess-flow valve; one
double or two single back-pressure
check valves; or a positive shutoff
valve in conjunction with either an internal back-pressure check valve or an
internal excess flow valve.
(ii) All liquid and vapor connections
to containers except filling pipes, safety relief connections, and liquid-level
gaging and pressure gage connections
provided with orifices not larger than
No. 54 drill size as required in paragraphs (b)(6) (iv) and (v) of this section
shall be equipped with excess-flow
valves.
(iii) Each storage container shall be
provided with a pressure gage graduated from 0 to 400 p.s.i. Gages shall be
designated for use in ammonia service.
(iv) All containers shall be equipped
with vapor return valves.
(3) Safety-relief devices. (i) Every container shall be provided with one or
more safety-relief valves of the springloaded or equivalent type in accordance with paragraph (b)(9) of this section.
(ii) The rate of discharge of springloaded safety relief valves installed on
underground containers may be reduced to a minimum of 30 percent of
the rate of discharge specified in Table

H–36. Containers so protected shall not
be uncovered after installation until
the liquid ammonia has been removed.
Containers which may contain liquid
ammonia before being installed underground and before being completely
covered with earth are to be considered
aboveground containers when determining the rate of discharge requirements of the safety-relief valves.
(iii) On underground installations
where there is a probability of the
manhole or housing becoming flooded,
the discharge from vent lines shall be
located above the high water level. All
manholes or housings shall be provided
with ventilated louvers or their equivalent, the area of such openings equalling or exceeding combined discharge
areas of safety-relief valves and vent
lines which discharge their content
into the manhole housing.
(iv) Vent pipes, when used, shall not
be restricted or of smaller diameter
than the relief-valve outlet connection.
(v) If desired, vent pipes 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 the capacity of such header is at
least equal to the sum of the capacities
of the individual discharge lines.
(4) Reinstallation of containers. (i) Containers once installed under ground
shall not later be reinstalled above
ground or under ground, unless they
successfully
withstand
hydrostatic
pressure retests at the pressure specified for the original hydrostatic test as
required by the code under which constructed and show no evidence of serious corrosion.
(ii) Where containers are reinstalled
above ground, safety devices or gaging
devices shall comply with paragraph
(b)(9) of this section and this paragraph
respectively for aboveground containers.
(5) Installation of storage containers. (i)
Containers installed above ground, except as provided in paragraph (c)(5)(v)
of this section shall be provided with
substantial concrete or masonry supports, or structural steel supports on
firm concrete or masonry foundations.
All foundations shall extend below the
frost line.

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(ii) Horizontal aboveground containers shall be so mounted on foundations as to permit expansion and contraction. Every container shall be supported to prevent the concentration of
excessive loads on the supporting portion of the shell. That portion of the
container in contact with foundations
or saddles shall be protected against
corrosion.
(iii)
Containers
installed
under
ground shall be so placed that the top
of the container is below the frost line
and in no case less than 2 feet below
the surface of the ground. Should
ground conditions make compliance
with these requirements impracticable,
installation shall be made otherwise to
prevent physical damage. It will not be
necessary to cover the portion of the
container to which manhole and other
connections are affixed. When necessary to prevent floating, containers
shall be securely anchored or weighted.
(iv) Underground containers shall be
set on a firm foundation (firm earth
may be used) and surrounded with
earth or sand well tamped in place. The
container, prior to being placed under
ground, shall be given a corrosion resisting protective coating. The container thus coated shall be so lowered
into place as to prevent abrasion or
other damage to the coating.
(v) Containers with foundations attached (portable or semiportable tank
containers with suitable steel ‘‘runners’’ or ‘‘skids’’ and commonly known
in the industry as ‘‘skid tanks’’) shall
be designed and constructed in accordance with paragraph (c)(1) of this section.
(vi) Secure anchorage or adequate
pier height shall be provided against
container flotation wherever sufficiently high flood water might occur.
(vii) The distance between underground containers of over 2,000 gallons
capacity shall be at least 5 feet.
(6) Protection of appurtenances. (i)
Valves, regulating, gaging, and other
appurtenances
shall
be
protected
against tampering and physical damage. Such appurtenances shall also be
protected during transit of containers.
(ii) All connections to underground
containers shall be located within a
dome, housing, or manhole and with

§ 1910.111

access thereto by means of a substantial cover.
(7) Damage from vehicles. Precaution
shall be taken against damage to ammonia systems from vehicles.
(d) Refrigerated storage systems. This
paragraph applies to systems utilizing
containers with the storage of anhydrous ammonia under refrigerated conditions. All applicable rules of paragraph (b) of this section apply to this
paragraph unless otherwise noted.
(1) Design of containers. (i) The design
temperature shall be the minimum
temperature to which the container
will be refrigerated.
(ii) Containers with a design pressure
exceeding 15 p.s.i.g. shall be constructed in accordance with paragraph
(b)(2) of this section, and the materials
shall be selected from those listed in
API Standard 620, Recommended Rules
for Design and Construction of Large,
Welded, Low-Pressure Storage Tanks,
Fourth Edition, 1970, Tables 2.02, R2.2,
R2.2(A), R2.2.1, or R2.3 which are incorporated by reference as specified in
§ 1910.6.
(iii) Containers with a design pressure of 15 p.s.i.g. and less shall be constructed in accordance with the applicable requirements of API Standard 620
including its appendix R.
(iv) When austenitic steels or nonferrous materials are used, the Code
shall be used as a guide in the selection
of materials for use at the design temperature.
(v) The filling density for refrigerated storage containers shall be such
that the container will not be liquid
full at a liquid temperature corresponding to the vapor pressure at the
start-to-discharge pressure setting of
the safety-relief valve.
(2) Installation of refrigerated storage
containers. (i) Containers shall be supported on suitable noncombustible
foundations designed to accommodate
the type of container being used.
(ii) Adequate protection against flotation or other water damage shall be
provided wherever high flood water
might occur.
(iii) Containers for product storage at
less than 32 °F. shall be supported in
such a way, or heat shall be supplied,
to prevent the effects of freezing and
consequent frost heaving.

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29 CFR Ch. XVII (7–1–10 Edition)

(3) Shutoff valves. When operating
conditions make it advisable, a check
valve shall be installed on the fill connection and a remotely operated shutoff valve on other connections located
below the maximum liquid level.
(4) Safety relief devices. (i) Safety relief valves shall be set to start-to-discharge at a pressure not in excess of
the design pressure of the container
and shall have a total relieving capacity sufficient to prevent a maximum
pressure in the container of more than
120 percent of the design pressure. Relief valves for refrigerated storage containers shall be self-contained springloaded, weight-loaded, or self-contained pilot-operated type.
(ii) The total relieving capacity shall
be the larger of:
(a) Possible refrigeration system
upset such as (1) cooling water failure,
(2) power failure, (3) instrument air or
instrument failure, (4) mechanical failure of any equipment, (5) excessive
pumping rates.
(b) Fire exposure determined in accordance with Compressed Gas Association (CGA) S–1, Part 3, Safety Relief
Device Standards for Compressed Gas
Storage Containers, 1959, which is incorporated by reference as specified in
§ 1910.6, except that ‘‘A’’ shall be the
total exposed surface area in square
feet up to 25 foot above grade or to the
equator of the storage container if it is
a sphere, whichever is greater. If the
relieving capacity required for fire exposure is greater than that required by
(a) of this subdivision, the additional
capacity may be provided by weak roof
to shell seams in containers operating
at essentially atmospheric pressure
and having an inherently weak roof-toshell seam. The weak roof-to-shell
seam is not to be considered as providing any of the capacity required in
(a) of this subdivision.
(iii) If vent lines are installed to conduct the vapors from the relief valve,
the back pressure under full relieving
conditions shall not exceed 50 percent
of the start-to-discharge pressure for
pressure balanced valves or 10 percent
of the start-to-discharge pressure for
conventional valves. The vent lines
shall be installed to prevent accumulation of liquid in the lines.

(iv) The valve or valve installation
shall provide weather protection.
(v) Atmospheric storage shall be provided with vacuum breakers. Ammonia
gas, nitrogen, methane, or other inert
gases can be used to provide a pad.
(5) Protection of container appurtenances. Appurtenances shall be protected against tampering and physical
damage.
(6) Reinstallation of refrigerated storage
containers. Containers of such size as to
require field fabrication shall, when
moved and reinstalled, be reconstructed and reinspected in complete
accordance with the requirements
under which they were constructed.
The containers shall be subjected to a
pressure retest and if rerating is necessary, rerating shall be in accordance
with applicable requirements.
(7) Damage from vehicles. Precaution
shall be taken against damage from vehicles.
(8) Refrigeration load and equipment.
(i) The total refrigeration load shall be
computed as the sum of the following:
(a) Load imposed by heat flow into
the container caused by the temperature differential between design ambient temperature and storage temperature.
(b) Load imposed by heat flow into
the container caused by maximum sun
radiation.
(c) Maximum load imposed by filling
the container with ammonia warmer
than the design storage temperature.
(ii) More than one storage container
may be handled by the same refrigeration system.
(9) Compressors. (i) A minimum of two
compressors shall be provided either of
which shall be of sufficient size to handle the loads listed in paragraphs
(d)(8)(i) (a) and (b) of this section.
Where more than two compressors are
provided minimum standby equipment
equal to the largest normally operating
equipment shall be installed. Filling
compressors may be used as standby
equipment for holding compressors.
(ii) Compressors shall be sized to operate with a suction pressure at least
10 percent below the minimum setting
of the safety valve(s) on the storage

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container and shall withstand a suction pressure at least equal to 120 percent of the design pressure of the container.
(10) Compressor drives. (i) Each compressor shall have its individual driving unit.
(ii) An emergency source of power of
sufficient capacity to handle the loads
listed in paragraphs (d)(8)(i) (a) and (b)
of this section shall be provided unless
facilities are available to safely dispose
of vented vapors while the refrigeration system is not operating.
(11) Automatic control equipment. (i)
The refrigeration system shall be arranged with suitable controls to govern
the compressor operation in accordance with the load as evidenced by the
pressure in the container(s).
(ii) An emergency alarm system shall
be installed to function in the event
the pressure in the container(s) rises to
the maximum allowable operating
pressure.
(iii) An emergency alarm and shutoff
shall be located in the condenser system to respond to excess discharge
pressure caused by failure of the cooling medium.
(iv) All automatic controls shall be
installed in a manner to preclude operation of alternate compressors unless
the controls will function with the alternate compressors.
(12) Separators for compressors. (i) An
entrainment separator of suitable size
and design pressure shall be installed
in the compressor suction line of lubricated compression. The separator shall
be equipped with a drain and gaging device.
(ii) [Reserved]
(13) Condensers. The condenser system may be cooled by air or water or
both. The condenser shall be designed
for at least 250 p.s.i.g. Provision shall
be made for purging noncondensibles
either manually or automatically.
(14) Receiver and liquid drain. A receiver shall be provided with a liquidlevel control to discharge the liquid
ammonia to storage. The receiver shall
be designed for at least 250 p.s.i.g. and
be equipped with the necessary connections, safety valves, and gaging device.
(15) Insulation. Refrigerated containers and pipelines which are insulated shall be covered with a material

§ 1910.111

of suitable quality and thickness for
the temperatures encountered. Insulation shall be suitably supported and
protected against the weather. Weatherproofing shall be of a type which will
not support flame propagation.
(e) Systems utilizing portable DOT containers—(1)
Conformance.
Cylinders
shall comply with DOT specifications
and shall be maintained, filled, packaged, marked, labeled, and shipped to
comply with 49 CFR chapter I and the
marking requirements set forth in
§ 1910.253(b)(1)(ii).
(2) Storage. Cylinders shall be stored
in an area free from ignitable debris
and in such manner as to prevent external corrosion. Storage may be indoors or outdoors.
(3) Heat protection. Cylinders filled in
accordance with DOT regulations will
become liquid full at 145 °F. Cylinders
shall be protected from heat sources
such as radiant flame and steampipes.
Heat shall not be applied directly to
cylinders to raise the pressure.
(4) Protection. Cylinders shall be
stored in such manner as to protect
them from moving vehicles or external
damage.
(5) Valve cap. Any cylinder which is
designed to have a valve protection cap
shall have the cap securely in place
when the cylinder is not in service.
(f) Tank motor vehicles for the transportation of ammonia. (1) This paragraph
applies to containers and pertinent
equipment mounted on tank motor vehicles including semitrailers and full
trailers used for the transportation of
ammonia. This paragraph does not
apply to farm vehicles. For requirements covering farm vehicles, refer to
paragraphs (g) and (h) of this section.
Paragraph (b) of this section applies to
this paragraph unless otherwise noted.
Containers and pertinent equipment
for tank motor vehicles for the transportation of anhydrous ammonia, in
addition to complying with the requirements of this section, shall also
comply with the requirements of DOT.
(2) Design pressure and construction of
containers. (i) The minimum design
pressure for containers shall be that
specified in the regulations of the DOT.
(ii) The shell or head thickness of
any container shall not be less than
three-sixteenth inch.

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29 CFR Ch. XVII (7–1–10 Edition)

(iii) All container openings, except
safety relief valves, liquid-level gaging
devices, and pressure gages, shall be labeled to designate whether they communicate with liquid or vapor space.
(3) Container appurtenances. (i) All appurtenances shall be protected against
physical damage.
(ii) All connections to containers, except filling connections, safety relief
devices, and liquid-level and pressure
gage connections, shall be provided
with suitable automatic excess flow
valves, or in lieu thereof, may be fitted
with quick-closing internal valves,
which shall remain closed except during delivery operations. The control
mechanism for such valves may be provided with a secondary control remote
from the delivery connections and such
control mechanism shall be provided
with a fusible section (melting point
208 °F. to 220 °F.) which will permit the
internal valve to close automatically
in case of fire.
(iii) Filling connections shall be provided with automatic back-pressure
check valves, excess-flow valves, or
quick-closing internal valves, to prevent back-flow in case the filling connection is broken. Where the filling
and discharge connect to a common
opening in the container shell and that
opening is fitted with a quick-closing
internal valve as specified in paragraph
(f)(3)(ii) of this section, the automatic
valve shall not be required.
(iv) All containers shall be equipped
for spray loading (filling in the vapor
space) or with an approved vapor return valve of adequate capacity.
(4) Piping and fittings. (i) All piping,
tubing, and fittings shall be securely
mounted and protected against damage. Means shall be provided to protect
hoses while the vehicle is in motion.
(ii) Fittings shall comply with paragraph (b)(6) of this section. Pipe shall
be Schedule 80.
(5) Safety relief devices. (i) The discharge from safety relief valves shall
be vented away from the container upward 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. Size of discharge lines from
safety valves shall not be smaller than
the nominal size of the safety-relief

valve outlet connection. Suitable provision shall be made for draining condensate which may accumulate in the
discharge pipe.
(ii) Any portion of liquid ammonia
piping which at any time may be closed
at both ends shall be provided with a
hydrostatic relief valve.
(6) Transfer of liquids. (i) The content
of tank motor vehicle containers shall
be determined by weight, by a suitable
liquid-level gaging device, or other approved methods. If the content of a
container is to be determined by liquid-level measurement, the container
shall have a thermometer well so that
the internal liquid temperature can be
easily determined. This volume when
converted to weight shall not exceed
the filling density specified by the
DOT.
(ii) Any pump, except a constant
speed centrifugal pump, shall be
equipped with a suitable pressure actuated bypass valve permitting flow from
discharge to suction when the discharge pressure rises above a predetermined point. Pump discharge shall also
be equipped with a spring-loaded safety
relief valve set at a pressure not more
than 135 percent of the setting of the
bypass valve or more than 400 p.s.i.g.,
whichever is larger.
(iii) Compressors shall be equipped
with manually operated shutoff valves
on both suction and discharge connections. Pressure gages of bourdon-tube
type shall be installed on the suction
and discharge of the compressor before
the shutoff valves. The compressor
shall not be operated if either pressure
gage is removed or is inoperative. A
spring-loaded, safety-relief valve capable of discharging to atmosphere the
full flow of gas from the compressor at
a pressure not exceeding 300 p.s.i.g.
shall be connected between the compressor discharge and the discharge
shutoff valve.
(iv) Valve functions shall be clearly
and legibly identified by metal tags or
nameplates permanently affixed to
each valve.
(7)–(8) [Reserved]
(9) Chock blocks. At least two chock
blocks shall be provided. These blocks
shall be placed to prevent rolling of the
vehicle whenever it is parked during
loading and unloading operations.

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(10) Portable tank containers (skid
tanks). Where portable tank containers
are used for farm storage they shall
comply with paragraph (c)(1) of this
section. When portable tank containers
are used in lieu of cargo tanks and are
permanently mounted on tank motor
vehicles for the transportation of ammonia, they shall comply with the requirements of this paragraph.
(g) Systems mounted on farm vehicles
other than for the application of ammonia—(1) Application. This paragraph applies to containers of 1,200 gallons capacity or less and pertinent equipment
mounted on farm vehicles (implements
of husbandry) and used other than for
the application of ammonia to the soil.
Paragraph (b) of this section applies to
this paragraph unless otherwise noted.
(2) Design pressure and classification of
containers. (i) The minimum design
pressure for containers shall be 250
p.s.i.g.
(ii) The shell or head thickness of
any container shall be not less than
three-sixteenths of an inch.
(3) Mounting containers. (i) A suitable
‘‘stop’’ or ‘‘stops’’ shall be mounted on
the vehicle or on the container in such
a way that the container shall not be
dislodged from its mounting due to the
vehicle coming to a sudden stop. Back
slippage shall also be prevented by
proper methods.
(ii) A suitable ‘‘hold down’’ device
shall be provided which will anchor the
container to the vehicle at one or more
places on each side of the container.
(iii) When containers are mounted on
four-wheel trailers, care shall be taken
to insure that the weight is distributed
evenly over both axles.
(iv) When the cradle and the tank are
not welded together suitable material
shall be used between them to eliminate metal-to-metal friction.
(4) Container appurtenances. (i) All
containers shall be equipped with a
fixed liquid-level gage.
(ii) All containers with a capacity exceeding 250 gallons shall be equipped
with a pressure gage having a dial
graduated from 0–400 p.s.i.
(iii) The filling connection shall be
fitted with combination back-pressure
check valve and excess-flow valve; one
double or two single back-pressure
check valves; or a positive shutoff

§ 1910.111

valve in conjunction with either an internal back-pressure check valve or an
internal excess flow valve.
(iv) All containers with a capacity
exceeding 250 gallons shall be equipped
for spray loading or with an approved
vapor return valve.
(v) All vapor and liquid connections
except safety-relief valves and those
specifically exempted by paragraph
(b)(6)(v) of this section shall be
equipped with approved excess-flow
valves or may be fitted with quickclosing internal valves which, except
during operating periods, shall remain
closed.
(vi) Fittings shall be adequately protected from damage by a metal box or
cylinder with open top securely fastened to the container or by rigid
guards, well braced, welded to the container on both sides of the fittings or
by a metal dome. If a metal dome is
used, the relief valve shall be properly
vented through the dome.
(vii) If a liquid withdrawal line is installed in the bottom of a container,
the connections thereto, including
hose, shall not be lower than the lowest horizontal edge of the vehicle axle.
(viii) Provision shall be made to secure both ends of the hose while in
transit.
(5) Marking the container. There shall
appear on each side and on the rear end
of the container in letters at least 4
inches high, the words, ‘‘Caution—Ammonia’’ or the container shall be
marked in accordance with DOT regulations.
(6) Farm vehicles. (i) Farm vehicles
shall conform with State regulations.
(ii) All trailers shall be securely attached to the vehicle drawing them by
means of drawbars supplemented by
suitable safety chains.
(iii) A trailer shall be constructed so
that it will follow substantially in the
path of the towing vehicle and will not
whip or swerve dangerously from side
to side.
(iv) All vehicles shall carry a can
containing 5 gallons or more of water.
(h) Systems mounted on farm vehicles
for the application of ammonia. (1) This
paragraph applies to systems utilizing
containers of 250 gallons capacity or
less which are mounted on farm vehicles (implement of husbandry) and used

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§§ 1910.112–1910.113

29 CFR Ch. XVII (7–1–10 Edition)

for the application of ammonia to the
soil. Paragraph (b) of this section applies to this paragraph unless otherwise noted. Where larger containers are
used, they shall comply with paragraph
(g) of this section.
(2) Design pressure and classification of
containers. (i) The minimum design
pressure for containers shall be 250
p.s.i.g.
(ii) The shell or head thickness of
any container shall not be less than
three-sixteenths inch.
(3) Mounting of containers. All containers and flow-control devices shall
be securely mounted.
(4) Container valves and accessories. (i)
Each container shall have a fixed liquid-level gage.
(ii) The filling connection shall be
fitted with a combination back-pressure check valve and an excess-flow
valve; one double or two single backpressure check valves: or a positive
shutoff valve in conjunction with an
internal back-pressure check valve or
an internal excess-flow valve.
(iii) The applicator tank may be
filled by venting to open air provided
the bleeder valve orifice does not exceed seven-sixteenths inch in diameter.
(iv) Regulation equipment may be
connected directly to the tank coupling or flange, in which case a flexible
connection shall be used between such
regulating equipment and the remainder of the liquid withdrawal system.
Regulating equipment not so installed
shall be flexibly connected to the container shutoff valve.
(v) No excess flow valve is required in
the liquid withdrawal line provided the
controlling orifice between the contents of the container and the outlet of
the shutoff valve does not exceed
seven-sixteenths inch in diameter.
[39 FR 23502, June 27, 1974, as amended at 43
FR 49748, Oct. 24, 1978; 49 FR 5322, Feb. 10,
1984; 53 FR 12122, Apr. 12, 1988; 61 FR 9238,
Mar. 7, 1996; 63 FR 1269, Jan. 8, 1998; 63 FR
33466, June 18, 1998; 72 FR 71069, Dec. 14, 2007]

§§ 1910.112–1910.113

[Reserved]

rmajette on DSK29S0YB1PROD with CFR

§ 1910.119 Process safety management
of highly hazardous chemicals.
Purpose. This section contains requirements for preventing or minimizing the consequences of cata-

strophic releases of toxic, reactive,
flammable, or explosive chemicals.
These releases may result in toxic, fire
or explosion hazards.
(a) Application. (1) This section applies to the following:
(i) A process which involves a chemical at or above the specified threshold
quantities listed in appendix A to this
section;
(ii) A process which involves a flammable liquid or gas (as defined in
1910.1200(c) of this part) on site in one
location, in a quantity of 10,000 pounds
(4535.9 kg) or more except for:
(A) Hydrocarbon fuels used solely for
workplace consumption as a fuel (e.g.,
propane used for comfort heating, gasoline for vehicle refueling), if such fuels
are not a part of a process containing
another highly hazardous chemical
covered by this standard;
(B) Flammable liquids stored in atmospheric tanks or transferred which
are kept below their normal boiling
point without benefit of chilling or refrigeration.
(2) This section does not apply to:
(i) Retail facilities;
(ii) Oil or gas well drilling or servicing operations; or,
(iii) Normally unoccupied remote facilities.
(b) Definitions. Atmospheric tank
means a storage tank which has been
designed to operate at pressures from
atmospheric through 0.5 p.s.i.g. (pounds
per square inch gauge, 3.45 Kpa).
Boiling point means the boiling point
of a liquid at a pressure of 14.7 pounds
per square inch absolute (p.s.i.a.) (760
mm.). For the purposes of this section,
where an accurate boiling point is unavailable for the material in question,
or for mixtures which do not have a
constant boiling point, the 10 percent
point of a distillation performed in accordance with the Standard Method of
Test for Distillation of Petroleum
Products, ASTM D–86–62, which is incorporated by reference as specified in
§ 1910.6, may be used as the boiling
point of the liquid.
Catastrophic release means a major
uncontrolled emission, fire, or explosion, involving one or more highly hazardous chemicals, that presents serious
danger to employees in the workplace.

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