[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: 29CFR1910.103]
[Page 226-234]
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. 1910.103 Hydrogen.
(a) General--(1) Definitions. As used in this section (i) Gaseous
hydrogen system is one in which the hydrogen is delivered, stored and
discharged in the gaseous form to consumer's piping. The system includes
stationary or movable containers, pressure regulators, safety relief
devices, manifolds, interconnecting piping and controls. The system
terminates at the point where hydrogen at service pressure first enters
the consumer's distribution piping.
(ii) Approved--Means, unless otherwise indicated, listed or approved
by a nationally recognized testing laboratory. Refer to Sec. 1910.7 for
definition of nationally recognized testing laboratory.
(iii) Listed--See ``approved''.
(iv) ASME--American Society of Mechanical Engineers.
(v) DOT Specifications--Regulations of the Department of
Transportation published in 49 CFR Chapter I.
(vi) DOT regulations--See Sec. 1910.103 (a)(1)(v).
(2) Scope--(i) Gaseous hydrogen systems. (a) Paragraph (b) of this
section applies to the installation of gaseous hydrogen systems on
consumer premises where the hydrogen supply to the consumer premises
originates outside the consumer premises and is delivered by mobile
equipment.
(b) Paragraph (b) of this section does not apply to gaseous hydrogen
systems having a total hydrogen content of less than 400 cubic feet, nor
to hydrogen manufacturing plants or other establishments operated by the
hydrogen supplier or his agent for the purpose of storing hydrogen and
refilling portable containers, trailers, mobile supply trucks, or tank
cars.
(ii) Liquefied hydrogen systems. (a) Paragraph (c) of this section
applies to the installation of liquefied hydrogen systems on consumer
premises.
(b) Paragraph (c) of this section does not apply to liquefied
hydrogen portable containers of less than 150 liters (39.63 gallons)
capacity; nor to liquefied hydrogen manufacturing plants or other
establishments operated by the hydrogen supplier or his agent for the
sole purpose of storing liquefied hydrogen and refilling portable
containers, trailers, mobile supply trucks, or tank cars.
(b) Gaseous hydrogen systems--(1) Design--(i) Containers. (a)
Hydrogen containers shall comply with one of the following:
(1) Designed, constructed, and tested in accordance with appropriate
requirements of ASME Boiler and Pressure Vessel Code, Section VIII--
Unfired Pressure Vessels--1968, which is incorporated by reference as
specified in Sec. 1910.6.
(2) Designed, constructed, tested and maintained in accordance with
U.S. Department of Transportation Specifications and Regulations.
(b) Permanently installed containers shall be provided with
substantial noncombustible supports on firm noncombustible foundations.
(c) Each portable container shall be legibly marked with the name
``Hydrogen'' in accordance with ``Marking Portable Compressed Gas
Containers to Identify the Material Contained'' ANSI Z48.1--1954, which
is incorporated by reference as specified in Sec. 1910.6. Each
manifolded hydrogen supply unit shall be legibly marked with the name
Hydrogen or a legend such as ``This unit contains hydrogen.''
(ii) Safety relief devices. (a) Hydrogen containers shall be
equipped with safety relief devices as required by the ASME Boiler and
Pressure Vessel Code, Section VIII Unfired Pressure Vessels, 1968 or the
DOT Specifications and
[[Page 227]]
Regulations under which the container is fabricated.
(b) Safety relief devices shall be arranged to discharge upward and
unobstructed to the open air in such a manner as to prevent any
impingement of escaping gas upon the container, adjacent structure or
personnel. This requirement does not apply to DOT Specification
containers having an internal volume of 2 cubic feet or less.
(c) Safety relief devices or vent piping shall be designed or
located so that moisture cannot collect and freeze in a manner which
would interfere with proper operation of the device.
(iii) Piping, tubing, and fittings. (a) Piping, tubing, and fittings
shall be suitable for hydrogen service and for the pressures and
temperatures involved. Cast iron pipe and fittings shall not be used.
(b) Piping and tubing shall conform to Section 2--``Industrial Gas
and Air Piping''--Code for Pressure Piping, ANSI B31.1-1967 with addenda
B31.1-1969, which is incorporated by reference as specified in Sec.
1910.6.
(c) Joints in piping and tubing may be made by welding or brazing or
by use of flanged, threaded, socket, or compression fittings. Gaskets
and thread sealants shall be suitable for hydrogen service.
(iv) Equipment assembly. (a) Valves, gauges, regulators, and other
accessories shall be suitable for hydrogen service.
(b) Installation of hydrogen systems shall be supervised by
personnel familiar with proper practices with reference to their
construction and use.
(c) Storage containers, piping, valves, regulating equipment, and
other accessories shall be readily accessible, and shall be protected
against physical damage and against tampering.
(d) Cabinets or housings containing hydrogen control or operating
equipment shall be adequately ventilated.
(e) Each mobile hydrogen supply unit used as part of a hydrogen
system shall be adequately secured to prevent movement.
(f) Mobile hydrogen supply units shall be electrically bonded to the
system before discharging hydrogen.
(v) Marking. The hydrogen storage location shall be permanently
placarded as follows: ``HYDROGEN--FLAMMABLE GAS--NO SMOKING--NO OPEN
FLAMES,'' or equivalent.
(vi) Testing. After installations, all piping, tubing, and fittings
shall be tested and proved hydrogen gas tight at maximum operating
pressure.
(2) Location--(i) General. (a) The system shall be located so that
it is readily accessible to delivery equipment and to authorized
personnel.
(b) Systems shall be located above ground.
(c) Systems shall not be located beneath electric power lines.
(d) Systems shall not be located close to flammable liquid piping or
piping of other flammable gases.
(e) Systems near aboveground flammable liquid storage shall be
located on ground higher than the flammable liquid storage except when
dikes, diversion curbs, grading, or separating solid walls are used to
prevent accumulation of flammable liquids under the system.
(ii) Specific requirements. (a) The location of a system, as
determined by the maximum total contained volume of hydrogen, shall be
in the order of preference as indicated by Roman numerals in Table H-1.
Table H-1
----------------------------------------------------------------------------------------------------------------
Size of hydrogen system
Nature of location --------------------------------------------------------------------------
Less than 3,000 CF 3,000 CF to 15,000 CF In excess of 15,000 CF
----------------------------------------------------------------------------------------------------------------
Outdoors............................. I...................... IDI....................
In a separate building............... II..................... II..................... II.
In a special room.................... III.................... III.................... Not permitted.
Inside buildings not in a special IV..................... Not permitted.......... Not permitted.
room and exposed to other
occupancies.
----------------------------------------------------------------------------------------------------------------
(b) The minimum distance in feet from a hydrogen system of indicated
capacity located outdoors, in separate buildings or in special rooms to
any specified outdoor exposure shall be in accordance with Table H-2.
(c) The distances in Table H-2 Items 1 and 3 to 10 inclusive do not
apply where protective structures such as adequate fire walls are
located between the system and the exposure.
[[Page 228]]
Table H-2
----------------------------------------------------------------------------------------------------------------
Type of outdoor exposure Size of hydrogen system
----------------------------------------------------------------------------------------------------------------
3,000 CF In excess
Less than to 15,000 of 15,000
3,000 CF CF CF
----------------------------------------------------------------------------------------------------------------
1. Building or structure................. Wood frame construction \1\...... 10 25 50
Heavy timber, noncombustible or 0 10 \2\ 25
ordinary construction \1\.
Fire-resistive construction \1\.. 0 0 0
2. Wall openings......................... Not above any part of a system... 10 10 10
Above any part of a system....... 25 25 25
3. Flammable liquids above ground........ 0 to 1,000 gallons............... 10 25 25
In excess of 1,000 gallons....... 25 50 50
4. Flammable liquids below ground--0 to Tank............................. 10 10 10
1,000 gallons. Vent or fill opening of tank..... 25 25 25
5. Flammable liquids below ground--in Tank............................. 20 20 20
excess of 1,000 gallons.. Vent or fill opening of tank..... 25 25 25
6. Flammable gas storage, either high 0 to 15,000 CF capacity.......... 10 25 25
pressure or low pressure.. In excess of 15,000 CF capacity.. 25 50 50
7. Oxygen storage........................ 12,000 CF or less \4\............ .......... .......... ..........
More than 12,000 CF \5\.......... .......... .......... ..........
8. Fast burning solids such as ordinary lumber, excelsior or paper.......... 50 50 50
9. Slow burning solids such as heavy timber or coal......................... 25 25 25
10. Open flames and other sources of ignition............................... 25 25 25
11. Air compressor intakes or inlets to ventilating or air-conditioning 50 50 50
equipment.
12. Concentration of people \3\............................................. 25 50 50
----------------------------------------------------------------------------------------------------------------
\1\ Refer to NFPA No. 220 Standard Types of Building Construction for definitions of various types of
construction. (1969 Ed.)
\2\ But not less than one-half the height of adjacent side wall of the structure.
\3\ In congested areas such as offices, lunchrooms, locker rooms, time-clock areas.
\4\ Refer to NFPA No. 51, gas systems for welding and cutting (1969).
\5\ Refer to NFPA No. 566, bulk oxygen systems at consumer sites (1969).
(d) Hydrogen systems of less than 3,000 CF when located inside
buildings and exposed to other occupancies shall be situated in the
building so that the system will be as follows:
(1) In an adequately ventilated area as in paragraph (b)(3)(ii)(b)
of this section.
(2) Twenty feet from stored flammable materials or oxidizing gases.
(3) Twenty-five feet from open flames, ordinary electrical equipment
or other sources of ignition.
(4) Twenty-five feet from concentrations of people.
(5) Fifty feet from intakes of ventilation or air-conditioning
equipment and air compressors.
(6) Fifty feet from other flammable gas storage.
(7) Protected against damage or injury due to falling objects or
working activity in the area.
(8) More than one system of 3,000 CF or less may be installed in the
same room, provided the systems are separated by at least 50 feet. Each
such system shall meet all of the requirements of this paragraph.
(3) Design consideration at specific locations--(i) Outdoor
locations. (a) Where protective walls or roofs are provided, they shall
be constructed of noncombustible materials.
(b) Where the enclosing sides adjoin each other, the area shall be
properly ventilated.
(c) Electrical equipment within 15 feet shall be in accordance with
subpart S of this part.
(ii) Separate buildings. (a) Separate buildings shall be built of at
least noncombustible construction. Windows and doors shall be located so
as to be readily accessible in case of emergency. Windows shall be of
glass or plastic in metal frames.
(b) Adequate ventilation to the outdoors shall be provided. Inlet
openings shall be located near the floor in exterior walls only. Outlet
openings shall be located at the high point of the room in exterior
walls or roof. Inlet and outlet openings shall each have minimum total
area of one (1) square foot per 1,000 cubic feet of room volume.
Discharge from outlet openings shall be directed or conducted to a safe
location.
(c) Explosion venting shall be provided in exterior walls or roof
only. The venting area shall be equal to not
[[Page 229]]
less than 1 square foot per 30 cubic feet of room volume and may consist
of any one or any combination of the following: Walls of light,
noncombustible material, preferably single thickness, single strength
glass; lightly fastened hatch covers; lightly fastened swinging doors in
exterior walls opening outward; lightly fastened walls or roof designed
to relieve at a maximum pressure of 25 pounds per square foot.
(d) There shall be no sources of ignition from open flames,
electrical equipment, or heating equipment.
(e) Electrical equipment shall be in accordance with subpart S of
this part for Class I, Division 2 locations.
(f) Heating, if provided, shall be by steam, hot water, or other
indirect means.
(iii) Special rooms. (a) Floor, walls, and ceiling shall have a
fire-resistance rating of at least 2 hours. Walls or partitions shall be
continuous from floor to ceiling and shall be securely anchored. At
least one wall shall be an exterior wall. Openings to other parts of the
building shall not be permitted. Windows and doors shall be in exterior
walls and shall be located so as to be readily accessible in case of
emergency. Windows shall be of glass or plastic in metal frames.
(b) Ventilation shall be as provided in paragraph (b)(3)(ii)(b) of
this section.
(c) Explosion venting shall be as provided in paragraph
(b)(3)(ii)(c) of this section.
(d) There shall be no sources of ignition from open flames,
electrical equipment, or heating equipment.
(e) Electric equipment shall be in accordance with the requirements
of subpart S of this part for Class I, Division 2 locations.
(f) Heating, if provided, shall be by steam, hot water, or indirect
means.
(4) Operating instructions. For installations which require any
operation of equipment by the user, legible instructions shall be
maintained at operating locations.
(5) Maintenance. The equipment and functioning of each charged
gaseous hydrogen system shall be maintained in a safe operating
condition in accordance with the requirements of this section. The area
within 15 feet of any hydrogen container shall be kept free of dry
vegetation and combustible material.
(c) Liquefied hydrogen systems--(1) Design--(i) Containers. (a)
Hydrogen containers shall comply with the following: Storage containers
shall be designed, constructed, and tested in accordance with
appropriate requirements of the ASME Boiler and Pressure Vessel Code,
Section VIII--Unfired Pressure Vessels (1968) or applicable provisions
of API Standard 620, Recommended Rules for Design and Construction of
Large, Welded, Low-Pressure Storage Tanks, Second Edition (June 1963)
and appendix R (April 1965), which is incorporated by reference as
specified in Sec. 1910.6.
(b) Portable containers shall be designed, constructed and tested in
accordance with DOT Specifications and Regulations.
(ii) Supports. Permanently installed containers shall be provided
with substantial noncombustible supports securely anchored on firm
noncombustible foundations. Steel supports in excess of 18 inches in
height shall be protected with a protective coating having a 2-hour
fire-resistance rating.
(iii) Marking. Each container shall be legibly marked to indicate
``LIQUEFIED HYDROGEN--FLAMMABLE GAS.''
(iv) Safety relief devices. (a)(1) Stationary liquefied hydrogen
containers shall be equipped with safety relief devices sized in
accordance with CGA Pamphlet S-1, Part 3, Safety Relief Device Standards
for Compressed Gas Storage Containers, which is incorporated by
reference as specified in Sec. 1910.6.
(2) Portable liquefied hydrogen containers complying with the U.S.
Department of Transportation Regulations shall be equipped with safety
relief devices as required in the U.S. Department of Transportation
Specifications and Regulations. Safety relief devices shall be sized in
accordance with the requirements of CGA Pamphlet S-1, Safety Relief
Device Standards, Part 1, Compressed Gas Cylinders and Part 2, Cargo and
Portable Tank Containers.
(b) Safety relief devices shall be arranged to discharge
unobstructed to the outdoors and in such a manner as to prevent
impingement of escaping
[[Page 230]]
liquid or gas upon the container, adjacent structures or personnel. See
paragraph (c)(2)(i)(f) of this section for venting of safety relief
devices in special locations.
(c) Safety relief devices or vent piping shall be designed or
located so that moisture cannot collect and freeze in a manner which
would interfere with proper operation of the device.
(d) Safety relief devices shall be provided in piping wherever
liquefied hydrogen could be trapped between closures.
(v) Piping, tubing, and fittings. (a) Piping, tubing, and fittings
and gasket and thread sealants shall be suitable for hydrogen service at
the pressures and temperatures involved. Consideration shall be given to
the thermal expansion and contraction of piping systems when exposed to
temperature fluctuations of ambient to liquefied hydrogen temperatures.
(b) Gaseous hydrogen piping and tubing (above -20 [deg]F.) shall
conform to the applicable sections of Pressure Piping Section 2--
Industrial Gas and Air Piping, ANSI B31.1-1967 with addenda B31.1-1969.
Design of liquefied hydrogen or cold (-20 [deg]F. or below) gas piping
shall use Petroleum Refinery Piping ANSI B31.3-1966 or Refrigeration
Piping ANSI B31.5-1966 with addenda B31.5a-1968 as a guide, which are
incorporated by reference as specified in Sec. 1910.6.
(c) Joints in piping and tubing shall preferably be made by welding
or brazing; flanged, threaded, socket, or suitable compression fittings
may be used.
(d) Means shall be provided to minimize exposure of personnel to
piping operating at low temperatures and to prevent air condensate from
contacting piping, structural members, and surfaces not suitable for
cryogenic temperatures. Only those insulating materials which are rated
nonburning in accordance with ASTM Procedures D1692-68, which is
incorporated by reference as specified in Sec. 1910.6, may be used.
Other protective means may be used to protect personnel. The insulation
shall be designed to have a vapor-tight seal in the outer covering to
prevent the condensation of air and subsequent oxygen enrichment within
the insulation. The insulation material and outside shield shall also be
of adequate design to prevent attrition of the insulation due to normal
operating conditions.
(e) Uninsulated piping and equipment which operate at liquefied-
hydrogen temperature shall not be installed above asphalt surfaces or
other combustible materials in order to prevent contact of liquid air
with such materials. Drip pans may be installed under uninsulated piping
and equipment to retain and vaporize condensed liquid air.
(vi) Equipment assembly. (a) Valves, gauges, regulators, and other
accessories shall be suitable for liquefied hydrogen service and for the
pressures and temperatures involved.
(b) Installation of liquefied hydrogen systems shall be supervised
by personnel familiar with proper practices and with reference to their
construction and use.
(c) Storage containers, piping, valves, regulating equipment, and
other accessories shall be readily accessible and shall be protected
against physical damage and against tampering. A shutoff valve shall be
located in liquid product withdrawal lines as close to the container as
practical. On containers of over 2,000 gallons capacity, this shutoff
valve shall be of the remote control type with no connections, flanges,
or other appurtenances (other than a welded manual shutoff valve)
allowed in the piping between the shutoff valve and its connection to
the inner container.
(d) Cabinets or housings containing hydrogen control equipment shall
be ventilated to prevent any accumulation of hydrogen gas.
(vii) Testing. (a) After installation, all field-erected piping
shall be tested and proved hydrogen gas-tight at operating pressure and
temperature.
(b) Containers if out of service in excess of 1 year shall be
inspected and tested as outlined in (a) of this subdivision. The safety
relief devices shall be checked to determine if they are operable and
properly set.
(viii) Liquefied hydrogen vaporizers. (a) The vaporizer shall be
anchored and its connecting piping shall be sufficiently flexible to
provide for the effect of expansion and contraction due to temperature
changes.
[[Page 231]]
(b) The vaporizer and its piping shall be adequately protected on
the hydrogen and heating media sections with safety relief devices.
(c) Heat used in a liquefied hydrogen vaporizer shall be indirectly
supplied utilizing media such as air, steam, water, or water solutions.
(d) A low temperature shutoff switch shall be provided in the
vaporizer discharge piping to prevent flow of liquefied hydrogen in the
event of the loss of the heat source.
(ix) Electrical systems. (a) Electrical wiring and equipment located
within 3 feet of a point where connections are regularly made and
disconnected, shall be in accordance with subpart S of this part, for
Class I, Group B, Division 1 locations.
(b) Except as provided in (a) of this subdivision, electrical
wiring, and equipment located within 25 feet of a point where
connections are regularly made and disconnected or within 25 feet of a
liquid hydrogen storage container, shall be in accordance with subpart S
of this part, for Class I, Group B, Division 2 locations. When equipment
approved for class I, group B atmospheres is not commercially available,
the equipment may be--
(1) Purged or ventilated in accordance with NFPA No. 496-1967,
Standard for Purged Enclosures for Electrical Equipment in Hazardous
Locations,
(2) Intrinsically safe, or
(3) Approved for Class I, Group C atmospheres. This requirement does
not apply to electrical equipment which is installed on mobile supply
trucks or tank cars from which the storage container is filled.
(x) Bonding and grounding. The liquefied hydrogen container and
associated piping shall be electrically bonded and grounded.
(2) Location of liquefied hydrogen storage--(i) General
requirements. (a) The storage containers shall be located so that they
are readily accessible to mobile supply equipment at ground level and to
authorized personnel.
(b) The containers shall not be exposed by electric power lines,
flammable liquid lines, flammable gas lines, or lines carrying oxidizing
materials.
(c) When locating liquified hydrogen storage containers near above-
ground flammable liquid storage or liquid oxygen storage, it is
advisable to locate the liquefied hydrogen container on ground higher
than flammable liquid storage or liquid oxygen storage.
(d) Where it is necessary to locate the liquefied hydrogen container
on ground that is level with or lower than adjacent flammable liquid
storage or liquid oxygen storage, suitable protective means shall be
taken (such as by diking, diversion curbs, grading), with respect to the
adjacent flammable liquid storage or liquid oxygen storage, to prevent
accumulation of liquids within 50 feet of the liquefied hydrogen
container.
(e) Storage sites shall be fenced and posted to prevent entrance by
unauthorized personnel. Sites shall also be placarded as follows:
``Liquefied Hydrogen--Flammable Gas--No Smoking--No Open Flames.''
(f) If liquified hydrogen is located in (as specified in Table H-3)
a separate building, in a special room, or inside buildings when not in
a special room and exposed to other occupancies, containers shall have
the safety relief devices vented unobstructed to the outdoors at a
minimum elevation of 25 feet above grade to a safe location as required
in paragraph (c)(1)(iv)(b) of this section.
(ii) Specific requirements. (a) The location of liquefied hydrogen
storage, as determined by the maximum total quantity of liquified
hydrogen, shall be in the order of preference as indicated by Roman
numerals in the following Table H-3.
Table H-3--Maximum Total Quantity of Liquefied Hydrogen Storage Permitted
----------------------------------------------------------------------------------------------------------------
Size of hydrogen storage (capacity in gallons)
-------------------------------------------------------------------------------
Nature of location 39.63 (150 liters)
to 50 51 to 300 301 to 600 In excess of 600
----------------------------------------------------------------------------------------------------------------
Outdoors........................ I................. I................. I................. I.
In a separate building.......... II................ II................ II................ Not permitted.
In a special room............... III............... III............... Not permitted..... Do.
[[Page 232]]
Inside buildings not in a IV................ Not permitted..... ......do.......... Do.
special room and exposed to
other occupancies.
----------------------------------------------------------------------------------------------------------------
Note: This table does not apply to the storage in dewars of the type generally used in laboratories for
experimental purposes.
(b) The minimum distance in feet from liquefied hydrogen systems of
indicated storage capacity located outdoors, in a separate building, or
in a special room to any specified exposure shall be in accordance with
Table H-4.
Table H-4--Minimum Distance (Feet) From Liquefied Hydrogen Systems to
Exposure \1,2\
------------------------------------------------------------------------
Liquefied hydrogen storage
(capacity in gallons)
-----------------------------
Type of exposure 39.63
(150 3,501 to 15,001
liters) 15,000 to
to 3,500 30,000
------------------------------------------------------------------------
1. Fire-resistive building and fire walls 5 5 5
\3\......................................
2. Noncombustible building \3\............ 25 50 75
3. Other buildings \3\.................... 50 75 100
4. Wall openings, air-compressor intakes, 75 75 75
inlets for air-conditioning or
ventilating equipment....................
5. Flammable liquids (above ground and 50 75 100
vent or fill openings if below ground)
(see 513 and 514)........................
6. Between stationary liquefied hydrogen 5 5 5
containers...............................
7. Flammable gas storage.................. 50 75 100
8. Liquid oxygen storage and other 100 100 100
oxidizers (see 513 and 514)..............
9. Combustible solids..................... 50 75 100
10. Open flames, smoking and welding...... 50 50 50
11. Concentrations of people.............. 75 75 75
------------------------------------------------------------------------
\1\ The distance in Nos. 2, 3, 5, 7, 9, and 12 in Table H-4 may be
reduced where protective structures, such as firewalls equal to height
of top of the container, to safeguard the liquefied hydrogen storage
system, are located between the liquefied hydrogen storage
installation and the exposure.
\2\ Where protective structures are provided, ventilation and
confinement of product should be considered. The 5-foot distance in
Nos. 1 and 6 facilitates maintenance and enhances ventilation.
\3\ Refer to Standard Types of Building Construction, NFPA No. 220-1969
for definitions of various types of construction.
In congested areas such as offices, lunchrooms, locker rooms, time-clock
areas.
(iii) Handling of liquefied hydrogen inside buildings other than
separate buildings and special rooms. Portable liquefied hydrogen
containers of 50 gallons or less capacity as permitted in Table H-3 and
in compliance with subdivision (i)(f) of this subparagraph when housed
inside buildings not located in a special room and exposed to other
occupancies shall comply with the following minimum requirements:
(a) Be located 20 feet from flammable liquids and readily
combustible materials such as excelsior or paper.
(b) Be located 25 feet from ordinary electrical equipment and other
sources of ignition including process or analytical equipment.
(c) Be located 25 feet from concentrations of people.
(d) Be located 50 feet from intakes of ventilation and air-
conditioning equipment or intakes of compressors.
(e) Be located 50 feet from storage of other flammable-gases or
storage of oxidizing gases.
(f) Containers shall be protected against damage or injury due to
falling objects or work activity in the area.
(g) Containers shall be firmly secured and stored in an upright
position.
(h) Welding or cutting operations, and smoking shall be prohibited
while hydrogen is in the room.
(i) The area shall be adequately ventilated. Safety relief devices
on the containers shall be vented directly outdoors or to a suitable
hood. See paragraphs (c)(1)(iv)(b) and (c)(2)(i)(f) of this section.
(3) Design considerations at specific locations--(i) Outdoor
locations. (a) Outdoor location shall mean outside of any building or
structure, and includes locations under a weather shelter or canopy
provided such locations are not enclosed by more than two walls set at
right angles and are provided with vent-space between the walls and
vented roof or canopy.
(b) Roadways and yard surfaces located below liquefied hydrogen
piping,
[[Page 233]]
from which liquid air may drip, shall be constructed of noncombustible
materials.
(c) If protective walls are provided, they shall be constructed of
noncombustible materials and in accordance with the provisions of
paragraph (c)(3)(i)(a) of this section.
(d) Electrical wiring and equipment shall comply with paragraph
(c)(1)(ix) (a) and (b) of this section.
(e) Adequate lighting shall be provided for nighttime transfer
operation.
(ii) Separate buildings. (a) Separate buildings shall be of light
noncombustible construction on a substantial frame. Walls and roofs
shall be lightly fastened and designed to relieve at a maximum internal
pressure of 25 pounds per square foot. Windows shall be of shatterproof
glass or plastic in metal frames. Doors shall be located in such a
manner that they will be readily accessible to personnel in an
emergency.
(b) Adequate ventilation to the outdoors shall be provided. Inlet
openings shall be located near the floor level in exterior walls only.
Outlet openings shall be located at the high point of the room in
exterior walls or roof. Both the inlet and outlet vent openings shall
have a minimum total area of 1 square foot per 1,000 cubic feet of room
volume. Discharge from outlet openings shall be directed or conducted to
a safe location.
(c) There shall be no sources of ignition.
(d) Electrical wiring and equipment shall comply with paragraphs
(c)(1)(ix) (a) and (b) of this section except that the provisions of
paragraph (c)(1)(ix)(b) of this section shall apply to all electrical
wiring and equipment in the separate building.
(e) Heating, if provided, shall be by steam, hot water, or other
indirect means.
(iii) Special rooms. (a) Floors, walls, and ceilings shall have a
fire resistance rating of at least 2 hours. Walls or partitions shall be
continuous from floor to ceiling and shall be securely anchored. At
least one wall shall be an exterior wall. Openings to other parts of the
building shall not be permitted. Windows and doors shall be in exterior
walls and doors shall be located in such a manner that they will be
accessible in an emergency. Windows shall be of shatterproof glass or
plastic in metal frames.
(b) Ventilation shall be as provided in paragraph (c)(3)(ii)(b) of
this section.
(c) Explosion venting shall be provided in exterior walls or roof
only. The venting area shall be equal to not less than 1 square foot per
30 cubic feet of room volume and may consist of any one or any
combination of the following: Walls of light noncombustible material;
lightly fastened hatch covers; lightly fastened swinging doors opening
outward in exterior walls; lightly fastened walls or roofs designed to
relieve at a maximum pressure of 25 pounds per square foot.
(d) There shall be no sources of ignition.
(e) Electrical wiring and equipment shall comply with paragraph
(c)(1)(ix) (a) and (b) of this section except that the provision of
paragraph (c)(1)(ix)(b) of this section shall apply to all electrical
wiring and equipment in the special room.
(f) Heating, if provided, shall be steam, hot water, or by other
indirect means.
(4) Operating instructions--(i) Written instructions. For
installation which require any operation of equipment by the user,
legible instructions shall be maintained at operating locations.
(ii) Attendant. A qualified person shall be in attendance at all
times while the mobile hydrogen supply unit is being unloaded.
(iii) Security. Each mobile liquefied hydrogen supply unit used as
part of a hydrogen system shall be adequately secured to prevent
movement.
(iv) Grounding. The mobile liquefied hydrogen supply unit shall be
grounded for static electricity.
(5) Maintenance. The equipment and functioning of each charged
liquefied hydrogen system shall be maintained in a safe operating
condition in accordance with the requirements of this section. Weeds or
similar combustibles
[[Page 234]]
shall not be permitted within 25 feet of any liquefied hydrogen
equipment.
[39 FR 23502, June 27, 1974, as amended at 43 FR 49746, Oct. 24, 1978;
53 FR 12121, Apr. 12, 1988; 55 FR 32015, Aug. 6, 1990; 58 FR 35309, June
30, 1993; 61 FR 9236, 9237, Mar. 7, 1996; 69 FR 31881, June 8, 2004]
