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1910.103(c) Liquefied Hydrogen Systems
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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.
Portable containers shall be designed, constructed and tested in accordance with DOT Specifications and Regulations.
Each container shall be legibly marked to indicate "LIQUEFIED HYDROGEN - FLAMMABLE GAS".
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.
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.
Safety relief devices shall be arranged to discharge unobstructed to the outdoors and in such a manner as to prevent impingement of escaping 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.
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.
Safety relief devices shall be provided in piping wherever liquefied hydrogen could be trapped between closures.
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.
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 -
Purged or ventilated in accordance with NFPA No. 496-1967, Standard for Purged Enclosures for Electrical Equipment in Hazardous Locations,
Intrinsically safe, or
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.
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.
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 is incorporated by reference as specified in Sec. 1910.6.
Joints in piping and tubing shall preferably be made by welding or brazing; flanged, threaded, socket, or suitable compression fittings may be used.
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.
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.
Valves, gauges, regulators, and other accessories shall be suitable for liquefied hydrogen service and for the pressures and temperatures involved.
Installation of liquefied hydrogen systems shall be supervised by personnel familiar with proper practices and with reference to their construction and use.
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.
Cabinets or housings containing hydrogen control equipment shall be ventilated to prevent any accumulation of hydrogen gas.
After installation, all field-erected piping shall be tested and proved hydrogen gas-tight at operating pressure and temperature.
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.
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.
The vaporizer and its piping shall be adequately protected on the hydrogen and heating media sections with safety relief devices.
Heat used in a liquefied hydrogen vaporizer shall be indirectly supplied utilizing media such as air, steam, water, or water solutions.
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.
The liquefied hydrogen container and associated piping shall be electrically bonded and grounded.
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.
The storage containers shall be located so that they are readily accessible to mobile supply equipment at ground level and to authorized personnel.
The containers shall not be exposed by electric power lines, flammable liquid lines, flammable gas lines, or lines carrying oxidizing materials.
When locating liquefied 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.
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.
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".
If liquefied 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.
NOTE: This table does not apply to the storage in dewars of the type generally used in laboratories for experimental purposes.
| Nature of location | Sizeof hydrogen storage (capacity in gallons) | |||
| 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 | II | Not permitted | Do. |
| Inside buildings not in a special room and exposed to other occupancies |
IV | Not permitted | Do. | Do. |
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:
Be located 20 feet from flammable liquids and readily combustible materials such as excelsior or paper.
Be located 25 feet from ordinary electrical equipment and other sources of ignition including process or analytical equipment.
Be located 25 feet from concentrations of people.
Be located 50 feet from intakes of ventilation and air-conditioning equipment or intakes of compressors.
Be located 50 feet from storage of other flammable-gases or storage of oxidizing gases.
Containers shall be protected against damage or injury due to falling objects or work activity in the area.
Containers shall be firmly secured and stored in an upright position.
Welding or cutting operations, and smoking shall be prohibited while hydrogen is in the room.
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.
The location of liquefied hydrogen storage, as determined by the maximum total quantity of liquefied hydrogen, shall be in the order of preference as indicated by Roman numerals in the following Table H-3.
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.
Footnote(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.
Footnote(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.
Footnote(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.
| Type of Exposure | Liquefied hydrogen storage (capacity in gallons) |
||
| 39.63 (150 liters) to 3,500 |
3,501 to 15,000 |
15,001 to 30,000 |
|
| 1. Fire-resistive building and fire walls(3) | 5 | 5 | 5 |
| 2. Noncombustible building(3) | 25 | 50 | 75 |
| 3. Other buildings(3) | 50 | 75 | 100 |
| 4. Wall openings, air-compressor intakes, inlets for air-conditioning or ventilating equipment | 75 | 75 | 75 |
| 5. Flammable liquids (above ground and vent or fill openings if below ground) (see 513 and 514) | 50 | 75 | 100 |
| 6. Between stationary liquefied hydrogen containers | 5 | 5 | 5 |
| 7. Flammable gas storage | 50 | 75 | 100 |
| 8. Liquid oxygen storage and other oxidizers (see 513 and 514) | 100 | 100 | 100 |
| 9. Combustible solids | 50 | 75 | 100 |
| 10. Open flames, smoking and welding | 50 | 50 | 50 |
| 11. Concentrations of people | 75 | 75 | 75 |
Footnote(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.
Footnote(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.
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.
Roadways and yard surfaces located below liquefied hydrogen piping, from which liquid air may drip, shall be constructed of noncombustible materials.
If protective walls are provided, they shall be constructed of noncombustible materials and in accordance with the provisions of paragraphs (c)(3)(i)(a) of this section as applicable.
Electrical wiring and equipment shall comply with paragraph (c)(1)(ix)(a) and (b) of this section.
Adequate lighting shall be provided for nighttime transfer operation.
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.
Ventilation shall be as provided in paragraph (c)(3)(ii)(b) of this section.
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