Table H-1
Nature of location | Size of hydrogen system | ||
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 room and exposed to other occupancies | IV | Not permitted | Not permitted. |
Table H-2
Type of outdoor exposure | Size of hydrogen system | |||
Less than 3,000 CF | 3,000 CF to 15,000 CF | In excess of 15,000 CF | ||
1. Building or structure | Wood frame construction1 | 10 | 25 | 50 |
Heavy timber, noncombustible or ordinary construction1 | 0 | 10 | 2 25 | |
Fire-resistive construction1 | 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 In excess of 1,000 gallons | 10 25 | 25 50 | 25 50 |
4. Flammable liquids below ground-0 to 1,000 gallons | Tank Vent or fill opening of tank | 10 25 | 10 25 | 10 25 |
5. Flammable liquids below ground-in excess of 1,000 gallons. | Tank Vent or fill opening of tank | 20 25 | 20 25 | 20 25 |
6. Flammable gas storage, either high pressure or low pressure. | 0 to 15,000 CF capacity In excess of 15,000 CF capacity | 10 25 | 25 50 | 25 50 |
7. Oxygen storage | 12,000 CF or less4 | |||
More than 12,000 CF5 | ||||
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 equipment | 50 | 50 | 50 | |
12. Concentration of people3 | 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).
Table H-3-Maximum Total Quantity of Liquefied Hydrogen Storage Permitted
Nature of location | Size of 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 | III | Not permitted | Do. |
Inside buildings not in a special room and exposed to other occupancies | IV | Not permitted | ......do | Do. |
NOTE: This table does not apply to the storage in dewars of the type generally used in laboratories for experimental purposes.
Table H-4-Minimum Distance (Feet) From Liquefied Hydrogen Systems to Exposure1 2
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 walls3 | 5 | 5 | 5 |
2. Noncombustible building3 | 25 | 50 | 75 |
3. Other buildings3 | 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 |
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.
29 C.F.R. §1910.103