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(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 Less 3,000 CF In Excess Nature of Location than to of 3,000 CF 15,000 CF 15,000 CF Outdoors I I I In a separate building II II II In a special room III III Not Permitted Inside buildings not in a Not Not special room and exposed IV Permitted Permitted 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 distance in Table H-2, Items 1, 14 and 3 to 10 inclusive do not apply where protective structures such as adequate fire walls are located between the system and the exposure.
(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 Section 5475(b).
(2) 20 feet from stored flammable materials or oxidizing gases.
(3) 25 feet from open flames, ordinary electrical equipment or other sources of ignition.
(4) 25 feet from concentrations of people.
(5) 50 feet from intakes of ventilation or air conditioning equipment and air compressors.
(6) 50 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 Section.
Table H-2 Size of Hydrogen System Less 3,000 CF In Excess Type of Outdoor Exposure than to of 3,000 CF 15,000 CF 15,000 CF 1. Building or Wood Frame Construction* 10 25 50 Structure Heavy Timber, Noncom- bustible or Ordinary Con- struction* 0 10 25* Fire Resistive Construction* 0 0 0 2. Wall Openings Not above any part of a 10 10 10 system Above any part of a system 25 25 25 3. Flammable liquids 0-1,000 gallons 10 25 25 above ground In excess of 1,000 gallons 25 50 50 4. Flammable liquids Tank 10 10 10 below ground-- 0-1,000 gallons Vent or fill opening of tank 25 25 25 5. Flammable liquids Tank 20 20 20 below ground-- in excess of 1,000 gallons Vent or fill opening of tank 25 25 25 6. Flammable gas storage 0-15,000 CF capacity 10 25 25 age, either high pressure or low in excess of 15,000 CF pressure capacity 25 50 50 7. Oxygen Storage 12,000 CF or less Refer to NFPA No. 51, Gas Systems for Welding and Cutting More than 12,000 CF Refer to NFPA No. 50, Bulk Oxygen Systems at Consumer Sites 8. Fast burning solids such as ordinary lumber, 50 50 50 excelsior or paper 9. Slow burning solids such as heavy timber or 25 25 25 coal 10. Open flames and other sources of ignition 25 25 25 11. Air compressor intakes or inlets to 50 50 50 ventilating or air-conditioning equipment 12. Concentration of people*** 25 50 50 13. Public Sidewalks 15 15 15 14. Line of adjoining property which may be built 5 5 5 upon
* Refer to NFPA No. 220, Standard Types of Building Construction for definitions of various types of construction.
** But not less than one-half the height of adjacent side wall of the structure.
*** In congested areas such as offices, lunchrooms, locker rooms, time-clock areas and places of public assembly.
1. Editorial correction of Table H-2 (Register 76, No. 9).