§ 5473. 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
	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 [FNa1]	10	25	50
Structure	Heavy Timber, Noncom-
	bustible or Ordinary Con-
	struction [FNa1]	0	10	25 [FNa1]
	Fire Resistive
	Construction [FNa1]	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 ventilating		50	50	50
or air-conditioning equipment
12. Concentration of people [FNaaa1]		25	50	50
13. Public Sidewalks		15	15	15
14. Line of adjoining property which may be built		5	5	5
upon

[FNa1] Refer to NFPA No. 220, Standard Types of Building Construction for definitions of various types of construction.

[FNaa1] But not less than one-half the height of adjacent side wall of the structure.

[FNaaa1] In congested areas such as offices, lunchrooms, locker rooms, time-clock areas and places of public assembly.

HISTORY

1. Editorial correction of Table H-2 (Register 76, No. 9).