Cal. Code Regs. tit. 8, § 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
Nature of Location
Less than 3,000 CF
3,000 CF to 15,000 CF
In Excess of 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 special room and exposed to other occupancies
IV
Not Permitted
Not Permitted
(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. (1) In an adequately ventilated area as in Section 5475(b).
2. (2) 20 feet from stored flammable materials or oxidizing gases.
3. (3) 25 feet from open flames, ordinary electrical equipment or other sources of ignition.
4. (4) 25 feet from concentrations of people.
5. (5) 50 feet from intakes of ventilation or air conditioning equipment and air compressors.
6. (6) 50 feet from other flammable gas storage.
7. (7) Protected against damage or injury due to falling objects or working activity in the area.
8. (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
  Type of Outdoor Exposure
  Less than 3,000 CF
  3,000 CF to 15,000 CF
  In Excess of 15,000 CF
  1.
  Building or
  Wood Frame Construction^*
  10
  25
  50
  Structure
  Heavy Timber, Noncombustible or Ordinary Construction^*
  0
  10
  25^*
  Fire Resistive Construction^*
  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
  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 pressure
  in excess of 15,000 CF 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, 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 people^***
  25
  50
  50
  13.
  Public Sidewalks
  15
  15
  15
  14.
  Line of adjoining property which may be built upon
  5
  5
  5
  * 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.

History

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