Table 1. Recommended distances of pyrophoric gas cylinders from fences and walls

Spontaneous Heating and Pyrophoricity

DOE-HDBK-1081-94

PYROPHORIC GASES AND LIQUIDS

Pyrophoric storage and dispensing areas should be located exterior to the

building, or in an approved shelter as specified in NFPA 318, Standard for the

Protection of Clean Rooms.

When used in a manifold or dispensing rack system, pyrophoric gas cylinders

should be separated from each other by a steel plate 6 mm (1/4 in.) thick,

extending 76 mm (3 in.) beyond the footprint of the cylinder. The steel plate

should extend from the top of the purge panel to 305 mm (12 in.) below the

cylinder valve.

Mechanical or natural ventilation at a minimum of .00047 m3 /s per .09 m2

(1.0 ft3/minute per sq ft) of storage and dispensing area should be provided.

Cylinders located in cabinets should be provided with mechanical ventilation at

a minimum of .762 m/s [200 ft per min (fpm)] across the cylinder neck and the

purge panel. The ventilation system should be provided with an automatic

emergency back-up source of power to operate at full capacity.

Remote manual shutdown of process gas flow should be provided outside each

gas cabinet or near each gas panel. The dispensing area should have an

emergency shutdown for all gases that can be operated at a minimum distance

of 4.6 m (15 ft) from the dispensing area.

Gas cabinets and cylinders not located in shelters or bunkers containing silane

or silane mixes should be provided with a security chain link fence to prevent

unauthorized entry and to reduce the impact of an explosion at the perimeter.

The area should also be separated from structures in accordance with Table 1.

Gas cabinets and cylinders located in shelters containing silane or silane mixes

should comply with the Table 1 without regard to shelter walls.

When gas cabinets are used, only single cylinder cabinets should be used for

pyrophorics and pyrophoric mixes.

Gas cabinets should be provided with sprinklers to protect cylinders from

exposure to external fires.

Table 1. Recommended distances of pyrophoric gas cylinders from fences and walls.

Distance to Fence in Ft

Distance to Wall in Ft

Unconfined Cylinders

Single Cylinder Cabinets

NFPA 70, National Electrical Code, should be consulted for explosion proofing of electrical

equipment near flammable gas storage areas.

Rev. 0

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Pyrophoricity