197.340—Breathing gas supply.
(a)
A primary breathing gas supply for surface-supplied diving must be sufficient to support the following for the duration of the planned dive:
(3)
The decompression chamber, when required by § 197.432(e)(2) or by § 197.434(a) for the duration of the dive and for one hour after completion of the planned dive.
(b)
A secondary breathing gas supply for surface-supplied diving must be sufficient to support the following:
(4)
The decompression chamber when required by § 197.432(e)(2) or by § 197.434(a) for the duration of the dive and one hour after the completion of the planned dive.
(c)
A diver-carried reserve breathing gas supply for surface-supplied diving must be sufficient to allow the diver to—
(d)
A primary breathing gas supply for SCUBA diving must be sufficient to support the diver for the duration of the planned dive through his return to the dive location or planned pick-up point.
(e)
A diver-carried reserve breathing gas supply for SCUBA diving must be sufficient to allow the diver to return to the dive location or planned pick-up point from the greatest depth of the planned dive.
(h)
Helium used for breathing mixtures must be grades A, B, or C produced by the Federal Government, or equivalent.
(iv)
25 parts per million of hydrocarbons (includes methane and all other hydrocarbons expressed as methane).