197.434—Surface-supplied mixed-gas diving.
The diving supervisor shall insure that—
(a)
When mixed-gas diving is conducted, a decompression chamber or a closed bell meeting the requirements of § 197.332 is ready for use at the dive location;
(c)
A bell is used for dives deeper than 220 fsw or when the dive involves in-water decompression times greater than 120 minutes, except when the diver is using a heavy-weight diving outfit or is diving in a physically confining space;
(d)
A closed bell is used for dives at depths greater than 300 fsw, except when diving is conducted in a physically confining space;
(1)
A standby diver is available when the closed bell leaves the dive location until the divers are in saturation; and
(2)
A member of the dive team at the dive location is a diver able to assist in the recovery of the closed bell or its occupants, if required;
(h)
When closed bell operations are conducted, a diver is available in the closed bell to assist a diver in the water;
(i)
When a diver is in a physically confining space, another diver is stationed at the underwater point of entry and is line-tending the diver;
(j)
Each diving operation has a primary and secondary breathing gas supply meeting the requirements of § 197.340; and