46 CFR §197.434

1. (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;
2. (b)A diving stage is used except when a bell is provided;
3. (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;
4. (d)A closed bell is used for dives at depths greater than 300 fsw, except when diving is conducted in a physically confining space;
5. (e)A separate dive team member tends each diver in the water;
6. (f)A standby diver is available during all nonsaturation dives;
7. (g)When saturation diving is conducted—
   1. (1)A standby diver is available when the closed bell leaves the dive location until the divers are in saturation; and
   2. (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;
8. (h)When closed bell operations are conducted, a diver is available in the closed bell to assist a diver in the water;
9. (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;
10. (j)Each diving operation has a primary and secondary breathing gas supply meeting the requirements of § 197.340; and
11. (k)The surface-supplied mixed-gas diver has the equipment required by § 197.346 (b) or (d).