46 CFR §197.432

1. (a)Surface-supplied air diving is conducted at depths less than 190 fsw, except that dives with bottom times of 30 minutes or less may be conducted to depths of 220 fsw;
2. (b)Each diving operation has a primary breathing gas supply;
3. (c)Each diver is continuously tended while in the water;
4. (d)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;
5. (e)For dives deeper than 130 fsw or outside the no-decompression limits—
   1. (1)Each diving operation has a secondary breathing gas supply;
   2. (2)A decompression chamber is ready for use at the dive location;
   3. (3)A diving stage is used except when a bell is provided;
   4. (4)A bell is used for dives with an in-water decompression time greater than 120 minutes, except when the diver is using a heavy-weight diving outfit or is diving in a physically confining space;
   5. (5)A separate dive team member tends each diver in the water;
   6. (6)A standby diver is available while a diver is in the water; and
   7. (7)Each diver has a diver-carried reserve breathing gas supply except when using a heavy-weight diving outfit or when diving in a physically confining space; and
6. (f)The surface-supplied air diver has the equipment required by § 197.346 (b) or (d).