46 CFR §197.332

1. (a)Meet the requirements of § 197.328;
2. (b)Have internal dimensions sufficient to accommodate a diver lying in a horizontal position and another person tending the diver;
3. (c)Have a capability for ingress and egress of personnel and equipment while the occupants are under pressure;
4. (d)Have a means of operating all installed man-way locking devices, except disabled shipping dogs, from both sides of a closed hatch;
5. (e)Have interior illumination sufficient to allow visual observation, diagnosis, and medical treatment of an occupant.
6. (f)Have one bunk for each two occupants;
7. (g)Have a capability that allows bunks to be seen over their entire lengths from the exterior;
8. (h)Have a minimum pressure capability of—
   1. (1)6 ATA, when used for diving to 300 fsw; or
   2. (2)The maximum depth of the dive, when used for diving operations deeper than 300 fsw, unless a closed bell meeting the requirements of § 197.330(a) (3), (4), and (5) is used;
      1. (i)Have a minimum pressurization rate of 2 ATA per minute to 60 fsw and at least 1 ATA per minute thereafter;
9. (j)Have a decompression rate of 1 ATA per minute to 33 fsw;
10. (k)Have an external pressure gage for each pressurized compartment;
11. (l)Have a capability to supply breathing mixtures at the maximum rate required by each occupant doing heavy work; and
12. (m)Have a sound-powered headset or telephone as a backup to the communications system required by § 197.328(c) (5) and (6), except when that communications system is a sound-powered system.