---
kind: "section"
citation: "46 C.F.R. § 197.434"
title: "46"
number: "197.434"
heading: "Surface-supplied mixed-gas diving."
url: "https://uscodex.org/cfr/46/197.434"
---

# §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](/cfr/46/197.332.md) is ready for use at the dive location;
- (b) A diving stage is used except when a bell is provided;
- (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;
- (e) A separate dive team member tends each diver in the water;
- (f) A standby diver is available during all nonsaturation dives;
- (g) **When saturation diving is conducted—**
  - (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](/cfr/46/197.340.md); and
- (k) The surface-supplied mixed-gas diver has the equipment required by § [197.346 (b)](/cfr/46/197.346.md?p=b) or [(d)](/cfr/46/197.346.md?p=d).

## Notes

### Authority

Authority: 33 U.S.C. 1509; 43 U.S.C. 1333; 46 U.S.C. 3306, 3703, 6101; Department of Homeland Security Delegation No. 0170.1.

### Source

Source: CGD 76-009, 43 FR 53683, Nov. 16, 1978, unless otherwise noted.