---
kind: "section"
citation: "46 C.F.R. § 147.66"
title: "46"
number: "147.66"
heading: "Inert gas fire extinguishing systems."
url: "https://uscodex.org/cfr/46/147.66"
---

# §147.66. Inert gas fire extinguishing systems.

- (a) Inert gas cylinders forming part of a clean agent fixed fire extinguishing system must be retested every 12 years.
- (b) An inert gas cylinder must be removed from service if it:
  - (1) Leaks;
  - (2) Is dented, bulging, severely corroded, or otherwise weakened;
  - (3) Has lost more than 5 percent of its tare weight; or
  - (4) **Has been involved in a fire.**
- (c) Flexible connections between cylinders and discharge piping for fixed inert gas fire extinguishing systems must be renewed or retested in accordance with [section 7.3](/cfr/46/7.3.md) of NFPA 2001 (incorporated by reference, see [§ 147.7](/cfr/46/147.7.md)), except that this renewal or retesting must occur when the cylinders are retested.

## Notes

### Amendments

[USCG-2006-24797, 77 FR 33886, June 7, 2012, as amended by USCG-2020-0519, 89 FR 76701, Sept. 18, 2024]

### Authority

Authority: 46 U.S.C. 3306; E.O. 12234, 45 FR 58801, 3 CFR, 1980 Comp., p. 277; DHS Delegation 00170.1, Revision No. 01.4.

### Source

Source: CGD 84-044, 53 FR 7749, Mar. 10, 1988, unless otherwise noted.

### Amendments

[USCG-2006-24797, 77 FR 33886, June 7, 2012, as amended by USCG-2020-0519, 89 FR 76701, Sept. 18, 2024]