46 CFR § 147.66 - Inert gas fire extinguishing systems.

---
identifier: "/us/cfr/t46/s147.66"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "46 CFR § 147.66 - Inert gas fire extinguishing systems."
title_number: 46
title_name: "Shipping"
section_number: "147.66"
section_name: "Inert gas fire extinguishing systems."
chapter_name: "COAST GUARD, DEPARTMENT OF HOMELAND SECURITY"
subchapter_number: "N"
subchapter_name: "DANGEROUS CARGOES"
part_number: "147"
part_name: "HAZARDOUS SHIPS' STORES"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
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."
regulatory_source: "CGD 84-044, 53 FR 7749, Mar. 10, 1988, unless otherwise noted."
cfr_part: "147"
---


# 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 of NFPA 2001 (incorporated by reference, see § 147.7), except that this renewal or retesting must occur when the cylinders are retested.

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