46 CFR 143.220: Machinery space fire prevention

Last reviewed: October 14, 2026

This section sets fire prevention rules for machinery spaces. Seals and gaskets must be maintained to prevent leaks, hot components must be insulated, and flammable and combustible products may be stored there only in suitable containers.

What it says

  1. All seals and gaskets must be properly maintained to prevent leaks of flammable or combustible liquid into the machinery space.

    46 CFR 143.220(a)“All seals and gaskets must be properly maintained to prevent leaks of flammable or combustible liquid”

  2. The terms flammable liquid and combustible liquid have the meanings given in 46 CFR subpart 30.10.

    46 CFR 143.220(a)“as those terms are defined in 46 CFR subpart 30.10, into the machinery space”

  3. Piping and machinery components that exceed 220 °C (428 °F) must be insulated. This includes fittings, flanges, valves, exhaust manifolds, and turbochargers.

    46 CFR 143.220(b)“Piping and machinery components that exceed 220 °C (428 °F), including fittings, flanges, valves, exhaust manifolds, and turbochargers, must be insulated.”

  4. Measures must be in place to prevent leaks from flammable or combustible liquid piping from touching these hot components.

    46 CFR 143.220(b)“Measures must be in place to prevent flammable or combustible liquid piping leaks from coming into contact with these components.”

  5. Flammable and combustible products must not be stored in machinery spaces, unless they are in a suitable container that meets the requirements of § 142.225 of this subchapter.

    46 CFR 143.220(c)“Flammable and combustible products must not be stored in machinery spaces, unless they are stored in a suitable container that meets the requirements of § 142.225 of this subchapter.”

Common questions

What temperature requires insulation in a towing vessel machinery space?

Piping and machinery components that exceed 220 °C (428 °F) must be insulated. This includes items such as exhaust manifolds and turbochargers.

“Piping and machinery components that exceed 220 °C (428 °F), including fittings, flanges, valves, exhaust manifolds, and turbochargers, must be insulated.”

Can I store flammable products in the machinery space?

Not generally. They may be stored there only in a suitable container that meets the requirements of § 142.225 of this subchapter.

“Flammable and combustible products must not be stored in machinery spaces, unless they are stored in a suitable container that meets the requirements of § 142.225 of this subchapter.”

What must be done about seals and gaskets in machinery spaces?

All seals and gaskets must be properly maintained to prevent leaks of flammable or combustible liquid into the machinery space.

“All seals and gaskets must be properly maintained to prevent leaks of flammable or combustible liquid”

The text of 46 CFR 143.220

Electronic Code of Federal Regulations (eCFR), current as of April 16, 2026 · Read it on eCFR

Machinery space fire prevention

(a) All seals and gaskets must be properly maintained to prevent leaks of flammable or combustible liquid, as those terms are defined in 46 CFR subpart 30.10, into the machinery space.

(b) Piping and machinery components that exceed 220 °C (428 °F), including fittings, flanges, valves, exhaust manifolds, and turbochargers, must be insulated. Measures must be in place to prevent flammable or combustible liquid piping leaks from coming into contact with these components.

(c) Flammable and combustible products must not be stored in machinery spaces, unless they are stored in a suitable container that meets the requirements of § 142.225 of this subchapter.

Sections it refers to

The plain-English explanation on this page was written with AI from the regulation text above and checked automatically before publishing: every quote appears in the text, every number comes from it, and a second model confirmed each statement adds nothing the text doesn't say. Regulation text current as of April 16, 2026. The regulation text governs. RegKnot is not affiliated with the U.S. Coast Guard.