---
kind: "section"
citation: "46 C.F.R. § 169.640"
title: "46"
number: "169.640"
heading: "General."
url: "https://uscodex.org/cfr/46/169.640"
---

# §169.640. General.

- (a) Vital piping systems, as defined in [§ 169.642](/cfr/46/169.642.md) of this subpart, must meet the material and pressure design requirements of Subchapter F of this chapter.
- (b) Except as provided in this paragraph, nonmetallic piping system materials must meet the applicable requirements of [46 CFR 56.60-25](/cfr/46/56.60-25.md).
  - (1) Rigid nonmetallic materials are acceptable for use in bilge, ballast, and machinery-connected piping systems on vessels less than 120 feet in length, provided that bilge and fire systems do not use the same piping.
  - (2) **Nonmetallic piping is prohibited in fuel systems except where flexible hose is permitted.**
  - (3) Rigid nonmetallic materials may be used in non-vital systems.

## Notes

### Authority

Authority: 33 U.S.C. 1321(j); 46 U.S.C. 3306, 6101; Pub. L. 103-206, 107 Stat. 2439; E.O. 11735, 38 FR 21243, 3 CFR, 1971-1975 Comp., p. 793; DHS Delegation 00170.1, Revision No. 01.4; § 169.117 also issued under the authority of 44 U.S.C. 3507.

### Source

Source: CGD 83-005, 51 FR 896, Jan. 9, 1986, unless otherwise noted.