---
kind: "section"
citation: "46 C.F.R. § 154.805"
title: "46"
number: "154.805"
heading: "Vent masts."
url: "https://uscodex.org/cfr/46/154.805"
---

# §154.805. Vent masts.


Relief valves or common vent headers from relief valves must discharge to a vent mast that:

- (a) Discharges vertically upward;
- (b) Has a rain cap or other means of preventing the entrance of rain or snow;
- (c) Has a screen with 25mm (1 inch) wire mesh or bars not more than 25mm (1 in.) apart on the discharge port;
- (d) Extends at least to a height of B/3 or 6m (19.7 ft.), whichever is greater, above the weather deck and 6m (19.7 ft.) above the working level;
- (e) For a cargo tank, does not exhaust cargo vapors within a radius of B or 25m (82 ft.), whichever is less, from any forced or natural ventilation intake or other opening to an accommodation, service, control station, or other gas-safe space, except that for vessels less than 90m (295 ft.) in length, shorter distances may be specially approved by the Commandant (CG-OES);
- (f) For a containment system, except a cargo tank, does not exhaust vapor within a radius of 10m (32.8 ft.) or less from any forced or natural ventilation intake or other opening to an accommodation, service, control station, or other gas-safe space;
- (g) Has drains to remove any liquid that may accumulate; and
- (h) **Prevents accumulations of liquid at the relief valves.**

## Notes

### Amendments

[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]

### Authority

Authority: 46 U.S.C. 3703, 9101; Department of Homeland Security Delegation No. 0170.1.

### Source

Source: CGD 74-289, 44 FR 26009, May 3, 1979, unless otherwise noted.

### Amendments

[CGD 74-289, 44 FR 26009, May 3, 1979, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983]