{"data":{"id":"us/46-cfr-154.805","jurisdiction":"us","citation":"46 CFR 154.805","heading":"Vent masts.","body":"Relief valves or common vent headers from relief valves must discharge to a vent mast that:\n(a) Discharges vertically upward;\n(b) Has a rain cap or other means of preventing the entrance of rain or snow;\n(c) Has a screen with 25mm (1 inch) wire mesh or bars not more than 25mm (1 in.) apart on the discharge port;\n(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;\n(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);\n(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;\n(g) Has drains to remove any liquid that may accumulate; and\n(h) Prevents accumulations of liquid at the relief valves.","path":["Title 46—Shipping","CHAPTER I—COAST GUARD, DEPARTMENT OF HOMELAND SECURITY","SUBCHAPTER O—CERTAIN BULK DANGEROUS CARGOES","PART 154—SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES","Subpart C—Design, Construction and Equipment"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-46.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:22Z","sha256":"789c5b182628c14c3395f4c7062f00a36ae64af6c036ed2d23df45b134ff1444","source_id":"us-cfr","stale":true,"prev":"us/46-cfr-154.804","next":"us/46-cfr-154.806"},"notice":"GroundRules: Original legal text. Not legal advice."}