46 CFR § 154.345 - Air locks.
---
identifier: "/us/cfr/t46/s154.345"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "46 CFR § 154.345 - Air locks."
title_number: 46
title_name: "Shipping"
section_number: "154.345"
section_name: "Air locks."
chapter_name: "COAST GUARD, DEPARTMENT OF HOMELAND SECURITY"
subchapter_number: "O"
subchapter_name: "CERTAIN BULK DANGEROUS CARGOES"
part_number: "154"
part_name: "SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "46 U.S.C. 3703, 9101; Department of Homeland Security Delegation No. 0170.1."
regulatory_source: "CGD 74-289, 44 FR 26009, May 3, 1979, unless otherwise noted."
cfr_part: "154"
---
# 154.345 Air locks.
(a) An air lock may be used for access from a gas-dangerous zone on the weather deck to a gas-safe space.
(b) Each air lock must:
(1) Consist of two steel doors, at least 1.5 m (4.9 ft.) but not more than 2.5 m (8.2 ft.) apart, each gasketed and tight when tested with a fire hose at not less 207 kPa gauge (30 psig);
(2) Have self-closing doors with no latches or other devices for holding them open;
(3) Have an audible and visual alarm on both sides which are actuated when both door securing devices are in other than the fully closed position at the same time;
(4) Have mechanical ventilation in the space between the doors from a gas-safe area;
(5) Have a pressure greater than that of the gas-dangerous area on the weather deck;
(6) Have the rate of air change in the space between the doors of at least 8 changes per hour; and
(7) Have the space between the doors monitored for cargo vapor leaks under § 154.1350.
(c) In addition to the requirements of paragraphs (a) and (b) of this section, no gas-safe space on a liquefied flammable gas carrier may have an air lock unless the space:
(1) Is mechanically ventilated to make the pressure in the space greater than that in the air lock; and
(2) Has a means of automatically de-energizing all electrical equipment that is not explosion-proof in the space when the pressure in the space falls to or below the pressure in the air lock.