46 CFR § 154.1710 - Exclusion of air from cargo tank vapor spaces.

---
identifier: "/us/cfr/t46/s154.1710"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "46 CFR § 154.1710 - Exclusion of air from cargo tank vapor spaces."
title_number: 46
title_name: "Shipping"
section_number: "154.1710"
section_name: "Exclusion of air from cargo tank vapor spaces."
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"
---


# 154.1710 Exclusion of air from cargo tank vapor spaces.

When a vessel is carrying acetaldehyde, butadiene, ethylene oxide, or vinyl chloride, the master shall ensure that air is:

(a) Purged from the cargo tanks and associated piping before the cargo is loaded; and

(b) Excluded after the cargo is loaded by maintaining a positive pressure of at least 13.8 kPa gauge (2 psig) by:

(1) Introducing a gas that:

(i) Is not reactive;

(ii) Is not flammable; and

(iii) Does not contain more than 0.2% oxygen by volume; or

(2) Controlling the cargo temperature.