---
kind: "section"
citation: "46 C.F.R. § 32.55-30"
title: "46"
number: "32.55-30"
heading: "Venting of cargo tanks of tank vessels constructed between November 10, 1936, and July 1, 1951—TB/ALL."
url: "https://uscodex.org/cfr/46/32.55-30"
---

# §32.55-30. Venting of cargo tanks of tank vessels constructed between November 10, 1936, and July 1, 1951—TB/ALL.

- (a) **Venting required.** On all tank vessels, the construction or alteration of which is started on or after November 10, 1936, and prior to July 1, 1951, each cargo tank shall be equipped with a vent. The details of the venting system shall meet the requirements of this section, or alternatively, the requirements of either [§ 32.55-20](/cfr/46/32.55-20.md) or [§ 32.55-25](/cfr/46/32.55-25.md), as applicable, shall be met.
- (b) **Grade A liquids.**
  - (1) Cargo tanks in which Grade A liquids are to be transported shall be fitted with a venting system consisting of branch vent line from each cargo tank connected to a vent header which shall extend to a reasonable height above the weather deck and be fitted with a flame arrester or pressure-vacuum relief valve. Each branch vent line may be provided with a manually operated control valve, provided it is bypassed with a pressure-vacuum relief valve or each cargo tank to which such a branch vent line is connected is fitted with an independent pressure-vacuum relief valve. The vent header system shall be provided with suitable connections for flushing and draining.
  - (2) In barges with independent tanks carrying Grade A liquids, separate discharge pipes may be fitted to each pressure-vacuum relief valve, or the pressure-vacuum relief valve may be elevated, so that in either case the discharge from such valve will not be less than 7 feet above the deck where practicable.
- (c) **Grade B or C liquids.** Cargo tanks in which Grade B or C liquids are to be transported shall be fitted with individual pressure-vacuum relief valves or shall be fitted with a venting system consisting of branch vent lines connected to a vent header which shall extend to a reasonable height above the weather deck and be fitted with a flame arrester or a pressure-vacuum relief valve.
- (d) **Grade D or E liquids.** Cargo tanks in which Grade D or E liquids only are to be transported shall be fitted with gooseneck vents and flame screens unless such tanks are vented by pressure-vacuum relief valves or a venting system of branch vent lines and a vent header.

## Notes

### Authority

Authority: 46 U.S.C. 2103, 3306, 3703, 3719; E.O. 12234, 45 FR 58801, 3 CFR, 1980 Comp., p. 277; DHS Delegation No. 00170.1, Revision No. 01.4; Subpart 32.59 also issued under the authority of Sec. 4109, Pub. L. 101-380, 104 Stat. 515.

### Source

Source: CGFR 65-50, 30 FR 16671, Dec. 30, 1965, unless otherwise noted.