---identifier: "/us/cfr/t46/s153.358"source: "ecfr"legal_status: "authoritative_unofficial"title: "46 CFR § 153.358 - Venting system flow capacity."title_number: 46title_name: "Shipping"section_number: "153.358"section_name: "Venting system flow capacity."chapter_name: "COAST GUARD, DEPARTMENT OF HOMELAND SECURITY"subchapter_number: "O"subchapter_name: "CERTAIN BULK DANGEROUS CARGOES"part_number: "153"part_name: "SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS"positive_law: falsecurrency: "2026-04-05"last_updated: "2026-04-05"format_version: "1.1.0"generator: "[email protected]"authority: "46 U.S.C. 3703; Department of Homeland Security Delegation No. 0170.1. Section 153.40 issued under 49 U.S.C. 5103. Sections 153.470 through 153.491, 153.1100 through 153.1132, and 153.1600 through 153.1608 also issued under 33 U.S.C. 1903 (b)."regulatory_source: "CGD 73-96, 42 FR 49027, Sept. 26, 1977, unless otherwise noted."cfr_part: "153"---
Identifier
/us/cfr/t46/s153.358
Currency
2026-04-05
Positive Law
No
Updated
2026-04-05
Chapter
Coast Guard, Department of Homeland Security
Authority
46 U.S.C. 3703; Department of Homeland Security Delegation No. 0170.1. Section 153.40 issued under 49 U.S.C. 5103. Sections 153.470 through 153.491, 153.1100 through 153.1132, and 153.1600 through 153... 46 U.S.C. 3703; Department of Homeland Security Delegation No. 0170.1. Section 153.40 issued under 49 U.S.C. 5103. Sections 153.470 through 153.491, 153.1100 through 153.1132, and 153.1600 through 153.1608 also issued under 33 U.S.C. 1903 (b).
# 153.358 Venting system flow capacity.(a) The cross-sectional flow area of any vent system segment, including any PV or SR valve, must at no point be less than that of a pipe whose inside diameter is 6.4 cm (approx. 2.5 in.).(b) When Table 1 requires a closed or restricted gauging system, calculations must show that, under conditions in which a saturated cargo vapor is discharged through the venting system at the maximum anticipated loading rate, the pressure differential between the cargo tank vapor space and the atmosphere does not exceed 28 kPa gauge (approx. 4 psig), or, for independent tanks, the maximum working pressure of the tank.