46 CFR § 154.451 - Design vapor pressure.

---
identifier: "/us/cfr/t46/s154.451"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "46 CFR § 154.451 - Design vapor pressure."
title_number: 46
title_name: "Shipping"
section_number: "154.451"
section_name: "Design vapor pressure."
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"
---


# 154.451 Design vapor pressure.

The P<sub>o</sub> (kPa) of an independent tank type C must be calculated by the following formula:

P<sub>o</sub> = 196 + AC(<sub>ρ</sub>) 
3/2

where:

A = 1.813 (σ<sub>m</sub>/<sub>Δ</sub>σ<sub>A</sub>) 
<sup>2</sup>;

σ<sub>m</sub> = design primary membrane stress;

<sub>Δ</sub>σ<sub>A</sub> = (allowable dynamic membrane stress for double amplitude at probability level Q = 10<sub>−8</sub>) 53.9 MPa (7821 psi) for ferritic and martensitic steels and 24.5 MPa (3555 psi) for 5083-0 aluminum;

C = a characteristic tank dimension that is the greatest of h, 0.75b, or 0.45 l;

where:

h = the height of the tank or the dimension in the vessel's vertical direction, in meters;

b = the width of the tank or the dimension in the vessel's transverse direction; in meters; and

l = the length of the tank or the dimension in the vessel's longitudinal direction, in meters; and

<sub>ρ</sub> = the specific gravity of the cargo.