{"data":{"id":"us/46-cfr-154.451","jurisdiction":"us","citation":"46 CFR 154.451","heading":"Design vapor pressure.","body":"The Po (kPa) of an independent tank type C must be calculated by the following formula:\nPo = 196 + AC(ρ) 3/2\nwhere:\nA = 1.813 (σm/ΔσA) 2;\nσm = design primary membrane stress;\nΔσA = (allowable dynamic membrane stress for double amplitude at probability level Q = 10−8) 53.9 MPa (7821 psi) for ferritic and martensitic steels and 24.5 MPa (3555 psi) for 5083-0 aluminum;\nC = a characteristic tank dimension that is the greatest of h, 0.75b, or 0.45 l;\nwhere:\nh = the height of the tank or the dimension in the vessel's vertical direction, in meters;\nb = the width of the tank or the dimension in the vessel's transverse direction; in meters; and\nl = the length of the tank or the dimension in the vessel's longitudinal direction, in meters; and\nρ = the specific gravity of the cargo.","path":["Title 46—Shipping","CHAPTER I—COAST GUARD, DEPARTMENT OF HOMELAND SECURITY","SUBCHAPTER O—CERTAIN BULK DANGEROUS CARGOES","PART 154—SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES","Subpart C—Design, Construction and Equipment"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-46.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:22Z","sha256":"90e9de2fbb7eb46c4ab9fa9a8753907323db8026f0e4fef857fa58b2270965e4","source_id":"us-cfr","stale":true,"prev":"us/46-cfr-154.450","next":"us/46-cfr-154.452"},"notice":"GroundRules: Original legal text. Not legal advice."}