Combustible liquids, having a flash point of 38 °C (100 °F) or higher, may be transported by vessel only in one of the portable tanks as specified below:
(a) Specification portable tanks authorized in § 173.241 of this subchapter.
(b) In nonspecification portable tanks, subject to the following conditions:
(1) Each portable tank must conform to a DOT specification 57 portable tank, except as otherwise provided in this paragraph;
(2) The rated capacity of the tank may not exceed 4,542 L (1,200 gallons), and the rated gross weight may not exceed 13,608 kg (30,000 pounds);
(3) The vibration test need not be performed;
(4) When the total surface area of the tank exceeds 14.9 square meters (160 square feet), the total emergency venting capacity must be determined in accordance with table I in § 178.345-10 of this subchapter;
(5) ln place of a specification identification marking, the tank must be marked, on two sides in letters at least 5 cm (2 inches) high on contrasting background: “FOR COMBUSTIBLE LIQUIDS ONLY” and “49 CFR 176.340”. This latter marking constitutes certification by the person offering the combustible liquid materials for transportation that the portable tank conforms to this paragraph;
(6) Each tank must be made of steel;
(7) The design pressure of the tank must be not less than 62 kPa (9 psig);
(8) No pressure relief device may open at less than 34.4 kPa (5 psig);
(9) Each tank must be retested and marked at least once every 2 years in accordance with the requirements applicable to a DOT specification 57 portable tank in § 180.605 of this subchapter; and
(10) Each tank must conform to the provisions of § 173.24 of this subchapter and § 180.605(b) and (j) of this subchapter.
(c) Portable tanks approved by the Commandant (G-MSO), USCG.