(a) Vessels greater than 100 gross tons. (1) The diesel fuel system must comply with §§ 56.50-60, 56.50-85, and 56.50-90. The fuel supply piping to engines must be of seamless steel, annealed seamless copper or brass pipe or tubing, or of nickel copper or copper nickel alloy meeting the requirements of subpart 56.60 for materials and § 56.50-70(a)(2) for thickness. Fuel oil service pumps must comply with § 58.01-25 of this subchapter.

(2) The installation must comply with § 56.50-70(b).

(3) Tubing connections and fittings must be drawn or forged metal of the flared type except that flareless fittings of the nonbite type may be used when the tubing system is steel, nickel-copper, or copper-nickel. When making flared tube connections the tubing must be cut square and flared by suitable tools. Tube ends must be annealed before flaring.

(b) Vessels of 100 gross tons and less and tank barges—(1) Materials. Fuel supply piping must be of copper, nickel copper, copper nickel, seamless steel, or other materials having a minimum wall thickness of 0.035 inch.

(2) Tubing connections and fittings. Tubing connections must comply with the provisions of paragraph (a)(3) of this section.

(3) Installation. The installation of diesel fuel piping must comply with the requirements of § 56.50-70(b).

(4) Shutoff valves. Shutoff valves must be installed in the fuel supply lines, one as close to each tank as practicable, and one as close to each fuel pump as practicable. Valves must be accessible at all times.

(5) Outlets and drains. Valves for removing water or impurities from fuel oil systems will be permitted in the machinery space provided such valves are fitted with caps or plugs to prevent leakage.

(6) Filling pipe. Tank filling pipes must terminate on an open deck and must be fitted with suitable shutoff valves, deck plugs, or caps.

(7) Vent pipes. Each tank must be fitted with a vent pipe complying with § 56.50-85.

(8) Independent diesel fuel tanks. See subpart 58.50 of this subchapter for specific requirements.