(a) The following piping systems must be hydrostatically leak tested in the presence of a marine inspector at a pressure of 1.5 times the maximum allowable working pressure of the system:

(1) Class I steam, feedwater, and blowoff piping. Where piping is attached to boilers by welding without practical means of blanking off for testing, the piping must be subjected to the same hydrostatic pressure to which the boiler is tested. The maximum allowable working pressures of boiler feedwater and blowoff piping must be the design pressures specified in §§ 56.50-30(a)(3) and 56.50-40(b) of this subpart, respectively.

(2) Fuel oil discharge piping between the pumps and the burners.

(3) Flammable or corrosive liquids and compressed gas cargo piping, but not less than 150 psig.

(4) Any Class I, I-L, II-L piping.

(5) Cargo oil piping.

(6) Firemains.

(7) Fuel oil transfer and filling piping.

(8) Class I compressed air piping.

(9) Fixed oxygen-acetylene system piping.

(b) Installation testing requirements for refrigeration, fluid power, and liquefied petroleum gas cooking and heating systems may be found in part 58 of this subchapter.

(c) Class II piping systems must be tested under working conditions as specified in the section on initial service leak test, § 56.97-38.

[CGFR 68-82, 33 FR 18843, Dec. 18, 1968, as amended by CGFR 69-127, 35 FR 9980, June 17, 1970; CGD 72-206R, 38 FR 17229, June 29, 1973 CGD 73-254, 40 FR 40168, Sept. 2, 1975; CGD 95-028, 62 FR 51202, Sept. 30, 1997]