Integral fuel tanks.

(a) Gasoline fuel tanks must be independent of the hull. (b) Diesel fuel tanks may not be built integral with the hull of a vessel unless the hull is made of: (1) Steel; (2) Aluminum; or (3) Fiber reinforced plastic when: (i) Sandwich construction is not used; or (ii) Sandwich construction is used with only a core material of closed cell polyvinyl chloride or equivalent. (c) During the initial inspection for certification of a vessel, integral fuel tanks must withstand a hydrostatic pressure test of 35 kPa (5 psig), or the maximum pressure head to which they may be subjected in service, whichever is greater. A standpipe of 3.5 meters (11.5 feet) in height attached to the tank may be filled with water to accomplish the 35 kPa (5 psig) test. [CGD 85-080, 61 FR 986, Jan. 10, 1996, as amended at 62 FR 51358, Sept. 30, 1997]