6 Design
6.1 Petrol tanks shall have all fittings and openings on top, except metallic fill and ventilation pipes, which may be connected to the sides or ends of metal petrol tanks, provided that they are welded to the tank and reach above the top of the tank.
Tank drains are not permitted on petrol tanks.
6.2 Diesel tanks may have side inspection openings. Fittings in the bottom, sides or ends are allowed provided that each such connection has a shut-off valve closely coupled to the tank. The valve shall be protected or located to prevent physical damage or be of at least 25 mm nominal diameter.
6.3 Diesel tank drains, where fitted, shall have a shut-off valve having a plug on the outlet that can only be removed by the use of tools.
6.4 Metal tanks shall be so designed or installed that no exterior surface will trap water.
6.5 Rigid fuel suction tubes and fill pipes which extend near the tank bottom shall have sufficient clearance to prevent contact with the bottom due to flexing of the tank.
6.6 Supports, chocks or hangers shall be separated from the surface of metal tanks by a non-metallic, non-hygroscopic, non-abrasive material or welded to the tank.
