|(a) Piping that carries fuel shall be fabricated to minimize vibration and shall be shielded or installed in a protected location to prevent damage from unsecured objects. (b) Fuel lines shall be mounted, braced, and supported to minimize vibration and protected against damage, corrosion, or breaking due to strain or wear. Fuel lines shall be supported at least every 21 to 27 inches. (c) Fuel lines passing through a panel shall be protected against abrasion by grommets or similar devices such as fittings, which shall snugly fit both the supply lines and the holes in the panel. (d) Fuel lines shall have a minimum clearance of eight inches from the engine exhaust system or shall be shielded against direct heat. (e) Piping or tubing shall pass through the floor of a vehicle directly beneath or adjacent to the container. If a branch line is required, the tee connection shall be in the main fuel line under the floor and outside the vehicle. (f) Hydrostatic relief valves shall be installed in each section of piping or tubing in which LNG can be isolated between shutoff valves to relieve to a safe atmosphere the pressure which could develop from the trapped fuel. The pressure relief valve shall have a pressure not greater than the maximum allowable working pressure of the line it protects. (g) Joint compound or tape acceptable for use with LNG shall be applied to all male pipe threads prior to assembly. (h) Piping and fittings shall be clean and free from cutting or threading burrs and scaling. The ends of all piping shall be reamed. (i) Bends in piping or tubing are prohibited if the bend weakens the pipe or tubing. Bends shall be made by bending tools designated for this purpose. (j) Joints or connections shall be located only in an accessible location. (k) Fuel connections between a tractor and trailer or other vehicle units are prohibited.