(1) The unrelieved fuel pressure inside the container shall not exceed 100 psi within a total 72-hour period consisting of 48 hours at 60 degrees F, 12 hours at 70 degrees F, and 12 hours at 90 degrees F ambient temperatures when the container has been filled with LNG conditioned at one atmosphere.

(2) The container shall be equipped with a liquid level gauging device and a dip tube to prevent filling beyond 90% by volume at atmospheric pressure.

(3) Each completed container, including its supporting structure and valves, enclosures, and lines normally attached thereto, shall have structural integrity to withstand damage from deceleration and acceleration forces resulting from 30 mph front-end and rear-end collision of the type of vehicle in which the container is installed. A test or other means shall demonstrate that the container and its openings do not rupture in such collisions.

(4) Fuel Supply Container Markings. Each LNG fuel supply container shall have the following permanent identification markings:

(1) Safety Relief Valves. Each container shall be equipped with one or more safety relief valves. The safety relief valve shall be installed in a line that communicates with the vapor space of the container. A safety relief valve shall be installed between two shut-off valves in a supply line to prevent a buildup of pressure between the valves in the off position. The discharge pressure of safety relief valves shall not exceed 125% of the service pressure of the container. Relief valves shall have sufficient capacity to meet the requirements of either the Bureau of Explosives for approval of safety relief valves or NFPA 59(A) Appendix A and be capable of preventing explosion of the normally charged cylinder when it is placed in a fire. Relief valves shall have the following permanent identification markings:

(2) Shut-off Valves. One manually operated shut-off valve shall be secured directly to the tank vapor outlet with no intervening fitting other than the relief valve and shall be marked with the words “VAPOR SHUT-OFF VALVE.” Another manually operated shut-off valve shall be secured directly to the tank liquid outlet and shall be marked with the words “LIQUID SHUT-OFF VALVE.” (Decals or stencils are acceptable.) Normally closed automatic shut-off valves that are held open by electrical current may be used in lieu of manual shut-off valves at either the tank vapor port or tank liquid port, or both. An automatic shut-off valve shall be wired so it shuts off when the ignition switch is in the off and accessory positions and when engine vacuum is not present.

(3) Control Valve. A positive shut-off control valve shall be installed in the fuel supply lines as close to the containers as possible, automatically closing off and preventing the flow of fuel to the carburetor when the ignition switch is off or in the accessory position.

(1) Gauging devices shall be designed for the most severe pressure and temperature conditions to which the devices may be subjected with a pressure safety factor of not less than four.

(2) All gauges shall be securely mounted and shall be shielded or installed in a protected location to prevent damage from vibration and unsecured objects.

(3) Gauging devices that require bleeding of the product shall be bled to the outside of the vehicle compartment.