5806.4 Underground Tanks for Liquid Hydrogen
Storage tanks shall be located outside in accordance with the following:
- Tanks and associated equipment shall be located with respect to foundations and supports of other structures such that the loads carried by the latter cannot be transmitted to the tank.
- The distance from any part of the tank to the nearest wall of a basement, pit, cellar or lot line shall be not less than 3 feet (914 mm).
- A minimum distance of 1 foot (305 mm), shell to shell, shall be maintained between underground tanks.
The tank shall be buried such that the top of the vacuum jacket is covered with not less than 1 foot (305 mm) of earth and with concrete not less than 4 inches (102 mm) thick placed over the earthen cover. The concrete shall extend not less than 1 foot (305 mm) horizontally beyond the footprint of the tank in all directions. Underground tanks shall be set on firm foundations constructed in accordance with the International Building Code and surrounded with not less than 6 inches (152 mm) of noncorrosive inert material, such as sand.
Exception: The vertical extension of the vacuum jacket as required for service connections.