Automatic Shut-off Valve

An automatic shut-off valve should be located in liquid hydrogen withdrawal piping as close to the vessel as practical. Per NFPA 55, automatic shut-off valves aren't required on tanks smaller than 2,000 gallons, but they are recommended for all tanks.

On vessels over 2,000 gallons capacity, this shut-off valve shall be operable by remote control.

There should not be any connections, flanges, or other appurtenances (other than a welded manual shut-off valve) allowed in the piping between the shut-off valve and its connection to the vessel.