What code resources are available to ensure the safe liquefaction of hydrogen?

There are no specific code resources that specifically cover hydrogen liquefaction plants, but they must be built to the general building, electrical, machinery, piping, and mechanical codes for process plants. Codes such as NFPA 2, Hydrogen Technologies Code, for installation and emergency response may also be used for reference. It may also be beneficial to break down the requirements into process safety and storage. For general process safety, there is good guidance for large plants. The Center for Chemical Process Safety provides guidance that is not specific to liquid hydrogen but instead addresses process safety. Other resources include the Hydrogen Safety Panel (HSP) and the Center for Hydrogen Safety (CHS).