CGA G-5.5 – Hydrogen Vent Systems

This publication provides information for personnel who design, install, and maintain hydrogen vent systems.

This publication provides design guidelines for hydrogen vent systems used in gaseous and liquid hydrogen systems at user sites and provides recommendations for safe operation of these vents. It begins at the discharge port of safety devices and other components that control the release of hydrogen and ends at the point where hydrogen concentration in the atmosphere is below the lower flammable limits.

It also provides information on the production, transportation, handling, and storage of compressed hydrogen, cryogenic liquid hydrogen, and related products. Additional information on hydrogen can be found in CGA G-5, Hydrogen, CGA G-5.4, Standard for Hydrogen Piping Systems at User Locations, CGA Handbook of Compressed Gases, and NFPA 55, Compressed Gases and Cryogenic Fluids Code, and NFPA 2, Hydrogen Technologies Code.

Pressure relief devices (PRDs) for cylinders and tube trailers required by U.S. Department of Transportation (DOT) in 49 CFR are not covered in the scope of this publication.