The Compressed Gas Association (CGA), working through the International Harmonization Council (IHC), has released CGA G-5.5, Standard for Hydrogen Vent Systems. This updated publication provides harmonized safety guidance for designing, fabricating, testing, and operating hydrogen vent systems.
CGA G-5.5 supports a consistent approach to hydrogen vent systems across CGA, the Asia Industrial Gases Association (AIGA), European Industrial Gases Association (EIGA), and Japan Industrial and Medical Gases Association (JIMGA).
CGA G-5.5 is referenced in many CGA publications from the Hydrogen Technology and the Hydrogen Production committees. In addition, CGA G-5.5 is also cited in codes and standards from external organizations, including the National Fire Protection Association (NFPA), the CSA group, the International Code Council (ICC), and others.
CGA G-5.5 provides design guidelines for hydrogen vent systems used in gaseous and liquid hydrogen systems and gives recommendations for safe operation of these vents. Coverage begins at the discharge port of relief 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.
The publication has been re-organized to make the design process easier to follow. Updated content includes:
- Determining the height and location of vent stacks to reduce the impact of thermal radiation from vent stack fires. This material is based on extensive data collection from vent stack releases and ignitions.
- Determining thermal radiation regions to provide safe areas for personnel and equipment.
- Determining noise from venting.
- Mechanically designing a vent system and its components.
- Manually and automatically operating a vent system.
- Providing multiple sets of sample calculations to make CGA G-5.5 easier to follow.
Please download a copy of CGA G-5.5 to begin using this updated standard. CGA will provide a webinar on the details of CGA G-5.5 at a CGANext webinar on December 15. We hope to see you there – make sure to bring your questions with you!
