ANSI/CGA P-18-2020 specifies bulk inert gas systems.
The Dangers of Inert Gases
Inert gases, such as argon, nitrogen, and helium, do not react readily with other materials under normal temperatures and pressures. These elements are all around us. Nitrogen comprises nearly four-fifths of the earth’s atmosphere. Argon accounts for around one percent. Helium exists in atmospheric concentrations in trace amounts (5 parts per million). These gases, at atmospheric temperatures and pressures, are colorless, odorless, and tasteless.
Inert gases have the ability to displace oxygen in air. This property, while useful in industry for keeping oxygen out of environments that need a specific purity, poses a serious hazard to life. Asphyxiants can bring forth oxygen-deficient atmospheres that rapidly overcome an individual and bring about unconsciousness without warning.
Inert gases can maintain cold temperatures and do not support combustion. This makes them ideal gases for cryogenic liquids. Unfortunately, this usage creates the possibility for cold-contact burns, skin or eye frostbite, and boiling or splashing for personnel.
ANSI/CGA P-18-2020 addresses the means of mitigating these personnel hazards. Supplier safety data sheets (SDSs) for a specific inert gas should be on-site and available for reference. Furthermore, users of this standard can refer to the following publications also developed by the Compressed Gas Association (an ANSI-accredited standards developing organization) for further information about the properties and safe handling techniques for inert gases:
- CGA P-1-2015: Standard For Safe Handling Of Compressed Gases In Containers
- CGA P-9 – The Inert Gases: Argon, Nitrogen, And Helium
- CGA P-12-2017: Safe Handling Of Cryogenic Liquids
- CGA P-76-2018: Hazards Of Oxygen-Deficient Atmospheres
Types of Inert Gas Supply Systems
ANSI/CGA P-18-2020 applies to a range of inert gas supply systems. These include:
- cryogenic storage tank
- gas storage vessels (receivers)
- valves including manual and automatic shutoff valves and check valves
- pressure control equipment including regulators and control valves
- piping (pipe and tubing)
- cryogenic pumps
- snubbers and pulsation dampeners
- monitoring and control systems including electrical and instrumentation
About ANSI/CGA P-18-2020
A bulk inert gas system contains greater than 20,000 scf (566 m3) of inert gas. ANSI/CGA P-18-2020 applies to these systems, but it is limited to those operating up to 15,000 psi (103.4 MPa).
For liquid and gas bulk inert supply systems, ANSI/CGA P-18-2020 addresses a breadth of necessary information, specifically the minimum requirements for locating/siting, selecting equipment, installing, starting up, maintaining, and removing bulk inert gas supply systems.
ANSI/CGA P-18-2020: Bulk Inert Gas Systems – Fifth Edition is available on the ANSI Webstore.
Guidance for Carbon Dioxide Systems
ANSI/CGA P-18-2020 does not apply to carbon dioxide systems. For bulk carbon dioxide system requirements, please refer to:
- NFPA 55-2020: Compressed Gases And Cryogenic Fluids Code
- CGA G-6.1: Standard For Insulated Liquid Carbon Dioxide Systems At Consumer Sites
Further Guidance for Bulk Inert Gas Systems in Healthcare
In healthcare spaces, bulk inert gas systems demand further guidance beyond ANSI/CGA P-18-2020. This can be found in: