ANSI/IAS NGV 4.6-1999 (R2019)/CSA 12.56-M99 (R2018)
Manually Operated Valves for Natural Gas Dispensing Systems
These requirements apply to manually operated valves for high pressure natural gas.
These requirements do not apply to cylinder shut-off valves.
A valve that complies with the requirements for a Class A valve may be used for a Class B valve application, however, a Class B valve may not be substituted for a Class A valve.