Emergency valves are any valves used to isolate gas pipeline sections or a facility in an emergency. Emergency valves have special code requirements for annual maintenance and testing in an attempt to ensure that they will be functional at all times. Valves that typically carry emergency designation include:
- Main line valves such as line rupture control valves
- Blowdown valves that must be opened to de-energize a specific piping system
- Automatic valves that close to isolate compressor stations from the pipeline and others that open to vent the station piping to the atmosphere
- Manual valves that perform the same function in smaller stations.