During the process of purging a gas "into service," what should your CGI reading be at?

When purging a gas system "into service," the CGI (Combustible Gas Indicator) reading is intended to confirm that the gas concentration is at a safe and usable level. A CGI reading of 95% indicates that the gas mixture is sufficiently enriched and that there is only a minimal amount of air remaining in the system.

Achieving a CGI reading of 95% means that the majority of the air, which can cause an unsafe mixture or even a potential for an explosion, has been successfully purged out of the system. This high concentration of combustible gas ensures that the gas will ignite and function properly when the system is started.

A reading less than this threshold could indicate that there could still be air in the system, which poses risks such as improper combustion or the potential for an explosion if the ignition source is introduced. Therefore, it’s critical to monitor and maintain the CGI levels appropriately to ensure the safety and functionality of the gas system during the purging process.