SF6 gas: Due to it's best arc quenching properties or we can say its insulating property used in Ckt breaker. It is generally colorless, odorless, inflammable gas. It goes not get expired quickly rather it stored in ckt breaker vessel a long period of time. what we need to do it, we need to maintain its pressure level (5kg/cm2) for Gas ckt breaker(132kv)

Actually, the quality of SF6 gas does not deteriorate under the normal operating condition as the time passes. It is normally reused after proper filtering.In some cases, disposal of the gas is necessary when it doesn't meet the required performance parameter like concentration, dew point, moisture level etc.