6 gas must be a minimum of 97% pure. Only gas meeting this purity may be installed in existing gas insulated equipment. If the gas is not 97% pure it may be removed with a gas reclaimer but can not be returned to the equipment until 97% pure. 2. Remove the gas using a SF 6gas reclaimer. Refer to the operating manual for proper operation. Gas Insulated Substation Industry Is Assessed To Register 5.7% CAGR Between 2021 And 2031: FMI mobile substations to Siemens last December. Vanguard had on Monday noted that the ongoing war in Ukraine has culminated in the shutdown of Siemens manufacturing plants, thus affecting the Gas Insulated Substations (G.I. S) Definition : A gas insulated substation (GIS) is a substation that uses a superior dielectric gas, sulfur hexafluoride (SF6), high-voltage. The basic principle of gas-insulated equipment : Is that the high-voltage current- carrying parts are within a metal enclosure and are held in a concentric configuration by cast epoxy spacer insulators.