Insulating gasket kits are used to seal flanges and electrically insulate them, thereby maintaining the integrity of the piping system. By preventing metal-to-metal contact, they can reduce corrosion caused by the action of electric current or when used in conjunction with cathodic protection systems.
It includes gaskets used to separate flanges in metal piping systems, as well as non-conductive bushings and gaskets used to prevent current from passing through the connection. However, if these kits are not specified, manufactured, and installed correctly, they may fail.
The insulating gasket kit also includes an insulating sleeve that electrically isolates the bolt from the flange, and a non-conductive washer that electrically isolates the nut that fixes the bolt. The specifications of isolation sleeves usually require them to be "full-length", which is an uncertain measurement and there is no known industry standard. In practice, the sleeve should extend to at least half of the steel preparation gasket behind the spacer gasket.