Buried pipelines for oil, gas and other inflammable materials are normally provided with cathodic. This, in turn, requires the use of insulating flanges at terminal points on the pipeline system, such as at tank farms, governor stations, etc. In order to limit the extent of the applied cathodic protection and prevent the loss of protective current to other buried metallic structures.
In these locations, in the event of a lightning strike on to any above ground pipework or connected structure, or an electrical fault causing a voltage surge on the pipe, a flashover across the insulating components to the flange could occur.
Potential hazards caused by such an incident in an area classified as “Hazardous” (Zone 2) due to the possible presence of an explosive atmosphere, can
be avoided by the use of an Explosion-proof Spark Gap type SG4. The spark gap is connected in a parallel across the insulating flange and, since the
connection is made using a flexible Technical Characteristics are as follows: