Cement lined, raised face flanges require a special flange gasket.  The I.D. of the gasket must be the I.D. of the cement lining and the O.D. of the gasket must be the O.D. of the raised face.  The gasket may be made of asbestos or an elastomer if the pressure is above 1,200 psi or a special spiral type metal gasket may be used.



If a standard raised face gasket is used which has the I.D. of the raised face, a small area of steel will be exposed to the corrosive fluid at the cement-flange wall interface and a failure due to corrosion at that location may occur.

Gaskets can be furnished by Permian Enterprises or produced by any company which cuts gaskets.

The face of a ring type joint flange must be coated with an epoxy coating which laps onto the cement lining.