Non-metallic gaskets are manufactured with non-asbestos material or Compressed Asbestos Fibre (CAF). Usually composite sheet materials are used with flat face flanges and low pressure class applications. Non-asbestos types includes arimid fibre, glass fibre, elastomer, PTFE and flexible graphite.
Semi-metallic gaskets are composites of metal and non-metallic materials. The metal offers strength and resiliency while the non-metallic flexible portion provides conformability and sealability. Commonly used Semi-metallic are Spiral wound, Metal Jacketed,Rubber with Metallic Insert ,PTFE Envelop & Flexible Graphite with Metallic Insert,etc.
Metallic gasket is fabricated from one or more combination of metal to the desired shape and size. It is suitable for high-pressure and temperature applications and require high bolt load to seal. Common metallic gasket used is Ring-Joint Gaskets, Lens rings, Corrugated Gaskets & Metal Grooved Gaskets,etc.