Gaskets

Gaskets are mechanical seals placed between mating surfaces to prevent leakage of liquids and gases under compression. They deform to fill gaps and maintain a sealing load when bolts apply pressure. Gaskets are used in static joints such as pipe flanges and in some dynamic applications.

Materials for gaskets vary widely. Elastomeric polymers such as nitrile (NBR), EPDM, fluorocarbon (FKM/Viton), and silicone are common for moderate temperatures and flexibility. For higher temperatures or rigid seals, metals, composites, or laminated sheets such as graphite, PTFE, and metal-backed graphite are used. Common types include sheet gaskets cut to size, ring gaskets for flanges, and O-rings for circular seals. Asbestos-containing gaskets are largely discontinued for health reasons.

Design considerations include temperature and pressure ratings, chemical compatibility, flange material and finish, and seating stress. Gasket thickness, compression, and surface cleanliness influence performance. Installation should ensure clean and flat surfaces, correct gasket type and size, and torque per manufacturer specifications to achieve a uniform seal.

Gaskets find wide use in automotive engines, piping systems, chemical plants, HVAC, and aerospace. Failures can result from improper material selection, aging, creep or cold flow, or improper tightening, as well as surface imperfections. Standards from ISO and ASME guide gasket selection, testing, and installation to ensure reliable sealing.