gasket

A gasket is a mechanical seal that fills the space between two mating surfaces to prevent leakage of liquids or gases under compression. Gaskets are used in static joints such as flanges and covers, and in some dynamic applications; when compressed they deform to fill surface imperfections and create a leak-tight seal.

Common types include flat gaskets cut from sheet materials, ring gaskets (O-rings), spiral-wound and Kammprofile gaskets, and solid metal or graphite composites. Materials range from elastomers (NBR, EPDM, silicone, fluorocarbon) to PTFE, cork, graphite, and various metals. Selection depends on pressure, temperature, media, and flange design.

Key design considerations are compatible materials, flange surface finish, gasket thickness, and seating stress. The goal is to achieve reliable sealing without excessive bolt load, and to prevent extrusion or creep. Installation requires clean mating surfaces, correct alignment, and following torque specifications; lubrication is used only as appropriate for the material.

Standards exist to guide gasket selection and testing, notably ASME B16.21 and ISO/EN standards for gaskets and flange connections. Applications include plumbing, automotive engines, chemical processing, and power generation, where joints must seal under varying conditions.

Common failures include leakage due to improper seating, gasket blowout, extrusion, cold flow, chemical attack, or flange misalignment. Proper material selection and maintenance help extend service life.