Seal compression

Illustrated explanation

Compression, sealing faces and extrusion

1Seal compression
Seal compression and extrusion sectionsThree conceptual sections show a free seal, a compressed face seal and a seal deforming into an unsupported gap. Callout 1 marks compression between the free and installed states, 2 marks the opposing sealing faces and 3 marks extrusion into a clearance. Deformation is exaggerated and does not specify acceptable squeeze. Current term: Seal compression, callout 1. 1 2 3 Free shapeUnsupported gapBefore assembly
  1. Seal compressionThis term

    Squeeze changes the seal cross-section between the free and installed states. More compression does not always improve sealing.

  2. Face seal

    A face seal acts between opposing surfaces. Check the gasket, seating faces and available compression space.

  3. Seal extrusion

    An unsupported gap can allow elastomer to move out of its intended space. Check clearance, pressure, temperature and material.

A supported elastomer changes shape when compressed between mating faces. A separate example shows material pushed into an unsupported clearance under load or pressure.

Conceptual gasket sections with exaggerated deformation. Required squeeze, housing dimensions, material and pressure limits depend on the specified seal.

ReferencesIEC 62444:2010 — Cable glands for electrical installationsISO 3601-2:2025 — O-rings — Housing dimensions