A flange gasket is a compressible sealing component used in pressure pipe systems to create a watertight, pressure-tight seal between two flanged pipe ends that are bolted together.
Why Gaskets Are Needed
PVCu flange faces are rigid and do not deform enough on their own to seal reliably, so liquids can easily slip through. A flexible gasket made from a material such as EPDM provides:
Leak Prevention: The gasket compensates for surface irregularities
Even Load Distribution: Across the flange face
Protection of flange faces from direct contact and damage
Without a gasket, even correctly torqued bolts are unlikely to produce a dependable seal.
Types of Gaskets
The most common types of gaskets used in PVCu Pressure Pipe systems are full-face and stub flange gaskets. They both serve the same purpose but in different ways.
Full Face Flange Gaskets
These gaskets cover the entire surface of a drilled flange, with holes cut out for each bolt. They provide a full seal across the entire face of the flange and help to distribute load and protect the flange faces from damage, ensuring a reliable seal.
These gaskets can also come in a few different patterns, which refer to how the bolt holes are drilled on the flanges, so ensure you get the right gasket for the flange you have, e.g. PN10/16 or Table D/E.
Stub Flange Gaskets
Stub flange gaskets are used in systems where backing rings are needed, usually for larger diameter flanged connections. A stub flange is used to connect the two pipes, sealed with a gasket in the middle. The two stub flanges are then pulled into each other by the backing rings via bolts, compressing the gasket and forming a watertight seal.
Full Face
Stub
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