Gaskets

Seal House USA full face flange gaskets are cut from red rubber (SBR), 1/8 in. thick, for 150 lb steel and 125 lb cast iron flanges in pipe sizes 1-1/4 in. to 12 in. A full face gasket covers the whole flange face, bolt holes and all, which makes it the right gasket for flat-faced flanges — especially cast iron, where a ring gasket can let the flange bend as the bolts are tightened. Class 125 and Class 150 share the same bolt pattern in these sizes, so one gasket fits both. How to find your size Pipe size is a name, not a measurement — nothing on a 4 in. gasket measures 4 in. The quick check is the outside diameter: measure across the flange face and match it to the Gasket OD column below. Every size has its own OD, so that one number tells you which gasket you need. The bolt count confirms it: 4 holes up to 3 in., 8 holes from 4 in. to 8 in., 12 holes at 10 in. and 12 in.