Gasket Piping Class

Hello

Starting with 3" size, the flanges pressure class 900# are different from flanges pressure class 1500#. All dimensions of flanges 1500# are biger than flanges 900# including 3 inches size.

Look here:
http://www.texasflange.com/Catalog.pdf

Hello, I was under the impression that if it has the 900/1500 stamped on the Flextalic type spiral wound gaskets that it will fit any flange between the 2 stamped sizes that has a flat gasket surface. Although the bolt size, O.D and thickness of the flanges will be different for different class flanges the sealing surface will be close enough that a gasket can be made that will work for either. Therefore one gasket can be used instead of buying several different gaskets as long as it is built and stamped to be used that way. I am not sure about this on below 3" pipe size on 900/1500 class gaskets but I will check into it. At the mill I work at we buy one gasket in each nominal pipe size that will work on 150/300 lb. rated flanges just to keep our stock down as well as to prevent someone from accidentally using a 150 lb. class flange gasket on a 300 lb class flange. This is not only on spiral wound gaskets but on some other types of gaskets as well.

pipewelder

hello,

How can 3" spiral-wound gasket of 900# fits into 1500#,if we consider it as per dimensionwise.As outside diameter of centering ring of spiral-wound gasket of 900 and 1500# are different.As per ASME B 16.20(1998)

3",900#,outside diameter of centering ring-6.63"

3",1500#,outside diameter of centering ring-6.88"

A handy pipe gasket dimensions guide can be found here http://www.ramgaskets.co.uk/uploads/Pipe_Gasket_Dimensions_1.pdf.