What is the effect of using spiral wound gaskets on 150# insert flanges?
Spiral wound gaskets have been around for a long time, have a good record, and can be used to seal a wide variety of fluids and vapors. They do however require large bolting forces to achieve adequate sealing. It is a well known fact that these forces, particularly those required during a hydrostatic test, will theoretically overstress certain size 150# ASME/ANSI flanges. Piping and pressure vessel engineers and designers deal with this condition in several different ways. When some occasional leakage can be tolerated, many engineers will allow the situation to exist knowing that ASME/ANSI flanges are accepted by most of the codes without being subjected to a stress analysis as long as the design pressure and temperatures do not exceed the pressure/temperature ratings established. The long history of the usage of ASME/ANSI flanges has shown that this can be a safe approach as long as the flange and bolting materials operate in a temperature range that maintains their ductile state. Oth