ASME B16.5 and flange code is written for one-piece flanges. Obviously, an insert flange is a two-piece flange. AIF’s ASME Conforming line have thicknesses that are slightly more than that of the Conventional Line. The Conventional Line simply uses the standard flange thicknesses that a standard one-piece flange would use. The Conventional Line has existed much longer than the ASME Conforming one. However, we recommend now using our ASME Conforming Line unless you are replacing an old Conventional insert flange off of a pipeline. Therefore, for our ASME Conforming Line, engineering calculations were performed by American Insert Flange conforming to the ASME Boiler and Pressure Vessel Code, Section VIII, Division 1 to determine the minimum thickness of an insert flange so that they meet or exceed all pressure temperature ratings of the respective size and weight class, or ASME B16.5 MAWP. These calculations are based on using carbon steel (grades A-105 or SA515/516 Grade 70) for the flange and stainless steel (grades 304/304L and 316/316L) for the insert. The bolting is to SA-193-B7 and a spiral wound gasket material. If the material, bolting, or gasket is changed, the required dimensions of the insert flange could change. However, usually the thicknesses on our cut sheets will remain, and they change only in rare circumstances. This is how we make our ASME Conforming (sometimes called ASME Rated) Line.