Dear contributors,

I have checked ASME B16.5; Para 5.4.3 specifically talks about 150# flanges. Is says "It is recommended that only Annex C, Table C1, Group No.1 gaskets to be used for Class 150 flanged joints.". Group No.1 consists of two groups, Gasket Group No.1a and Gasket Group No 1b. The Gasket Group No 1b lists Spiral Wound and Corrugated jacketed gaskets and Group No 1a lists self energized gaskets, compressed sheets, polymers and elastomers. My suspicion is that Para 5.4.3 mistakenly writes Group No 1 instead of Group No 1a.
In this case my suspicion on the flange connection in my original post is correct. If the paragraph does not have any mistake, the para 5.4.3 needs to be reconsidered.

Ibrahim Demir