Iam trying to perform flange leakage check in which my gasket material is " Graphite-with/without stainless steel inserts"

But I dont find this material exactly in the ASME sec VIII DIV 1 TABLE 2-5.1 ( GASKET CONTACT AND FACINGS) to acquire the values of seating stress(Y), leak ratio(m) ,etc..

Request stress fraternity to guide me .In which code can I find the values mentioned above??

Does EN1591 talk about this???

Thanks in advance

I would think whoever is selling these gaskets has answered this question before. Can you contact your vendor? It's in their best interest to know.