Update of the Tabulated «M and Y» Values in the New Revisions of French Codes CODAP® and CODETI®: Development of a Testing Procedure to Determine «M and Y» Values for Several Tightness Classes

The existing tables giving “m and y” values, used in the Taylor Forge method for bolted flange connections calculation, have remained unchanged through years. Some gasket types do not appear in these tables and no reference is made to a Tightness Class associated to these values. The need for an update of the exiting tables has been raised by the supplier of French codes (CODAP® [1] and CODETI® [2]). A survey about the recommended values of “m and y” and their associated expected leakage rates for the gasket types available on the market has been performed. The wide discrepancy in the test procedures and the gasket parameter values showed the need for the development of a common test procedure. The new test procedure giving tables of “m and y” values depending on the tightness class is presented here. The application of this procedure on several gasket types, lead to the publication of new tables for “m and y” values, in the last French codes revision.