Suggested Procedure for Determining the PCC-1 Appendix O Gasket Properties

Abstract

Abstract The ASME Pressure Vessel and Boiler Code Section VIII – Appendix 2 – Rules for Bolted Flange Connections with Ring Type Joints [1] has been used successfully for many years. An experienced engineer will apply the rules and, in most cases, the vessel will be operated for many years without leakage. However, there have been many papers addressing its shortcomings [2–4]. The Gasket Properties of the Appendix 2 has never been updated with newer designs and materials. Its tabulated values are reminiscent of the “Asbestos time”. Properties such us maximum gasket stress and relaxation are not considered. The ASME – PCC-1 – Pressure Boundary Bolted Flange Joint Assembly [5] has introduced the Appendix 0 – Assembly Bolt Stress Determination to address some of the problems associated with the Appendix 2. Several new gasket properties were introduced without a procedure to determine them. Two papers presented at PVP Conferences [6,7] proposed a protocol to determine some of the gasket properties. In Europe the rules for calculating flanges and determining the gasket properties were updated with the EN 1591 - Flanges and their joints - Design rules for gasketed circular flange connections [8] and EN 13555 - Flanges and their joints – Gasket parameters and test procedures relevant to the design rules for gasketed circular flange connections [9]. Since their introduction there has been a major effort to test gaskets and determine their properties. Manufactures are publishing results and there are two public websites [10,11] where values are posted. With so many data available the purpose of this paper is to suggest a procedure to use the EN13555 data to determine the Appendix – O gasket properties.