On the Operating Tightness of B16.5 Flanged Joints

The operating leak rate and tightness of a range of ASME B16.5 flanged joints [1] are calculated and compared for several gasket types, service categories and assembly methods. The methodology used includes proposed tightness based gasket constants and application of the basic principles of proposed new ASME rules for design bolt loads. It is straightforward and will be useful to those tasked with bolted joint tightness evaluations. The margin of bolt load available for joint relaxation is also examined. It is found that for modern graphite based gaskets, properly assembled joints have adequate tightness. PTFE based gaskets were not included in this study. This paper updates a similar but unpublished study presented several years ago.