scope:

The current ASME code design rules utilize an effective gasket width (b) as the mechanism to account for the reduction in gasket contact area that occurs due to flange rotation during assembly. This concept has no theoretical basis, nor has it ever been verified experimentally. With the development of new leakage based flange design rules, there is a desire to empirically determine gasket effective width rules in order to allow enhanced accuracy of this new design procedure. Additionally, there exists a need to better understand the relationship between gasket contact width and leakage, so this relationship can be considered within the new design rules. Three PVRC sponsored research projects have been undertaken to identify the effect of both flange rotation and gasket width on the resultant leak rate of the gasket. This research has identified important trends and conclusions that will impact the developing new design rules. Part one of this research program has studied specifically the effect of flange rotation on leakage behavior, while the second and third parts studied the effect of gasket width on leakage behavior and the resultant new PVRC gasket factors. A limited number of gasket types were studied. The experimental and analytical analysis performed in part one of this research program has confirmed beneficial trends and limitations due to flange rotation, and has resulted in an improved, tentative model for better estimating the effective gasket width (b) for flange designers. The analysis and conclusions drawn from parts two and three confirm a relationship between gasket width and leakage rates however, due to the limitations and error bands within the testing protocol, additional experimentation and analysis will be required to validate and quantify this relationship for a broad range of materials