Westermann Bolting Technology Co. discovers a way to measure the performance [leak rate] of the Bolted Flanged Joint.

Through an intense research project Westermann Bolting Technology Co. studied and calculated the minute details of the Boiler and Pressure Vessel Code as it relates to the design and selection of components [flange gasket and bolting] to the Bolted Flange Joint [BFJ] when used in ASME B16.5 Group 1.1 applications.  One of the results of their research is the COLT™ Selection Process which helps the  user choose component materials for optimal performance.

Using their newly created COLT™ Selection Process Westermann chose components then calculated their performance using the method on analyzing joint tightness as described in the paper PVP2008-61561 “On the Operating Tightness of B16.5 Flanged Joints” by James R. Payne and robert W. Schneider This calculation created a  performance expression of the BFJ called tightness class factor or “tcf”. This expression allows component combinations to be compared against each other based on their performance.

By performing a joint tightness analysis for all sizes using the P-T ratings in ASME Non Mandatory Appendix A Westermann discovered :

1) Low strength bolting used with compressed fiber gaskets and Class 150 or 300 flanges did not achieve the minimum tcf value of 1 based on Tightness Class 2 [T2, tcf =>1].   In other words, low strength bolting did not have enough strength to seal the gasket at the given P-T values in ASME B16.5 Appendix Non Mandatory Appendix A to meet our minimum leak rate standards.

2) High strength bolting with compressed fiber gaskets easily achieved the minimum tcf  value 1 [T2, tcf=>1] and produced a substantially tighter joint than its low strength/compressed fiber combination counterpart.

By using “tcf” to measure performance one clearly recognizes that high strength bolting/compressed fiber combinations out performs low strength bolting/compressed fiber combinations when using ASME B16.5 Class 150 and 300 group 1.1 material flanges.  And, with further discussion, one can interpolate the maximum pressure the low strength bolting/compressed fiber combination should be subjected to and still pass the minimum performance standard of [T2, tcf=>1].  This is a valuable tool when leak rates are an important engineering discussion.

Using the COLT™ Selection Process