Dissecting the Dinosaur; Problems With B16.5 and B16.47 Flange Standards

ASME B16.5 and B16.47 flanges have been in existence for a very long time with very few changes made since their creation. That might lead the casual observer to think that the designs contained in those documents have been optimized and represent best in technology. While that may have been the case when they were first introduced, it is anything but the case at the moment. In fact, in many cases the design of these standard flanges is far from optimal. However, even worse than that, there are presently several significant issues with the flange standards that could be easily resolved, without adding cost to the flanges or requiring dimensional modifications.

These changes would eliminate some existing or potential joint integrity failures. This paper outlines a list of improvements, complete with justification for the need, which the author would like to see made to the ASME standard flange standards. Some of these suggestions have already gained support in industry and been relayed on to the B16.5 committee, however they have not yet been incorporated. These simple improvements can, for the most part, be implemented within existing company standards in order to immediately circumvent potential or existing joint leakage issues. The paper details suggestions for modification of the standard B16.5, B16.47 and B16.20 wording, both for consideration by the B16 committees and incorporation into corporate standards in the interim.