Session: CS-07-03: Recent Developments in ASME Codes and Standards - 3

Paper Number: 85659

85659 - Re-Visiting Asme b16.5 and b16.47 Flange Standards 

B16 flange standards date back to early 20th century and have been in use in many industries around the globe for almost a 100 years. In 2013, Brown [PVP2013-97813 Dissecting the Dinosaur; Problems with B16.5 and B16.47 Flange Standards], highlighted several perceived problems and provided recommendations for changes, particularly in ASME B16.5 and B16.47. The issues highlighted by Brown include:
-    Lack of science and extreme resistance to change.
-    All flanges in Class 150 do not have enough bolt area, while Classes 900 and 1500 have sub-optimal bolt sizes.
-    Apparent conflict between paragraphs 5.3.4 and 5.4.2 of ASME B16.5 with regard to use of low strength bolting.
-    Surface finish tolerance in 6.5.4.3 of ASME B16.5 is way too large.
-    Permissible imperfections in flange facing are excessive, up to 0.5 inch in the radial direction and up to 0.25 inch in depth for a NEW flange. Brown recommended that the limits specified in ASME PCC-1 Appendix D be used in lieu of those specified in ASME B16.5.
-    The hub angle for ASME B16.5 welding neck flanges is permitted to be anywhere between 18 degrees and 45 degrees, which can lead to significant variation in flange strength and flange rotation, and therefore, the leak tightness.
-     The general mechanical design of B16.47 Series A class 150 flanges is deficient, as they are relatively weak and have flange strength limits corresponding to only around 240 MPa (35 ksi) assembly bolt stress when standard gaskets are used.

In this presentation, the author will re-visits the same issues raised by Brown in greater depth and will provide more insight and different perspective on what or can not be changed in the standards.
 

Presenting Author: Ayman Cheta Shell Global Solutions (US)

Presenting Author Biography: I am a Fellow of IMechE and a registered Professional Engineer in Texas. I joined Shell in Dec 2005. Prior to Shell, I worked for Total, Amoco and BP. I am currently with P&amp;T Engineering in Houston. My 30+ year career spans roles in maintenance, reliability, inspection and integrity, as well as assets and major projects&#39; support.<br/>My industry leadership experience includes:<br/><br/>Vice Chair of API CRE Subcommittee on Piping and Valves 2006-2009<br/>Chair of ASME B16 Standards Committee SC C 2014-2020<br/>Head of US Delegation during ISO TC/5 meetings 2014<br/>Member of US TAG (Technical Advisory Group) to ANSI on ISO TC/5 and TC/193 related matters

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