Threaded and Socket Weld Fitting Class Designation

[GNCA]

In ASME B16.11 Threaded and Socket Welded Fitting rating shown as Class 2000lb, 3000lb, ..etc. Anybody knows where did this class designation come from?

 

[JLSeagull]

Read the forward in ASME B16.11. In 1960 the standard addressed threaded fittings and plugs covered by MSS SP-49/50. The wording was upgraded in 1972. Consider checking old copies of MSS 49 and 50.