Hello everybody in this forum. I'm curious as to why the "A" and "B" coefficients found in B31.1 Appendix B for carbon steel are slightly different now than they were back in 1986. A and B are 7.4 and 4.7 now and were 7.23 and 4.60 back in 1986. Regards and thanks for the replies.

Patrick LaPointe P. E.