Difference between ANSI B31.1-1973 and 1986

[Nounoue]

Hello,

I am working on a project where I am performing pipe stress analysis. I am using AutoPIPE. The code of record is 1973, but AutoPIPE only has 1986 and 1968. I am trying to come up with a justification on why I am using 1986. I compared the stress equations, the allowables, The SIF's eaquations, and the thermal expansion coefficients between the two versions. Am I missing other things that need to be covered in my justification?

Thanks

 

[racookpe1978]

Fundamentally, you need to be able to justify the "difference" between a very old code of record (1973 hand-typed rules) against either AutoPipe's "slightly newer" 1986 digital interpretation of the 1986 Code, or their digital version of the (even older!) 1968 hand-typed Code, right?

So, write your justification for using the (newer) 1986 Code, and look through the 1986 Code for changes from the 1973 Code. You will be looking for "relaxations" or "more liberal" assumptions. If you find any, cite them. Explain in simple but clear terms why those more liberal changes do not compromise the old plant's safety and integrity.

If you find no applicable "liberal" changes, or only find changes that move the 1986 Code to a more conservative position or analysis, say so. Be straightforward, but don't claim too much: "A review of the 1986 Code was completed with respect to the following sections of the baseline 1973 Piping Code. No applicable differences were found during this review. " Or "The following differences were found: a, b, c, d, e, f. These changes are considered acceptable for digital analysis according to these criteria .... by applying these rules .... "