Hi all,

I have a question about B31.1 para 102.3.2 : there are 2 equations to calculate Slp, which one do i have to use ?

Regards,

The word "or" appears between them.

Use whatever equation you want.

CAESAR II defaults to the more exact "P*Inside Area/Metal Area" (your equation 2) but you can throw a config switch to use PD/4t (Barlow; your equation 1).

Thinks Dave for your reply,

In fact, i used the first one but my colleague told me that i have to use the second because the thickness of pipe (42.4 mm x 7.11 mm) is greater than 1/10 the diameter !
I couldn't find this information.

In my opinion you should always use the 2nd equation. The PD/4t equation is a "thin wall approximation" - the key word here being "approximation".