Branch & Run pipe SIF

Dear All,

C-II is having same SIF at brach connection for Run pipe & branch pipe.

I wanted to know that Branch pipe & run pipe SIF is always same.

Regards,
Shamalia Bhavin

Check out the SIF equations in B31.3 Appendix D. Branch parameters are not addressed, so no option but to use the same values for run and branch.

One subtle point on B31.3 reduced outlet branches. The Code may use the same SIF but it provides an adjustment to Z used in reduced branches. So, yes, the SIF may be the same but the resulting stress may still change due to this "effective" section modulus.

Further to your reply Mr Dave, can we say all olets,unfabricated/fabricated welding tee comes under reduced branch connections for which there is a requirement of adjustment in Z by B31.3 code.
Pls advise.

All B31.3 branches use an effective section modulus (Ze). Ze=(pi)*((mean branch radius)^2)*Ts. Ts is the effective branch thickness and Ts equals the lesser of (run pipe thickness; in-plane SIF times branch thickness).
See 319.4.4