can anyone clarify my one doubt regarding SIF calculation? actually i have seen the table of sif's for different fittings in ASME B31.1 AND ASME B31.3. IN case of B31.1 there is no in plane or out plane SIF. but in B31.3 in plane and out plane sif is there. can plz calrify this differnce

First I give you credit for looking at appndx D!

The answer is B31.1 is "simplified" and applies only one SIF whichever is higher to a componenet.

Because of this a B31.1 analysis may indicate a particular component or construct has the highest stress level in a model when in actuality a different area may actually be greater! Study Chpt 2 of both code books for more info.

Note, too, Footnote 3 in B31.3 - "A single intensification factor equal to 0.9/h^(2/3) may be used for but ii and io if desired." This applies to the entire table.

I can't say it is more than gossip but I heard it said that the B31.1 people didn't think engineers could easily identify in- and out-plane orientation, therefore, no ii & io there.

Are you in????