What would be the best way of modelling forged 16.11 T and elbow? In this case fittings are #3000 and pipe 1" XS. I thought of using rigids plus correct SIF at the pipe to fitting connection. Alternatively bends could be double flanged. I would not expect stresses within the fitting to be the problem.

Newly promoted B31.3 M:

I prefer rigids and fillet welds sifs on the attached pipe elements.... an easy way to lower the SIF is to require unequal leg fillet welds.

Thanks. Picture did not want to show up. Connections are now threaded . Some items must come out or the whole system. Upgraded to M.