Many consultancies use code’s “reinforced tee” SIF for trunnions on straight pipe. The reasoning is like this…

There is no weakening hole cut on the pipe for a trunnion. The pad used in a reinforced branch compensates for this removed area and we get a branch like situation. So in effect a trunnion on straight pipe without pad is equivalent to a reinforced branch for SIF computations.

Of course this is not accurate but a reasonable approximation in most of the cases…