Trunnions on straight pipe can be modeled as unreinforced, or if needed, reinforced tees, but may optionally be analyzed via FEA.

Attachments on tees should have their SIFs calculated via FEA, such as FEBend.

Find more info here:
https://coade.typepad.com/coadeinsider/2016/10/20161206-caesar-webinar.html