Thanks, Steve.
I did not find any information directly related to cold service pipes, but did find some examples of corrosion on the inside of trunnions attributed to moisture ingress and condensation on the process pipe. So I'll take that as an example of the importance of keeping the surfaces...
I'm looking at our company standard drawings for dummy leg pipe supports for insulated lines, and there is no differentiation for use between hot lines and cold lines. No insulation is called out for the dummy leg itself, and the dummy leg is shown supported by a welded-on shoe.
For hot...