I need to model and analyze a steam system that will be installed using a hot tap. The system consists of a 10” steam header, a separate 6” header, and a cross connect with intervening valve from one to the other. The system will be installed when the 10” header is hot and the 6” header and x-connect are cold. The 6” line cannot be hot while the 10” is cold. My plan is to:

1) Model the 10” header (per my understanding of the hot tap guidelines in the COADE paper of 1996) by which is meant the header only will be modeled with nodes at every restraint but the actual restraints themselves will be omitted.
2) Run this model (thermal only) at the hot tap temperature (500F) to obtain movements.
3) Create new, separate, model including both headers and the cross connect – declare vector 1 displacements (D1) for all applicable nodes on the 10” header to be the movements obtained from 2) above (using CNODES).
4) Declare T1 temperature scheme for the new file to be everything 70F.
5) Declare T2 temp. scheme to be 70F for the 10” hdr. 500F for the x-connect and 6” header.
Run following load cases:
L1 = W+T1+P1+D1 (OPE)
L2 = W+T2+P1+D1 (OPE)
L3 = W+T1+P1 (OPE)
L4 = W+P1 (SUS)
L5 = L1-L2 (EXP)
L6 = L1-L3 (EXP)
L7 = L2-L3 (EXP)

Is this right, or wrong, and if wrong how?