With reference to Coade’s newsletter article on Hot Tapped piping, (article by Jhon C. Luf in October,1996 newsletter, found on this website), I have a doubt and need clarity:



Load Case3 (ope) : W+DIS+P1 ( Minimum Operating Conditions “system shutdown” )





The “DIS” was calculated based on T1 case, as the header pipe is operating when the tie in is made. Is the same “DIS” applicable for the shutdown case?
What am I missing here?

In the example the +Y at node 40 is displaced up ~ + 0.46". load cases 1,2,3 all impose the T1 displacement. Case 3 represents the thermal strain in the system when the system cools to ambient temperature. The +Y is pulled upwards when the system is cooled down because it was installed when the header was at T1.

The T1 displacement is the temperature present in the system at the time of the tie in.

See http://www.coade.com/newsletters/oct96.pdf