Dear Habib,

Could you please suggest any singal instance where the system has designed such a way that nozzle loads exeeds vendor or code allowable in WNC load case and passes in Design/Normal Operation/Sustanied load cases.If I come across such a design I have to simply scrap it.

We consider following load cases for nozzle evaluation.

1)Primary loads(Sustained load)-This load is caused by the internal pressure,pipe weight,inside fluid and insulation weight.

2)Primary load + Secondary load(operation load)-This load ia combination of primary load and secondary load caused by thermal expansion.

Now make appropriate combine load case for nozzle evaluation.
We make various load cases to analyse a piping system and we are not supposed to evaluate nozzle for each and every load case.
Does we do it?The answer is no.

The general practice in all engineering companies I worked for is to evaluate nozzle in Design,Normal operation and Sustained load cases.

If your piping routed and supported in a way that nozzle loads are within allowable in design/normal operation and sustained load cases then loads on nozzle in WNC load case can never exeeds allowable loads.

As I mensioned earlier one of the most important use of WNC load case is to check nozzle alignment.

I think I need to put some light on it.In addition to the nozzle loads check,it is required to perform displacement check at mating flange face of nozzle when pipe is empty and disconnected with the equipment to ensure the balance of piping and supports.Especially piping connecting to rotating equipment shall be check carefully.This is simmilar to the field allignment check.There is procedure to do that in caesar II and it varies with equipment to equipments.The general creiteria is that displacement at nozzle should be less then 1 mm in all direction.

I hope this clarifies all.

Regards,
Aslam