We have been facing the problem pump failure very frequently and tried to do piping stress analysis on the connected loops. The piping loop is connected with vessel at one end while other end is connected with the failed pump. The operating load case and sustained load case on the piping loop has passed. But while analysing the load case in the suction and discharge nozzles of the pumps as per API 610, the result showed Fx & My failed at suction nozzle. Similarly Fz & Mz failed in discharge nozzle.

There is no scope for providing any expansion loop in the existing piping. What should be done to overcome the failed cases?

Either add expansion joints or find some space to add pipe flexibility. Maybe move the pump ? There are no magic solutions for this sort of problem.

Add flexibilty first only use an EJ as a last resort.