I am trying to simulate a dynamic load due to water hammer using a static model by multiplying the dynamic load by the dynamic load factor (DLF) in order to apply it as a concentrated load (force) in the static model.

I have used a conservative DLF of 2.0 which has shown the pipework to be overstressed at some points according to PD8010 pt1. How accurate and relaible are the results when analysed as in this case? What better ways can the DLF be estimated inorder to get more relaistic results.

Regards,
Omon

A DLF of 2 is the maximum modal response to an impulse load. If you have it available, check out (nonmandatory) Appendix II in B31.1. It lays out the method to set DLF for a relief valve discharge assuming only one mode is activated by the event (a single degree of freedom system).

You might want to see how low the DLF must be to get the system to pass the stress check. Then check if that (lower) DLF is sensible.