Hydrotest of GRP Pipelines

http://www.bing.com/search?q=the+standards+for+hydrotest+of+GRP+pipelines&src=IE-SearchBox&Form=IE8SRC

In my opinion you should contact the manufacturer of your specific GRP (FRP) piping.

In my opinion, you should also check the "Code of Record" for the hydrotest requirements for the piping system.

Your particular piping system should have been designed with a "maximum allowable operating pressure". The hydrotest pressure is typically 1.5 or 1.3 times the MAOP for the system.