Testing a 24 inch PVC pipe with gasket joint 1000 Ft lenght. During filling we detect small leaks of Safety valves  in 4 joints, but once the pipes gets just a little pressure (about 35 PSI) the leak stops and pass the 2 hours test ay 150 PSI with no problem. The main problem now is that the inspection is killing me with questiong regarding to if this is normal. A couple of PVC pipe manufacturer told me that its perfectly normal, but when i ask to a document (standard, essay, textbook or something) they told me that there isn't any. It's this true? where i can find info about it if this is possible
It's fairly typical.  During installation, gaskets can slip to the inside edge of their retaining groove, and small gaps may open due to the corners rolling, or dirt pickup.  During filling, the pressure will eventually press the gasket to the outside of its groove, and provide a squeezing force, filling any small voids that may have opened. Gaskets often are displaced slightly when the spicket is pushed into the bell. Adding pressure returns them to the intended postion. You might also google "allowable leakage", it is a formula we use when testing pipe.

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