I would think the Hydro-test procedure would specify the type of dope to be used if it was a concern. I also don't think it would be a problem, since the tape only reduces friction, the same function as the dope performs. I think the main reason teflon tape is not used is that there are commercial dopes out there that are easier to use and more effective.
There is a void/gap at the thread tip, as most threads. The pipe dope plugs this void, and lubricates the thread. API pipe dope contains lead, copper, and ? particals to plug this void at high pressures encountered in oil/gas production. Teflon tape can plug the void for lower pressures /shorter times. It may be able to hold your pressure for the time of the hydro test; If it dosen't you have to use API dope.
What commercial dopes do you recomend? We currently use Jet-Lube Heavy duty PTFE thread sealant TF-15 or copper Kote.
Our procedur is to wrap with teflon tape then apply dope to the teflon tape before connecting male thread to femail thread. The test pressure is 2000psi. This has worked very well in the past when Hydro-testing. I have one client who says Teflon tape should not be used on 8 round threads. I am not able to find a procedure that is clear either way...
The API 5CT that I have is 1995 ed.: section 7.14 -Coupling Makeup- says the dope should conform to Bulletin 5A2 , OR whatever is specified on the purchase order ("the customer is always right" ).
At that time (1995) , API was trying to develope dope without metal powders for environmental reasons. So I do not know what may have changed.
