NPT pipe threads

I am looking for a torque spec for sealing 1\2" Npt threads.

 

[reichertc]

Hmmm... Torque values would likely be very dependant upon what kind of thread lubricant you are using. I have a copy of IPT's Industrial Fasteners Handbook, and they recommend for sizes 1" and under, NPT joints should be hand tightened 3 or 4 turns and then tightened by a wrench for 3 turns. Specifically for NPS 1/2", they recommend 7-1/2 turns.

One major caution that they mention is that a joint that is made-up too quickly will generate a lot of heat due to friction. A joint that is pressure tight immediately after assembly may leak once it has cooled...

Hope that helps.

 

[Hush]

To add to reichertc's info, API provides the following for LP threads (which are essentially the same as NPT).

2" and below 3 turns past hand tight
2-1/2" and above 2 turns past hand tight.