NPT Torque Values 3

[wallace24]

Need help to what is turning out to be an elusive question.
We have female 3/4" NPTF threads (material SA-105) mating to a stainless steel (304/316) valve with NGT threads.
We are using Teflon tape.
Could someone tell me what the acceptable torque range is to install these valves - leak free?
We have other pipe thread sizes for this situation also - any info or reference would be appreciated.
Thank you.

 

[winpop123]

Never seen a torque called out for NPT. Its always designated by the the amount of "make up" (ie) linear distance of travel. Would be interested to see a torque table as well....

According to "The Pipe Fitters Blue Book" W.V. Graves, 1973.

The amount of thread engagement must be 9/16" for a "tight joint"

Hope this helps.

 

[Zapster]

See discussion in: thread378-5045

 

[roadapple]

You might consider that API 5CT specs out various threads of the "NPT favor". These are used in various applications and typically have 8 or 10 threads per inch and have the same taper of 3/4" per foot.

For API - Power tight on these types of threads regardless of the size - is 2 complete turns past the hand tight plane.


roadapple

 

[wallace24]

Thank you all for the valuable information!!!