What is the max amount of torque that could be applied to 1 in male threaded NPT pipe when it is threaded into a 1 in female threaded body that is made from ASTM 126 cast iron. The dimensions of the threaded female body are shown below.
Thanks for the infoIt would seem that contacting the maker of the threaded pipe would be the best place to start.
They may have an 800 number that you can call.
Here's one such vendor
Torque installation of pipe fittings is not a recommended practice. Thread taper and quality, different port and fitting materials, plating thickness and types, varying thread sealants, orientation, and other factors reduce the reliability of a torqued connection.
I have never seen any plumber use a torque value on the npt fitting and piping joints. To be honest, they always use thread sealant and generally tighten joints until "it feels right" based upon their prior experience.