Pipe joint leakage is commonplace. The piping industry believes zero leaks are a worthwhile and practical goal. This will happen only when proper design, manufacturing and installation of joints occur.
A flange is a platelike device that allows the connection of two pipes, or the connection of a pipe and a valve, choke, tee or other piping. Flanges commonly connect pipes with an outer diameter of more than 2 inches.
Torque is a force that tends to revolve or rotate things. Torque generation occurs when you use a wrench to apply a force. Tightening flange bolts is a good example. You apply a force to the handle when you use a wrench. This force creates a torque on the flange bolt, which turns the bolt.
A torque table provides a guide for values based on ASME B16.5 class specifications. Torque values depend on pipe diameter, number of threads on the bolt, the flange surface and lubrication. For Class 150 flanges used on pipes 0.5 to 1.25 inches, the maximum torque specification is 60 ft./lb.