Plumbing – Should threaded pipe be torqued to spec


Most, if not all threaded automotive fasteners have specified torque, which is ensured by using torque wrenches. But how about threaded pipe, galvanized steel for water or black pipe for gas, especially the latter? Should it be torqued to spec using something like a torque version of a pipe wrench, to ensure a proper joint?

Best Answer

No. Automotive parts (generally anything you'd find a torque spec on) and fasteners are engineered to a degree that residential galvanized and gas piping simply isn't.

  • Automotive parts are designed to accommodate disassembly and maintenance - water pipes are typically not.
  • It's possible to get a bolt on, say, a brake caliper or a wheel hub on tight enough that it interferes with its safe function.
  • There's a minimum torque on head bolts to minimize the chance of gasket failure or blow-by.
  • It's also a good way to ensure that parts don't warp if they aren't tightened symmetrically around a perimeter.
  • Overtightened bolts can shear off or accumulate stresses that could cause pre-mature failure.

None of these are issues with water and gas lines (except with soft metals like copper). The proper amount of torque is somewhere between "it doesn't leak anymore" and "I can't move it with a wrench anymore" (assuming, of course, that the former comes before the latter).