What schedule is associated with the minimum wall thickness for small-diameter piping connected by threaded fittings?

What schedule is associated with the minimum wall thickness for small-diameter piping connected by threaded fittings?

• A. Schedule 10
• B. Schedule 20
• C. Schedule 40
• D. Schedule 80

Answer: (C)

When piping is connected with threaded fittings, the wall must be thick enough to support the threads and withstand the operating pressure without leaking or failing. Schedule 40 is the baseline thickness that provides this adequate strength for small-diameter steel pipe used with threaded joints. That thickness ensures the threads engage reliably and the joint remains durable during service and testing. Thinner schedules would be more prone to leaks or thread damage, while thicker schedules (like Schedule 80) add unnecessary weight and cost for typical standpipe service. So Schedule 40 is the minimum, balanced choice for small-diameter piping with threaded fittings.

When piping is connected with threaded fittings, the wall must be thick enough to support the threads and withstand the operating pressure without leaking or failing. Schedule 40 is the baseline thickness that provides this adequate strength for small-diameter steel pipe used with threaded joints. That thickness ensures the threads engage reliably and the joint remains durable during service and testing. Thinner schedules would be more prone to leaks or thread damage, while thicker schedules (like Schedule 80) add unnecessary weight and cost for typical standpipe service. So Schedule 40 is the minimum, balanced choice for small-diameter piping with threaded fittings.