The unthreaded portion of pipe exposed through a ceiling or wall should be at least how many inches?

The unthreaded portion of pipe exposed through a ceiling or wall should be at least how many inches?

• A. 1 inch
• B. 2 inches
• C. 1/2 inch
• D. 3 inches

Answer: (A)

Minimum unthreaded length through a wall or ceiling is 1 inch. This ensures there’s enough smooth pipe outside or through the surface so the threaded joint can be engaged or disconnected without damaging the threads, and it provides clearance for service, testing, and future adjustments without stressing the joint. Shorter installations risk damaging threads or making future disassembly difficult, while longer lengths aren’t required by the code.

Minimum unthreaded length through a wall or ceiling is 1 inch. This ensures there’s enough smooth pipe outside or through the surface so the threaded joint can be engaged or disconnected without damaging the threads, and it provides clearance for service, testing, and future adjustments without stressing the joint. Shorter installations risk damaging threads or making future disassembly difficult, while longer lengths aren’t required by the code.