Which of the following is an approved method for connecting corrugated metal pipe?

• A. slip joint
• B. bell
• C. welded
• D. band and clamp

Answer: (D)

When connecting corrugated metal pipe, you want a joint that seals well without distorting the pipe’s corrugations and that can handle movement from soil and frost. A band-and-clamp coupling fits that need nicely. It wraps a metal band around the outside ends of the pipe sections and tightens with clamps, usually with a gasket inside to create a watertight seal. This method distributes pressure evenly around the ridges, preserves the pipe’s strength, is easy to install in the field, and accommodates minor movement without leaking. Welding CMP is risky because the heat can warp the pipe and damage protective coatings, and slip joints or bell-and-spigot styles require ends that CMP often doesn’t provide, which can lead to leaks or poor fit. So the approved connection method for corrugated metal pipe is a band and clamp.