Deflection tests are required for which pipes?

• A. On all pipe
• B. Only on pipes over 48 inches
• C. Only on pipes under 8 inches
• D. Not required

Answer: (A)

Deflection testing checks how much a flexible pipe can deform under soil and live loads after installation. If the pipe deflects too much, joints can loosen, leaks can occur, and the line can lose alignment, leading to future failures. Because any pipe material and any size can experience some deflection once backfilled and loaded, the safe and standard practice is to test every pipe installation. That’s why the best answer is that deflection tests are required for all pipe.

The other ideas—testing only large pipes, only small pipes, or not testing at all—don’t fit because deflection can be a problem across a wide range of sizes and conditions, and verifying it helps prevent problems regardless of diameter.