Which statement best describes the effect of temperature on PVC piping installed in trenches?

• A. It expands and contracts
• B. It becomes stronger
• C. It becomes porous
• D. It requires no support

Answer: (A)

PVC piping changes size with temperature. It expands when warm and contracts when cool, because it’s a thermoplastic and responds to heat by increasing molecular motion. In trenches, these size changes matter along long runs or through temperature swings, so installers plan for movement with expansion joints, flexible couplings, and proper bedding that allows the pipe to shift slightly without stressing joints or the pipe itself.

That’s why the statement that it expands and contracts is the best description. It isn’t that PVC becomes stronger with heat, nor that it becomes porous under normal conditions, and buried plastic piping still needs appropriate support and allowances for movement rather than assuming it requires no support.