For heat traced piping, insulation pipe cover is typically

• A. one size larger
• B. same size
• C. one size smaller
• D. two sizes smaller

Answer: (C)

When protecting heat-traced piping, the outer insulation cover should fit tightly around what’s been installed. The insulation layer plus the heater cable add diameter, so the protective jacket is chosen to be slightly smaller than the bare pipe size. This one-size-smaller fit provides a snug, compression-like contact around the insulated assembly, helping seal seams, control moisture entry, and keep the jacket in place through temperature changes. If the cover were the same size or larger, gaps could form and moisture could penetrate; going two sizes smaller would make installation impractical and could crush the insulation or damage the tracing.