Single traced piping insulation should be sized as

• A. one size larger than the pipe size
• B. one size smaller than the pipe size
• C. the same size as the pipe
• D. two sizes larger than the pipe

Answer: (A)

Insulation adds material around the pipe, so you size it to accommodate that extra thickness. For a single traced layer, you pick the next standard insulation size up from the pipe size. This ensures the insulation fits around the pipe properly and leaves room for the outer jacket and fittings. If you used the same size as the pipe, the insulation would be tight or compress, and if you went two sizes larger, you’d end up with unnecessary bulk and cost.