What should be used to insulate single traced piping?

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

Answer: (A)

The key idea is that insulation must fit the pipe cleanly and leave no compression or gaps that could reduce performance. For single traced piping, selecting an insulation size with an inner bore just large enough to slip over the pipe and sit around it without squeezing is important. Choosing an insulation that is one size larger than the pipe size ensures a proper slip‑on fit and preserves the insulation’s thickness and thermal resistance. If you use the same size, it can be too tight to install and may crush the insulation, reducing its effectiveness. If it were two sizes larger, the fit would be loose, leaving gaps and potential movement that undermine protection and insulation performance.