Which statement best describes how flange overlap is determined relative to insulation thickness?

• A. Same as thickness
• B. Half the thickness
• C. Twice the thickness
• D. Four times the thickness

Answer: (C)

The idea being tested is how much insulation should extend over a flange to maintain a continuous thermal barrier. The overlap is twice the insulation thickness to ensure the flange face and bolt holes are fully covered once the flange is bolted and sealed. This extra coverage accounts for the flange’s recessed and protruding features and for any gaps that could occur around bolts, helping to preserve thermal continuity and minimize heat loss or condensation at the flange.

If the overlap were only the same as the thickness, half, or four times, it would either leave parts of the flange exposed, be insufficient to cover the flange geometry, or add unnecessary bulk, respectively. Doubling the thickness strikes a practical balance for proper coverage and fit.