An insulation that has absorbed moisture ___________.

An insulation that has absorbed moisture ___________.

• A. Has gained insulation value
• B. Has not changed
• C. Has lost some of its insulation value
• D. Becomes fireproof

Answer: (C)

Moisture in insulation reduces its ability to resist heat flow. The effectiveness of most insulation relies on trapped air pockets that limit heat transfer. When the material absorbs moisture, those air spaces are filled with water, and water conducts heat much better than air. Water also can cause fibers to clump or compress, further reducing the dead-air spaces that provide insulation. As a result, the material’s overall ability to slow heat transfer declines, so it has lost some of its insulation value. It doesn’t gain insulation value, and it isn’t unchanged or fireproof simply by absorbing moisture.

Moisture in insulation reduces its ability to resist heat flow. The effectiveness of most insulation relies on trapped air pockets that limit heat transfer. When the material absorbs moisture, those air spaces are filled with water, and water conducts heat much better than air. Water also can cause fibers to clump or compress, further reducing the dead-air spaces that provide insulation. As a result, the material’s overall ability to slow heat transfer declines, so it has lost some of its insulation value. It doesn’t gain insulation value, and it isn’t unchanged or fireproof simply by absorbing moisture.