Moisture & Exacerbated Heat Loss / Gain

It is important to understand the different properties of the insulation you use, because the measured performance of the material in its ‘fresh from the factory’ state may not be what you get in a real application.

For instance, moisture can end up in insulation in a number of ways e.g.:

• liquid water penetration through the vapour barrier jacket or any weather protection layer; or
• vapour penetration through the vapour barrier jacket and resulting condensation on chilled services.

Insulants are affected in different ways and degrees by this. For example, only 1% moisture content by volume within mineral fibre insulation can increase its thermal conductivity by up to 107%.

The closed cell construction of high performance rigid phenolic insulation, on the other hand, makes it almost impervious to moisture, and its thermal conductivity remains largely unaffected.

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