How Does Insulation Help Control Condensation?

When piping and equipment operate at temperatures lower than the ambient air, moisture in the air will condense, or freeze, on or within the insulation surface, or on the cold pipe surface. Unless the system is protected by sufficient thickness and by adequate vapor retarders, the insulation can become wet, causing corrosion, and causing the insulation to become ineffective. Specifying sufficient insulation thickness with an effective vapor retarder system is the most effective means of providing a system for controlling condensation on the membrane surface and within the insulation system on cold piping, ducts, chillers, and roof drains. Sufficient insulation thickness is needed to keep the surface temperature of the membrane above the highest possible design dew point temperature of the ambient air so condensation does not form on the surface. The effective vapor retarder system is needed to restrict moisture migration into the system through the facing, joints, seams, penetrations, hangers, and supports.