Condensation is the process whereby gaseous water vapour in the air condenses into liquid water when it comes into contact with a cold surface.
Why does condensation occur?
The ability of air to hold water vapour is dependent on the air temperature with warmer air capable of holding more water vapour.
Cooler air can't hold the same volume of gaseous water vapour and so, as warm air cools the water vapour is forced to condense into liquid water. This is why when warm air comes into contact with a cooler surface liquid water condenses onto the surface.
What are the problems with condensation?
All forms of pipe corrosion can be greatly accelerated by the presence of moisture.
On pipework operating below 0 °C condensation can freeze solidly around the pipe, damaging insulation and making maintenance impossible.
How can condensation be prevented?
Condensation only occurs when air comes into contact with a surface operating at below the dew point temperature. Applying insulation such as Kaiflex to a cold pipe or duct increases the surface temperature and reduces the risk of condensation occurring as a result.
Why does condensation not form inside the insulation?
Kaiflex has a very high resistance against the passage of water vapour that is inherent to the material. Every one of the many thousands of closed cells that comprise the material structure has its own water vapour barrier through which moisture cannot easily pass.
As water vapour can't pass through the closed cell structure, condensation can only occur on the insulation surface.