Insulation for cold pipework is normally expected to fulfil an energy saving function but this is generally a secondary consideration. As pipework falls below the ambient temperature the risk of condensation increases - applying insulation provides effective condensation control which is the primary role of insulation on cold pipework.
The thickness of insulation needed is intimately tied to the environmental conditions and operating temperatures of the pipe.
Pipe insulation plays a critical role in preventing condensation and pipe corrosion but the importance of selecting the correct insulation thickness is often overlooked.
As with pipe insulation on all mechanical systems, selecting the most appropriate insulation material is an important task for any consultant or contractor.
Material suitable for insulating heating and hot water pipework might not be appropriate for use on cold pipework due to the pressure of water vapour pushing moisture towards the pipe. Without a water vapour barrier this moisture can be pushed to the very surface of the pipe, condensing and accelerating corrosion.
The choice of insulation materials for cold pipework is, therefore, intimately tied to the choice of water vapour barrier. The most common form of water vapour barrier is an externally applied foil.
Closed cell foams, in which each cell has its own vapour resistant cell wall, provide an alternative to external vapour barriers. By layering thousands of cells together the material performs as if it possesses an “in-built” water vapour barrier. An “inbuilt” water vapour barrier is always preferable as it is easier to vapour seal and harder to pierce or damage.