Kingspan Insulation advises that it is important to distinguish between ‘Open Cell’ and ‘Closed Cell’ designs when comparing different rigid phenolic insulation boards. Open Cell and Closed Cell phenolic foams widely differ in their respective performance characteristics.
Kooltherm insulation boards available from Kingspan Insulation are made using Closed Cell phenolic foam. But how does an Open Cell system differ from a Closed Cell system?
Open Cell insulation foam
Open Cell insulation foam allows the blowing agent to quickly disperse, enabling transfer of air or water vapour through an ‘open’ or ‘porous’ interconnected material structure like a sponge. This is why only an aged R-value is a true representation of its performance and not the value achieved immediately after manufacture. The degree of movement through the body of the material is dependent on a range of factors, including the size and density of the cells, moisture ingress, as well as the chemical composition of the material itself.
However, porous, sponge-like characteristics are not ideal features for insulation because any flow through an insulating material defeats the very purpose by facilitating unwanted energy transference.
Closed Cell insulation foam
Closed Cell materials feature millions of unconnected cell pockets, which effectively contain the blowing agent long term. Kingspan Kooltherm insulation board is a high quality Closed Cell phenolic foam with a negligible Open Cell content (2%), providing ultra low thermal conductivity and a very high R-value.
Features such as a sound cell structure, tiny cell diameter and premium CFC/HCFC-free blowing agent clearly distinguish Closed Cell insulation foam from its competitors. Kooltherm’s superior Closed Cell technology provides reliable long-term thermal performance.
A pycnometer, which measures the impenetrable volume of the sample by gas, can be used to accurately analyse the qualitative differences between Closed and Open Cell systems. Test methods should conform to EN ISO 4590 standards (or equivalent), which take into account factors such as surface damage to open cells caused by the cutting of samples.
The Technical Bulletin can be accessed on the Kingspan Insulation website.