What is phenolic insulation?
Phenolic insulation is rigid insulation with a closed-cell structure. It is made by mixing phenolic resin with a catalyst and a blowing agent. This mix is then added directly to the bottom layer of the facing and due to a chemical reaction between the ingredients in the mix, it expands to meet the top layer of the facing. The chemical reaction releases heat and causes a network of bubbles to appear as the blowing agent is vapourised in the material, which locks in the gas and contributes to the thermal performance of the finished product. Once the boards are formed, they are cured and dried in an oven. After they are taken out of the oven, the boards are cut to size and packaged up. Over time a small quantity of the gas will escape which can change the thermal performance. This is called ageing. All Kingspan phenolic insulation products are tested and compliant to AS/NZS 4859.1:2018 and hence take into account the effects of ageing.
Benefits of phenolic insulation
Phenolic insulation is one of the most thermally efficient insulation commonly used. Thermal conductivity of phenolic insulation is generally lower than other insulation materials such as EPS, XPS, PIR or mineral fibre products. That is why phenolic insulation can help you achieve the required thermal performance in wall, roof and floor applications, which makes it a great solution for a range of constructions.
Fire performance of phenolic insulation
Phenolic insulation has proven fire performance, demonstrating low flame spread and smoke emission. Since it is a thermoset material, it hardens and chars during a fire giving off very little smoke; unlike thermoplastics, such as polystyrene which melt, soften, and can give off thick black smoke.
To better demonstrate the fire performance of Kingspan Kooltherm phenolic insulation, we have put it to the test in the following video.
In the video you can see a sample of Kingspan Kooltherm insulation being subjected to a blow torch flame. Kooltherm insulation chars when it is burnt which stops it from propagating fire and once the fire source is removed, it self-extinguishes.
The heat from the flame causes the insulation to undergo pyrolysis, which results in the black char that is formed on the surface of the board. The pyrolysis also releases combustible gasses, which cannot be seen, but the result of their subsequent combustion can be seen in the additional small flames that occur. These additional flames are most obvious in the first 30 seconds after the blow torch flame is introduced, whilst the initial char is formed. After this, the flames die down a little, and the amount of char gradually increases.
After 8 minutes the blow torch is removed, and you can see that the board itself does not propagate flaming across its surface without the blow torch flame, and that the board self-extinguishes. That happens because when the blow torch flame is taken away, the energy from combustion of pyrolysis gases alone is insufficient to support further pyrolysis, and the insulation self-extinguishes.
If you have any questions relating the fire performance of Kingspan Kooltherm, please feel free to reach out to our Technical Services team on 0800 806 595 or email
