Several industries have strict technical requirements for materials. Such is the case in construction, where foam materials are used for various purposes such as reflective insulation.
Reflective insulation can be used in the construction of a heat insulated floor system. Foamed polypropylene or polyethylene is often the material used for this type of insulation; however, it is important that the material has a reflective layer on top of it to avoid safety hazards. Not using a reflective layer on foamed insulation for heat insulated floor systems can result in the following concerns:
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Reduced heat loss of the “warm floor”- PE and PP foam insulates the entire structure and thus it prevents the heat from declining. If fact, the coefficient of thermal conductivity of PE and PP foam with a thickness of 4-5 mm and a density of 25-30 kg/m3 is about 0.035 - 0.038 W/m2, which is approximately 1.5-2 times lower than that of concrete. It is often believed that the reflective foil prevents heat loss, but this is not the case. Foam is critical, because the thermal conductivity of aluminum foil is very high and it cannot be used as an insulator without having an air gap underneath, this is where the foam fits into the equation. In fact, the use of PE & PP foam with a reflective foil layer with a thickness of only 25-30 microns will significantly increase the efficiency of the "warm floor" system, reduce the heating time of the concrete screed and reduce heat loss.
Reduced heat loss of the “warm floor”- PE and PP foam insulates the entire structure and thus it prevents the heat from declining. If fact, the coefficient of thermal conductivity of PE and PP foam with a thickness of 4-5 mm and a density of 25-30 kg/m3 is about 0.035 - 0.038 W/m2, which is approximately 1.5-2 times lower than that of concrete. It is often believed that the reflective foil prevents heat loss, but this is not the case. Foam is critical, because the thermal conductivity of aluminum foil is very high and it cannot be used as an insulator without having an air gap underneath, this is where the foam fits into the equation. In fact, the use of PE & PP foam with a reflective foil layer with a thickness of only 25-30 microns will significantly increase the efficiency of the "warm floor" system, reduce the heating time of the concrete screed and reduce heat loss. |
Reflective insulation
Damaged aluminum foil without protective layer under cement screed
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A protective polymer layer Is crucial
Using foil with a protective polymer layer on the reflective side in the lamination of foamed polypropylene or polyethylene is crucial. This is because the reaction of an alkaline solution (cement) with aluminum leads to its destruction due to the displacement of hydrogen. In this state the foil will eventually dissolve and only the foamed polymer will be left. This will cause uneven distribution of heat over the concrete screed, which can lead to overheating and cracks. The protective polymer layer functions as a buffer that prevents the reaction between the foil and alkaline solution.
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