Vejledning 3 - Isoleringssystemer / Polyurethane (PUR)

Polyurethane (PUR)

Insulation made of man-made materials

Polyurethane (PUR) insulation materials are made during chemical reaction of isocyanate7 and polyols8. During reaction of these chemical compounds, a material with closed pores is obtained (product of ammonia based product treatment with poisonous gas – phosgene).

Typical final product is PUR boards or loose-fill to fill in small cavities. Perforation and cutting of PUR boards can be done at the construction site without losing the thermal properties of the material.

Thermal properties are dependent on temperature, moisture and mass density of the material. Typical values for thermal conductivity is 0.02 – 0.03 W/(mK), while the reference standard EN 13165:2012 is 0.023 – 0.03 W/(mK) for dry material at 10 °C. Thermal conductivity of PUR increases 45 % (from 0.025 W/(mK) to 0.046 W/(mK)) in the case the moisture content in the insulation material increases from 0 vol% to 10 vol%.

Additional point of consideration is the hazardous properties of PUR materials in the case of fire. PUR is certified as safe for its intended use, but the chemically very poisonous initial materials that the product is made of are being released during a fire and badly affect the respiration system.