Kingspan Insulation Boards Thermawall TW50 is a high-performance insulation with a fibre-free rigid thermoset polyisocyanurate (PIR) core, insulant manufactured with a blowing agent that has zero Ozone Depletion Potential (OPD) and low Global Warming Potential (GWP). Low emissivity composite foil and thermal conductivity - 0.022W/mK. Kingspan Thermawall TW50 1.2 x 0.45-metre boards achieve a Green Guide Rating of A+. The TW50 is available in the following thicknesses: 25mm 30mm 40mm 50mm 60mm 70mm 75mm 90mm 100mm Contact us today.