Products > Therma > Therma TW55 > Overview Therma TW55 Insulation for timber and steel framing systems Kingspan Therma TW55 Properties Download PDF Thermal conductivity 0.022 W/m.K Facings Composite foil Core High performance rigid thermoset polyisocyanurate (PIR) insulant manufactured with a blowing agent that has zero Ozone Depletion Potential (ODP) and low Global Warming Potential (GWP). Board size 1.2 x 2.4 m