Products > Therma > Therma TW50 > Overview Therma TW50 Partial fill cavity wall insulation Kingspan Therma TW50 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 0.45 m