Products > Therma > Therma TW53 > Overview Therma TW53 External insulation for masonry walls Kingspan Therma TW53 Properties Download PDF Thermal conductivity 0.027 W/m.K (< 80 mm) 0.026 W/m.K (80 - 119 mm) 0.025 W/m.K (≥ 120 mm) Facings Glass tissue 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 0.6 m Agrément approved under certified systems.