b'R-VALUESGLOBAL STEWARDSHIPThickness 75 Mean 40 MeanR-VALUES2 15.72 16.952.5 19.45 21.19R-Values for 75 mean based on ASTM C518: Steady State Thermal Transmission. R-values3 23.18 25.42for 40 mean based on interpolated data from ASTM C1363: Hot Box Apparatus. Values shown are for general use only. They3.25 25.05 27.54do not reflect system or specific end-use insulation values. 4 30.65 33.895 38.12 42.366 45.59 50.8473'