Issue link: http://cp.revolio.com/i/1121626
Polystyrene Foam Insulation in Long-Term Building Applications – Effective R-values Page 15 Table 7. Applica on Moisture Absorp on and F H20 of EPS and XPS Application ASTM C578 Material Type EPS XPS Below-grade applications 3% by volume 3% by volume F H2O 0.89 0.93 Above-grade wall applications 0% by volume 0% by volume F H2O 1.0 1.0 Roof applications 0% by volume 0% by volume F H2O 1.0 1.0 The adjustment factors for aging, temperature, and moisture can now be used to predict the effective R-value, R EFFECTIVE , in various applications where R LAB is determined from ASTM C578 values at 75°F (24°C). Equation 2 R EFFECTIVE = R LAB x F AGE x F TEMP x F H20 Effective R-value Adjustment Examples Example 1 Equation Term ASTM C578 Material Type EPS XPS II IX X, IV R-value RSI R-value RSI R-value RSI R LAB (Table 1) 4.0 0.70 4.2 0.74 5.0 0.88 F age (Table 4) 1.0 1.0 1.0 1.0 0.86 0.86 F Temp (Table 6) 0.96 0.96 0.97 0.97 0.97 0.97 F h2o (Table 7) 1.0 1.0 1.0 1.0 1.0 1.0 R EFF 3.8 0.67 4.1 0.72 4.2 0.73 % Change -4% -3% -16% Effective R-value in long-term (50-year), above-grade wall applications for a summer condition with an outside temperature of 105°F (40°C) and an interior temperature of 75°F (24°C). The mean temperature will be (105°F +75°F)/2 = 90°F [(40°C +24°C)/2 = 32°C]. Table 8. R EFFECTIVE for Long-term, Above-grade Summer Wall Applica on of EPS and XPS