)will result in a loss Δ"p" / "L" of 0.02 kg / m2 / s2 (0.02 in H2O per 100 ft), illustrating the great gains in blower efficiency to be achieved by using modestly larger ducts.The following table gives flow rate "Q" such that friction loss per unit length Δ"p" / "L" (SI kg / m2 / s2) is 0.082, 0.245, and 0.816, respectively, for a variety of nominal duct sizes.