A Test Method to Determine Air Flow Resistance of Exterior Membranes and Sheathings

This note describes a test method for determination of air flow resistance of ex terior membranes and sheathings. The test specimen is placed between two chambers with different air pressures and the volumetric air flow rate through it at a steady state is determined. The relevant experimental quantities can presently be measured with precision better than 0.5% and with an accuracy of 2 to 3 % , using commercial instruments. However, the …