Method for measuring air permeability of porous sheet

The invention relates to a method for measuring the air permeability of a porous sheet, which comprises the following steps: cutting the porous sheet into a ring-disc-shaped sample, and placing the sample between two flat plates, one flat plate having no holes and the other flat plate having holes, the projection plane of the inner circle of the sample completely covering the holes; measuring the thickness of the clamped sample; introducing gas into the hole, and measuring the pressure drop or the gas flow generated when the gas passes through the sample; and calculating the air permeability value of the porous sheet according to the measured value. Compared with the prior art, the device has the advantages that a sample is placed between the two flat plates with one being provided with holes for air permeability testing, so that the difficulty of clamp sealing design is reduced; loads are applied to the two flat plates, so that the air permeability of the porous sheet under different ballast force conditions