ISO 5636-3:2013 specifies the Bendtsen method for determining the air permeance of paper and board using the Bendtsen apparatus. It is applicable to papers and boards which have air permeances between 0,35 µm/(Pa·s) and 15 µm/(Pa·s) when tested with the Bendtsen apparatus. It is unsuitable for rough-surfaced materials which cannot be securely clamped to avoid leakage.