Description
Air permeability is defined as ‘the velocity of air flow passing horizontally through a test specimen, under specified conditions of test area, pressure drop and time’.
The instrument forces air through a specimen and adjust the flow of air gradually until a pressure drop is achieved.
The measurements will be taken multiple times dependent on the standard, and a mean air permeability would be expressed in millimetres per second or metres per second.
James Heal Instruments Physical Testing
