Oxygen Permeability - ASTM D3985
The rate at which oxygen will pass through a material under specified conditions and specimen geometry. The volume of oxygen that will pass through a unit thickness of material per unit area per unit time per unit barometric pressure.
The test specimen is held such that it separates two sides of a test chamber. One side is exposed to a nitrogen atmosphere while the other is exposed to an oxygen atmosphere. A coulometric sensor monitoring the exit port of the nitrogen side measures the amount of oxygen present. Testing is complete when the concentration of oxygen in the nitrogen side atmosphere is constant.