1. Aluminium foil as a 100% crystalline metal inhibits any transport of matter 2. Conditional of manufacturing, there is no thin foil absolutely free of pinholes 3. As soon as pinholes are coated with polymers, their contribution to a permation rate can not be measured at all 4. Relative to their size, the effect of small pinholes is stronger A worst case permeation calculation system gives an indication of permeation rate (input: specific permeation rate and thickness of the polymers on one or both sides of the foil; number and average size of pinholes) 5. The functional barrier of aluminium foil persists even in the presence of pinholes.
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