AbstractAn apparatus for measuring the gas permeability of films and sheet material has been developed at the Central Laboratory TNO, Delft (The Netherlands). The apparatus consists of a high vacuum unit, connected to six film holders of a new design and construction. The pressure of the gas which permeates through the film in a constant volume, is measured with the aid of McLeod manometers. The apparatus was developed for rapid, accurate measurements of materials of very low permeability, but it is also suitable for films of high permeability, but it is also suitable for films of high permeability. The range of permeabilities to be measured is between 10−7and 10−13cm.3(S.T.P.)‐film thickness/cm.2‐sec.‐cm. Hg. The measuring time for the 10−13range is about 6 hr. (for plastic laminated with aluminum) and for the 10−7range is about 15 min. (for polyethylene). Measurements can be executed simultaneously on six heads and easily at various temperatures and relative humidities. The apparatus is suitable both for research purposes and for routine measurement
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