 CPC that has not been tested for the specific operating condition it is used in may not provide adequate protection.The same material, even at the same thickness, may provide different levels of protection depending on the manufacturer, since different manufacturers use different processes and may add different additives.Finally, while the test data will provide information on individual chemicals based on "worst-case scenario" continuous contact testing, most industrial exposures are not continuous and are in fact mixtures of chemical, for which permeation rates are different.