Permeation Index Numbers
Krister Forsberg, Lawrence H. Keith · 2019
A standard test method for measuring the permeation of chemicals through protective materials has been established under the American Society for Testing and Materials. This method evaluates the chemical resistance of a chemical protective clothing material versus liquids or gases. Two key parameters are reported using this method, i.e., breakthrough time and permeation rate. The index numbers provide a useful guide to help in selection of the best protective materials when there is more than one choice available or to provide some relative risk assessment if data is available for only one type of material. Clothing material test results with classification Index Numbers of 4 or 5 may exhibit one or more forms of degradation. It is important to note that a material which has an index number of 4 or 5 against one particular chemical may in fact be rated with an index number of 0 or 1 against some other chemical.