The chemical permeation 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. Final selection should also include degradation data when it is available.
Index 0 and Index 1 apply to the most resistant materials towards a specific chemical or test mixture.
Index Number 0 indicates a highly resistant material for this chemical and is one of the best of the models tested against this chemical.
Index Number1 indicates a highly resistant material for this chemical and may often be accepted by an industrial hygienist for harmful chemicals (e.g., as toxic as toluene or as corrosive as concentrated sodium hydroxide or as irritating as acetaldehyde).
Index Number 2 requires a greater degree of judgment by an industrial hygienist before it will be accepted. Industrial hygienists will not feel comfortable in recommending Index 2 materials for chemicals that are harmful (where a relatively small dose has a medium to moderate toxicity).
Index Number 3 materials are not usually sufficiently protective to be recommended by industrial hygienists unless there is no other choice or unless the work involves protection only against occasional splashes or compounds that are not very harmful.
Index Number 4 materials are usually not acceptable for protection in any situation except occasional splashes. When splashes occur with materials in either Index 3 or 4 the gloves, or other types of protective clothing, should be immediately removed and exchanged for new ones.
Index Number 5 materials may be considered dangerous by most industrial hygienists because of the lack of protection they offer towards the chemical(s) tested.
Chemical protective clothing (CPC) 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 manufacturer's material and model 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. Therefore, these Index Numbers are not to be construed as a general rating of a CPC. The rating is only applicable for protection against the specific chemical referenced and under the conditions of the measurements used, which include a specific manufacturer's material and model number.
Source: Instant Gloves + CPC Database, Copyright 1998 by Instant Reference Sources, Inc. and Digital Liaisons, Austin, Texas.