Protect Your People PermaSURE® - the future of chemical suit selection The PermaSURE® for ChemMax® Toxicity Modeller provides a simple and quick way to calculate how long you are safe against over 4000 chemicals. If you are involved in chemical suit selection you will be familiar with chemical permeation test breakthrough times - often incorrectly used to indicate whether a wearer is safe or not against a specific chemical. Graph of Permeation Rate However, test breakthrough does not indicate when the chemical first breaks through the fabric, but is recorded when the RATE OF PERMEATION reaches 1.0μg / min / cm2*. * In the CE standard test. The ASTM standard test uses 0.1ug / min / cm2. Thus, as the graph indicates, at the point of test breakthrough the chemical has already been permeating through the fabric and may have come into contact with the user. The problem of temperature. All permeation tests are conducted at 23oC in order to ensure compatibility of results. However, it is known that permeation rate increases with temperature, so if you work in a higher temperature, permeation will be faster than indicated by a test. Does this mean you are safe or not? Without more analysis of the volume permeated and the toxicity of the chemical, you simply don’t know. The fact is, permeation testing is designed and suitable for comparisons of fabric permeation resistance performance but provides no information about how long a user is safe against a specific chemical. Only through calculation of chemical volumes permeated and an understanding of the toxicity of the chemical can a ‘safe-use time’ be assessed. PermaSURE® provides a quick and easy way to make such assessments and to calculate real-world safe-use times. Fortunately safe-use times can be calculated. Two methods are described overleaf. PermaSURE® is Patent Pending and a Trade Name of Industrial Textiles & Plastics Ltd, York, UK.

How to calculate safe-use times Selection of a chemical suit should include consideration of how three groups of factors affect the choice: 2. The task/ hazard type? What form is the hazard? Dust? Liquid? Gas? Aerosol, light or jet spray? 3. Physical / enviroment factors What physical or other factors in the environment might influence garment choice? For a step-by-step guide to relevant factors, see the Lakeland Guide to Chemical Suit Selection Permeation test breakthrough does not indicate safe-use of a suit. A critical part of the chemical assessment is the calculation of a safe-use time....