[ Technical - Textiles - Smart fabrics up to the acid test.]

ITS fibresmart is a new coating developed by Itac, based in Manchester, UK, which gives a substrate the ability to change colour when it comes into contact with acid. The product, developed to meet specific customer demand, will function both indoors and outside in all types of conditions and at extremes of temperature, making it particularly suitable for a wide range of industrial lagging applications.
SOURCE
http://www.technical-textiles.net