This Technical Report acts as an introduction to the concepts used to develop the MICE environmental classification system used in cabling standards developed by ISO/IEC. It also provides detailed explanation of the sources used to define the boundaries of MICE classifications.Cross References:IEC 61918:2018ISO/IEC 11801-1:2017BS EN IEC 61918:2018IEC 60654-4:1987IEC 61000-6-1ISO/IEC 11801-5IEC 60068-2-5:1975ISO/IEC 11801-2IEC 61000-6-2ISO/IEC 11801-4ISO/IEC 11801-6IEC 60721-3-3IEC 61131-2IEC 60721-1ISO/IEC 11801-3IEC 60529:1987IEC 14763-3IEC 14763-2IEC 14709-1IEC TR 24746 IEC 14709-2IEC TR 24704Incorporates the following:Amendment, October 2019; Amendment, April 2014