Writes for specifiers such as architects, consultants and building operators. States that thermal imaging has the ability to detect potential faults in non-electrical building services installations which are characterised by temperature anomalies. Presents guidance to aid the specification of thermal imaging by identifying applications where its implementation is likely to have a potential net benefit and to provide information on interpretation of the temperature data collected. Also provides guidance on the use of thermal imaging for the building envelope. Part 1 includes relevant information, procedures and guidance. Part 2 is the standard specification.