Technical classes, often referred to as "classes of convenience", are classes of product performance established as a means of convenience for specifiers, manufacturers and purchasers where justified differences specified in Art. 3(2) of the CPD have not been identified or where a classification of product performance has not been identified as the means of expressing the range of requirement levels of the works. They are intended to make it easier to use the technical specification to relate a product’s performance to its intended use ...