This document specifies the scheme for the evaluation of conformity of fly ash according to EN 450-1:2005. The document provides technical rules for the production control by the producer, including autocontrol testing of samples. It also provides rules for actions to be followed in the event of non-conformity, the procedure for the certification of conformity and requirements for dispatching centres. Guidance EN 450-2 deals with the evaluation of conformity of fly ash submitted for certification. It deals in particular with cases where “further testing” of the product is undertaken, as is the case for attestation system 1 + under the Construction Products Directive. The product for which EN 450-2 applies is defined in EN 450-1:2005 as fly ash for the production of concrete which consists of a fine powder of mainly spherical, glassy particles, derived from burning of pulverised coal, with or without co-combustion materials, which has pozzolanic properties.