DIN 25410:2012-07

This standard applies to components and systems of nuclear facilities. The surface cleanliness is of crucial importance since impurities may lead to malfunction and material damages. For this reason clean condition areas are provided. These clean condition areas are divided into 3 cleanliness classes, each of which being designated by its respective graphic symbol. In addition, the document describes the measures to be taken to obtain, maintain or re-establish the surface cleanliness during manufacture, transport, installation and initial operation.