This European Standard describes the conditioning procedures for test specimens to be tested according to the European standards for reaction to fire. The rules for the selection of substrates for floorings and other construction products when carrying out reaction to fire tests are also detailed in this European Standard. This European Standard does not contain requirements for: - the pre-drying of test specimens for the non-combustibility test according to EN ISO 1182, as well as - methods of cleaning (for example washing) and other methods for the assessment of durability aspects, since these are dealt with in the relevant product standards. The Construction Products Directive requires construction products to be tested in their end use condition. For the purpose of substrates, this could lead to an economically unjustifiable, unrealistically large number of tests to be carried out. This large number has been reduced to a practical number of standard substrates that enables the majority of end use conditions to be represented. This way, this standard also contributes to saving costs in construction. Rules for the selection of such substrates are given in this European Standard. This European Standard is intended for use in conjunction with European standards covering the reaction to fire test methods for the relevant construction products. This European Standard has been prepared by CEN/TC 127 "Baulicher Brandschutz" ("Fire safety in buildings"). At DIN, the responsible Committee is NA 005-52-01 AA "Brandverhalten von Baustoffen und Bauteilen - Bauteile" ("Fire performance of building materials and building elements - Building elements") of the Building and Civil Engineering Standards Committee (NABau).