This European Standard provides guidance and rules to notified bodies (for fire dampers) to allow them to produce/validate an extended field of application report for fire dampers. This standard identifies the parameters that affect the fire resistance of dampers. It also identifies the factors that need to be considered when deciding whether, or by how much, the parameter can be extended when contemplating the fire resistance performance of an untested, or untestable variation in the construction. This European Standard explains the principles behind how a conclusion on the influence of specific parameters/constructional details relating to the relevant criteria (E, I, S) can be achieved. This European Standard does not cover dampers used for smoke control. This document has been prepared by Technical Committee CEN/TC 127 "Fire safety in buildings", the secretariat of which are held by BSI (United Kingdom). Working Committee NA 005-52-06 AA "Brandverhalten von Baustoff und Bauteilen - Lüftungsleitungen" ("Fire behaviour of building materials and building components - Ventilation installations") at Standards Committee Building and Civil Engineering (NABau) was responsible at DIN.