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 European Standard only applies to extended fields of application based on tests successfully undertaken to EN 1366-2. Only test reports that have a total test time where the criteria are fulfilled that is in excess of the required classification period by a margin of either 10 % or 12 min, whichever is the least, are to be considered. Each classification (E,I,S) is to be considered individually - consequently E (134 min achieved) may be extended, but EI (61 min achieved) may not be extended for a classification of EI60.Additionally, leakage determined during such tests is to be at least 10 % below the leakage limits for E, or for E-S, dependent on classification achieved, given in EN 13501-3 before the EXAP rules can be applied. The 10 % below the leakage limits is to be fulfilled for the extended period in addition to the classification period.By application of this European Standard, it should be possible to identify what specifications should be tested to maximize the field of application. Some information on test programmes is given for guidance purposes.