This standard specifies methods to be used for laboratory testing of air-to-air heat recovery devices or those recovering heat from flue gases of heating appliances in buildings (except process-process applications) to obtain rating data. It gives test requirements and procedures for performing such tests and specifies input criteria required for tests to verify performance data given by the manufacturer.For the purposes of this standard, the term exhaust air may also be taken to mean the products of combustion.This European Standard is applicable to the following categories of heat exchangers:Category I RecuperatorsCategory II With intermediary heat transfer mediumCategory IIa - without phase-changeCategory IIb - with phase-change (heat pipe, ...)Category III Regenerators (containing accumulating mass)Category IIIa - non hygroscopicCategory IIIb - hygroscopicHeat recovery devices with exchangers and intermediary heat transfer medium without phase-change (category IIa) are to be tested as one unit including pump and pipe system between the coils.This European Standard prescribes test methods for determining:a) the external leakage;b) the internal leakage of exhaust air to the supply-air within the device at a given pressure difference between air ducts, for recovery devices of categories I and II;c) the carry-over of exhaust air to the supply air in recovery devices of category III;d) the temperature and humidity ratios;e) the pressure drop of exhaust-air and supply-air sides.