This European Standard specifies laboratory methods for testing externally and internally mounted air transfer devices operating under pressure differences. This document applies to air transfer devices of the following types: air transfer devices with fixed opening(s); air transfer devices with manually adjustable opening(s); air transfer devices with pressure difference controlled opening(s); window openings specifically designed to act as an air transfer device. This document describes tests intended to characterize the following: flow rate/pressure; equivalent area reverse flow ability; air tightness when closed; free area; air diffusion in the occupied zone; sound insulation; water tightness. This document does not apply to evaluation of: air filtration; condensation risk; noise production.