This International Standard gives a method for measuring the Sound attenuation of screens intended for use in rooms to increase Speech privacy or noise insulation between working positions. Screen Sound attenuation measured according to this International Standard is intended to be used to classify screens. NOTE 1 Field conditions will, as a rule, deviate from the conditions specified in this method. Reflections from ceilings and Walls tan considerably lower the apparent Screen Sound attenuation. The classification obtained according to this International Standard is not valid in those practical situations where the Source is situated close to the floor. The directivity of the actual Sound Source and the Sound transmission properties of the Screen produce results that differ from those obtained by use of the method given in this International Standard.