This International Standard specifies a method for measuring the spatial sound distribution curve(s) of a given workroom. A method is given for determining, from the measured data, two descriptors of the acoustical performance of a workroom regarding noise control: i.e. the excess of sound pressure level with respect to a free field, and the sound pressure level decay per distance doubling. This International Standard does not deal with assessment of the acoustical quality with respect to speech communication or other psychological factors. This International Standard is applicable to workrooms of any shape and any dimensions provided that the number of microphone positions allows the regression calculation to be performed.