Comfort Distance-A Single-Number Quantity Describing Spatial Attenuation in Open-Plan Offices

ISO 3382-3 is globally used to determine the room acoustic conditions of open-plan offices using in situ measurements. The key outcomes of the standard are three single-number quantities: distraction distance, r(D), A-weighted sound pressure level of speech, L-p,L-A,L-S,L-4m, and spatial decay rate of speech, D-2,D-S. Quantities L-p,L-A,L-S,L-4m and D-2,D-S describe the attenuation properties of the office due to room and furniture absorption and geometry. Our purpose is to introduce a new single-number quantity, comfort distance r(C), which integrates the quantities L-p,L-A,L-S,L-4m and D-2,D-S. It describes the distance from an omnidirectional loudspeaker where the A-weighted sound pressure level of normal speech falls below 45 dB. The study explains why the comfort criterion level is set to 45 dB, explores the comfort distances in 185 offices reported in previous studies. Based on published data, the r(C) values lie typically within 3 m (strong attenuation) and 30 m (weak attenuation). Based on this data, a classification scheme was proposed. The new quantity could benefit the revised version of ISO 3382-3.

Automated summary

ISO 3382-3 standard is widely used for assessing room acoustic conditions in open-plan offices, with key outcomes quantifying distraction distance, sound pressure level of speech, and spatial decay rate. A new single-number quantity, comfort distance, has been introduced to describe the distance from a loudspeaker where speech falls below 45 dB, showing typically between 3 m (strong attenuation) and 30 m (weak attenuation). This new quantity could benefit the revised version of ISO 3382-3.