Experimental study of the noise effects of mini fans in collective study rooms

Abstract Study rooms are collective open-plan spaces with several workstations, either separated or not separated by partitions. This study analyses the interference in speech intelligibility and the conditions of acoustic comfort in collective study rooms caused by the noise produced by desk mini fans (plastic and metal) and air conditioning (split and window units). Six collective study rooms were evaluated in 11 configurations, varying the use of cooling equipment, through the NC and RC Mark II noise curves, reverberation time (TR), early decay time (EDT), speech transmission index (STI) and definition (D 50 ). The noise curve results show that all situations with the mini fans met the NC40 (45 dB) standard for collective offices, which did not occur with the use of air conditioning units. The study room configurations with that cooling equipment presented RC Mark II curves with hissy characteristic (unbalanced spectrum at high frequency). In addition, the physical conditions of the room, especially the small area of sound absorption, generated acoustic parameter values considered inappropriate for collective study activities, with the rooms with the highest volume having the worst results.