Precision of ISO 3382-2 and ISO 3382-3 – A Round-Robin test in an open-plan office

Abstract

International standards ISO 3382-2 and ISO 3382-3 are increasingly applied to determine the room acoustic conditions in open-plan offices because attention to noise control in such workplaces has increased. The precision of those standards in open-plan offices has not been published. The purpose of this study was to determine the precision of ISO 3382-2:2008 and ISO 3382-3:2012 in an open-plan office following the instructions of ISO 5725 standard. Furthermore, the results were analyzed in the light of ISO CD 3382-3:2020 involving improvements related to uncertainty. An accuracy experiment (a.k.a Round-Robin test, inter-laboratory test, intercomparison test) was arranged where nine independent participants conducted the measurements in the same open-plan office. For ISO 3382-3:2012, the reproducibility standard deviations were 530.5 dB, 1.3 dB, 1.3 dB, and 18% for spatial decay rate of speech (D2,S), A-weighted SPL of speech at 4 m distance (Lp,A,S,4m), A-weighted SPL of background noise (Lp,A,B), and distraction distance (rD). The corresponding values for ISO CD 3382-3:2020 were 0.3 dB, 1.1 dB, 0.6 dB, and 16%, respectively. The reproducibility standard deviations for reverberation time were 4.5–16% within 1/1-octave bands 125–8000 Hz. The measurement uncertainty of ISO CD 3382-3:2020 is smaller than that of ISO 3382-3:2012. The values depended mainly on between-laboratory differences while within-laboratory differences had only a marginal impact. The results can be used in the development of the standards.