ASHRAE RP 1852 toward a unified metric for speech privacy in high-performance buildings: Speech level variation by office environment and communication type

The loudness of speech is critical in predicting speech intelligibility and privacy in office environments. The surrounding environment can influence speech levels, necessitating accurate measurement in typical work settings to enhance predictions of speech privacy. Standardized speech levels and spectra, as outlined in ASTM or ANSI standards, can aid in predicting speech privacy or intelligibility. However, these data are collected in anechoic chambers with participants following scripted scenarios. This study presents a revised and updated examination of speech levels in two offices in Quebec, Canada, analyzing data from over 70 employees across different room types, communication scenarios, languages, and tasks. In open offices, desks with partitions showed higher speech levels (56 dBA) compared to those without partitions (52 dBA). Meeting rooms showed relatively consistent levels (52-54 dBA) regardless of size. Teleconference group meetings resulted in employees using slightly higher levels (54 dBA) compared to other communication methods within the same rooms (53 dBA). Statistical analysis revealed significant effects of office type, communication method, language, and task on speech levels. Individual variations in speech were more significant than office layout or communication methods. The observed variability in speech levels across different individual speakers and office settings suggests that current standardized methods for assessing speech privacy may need re-evaluation.