ASHRAE RP 1852 Toward a unified metric for speech privacy in high-performance buildings: Subjective survey results

Speech privacy in office environments is essential for occupant productivity and well-being. However, practitioners and researchers often rely on different speech privacy metrics for open-plan and closed offices, leading to inconsistent evaluations. This study aims to identify a universal acoustic metric that accurately reflects subjective speech privacy responses regardless of office configuration. A total of 82 participants from three office sites in Quebec, Canada were surveyed regarding perceived speech audibility, intelligibility, distraction, and expectations for their open-plan workstations, private offices, and meeting rooms. Acoustic measurements were then used to compute Speech Privacy Class (SPC), Privacy Index (PI), and Speech Privacy Potential (SPP) between the same locations. Among the metrics evaluated, SPC and PI calculated from “most-likely-receiver” locations showed the strongest correlations with subjective responses. Thresholds for descriptive terms for “Normal” and “Confidential” speech privacy were generally validated for both PI and SPC. The findings also suggest that SPC could serve as a promising candidate for a unified calculation metric of speech privacy in both open and closed office environments.