A Unified Metric for Speech Privacy in Open & Closed Offices

The Speech Privacy Dilemma

Speech privacy is consistently ranked as one of the lowest-scoring parameters in Indoor Environmental Quality (IEQ) satisfaction surveys. As acousticians, we have a multitude of metrics at our disposal - Privacy Factor (PF), Privacy Index (PI), Speech Privacy Class (SPC), Speech Privacy Potential (SPP), and STI, for example.

But which metric actually aligns most closely with what office occupants hear, understand, and find distracting - their experience? And why do we use different metrics for open-plan spaces versus closed rooms?

About the Webinar

Join us for an insightful 1-hour session as we hear from Roderick Mackenzie about the groundbreaking findings from ASHRAE Research Project 1852.

This session dives into a comprehensive field study that surveyed 82 office workers across three locations alongside rigorous in-situ objective acoustic measurements. By comparing subjective experiences of audibility, intelligibility, and distraction against calculated PI, SPP, and SPC values, this research reveals a clear winner for standardizing our approach to office acoustics.

Key Takeaways for Attendees:

• The Unified Metric: Discover why Speech Privacy Class (SPC) outperformed PI and SPP as the most robust, universally applicable metric for evaluating both open-plan workstations and acoustic performance between cellular rooms.
• Objective vs. Subjective: Learn the precise dB thresholds where speech transitions from "sometimes distracting" to "rarely audible" in the real world.
• Debunking Conservatism: Understand why current standards (like ASTM E2638) may be overly conservative for typical non-secure commercial spaces, leading to over-design.
• Practical Design: Learn how to apply a new, evidence-based descriptive table mapping SPC values to real human perception to better advise your clients.

Speaker Profile

Roderick Mackenzie, PhD, INCE Bd. Cert., C.Eng., FIOA Deputy Director of Consulting, Soft dB

Dr. Roderick Mackenzie is a Senior Acoustical Consultant at Soft dB, one of Canada’s largest specialised acoustic consultancies. Dr. Mackenzie recently completed the ASHRAE TC 2.6-sponsored research project (RP1852), to develop a universally-applicable speech privacy metric for use in both closed and open-plan commercial offices. In addition to his consulting work, Dr. Mackenzie is heavily involved in standards development, chairing the ASTM E33.02 Speech Privacy Sub-Committee, and serving on multiple Canadian (SCC), American (ANSI/ASA), and International (ISO) acoustics committees and working groups. 

(Paper co-authored with Rewan Toubar, BEng, EIT & Joonhee Lee, PhD, PEng - Concordia University)

Registration

This event is free for IOA members and the public, but registration is required.

 Click Here to Register for the Webinar on CPDTag (free to register)

https://www.cpdtag.com/app.php?event=CC7C813955059E29864A6A04795F18C

Meeting link will be distributed to registered attendees prior to the event.

Contact/Queries: ioa-ne-yorks@apexacoustics.co.uk