CONSTRUCTION INNOVATION, Sept. 2009

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Distraction from unwanted sounds and lack of privacy for many common office tasks are frequent complaints made by open-plan office occupants. A solution is at hand with the development of new speech privacy measurement software (SPMSoft) by NRC-IRC.

Traditional measurements of speech privacy in open-plan offices have proven cumbersome and usually have not identified causes of the problems. During traditional testing, sound attenuation (reduction in sound level) between workstations was measured using loud test sounds after hours in unoccupied offices. Results of these tests were combined with daytime measurements of ambient noise levels (a composite of sounds from sources both near and distant) and various privacy measures were calculated. This approach was costly, time consuming and not frequently used, often leaving acoustical problems unresolved. 

SPMSoft makes it possible to measure ambient noise and speech privacy during occupied conditions with minimal disturbance to occupants. The degree of speech privacy is quantified in terms of repeatable objective measurements including values of speech privacy measures. At the same time, it can provide diagnostic information to determine the most important causes of lack of speech privacy.

SPMSoft uses impulse response techniques to measure sound attenuation between workstations in an open-plan office. It avoids the use of loud, disturbing test sounds. The results can be displayed with the key sound paths identified so that users know if the more serious cause of the lack of speech privacy is sound reflecting from the ceiling or sound passing over workstation panels.

The ambient noise spectrum is measured during normal working hours so that it is representative of normal daytime sounds. Speech privacy measures are calculated to quantify speech privacy between various pairs of measurement positions.

Such improved measurements and diagnostics provide a new tool for consultants and make the systematic improvement of open-plan office acoustics a practical option.

SPMSoft was developed with the support of Public Works and Government Services Canada (PWGSC). Further software information and case study results are available at www.nrc-cnrc.gc.ca/eng/projects/irc/spmsoft/overview.html. Specific questions can be directed to Dr. John Bradley at (613) 993-9747 or email john.bradley@nrc-cnrc.gc.ca.