The Covid-19 situation has led to many reflecting on how the office is used. Some businesses are starting to consider reducing their real estate footprints and adopting a more flexible office environment in line with our changing needs. This could lead to an increase in office refurbishments, with a focus on video conferencing facilities, open-plan collaborative spaces and adaptable workspaces.
Speech privacy should be a key aspect to consider when planning for a "Covid Normal" office; layout, ambient noise, absorptive finishes and built elements all play a role in achieving successful acoustics in a working environment.
With an increasing number of workplaces facing the acoustic challenges of open-plan offices, more products are appearing on the market that claim to offer visual and acoustic seclusion and reduced distraction for individuals or small groups. Examples include furniture ensembles, such as a desk with privacy dividers or shrouded seating, and a full enclosure such as a phone booth or modular meeting room.
Until recently, there has been no standardised acoustic testing method that allows a like-for-like comparison of the sound reduction or speech privacy benefits provided by such products. To address these issues, ISO 23351-1:2020 Acoustics — Measurement of speech level reduction of furniture ensembles and enclosures – Part 1: Laboratory method (ISO 23351-1) was released in June 2020 and presents a standardised method of determining the speech level reduction rating (DS,A) for furniture ensembles and enclosures.
The testing method to derive the speech reduction rating involves placing a sound source in a reverberation test room and calculating the sound power level of the sound source. The enclosure or furniture ensemble is then installed around the sound source and the measurements are repeated. The difference between the measured sound power levels with and without the furniture ensemble or enclosure is used to establish the speech level reduction.
The detailed laboratory testing procedure prescribed by ISO 23351-1 means that a comparison of the DS,A rating for different products will give a quick indication of their relative performance. Though it is important to note, as the testing is undertaken in a reverberation room with reflective surfaces, we would expect that the speech level reduction achieved in practice within a well-designed open office would be higher due to the presence of an absorptive ceiling, office furnishings and wall coverings. However, it is acknowledged that it is necessary for the testing to be undertaken in a standardised laboratory environment to allow for comparable and repeatable testing in the many laboratories across the world.
Currently, there is only one Part to ISO 23351, so it will be interesting to see if additional Parts will eventually be published to provide a method for testing and calculating a speech level reduction rating in true open-plan office environments - in a manner similar to the ISO 16283 series for example.
Images courtesy of Zenith Interiors
From discussions with many of the Australian acoustic laboratories, it seems there is yet to be any significant interest from Australian suppliers in having their products tested and rated. This is understandable given the Standard is still very new and the industry is currently experiencing very challenging times. It will be interesting to see if, how and when manufacturers, suppliers, office designers and acoustic consultants will adopt this new metric into office design or product marketing strategies over time.
If you have questions about ISO 23351-1 or open-plan office design, Marshall Day Acoustics can help. Feel free to contact us today.
