Acoustics

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For the past 10 to 15 years, our understanding of acoustics in offices has progressed in leaps and bounds. While many of us intuitively know that noise in open plan offices is often a problem, there is now a large body of research to show that, not only does a poor acoustic environment affect one’s ability to carry out a task efficiently, it also affects productivity in general. The sense of comfort and wellbeing within the workspace is also impacted by an acoustically uncomfortable environment, contributing in a large part to what ergonomists describe as ‘presenteeism’.

Contrary to what many believe, people are able to work effectively in both quiet and noisy environments. For example, most of us, at some point, have had to work in an aeroplane or in a noisy café, and can do so relatively easily. But what is it about the open plan office that causes us so much distraction when noise levels are comparatively low? This question has been investigated again and again, and one factor stands out as the main cause of distraction – speech intelligibility. We are able to work in a space where speech is audible, however, the clearer and more intelligible the speech becomes, the less able we are to ignore it and focus on our work. This knowledge has changed the way we design good acoustics in a space, and the focus has shifted from lowering noise levels, to reducing speech intelligibility.

“A common misconception is that a product is acoustically effective simply because it is wrapped in fabric”

 

This new understanding of our biggest distractor has led to the development of the relatively recently adopted standard – BS EN ISO 3382-3 – which enables us to quantify the acoustics in an office in relation to speech intelligibility and distraction. By testing an open plan office to this standard, the number of people distracted by one speaker in the office can be established, as well as the level of speech at certain distances and the general rate at which loudness decreases as sound travels across the office. This powerful method of accurately assessing the quality of the acoustic environment has resulted in the development of better, more effective products, that are designed for purpose. 

Armed with this new insight into office acoustics, many designers have started to introduce the type of office furniture that will assist in reducing speech intelligibility with distance. Because of this, typical office furniture products, such as screens and booths, are increasingly being developed in such a way as to make them perform well in the speech frequency range.

Of course, the way these products are used is just as important as the performance of the products themselves and it is not unusual to see clients spend large sums on acoustic products, only to use them to solve a problem that the products are not designed for. In some cases, the installation of the incorrect product can make the acoustic environment worse!

With new acoustic products being developed all the time, it is important that the performance and appropriate use of these products be made clear to clients.

A common misconception is that a product is acoustically effective simply because it is wrapped in fabric. A more prevalent belief is that the quieter the office environment, the better. Both of these are oversimplifications and lead clients to make incorrect choices in selecting a solution. While no formal test standard exists to enable the user to compare, for instance, one high-backed sofa with another, there is a need for more data on how that product behaves in a real office, and a greater degree of transparency regarding what a client can expect from a product. Perhaps, if such a standard is developed, solving acoustic problems will become less of a ‘dark art’, enabling office-dwellers to design an environment that works for them.