The Evolution of Open-Plan Office Acoustics

The Evolution of Open-Plan Office Acoustics

Office space is changing.

During the industrial revolution, factories started bringing huge numbers of people together to work. Not long into the 20th century, rows of desks and tables were added to these large-volume spaces—early versions of the open-plan office. Over the last few decades, the open-plan office evolved further, from “innovations” like cubicles, which offer little acoustical privacy yet limit natural light and connections with colleagues, to the very open spaces that are trendy today.

When the 2020 pandemic started, many office workers were sent home to work. In recent months, people have trickled back in limited numbers due to social distancing rules. In open-plan spaces, having fewer workers creates some acoustical benefits, as well as some challenges. We’ll return to this a little later.

As it was, pre-2020, the acoustics in open-plan offices were a common source of complaints. A worker’s ability to focus and be productive can be impeded by insufficient privacy; a noisy overhead fan coil unit (or other equipment); a nearby colleague with a stentorian voice; general gossip (or unrelated conversations); or a myriad of other noise sources.

So why build open-plan offices?

This is well debated. The open-plan office layout can allow more people to fit within a fixed floor area. Companies believe innovation and collaboration is encouraged by the openness and visibility of an open-plan workspace. Yet studies show that open-plan workspaces can lead to fewer face-to-face interactions, and even gender discrimination.

In the early 2000s, the National Research Council of Canada (NRCC) carried out extensive research to determine optimum acoustical conditions for open-plan workspaces. The research focused on speech privacy, in terms of a parameter called the Speech Intelligibility Index (SII). The study found that for most open-plan spaces to obtain an acceptable level of speech privacy, fairly onerous measures would be required. Such measures include very high screens between workstations and powerful sound absorbers on all walls, ceilings, and screens. Today, these measures don’t typically complement practical design solutions, where both the designers and employees are looking for bright, open spaces, with visual lines of sight and natural light shared across the floor plate.

Progress Through WELL and LEED

The importance of the acoustical environment in open-plan offices is also emphasized in the newer versions of WELL (v2) and LEED, which have been further developed to promote better acoustics using sound absorption and sound masking. As new offices incorporate these standards, the acoustics in open-plan workspaces have improved.

At BKL, when we design the acoustics for open-plan offices, we look closely at the floor plan and activity layouts, distances between workstations, background noise levels, and sound masking, in addition to acoustical screens and acoustically absorbing surfaces. We also look at the room response, which involves locating sound-absorbing and sound-reflecting surfaces, and take the end users’ personal preferences into account.

We have found success by providing spaces with varied acoustic environments across a floor plate, so people can choose a work area that best suits their current activities.

New ISO Standard for Open-Office Acoustics

We’re excited that more help has come! A new international standard on open-office acoustics has been released recently. ISO 22955 – Acoustic Quality of Open Plan Office Spaces will help better address the acoustical environment of open-plan offices and facilitate conversations between acoustical consultants, owners, and design teams. Notably, this standard promotes acoustical comfort by limiting noise disturbances through careful planning during the design stages, and by providing a good acoustical environment for short-distance communications, where speech is contained as much as possible to a particular area while limiting speech propagation to adjacent areas.

Open-Plan Offices and COVID-19

The pandemic has brought on huge changes across the world, one of which is the shift to working from home. With some people now returning to the office, the lower capacity has some acoustical benefits. For example, having fewer people tends to mean fewer distractions, and privacy can more easily be achieved when people are spaced further apart.

This is not surprising: In 2003, the NRCC recommended larger workstations for good speech privacy. Their target was a minimum of 3 metres by 3 metres, but larger would be better. Yet lack of space means this minimum is rarely seen in practice. Now, with more people working from home, companies are in a better position to accommodate this spacing for people who do choose to, or need to, work at the office.

There are downsides to having fewer people within open-plan offices: Background noise levels are often lower (unless sound masking is used), and distracting activities can become more obvious (and therefore more distracting). So, with less background noise, there is less privacy.

The Evolution Continues

While the acoustical environment in open-plan offices has improved dramatically since people were first brought together in these shared spaces, it is important to be mindful that an open-plan workspace will never provide the same level of privacy as an enclosed space. It is good to see new standards, like ISO 22955, and schemes like WELL and LEED are helping make acoustics a bigger priority for open-plan offices.

At BKL, we have decades of experience consulting on office acoustics, and are highly familiar with the latest standards and design certifications, including two consultants accredited with WELL. If you want help designing the acoustics for your workspace, contact us today! Our consultants can provide acoustical design advice that will ensure your office meets the specific needs of your team.

If you want to read more about acoustics in offices and other commercial spaces, here are a few projects we’ve worked on.

Photo by Laura Davidson on Unsplash

Written by Katrina Scherebnyj

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