Why you should apply the new ISO standard for acoustics in open offices

Why do we need a standard for acoustics in open spaces?

“It is very difficult to convince people that acoustics is important. There is no common narrative about what good acoustics look like. The standard is a way to make the narrative around acoustics more cohesive. It tells you what good acoustics are about and what you need to do. The burden of the acoustic problem in offices has been revealed during the pandemic. Most people have found that they can be more productive at home. If you want people to come back to the office, you must make it a place they want to come to and where they can work.”

Who is the standard for, who is supposed to use it?

“The ISO standard grew out of the already existing French standard that has been very successful in France. It has been used not only by acousticians, but also by other people in the industry. The aim of the standard is that it should appeal to everybody who is responsible for the design, delivery, maintenance and operation of offices. The standard has for example a questionnaire that helps you find out which acoustic issues you have in the office. You can use this to improve the acoustic conditions without interfering with the room. It may be due to the layout of the office or the way it is used, or it can be about agreeing rules on how people should behave. One of the appendixes is about designing an open plan etiquette. There are no rules set out, it is just suggestions of behaviours that people may want to adopt.”

So the standard is as much about behaviour as design and technical aspects?

“Well, these appendices are just informative and supporting tools that you don’t have to implement to comply with the standard. The normative part of the standard, which are the things you must do, are strictly about the room acoustics. But these supporting appendices can help remind people that perhaps the larger part of acoustic satisfaction in open plan offices is not about the room acoustics at all.”

The standard classifies different types of spaces in an open plan office, defined by the main activities. Which are these activity types?

“This is one of the main new ideas that this standard introduces. The acoustic conditions you need depends on the activities that take place. The activity types defined in the standard are:

1. Vacant floor – activity still unknown.
2. Tele- and video communication – mainly focusing on external communication.
3. Primarily collaborative work – verbal communication with nearby colleagues.
4. Primarily individual work – little communication with nearby colleagues.
5. Reception areas – receiving the public.
6. Mixed spaces – combining two or more activities in the same space.

In the average office, you have people doing different things, unless it is a call centre for example. People do individual work, collaborate, have meetings and make phone calls, for example, in different proportions at different times. But in the traditional open plan office, all kinds of activities are taking place in the same space and context. If you can sufficiently separate these activities, so people don’t disturb each other, you can protect those people who need less disturbance to concentrate on individual work. For each of the different activity types, the standard has requirements of the performance or values for the speech level at 4 meters and the spatial decay of speech. It also has targets for the ambient noise level in use. Those numbers effectively infer the height of the screens and the amount of sound absorption you need.”

Can you apply the standard if you want to do an acoustic refurbishment, or is it mainly targeted to new designs and office buildings?

“You can definitely use the standard for a refurbishment. There are a lot of ways you can use it. One is the target values for ambient sounds. You can measure the sound levels in the office and compare with the target value to see if you have a noise problem. Another way is to use the questionnaire to find out what kind of noise problems you have, so you can redesign or use your office better.”

Do you need to be an acoustician to be able to understand and use the standard?

“Probably. Or you will need an acoustician to be involved. The core of the standard goes back to different values for room acoustics. Only an acoustician can really calculate those things. But you certainly don’t need to be an acoustician to use the questionnaire, for example.”

Is the standard associated with certification and revising costs?

“No, as a design standard there are no other costs involved except the cost of buying the standard itself. I haven’t seen anyone seek certification to this standard yet, and I would not anticipate that. It is a tool and a guideline for setting up good acoustics in offices.”

When you presented the standard at an industry conference, you said sound masking systems is the most contentious question in the standard. Why, and what does the standard say?

“Sound masking is a way to reduce the intelligibility of speech without an emphasis on the room acoustics. People have very polarized views on whether these systems are essential or intolerable. The French representatives have found them not working. Their conclusion is to turn them off. But in the United States they rarely design an office without sound masking. However, all numbers and values in the standard are from the presumption that there is no sound masking system in the space. In the end, the standard got an annex with a discussion about sound masking systems.”

What should you think of before going into a process of applying this standard?

“Take it seriously. You can’t just apply the standard as a blanket, you need to consider people’s acoustic needs. Just following the standard itself won’t necessarily give you good results. You must go through a process of understanding the different types of uses and how you want the office to work. In that process, the standard can give you some helpful tools.

Learn more about the new ISO 22955 standard:

ISO website
Acoustic Bulletin article
YouTube video: