A man sitting in a meeting pod

Building acoustics: What to do when noise annoys

When architects design smart buildings, noise performance is quite often the last thing on their minds. But acoustic design is a critical factor in making sure your workspace is a place where you can actually work

Smart buildings appear to be the ‘in’ thing at the moment. Everybody wants to talk about power conservation, controlling the heating remotely, all kinds of stuff - and yet, when you talk to an architect, they still start by showing you pictures. Nobody, but nobody, ever whips out an iPhone or speaker system and says “and this is what it will sound like”.This is puzzling to an extent because in spite of specious claims about how little of communication is contained in words, listening to people and understanding what you have just been told is a massively important side of business. That’s simple common sense but so few people take it seriously - and given an ageing workforce it’s not great news. Children hear dog whistles, and lose this ability as they grow up; the human ability to hear and process sound continues to diminish as we get older (you don’t go deaf necessarily, but your hearing isn’t what it was - and your ability to process what you’ve been told also shrinks back a fair bit).

Julian Treasure, author of ‘Sound Business’, is an acoustician and consultant. He outlined a few things people miss when they start planning a building, either at the refurbishment or new-build stages. “There are four cornerstones to managing sound,” he explains. “Those are acoustics, noise control, sound systems and content (ANSC). Sadly very few projects are built with any consideration for sound - most architects are very visually oriented and they love hard surfaces.”

Flutter echoes

This love for hardness means common mistakes enter the equation quite quickly. Rooms with exclusively hard surfaces with parallel walls lead to standing waves, flutter echoes. “You get meetings with stone floors and glass walls, and it’s really difficult because everyone’s on edge; when two people are talking at once it sounds like an argument.”

Anybody doubting this should go to a shopping centre at lunchtime and visit the food court; surfaces are often hard, and people have to shout to make themselves heard. This isn’t because everyone is speaking loudly, it’s because of the reverberation. With a reverb rate of more than a second, you end up with the Lombard Effect, which is when a background hubbub becomes a cacophony and makes working pretty much impossible.

One company that has taken steps to set its acoustic house in order is headset manufacturer and acoustic specialist Plantronics, first at its Royal Wootton Bassett office and subsequently in its new facility near Amsterdam.

George Coffin, facilities manager for the UK operation, explains that it started when Philip Vanhoutte, VP and managing director for the company in Europe, threw one of the company’s products to him. “He said, ‘what’s that?’ and I looked down and said, ‘it’s a headset’. And he said, ‘right, why do we have acoustic technology in there and not in our building?’ And I didn’t have an answer.”

This coincided with a complete rebuild of the Plantronics office in the UK, which was consolidating from three buildings to one. Perhaps ironically for an acoustics-based company, it didn’t realise the scale of the problem it faced before it started the new plans. Vanhoutte felt passionately about smarter working and acoustics came wrapped up as part of an entirely new working style for the organisation. “He involved our HR, IT and facilities departments, which we called the three Bs - bricks, bytes and behaviours,” explained Coffin. “He got us all thinking of what was required.”

Almost immediately, Coffin and his colleagues took two vital steps. First they asked for external help, on this occasion from a workplace consultancy called Leesman, and second they surveyed the staff extensively. Asking for external help was a very important step and one that would crop up more than once.

Some of the staff feedback goes back to theory developed by Royal College of Art Professor Jeremy Myerson, who identified four ‘acoustic zones’ people need to perform different tasks: collaboration, communication, concentration and contemplation. “They sound very simple but they can be very diverse,” said Coffin. “We’ve had to evolve them; a collaboration space can also be a contemplation and a concentration space.”

Peace and quiet

Once again Coffin sought expert help from acousticians able to advise on building materials and even room layouts.

Plantronics’ implementation of acoustics is worth considering in some depth. Meeting rooms tend not to have doors as these will reflect sound back at people; instead there are sound-damping materials built into the walls and initially there was a background noise (a minor hiss sounding like a quiet air conditioning unit) piped into the room so any noise from outside would be inaudible - in fact the background noise was dropped eventually as the extreme quiet was oppressive. The solution was to place the sound outside the room so it protected the colleagues from excessive noise but allowed them to hear each other clearly. There are tall chests for document storage but also for standing meetings, and above these are damping materials to absorb sound and retain some privacy.

There are also small priest-hole type booths for concentration - designed not to let too much sound in so people can focus, but once again without a door so the feeling of openness is retained. It’s worth stressing here that the move towards an acoustically-intelligent design has to be accompanied by a cultural shift so that people behave appropriately. In the priest-hole example, this works because everybody knows if someone has retreated to one of these they are not to be disturbed despite the absence of a door.

The idea has taken root sufficiently for a new building in Amsterdam to be developed with its own ‘soundscape’, which will also no doubt be revised and evolved as the staff feeds back.

Not everybody has the luxury of a new build and a senior VP who has already championed acoustics in this way, but it’s often possible to make a start without these advantages.

Treasure outlines some of the things that people miss. The first mistake is not to consider the sound aspects at all, and the second - echoing Myerson’s writings and Coffin’s experience - is the assumption that all work is the same, and therefore one size fits all. “That size is usually open plan,” he said. “Which is absolutely fine for collaborative working, but collaboration is only one of the types of work people need to do.” The others have their own needs, he suggests: contemplation, whether considering a problem or decompressing after a meeting, will need a zen-type silence, whereas concentration - maybe doing the accounts - needs more of a library-type atmosphere. Communication is different again, depending on the type of communication on offer, but acoustics are important. “We’ve all had experience of badly designed call centres; they call you up and you can barely hear them over the sound of the caller next to them,” he says.

Different types of soundscape are therefore necessary for different sorts of work, and it’s not always complicated. In terms of his four ANSC tenets, for example, Treasure suggests not putting noisy refrigerators, chiller cabinets and printers next to workplaces. “It’s very difficult to have a café in an office, for example, because the noise will reverberate.” Placement of teams can also be insensitive from a sound point of view; put a boisterous sales team next to the accounting personnel and you’re headed straight for conflict.

Another area people often miss is the idea of putting noise into a workplace, he says. “If you’re going to put sound into an office at all, make sure it’s a good enough system,” he argues. “Don’t put music, for example, through a system that was designed to carry alarm signals.” This is where content can be important; an unduly quiet office can be as unworkable as a noisy one. 45-55dB of babble is ideal, Treasure says, so that there’s a background murmur without being able to distinguish an individual voice. “It should provide enough sound to provide privacy, so that if I take a call you can’t hear me.”

Sounds that can be piped in can vary. Some people pipe in white or pink noise; Treasure’s preference is for a natural sound or even office babble. If the noise goes over 55dB people will get stressed and at higher levels people have to raise their voice, strain to hear and they get ill. “That’s where you have to build in elements to damp the space down,” he explained.

The treatments available for noisy offices are many, he adds. Noise-absorbent panels are available that can be printed upon, so a quiet office doesn’t have to be dull; if it’s too quiet then involve the staff, he suggests, but don’t opt for music. “It demands attention and is distracting,” he says,“but there are generative soundscapes from computers, running water, plenty to experiment with, remembering the idea is to mask.” 45-55dB should be about right, but ideally don’t use an app to measure it as they are rarely calibrated. Inexpensive A-weighted decibelometers are available relatively easily.

Starting points

So, having been part of a major revamp of a business, what advice would Coffin offer to someone starting the acoustic journey from scratch, either with a new building or more likely with a refurbishment? “You can start with a one-stop shop, an architect or designer, and within the design they will offer you acoustic solutions,” he explained. “However, they will only offer solutions for the transfer of sound, say from one room to another or from a meeting room to a corridor.”

Within the individual rooms the architects tend to have less to say, in his experience.“That’s why you need to go outside; we went to an acoustician who helped us during the design.”

The good news is that even the one-stop shops are taking acoustics into account, even if only to admit they need specialist input. “Most of them will add it in to their specifications.” This is useful because a lot of businesses are consolidating their existing spaces rather than expanding into new premises, so the need for better acoustic management increases. Facilities managers are realising the issue, believes Coffin, but they’re coming to it after the building is finished, which adds to the cost.

So his first lesson learned is to start on the acoustics before the design phase if possible. Ideally get an acoustician, but there are a few simple practical points to bear in mind. Treasure is a great advocate of carpets; they will absorb a lot more noise than a wooden floor, for example. Coffin differs: “If you want a place that looks nice and has different areas for different purposes, I disagree that you should have carpets absolutely everywhere. We have wooden flooring but we also have acoustic fabric underneath.”

Materials matter. If a building has low ceilings, consider the ceiling tiles, says Coffin. “The sort of tiles most people would buy absorb about 20 per cent of noise but there are acoustic tiles that absorb closer to 90 per cent.”

Whatever material you use, the basic technique of acoustic management can be summed up as ABC: Absorb, Block and Cover.

Once again it’s down to materials. Coffin comments that many people use screens to block noise but they use hard screens that throw the noise straight back and start echoing - put two hard screens in parallel and you’re back to the reverberation issue. “You can use a soft screen, a curtain, a blind between desks, so you can absorb and block at the same time,” he says.

Coffin’s final thought is to urge people not to assume it can’t be done. A lot of people don’t ask for help, he believes, but nobody is an oracle who knows all about it. Take input, be prepared to fail a few times and the results should be very positive.

Guy Clapperton is co-author with Philip Vanhoutte of ‘The Smarter Working Manifesto’.

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