Acoustics: are you hearing the message?

February 2011 – Acoustic performance in Australia’s offices, classrooms and other public buildings has been overshadowed in recent years by issues of energy and water efficiency. JEFF SALTON argues that sound quality deserves primary consideration in any building design or retrofit.

Any facility manager who has ever had to deal with a myriad of complaints from angry tenants fed up with unacceptable noise levels at their workplaces will no doubt be aware that, anecdotally, noise rates are second highest behind air temperature levels on the list of complaints in offices throughout Australia.
We’re not just talking about open plan offices here – there is an expected level of noise from fellow workers in this type of floorplan. No, we’re describing an often expensive office fitout where the walls appear to be made of paper, the floor is made of the same material as a tap dancing studio, the phones ring at 100dB, people shout over the noise of the elevator, and the air-conditioner resembles an A380 jet engine (good or bad, you decide).
Many offices resemble echo chambers and some boardrooms must have modelled themselves on Get Smart’s ‘cone of silence’, where it’s often easier to hear what’s being said outside the room than inside it.

WHY IS THERE A PROBLEM?
Why do companies neglect the one element that makes for a good working environment – acoustics? Acoustic material (soundproofing) for offices can protect privacy, limit distractions and improve concentration among workers, leading to better business decisions and improved productivity.
The answer appears to be a combination of a lack of enforceable building codes or standards, coupled with a lack of awareness among builders and prospective tenants of the existence of acoustic engineers and consultants.
The Association of Australian Acoustical Consultants (AAAC) says the Building Code of Australia (BCA) has no requirement for commercial buildings to incorporate any acoustic treatments to reduce external or internal noise levels – unless the building is striving for a Green Star rating. Even then, the requirement is small.
In residential developments, that’s another matter. There are well-defined standards for builders to adhere to regarding external noise penetration and sound travelling between apartments, etc.
But developers who construct commercial buildings where a Green Star rating isn’t part of the equation have no obligation to implement any acoustic improvements to the structure. Bad luck for the workers!
So the AAAC has spent close to three years compiling its own set of acoustic guidelines for almost every situation to help purchasers and tenants of commercial buildings gain a better acoustic outcome for themselves and their workers. The guidelines have been arranged into the following categories:

• apartments and townhouses
• educational facilities
• commercial buildings
• childcare centres, and
• how to select an acoustic consultant.

Chairman of the AAAC, Matthew Stead (who holds the position of global practice lead – acoustics for consulting firm AECOM), says that the guidelines, though not enforceable under the BCA, have been created from AAAC members’ experiences and outline acoustic recommendations for different types of buildings.
“Our members have been providing advice to clients of commercial buildings for some time now, but before we produced these guidelines, there weren’t any real benchmarks,” Stead says.
“Owners or tenants of buildings – whether they’re legal or accounting firms, finance or general business – haven’t had an industry standard against which they could compare their fitout or acoustic measurements.
“Now these people can make educated decisions on whether they need to spend more money to achieve their desired acoustic outcomes, or understand that what they require could be unachievable or even unnecessary.”

WHEN REALITY BITES
Stead explains that many owners who purchase a building or office space that is empty or a shell don’t have any idea of how noisy that space may become once it is occupied.
“Sure, people can identify external noises like street traffic, but what about when there are 20 or more people on one floor, or the elevator is constantly moving, the air-conditioning (AC) is running and the phones are ringing?” he asks.
“Having an idea of acceptable noise levels in advance, and what can be done to limit or control noise above these levels, can save clients a lot of money and angst.
“Using a qualified acoustic consultant before you occupy a site means you get the most from our service before it’s too late to change anything, and it is also a great way to get the business off to a good start in a new location.”
Stead notes that some clients have requested ‘total silence’ to improve productivity, but a so-called soundless environment often doesn’t lead to increased productivity in workers.
“There’s really no such thing as total quietude,” he says. “But when things are extremely quiet, any sound can become a distraction. A distant phone ringing, a door closing, a truck passing… having an ‘acceptable’ ambient noise level is usually what works best.”

MASKING NOISE
Stead says that an air-conditioning unit gently humming in the background can actually help disguise the odd louder, infrequent sound and make for a better work environment. The acoustics industry calls this a ‘masking’ noise or sound.
“In some of the greener buildings with passive heating and cooling, there are no moving parts and, hence, no masking sound, so these quiet buildings have their own set of noise issues because they’re too quiet.
“Back in the 1970s there were a couple of buildings with open plan offices that used sound systems to discreetly pump masking noise through in-ceiling speakers to provide an ambient sound level that made for a better workplace. It sounds silly now but it actually worked – the employees didn’t notice the noise, and it had the desired affect of masking the other sounds.”

IDENTIFYING PROBLEMS
Facility managers will know of the frustration they experience when tenants ring to complain about the ‘noise levels’ in their environment. Nicholas Tselios, a director at acoustics consulting firm Renzo Tonin and Associates, and a board member of the AAAC, says qualified consultants are great at identifying the source of problematic noise and offering solutions to help quell it.
“I hear it all the time,” says Tselios. “Tenants move into a new office and suddenly realise they can hear everyone else’s conversations and know that their private discussions are being overheard as well.
“The air-conditioning hum in the background can be heard when on speaker phone, or high levels of traffic noise make teleconferencing virtually impossible.
“Tenants below might hear every footstep on the tiled reception area above or the elevator doors opening and closing on the same floor level. There are many noise sources we can identify and help to treat,” he says.

HOW PROBLEMS ARISE
How do problems arise in the first place? “Normally,” Tselios says, “a developer will design and build the base building, the shell, excluding the fitout. Often the exterior comprises a curtain wall, a glass façade or something similar, to achieve some sort of energy efficiency or thermal ratings, but they don’t take into account any acoustics, especially those surrounding the mechanical services.
“Basically, they deliver a safe building for the best price.
“Then in comes the tenant who often doesn’t understand acoustics, erects office partitions, doors and walls, floor coverings, workstations, etc, and then it’s pretty much too late to do anything about poor acoustics.
“If they’d consulted with an acoustics engineer before beginning the fitout, many of these problems wouldn’t exist.
“Qualified consultants can also recognise what will be a problem when the office is occupied and can offer great assistance to fitout companies before the partitions go up.”
Stead adds: “We understand what causes noise and the different types of noise that can affect productivity. The sources include: intrusion (exterior noise like traffic, etc); background noise from mechanicals (elevators, etc); hydraulics; privacy (isolation); electrical (light hum, generators); and absorption (echoes, reverberation).
“Our new guidelines outline what are acceptable industry levels in these areas and talk about how to address each one,” he says. “They’re free for anyone to download, too.
“In our commercial buildings guidelines we don’t have a star rating system, we have recommendations and if you don’t comply with these, you should be able to demonstrate why not.”

TIGHT BUDGETS & EGOS
Often office designers will try to accommodate all the stakeholders’ wishes in the office layout, without any real regard to acoustic levels. This is usually driven by budget restrictions or egos.
Stead says that most complaints are from inter-office noise – a lack of privacy.
Tselios agrees, saying that often people will think the noise is traveling through the wall between offices when in fact most of it is travelling through the ceiling cavity above the offices. This occurs because the partitions stop at a common ceiling and usually doesn’t have good acoustic tiles.
“We can advise on the installation of better acoustic ceiling tiles that dampen noise, add thicker plasterboard between the offices and extend partition walls upwards beyond the ceiling grid,” he says. “Also, a reduction in the use of glass can improve privacy issues.”

BOARDROOMS, CONFERENCE ROOMS
Both men say that boardroom/conference rooms’ acoustics are a big concern for many companies.
“Based on my experience,” Tselios says, “one of the most common complaints from facility managers is about the noise levels from the AC unit in a conference room. Sure enough, there’s often a massive AC unit behind two standard cupboard doors with no soundproofing or insulation.
“Apart from a poor location choice, there’s been no thought about the noise it will create. It’s too expensive to relocate and there’s only so much noise suppression we can recommend. There will never be a perfect solution.
“If we had been involved earlier in such cases, we would have recommended locating the unit elsewhere where the noise wouldn’t be an issue.”
Tselios says AC noise can ruin any chance of a teleconference.
“Another huge concern we are aware of is when clients contact us to complain that the conference room is next to the reception area and sound travels between the two locations, breaching privacy and causing disruptions.”
Stead cautions: “The last thing senior management wants is for confidential conversations, conducted in person or on the phone, to be overheard by other staff members.”
Office gossip can be a dangerous thing, especially if only one side of a conversation is heard. But often, tough management decisions made in confidence can damage morale when ‘leaked’ to other staff members.
Having adequate acoustic control in these situations can be vital to running a successful business.

HORSES FOR COURSES
The AAAC guidelines for commercial buildings address different acoustic needs for different purposes, such as boardrooms, interview rooms, closed offices, open plan offices, meeting areas, kitchens and bathrooms.
“It addresses noise isolation and privacy issues, among other things,” Stead says. “Acoustic materials haven’t changed greatly in the past few years but we know a lot more now about how to use them effectively. Plasterboard is still a very good product and, when used properly and specified at the right grade, can achieve a desired result. Insulation material has changed to polyester but it does the same job as fibreglass products.”
Both Stead and Tselios have some good tips for facility managers who receive noise complaints from their tenants.
“Get them to describe the noise,” Stead advises. “Does the noise reverberate or echo, is it external, inter-office, mechanical, etc? Contact a reputable consultant for an on-site visit. A professional consultant will interview the people concerned. It’s almost like a medical appointment. We need to treat the cause, not just the symptoms. We don’t want to guess what the problem is. By interviewing staff we can often isolate the problem and treat it accordingly. For instance, double glazing the windows works for external noise levels but wouldn’t help with internal AC noises.”
Tselios elaborates: “We start with a meeting to gain an understanding of the issues and then begin diagnostic readings with the correct diagnostic and measuring tools.
“Is it a low-frequency rumble or high-frequency hiss? We check it against our guidelines to see if it’s acceptable or not.”
Both men say managing client expectations is a difficult job, especially if the facility manager is not skilled in the area of acoustics.
“As acoustics is a complex science, it is important that direct conversations be held between the client and acoustic consultants so that any issues and performance expectations can be discussed,” Stead says. “It is also possible to provide ‘auralisation’ (audio files) to represent how the finished design will sound. This helps clients understand how their building will sound.”
Tselios concludes: “I urge those facility managers who handle these types of noise complaints to contact a reputable acoustic consultant. Don’t despair, something can be done to improve noisy working conditions.”
The guidelines are available online at www.aaac.org.au/au/aaac/downloads.aspx

Matthew Stead, chairman of the AAAC, is the global practice lead – acoustics for consulting firm AECOM.
Nicholas Tselios, a board member of the AAAC, is a director at acoustics consulting firm Renzo Tonin and Associates.

More information
AAAC www.aaac.org.au
AECOM www.aecom.com.au
Renzo Tonin and Associates www.renzotonin.com.au