Open Work Spaces Require Careful Noise Management
September 27, 2012 - Contact FacilitiesNet Editorial Staff »
Today's tip is to minimize extraneous noise in open office settings. Many organizations have found that a more open environment, with movable partitions and plenty of meeting places, is more conducive to productivity than the permanent offices that prevailed 30-some years ago.
But openness means that employees are likely to be distracted by other employees' conversations, cell phones ringing, etc. To get the benefits of open office designs while minimizing distractions, a range of acoustical goals come into play, says Jeffrey Fullerton, director of architectural acoustics with Acentech. These include controlling the noise in common areas, creating some level of privacy and sound absorption for workers at their desks, and creating private rooms for confidential discussions.
It's easiest to achieve specific goals when the building is designed with acoustics in mind from the start, says Raj Patel, principal with Arup, an engineering and consulting firm. Otherwise, the costs to remedy any noise problems tend to spike.
When developing the acoustical environment, the acronym ABC comes into play, says Fullerton. That is, you want to absorb, block and cover sounds. Absorption requires what might be called passive tools, such as sound-absorbing ceiling panels. "It may be a greater cost initially, but it requires no maintenance or additional changes," says David Joiner, principal with JaffeHolden. Without sound-absorbing ceiling panels, employees' conversations and similar sounds will reflect off the ceiling.
Effective sound-absorbing ceiling materials will have an NRC, or noise reduction coefficient, of .85 or greater, meaning that they remove 85 percent of the sound bouncing off the ceiling. Fiberglass ceiling tiles with a painted finish tend to have NRCs that are about 25 percent higher than what mineral fiber tiles provide, says Thomas Trask, senior associate with Newcomb & Boyd. Fiberglass "is more absorptive at the same thickness versus mineral fiber."
To offer tiles that both block sound from the plenum and also absorb sound from offices below, some manufacturers are developing tiles that combine fiberglass and mineral fiber, Fullerton says.
Another situation where sounds need to be managed both from above and below is in open plenum spaces, where the bottom of the exposed concrete deck reflects sound. One solution is to incorporate sound-absorbing material into the design. Ceiling system manufacturers have developed products specifically for open plenum spaces.