Interiors Are Noisy Places But Buildings Can Be Retrofitted to Ensure Acoustic Comfort and Privacy

In large zones where noise can be an issue, ribbed wood wall panels and acoustical batting behind absorb sound and provide higher noise reduction coefficient.

In large zones where noise can be an issue, ribbed wood wall panels and acoustical batting behind absorb sound and provide higher noise reduction coefficient.

The Price of Noise Pollution

Employers and facility executives who choose to ignore acoustics do so at their own expense. “Generally speaking, poor acoustics negatively impacts occupants’ focus, speech privacy and comfort, which in turn affects the organization for which they work—by reducing attendance, productivity, confidentiality, teamwork, workplace satisfaction and even customer service,” Moeller suggests.

Research supports this assertion. The Center for the Built Environment (CBE) at the University of California, Berkeley, conducted a post-occupancy evaluation of 15 buildings by 4,096 respondents in a variety of office configurations. The CBE study found more than 60 percent of occupants in cubicles think acoustics interferes with their ability to get their jobs done. Further, 99 percent of respondents cited their concentration was impaired by office noise, such as unanswered phones and background speech, resulting in a 66 percent drop in performance, according to a London-based World Green Building Council report on health, wellbeing and productivity in offices.

Interestingly, Moeller points out Gensler’s “What We’ve Learned About Focus in the Workplace” report—based on a survey of 90,000 people from 155 companies across 10 industries—found offices designed to support individual focus work actually rate better for collaboration than those specifically designed to promote it. “Future designs need to be informed by these types of studies or we risk creating workspaces that are less—rather than more—effective,” he suggests.

The ABC’s of Acoustics

Given how prevalent acoustical problems are in commercial buildings today, it points to the need for further education and a more holistic approach to the planning process. At its core, acoustics is the science of sound; at a deeper level, it involves an area of physics that focuses on the wave behavior of sound energy, including propagation; control; materials; and, more recently, quantum mechanical behavior, which deals with sound at a molecular level, according to Hsu.

He says acoustics essentially can be broken down into two areas: isolation and acoustic signature. In buildings, isolation refers to keeping unwanted noise outside. For example, if an airplane flying overhead produces 120 decibels of noise outdoors but inside only 80 dB is registered, then 40 dB has been effectively isolated by the building envelope, Hsu explains.

The National Research Council’s optimum masking spectrum, as well as one-third octave band tolerances of ±2 DBA.

The National Research Council’s optimum masking spectrum, as well as one-third octave band tolerances of ±2 DBA.


The acoustic signature of a room, on the other hand, refers to a more subjective measurement by an occupant that determines whether it is pleasing to the ear or not. Hsu notes a room with a high level of reverberation, such as a tiled bathroom where sound bounces off hard surfaces, is fatiguing in the context of an office environment but may be pleasant or even awe-inspiring if heard while sitting in a grand cathedral, for instance.

Oftentimes the problem with addressing acoustics is that the approach tends to be oversimplified. Just install a few ceiling tiles or lay down some rugs or soft seating and you’re done. “Many still believe they can ‘tick that box’ simply by using one type of solution, but it actually requires a balanced application of three elements: sound masking, barriers and absorptive materials,” Moeller explains. “Ideally, acoustics should be considered during the design phase. When planning an interior, it’s helpful to refer to the formula acoustic professionals use called the ‘ABC Rule,’ which stands for absorb, block and cover.”

According to an article by acoustical consultant Benjamin Wolf of ABD Engineering & Design, Portland, Ore., each of the ABC’s are useful for resolving acoustic issues, especially in open plan environments. But effective acoustical design is never a “one-size-fits-all” approach. Although many clients assume more is better when it comes to absorption, for example, Wolf says too much absorption can make a space sound “dead,” which can be unnerving.

Similar to absorption, blocking isn’t about obstructing all sounds, “but rather the right amount of the right sounds in the right way,” Wolf writes. Blocking sound may be accomplished with walls, carpet and workstation panels, which can be a challenge in open plan offices where partitions heights are generally very low.

Finally, covering refers to masking sounds within an interior environment. Wolf says covering some sounds with an electronic masking system can be a great option but only if designed and deployed with precision.

Photo: Skidmore, Owings & Merrill
Image: K.R. Moeller Associates LTD.

About the Author

Robert Nieminen
Robert Nieminen is a freelance writer; the former editor of Interiors & Sources magazine; and retrofit’s editor at large, specializing in interiors. Under his direction, Interiors & Sources was the recipient of several publishing awards, as well as a pioneer of sustainability reporting.

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