Listen Up: Fix Your Acoustic Problems in 4 Steps

Industry experts offer sound advice to reduce occupant complaints

By Jenna Aker –

Acoustical wall modules can provide a design element while controlling sound in private and collaborative spaces. These units are upholstered in fabric and feature backlighting. PHOTOS COURTESY OF MARCO COVI COURTESY OF ARPER

Noise begets noise – the latter in the form of complaints.
Occupant complaints about acoustics are one of the most frequently heard by FMs. The Center for the Built Environment (CBE) at the University of California reports that more than 50% of employees are unhappy with speech privacy in their workspaces. CBE also found that 60% of office workers in cubicles say that acoustics directly interferes with their job performance.

Statistics like those are loud and clear: If you have acoustical issues, you want to remedy them.

ASSESSING THE COSTS OF ACOUSTICAL PROBLEMS
If you think addressing complaints about acoustics is a poor use of resources, you are wrong. The productivity cost of problems can be high.

According to Robert Marshall, Manager of Marketing Technical Services at CertainTeed Ceilings, “Poor acoustics in today’s open-plan office environments is a problem that can ultimately cost employers thousands of dollars. A noisy workplace can be distracting and frustrating for employees and it can lead to decreased productivity.”

Pinpoint the Cause of the Complaint

■    Complaints about noise in open offices generally result from not having high-performance, sound-absorbing ceilings, islands, or baffles overhead.

■    Complaints about noise transmitting from one enclosed room to another are mostly caused by leaks called flanking paths in the ceiling system and walls. Noise can travel through open return air grilles in the ceiling, through a common plenum above the ceiling and back down, or through the open air return grille in the adjacent room.
    Similar noise-flanking paths exist due to recessed lights, supply air ducts, penetrations for sprinkler heads, loudspeakers, etc. Flanking paths through demising walls are also possible and problematic, especially given the current trend of using lightweight, demountable partitions and sliding glass doors with no perimeter gaskets.

■    Complaints about unintelligible conversations over open microphones in meeting and conference rooms result from not having enough high-performance, sound-absorbing materials in the rooms. Conference rooms with concrete, metal, and glass surfaces do not work well due to excessive reverberation and loudness.

A recent study found that office productivity can drop as much as 66% when employees who are trying to read or write are disturbed by nearby conversations. “It can take up to 15 minutes for an office worker to regain concentration after being distracted by noise. Studies show that employees are almost twice as likely to attend to complex tasks in quiet office environments than in noisy ones,” adds Marshall.

If employees take a job elsewhere due to unhappiness with their current work environment, even higher costs can be incurred by an organization. The costs of hiring and training a replacement can run from 30% to 50% of the annual salary for an entry-level employee to 150% of the salary for a mid-level, Marshall says.

The noise level in office spaces averages 50 to 60 decibels. Exceeding that level is nothing to yawn at. Statistics link high levels of office noise to increased stress, accidents and illness. “When noise hits 65 decibels,” says Marshall, “the risk of heart attack increases.”

4 STEPS TO FIX ACOUSTICAL PROBLEMS
The following steps will help you discover and remedy common noise complaints.

1) Design for Acoustics. Consulting an acoustical engineer or expert during the design phase is the best way to avoid future noise complaints.

“The number one way to eliminate these problems is proper planning and zoning of office space for compatible uses,” says Michael Spencer, President and Principal Consultant at JMS Acoustics. “For example, don’t stick the conference room next to the copy room.”

“By incorporating specific acoustical products in the design stage, teams can prevent needing to shoehorn components around HVAC and sprinkler equipment after the fact,” adds Dave Ingersoll, Business Development Manager at Sound Seal. He also notes that it saves money to get an acoustical team involved initially – labor rates will generally be cheaper when specified early on, allowing the general contractor to layer in acoustical elements while installing walls and ceilings.

A building’s interior design can still be clean and modern – you just need to consider the materials, finishes, and intended use of the space. “The trend in architecture is open space and open ceiling, which looks great but is acoustically challenging since the reverberation time is typically too long because of the missing sound-absorbing materials,” says Joerg Hutmacher, CEO at pinta acoustics, inc.

And don’t forget noise from mechanical systems. “Design HVAC systems to absorb sound energy and reduce system-generated noise,” says Marshall. “Often the engineering firm charged with designing the HVAC isn’t focused on acoustic concerns, yet HVAC is a major contributor to unwanted noise.”

2) Diagnose the True Problem. Be sure to assess the root causes behind acoustic complaints. “It’s very easy to apply the wrong treatment to an acoustical problem,” says Ioana Pieleanu, Senior Consultant at Acentech. “Many people think, for instance, that adding sound-absorptive treatments will solve a sound isolation issue.” Often, spaces that have been repurposed from their intended use can provoke noise complaints, as can noisy mechanical systems. A professional can help you figure out the exact acoustical issue you are facing. Once the problem is pinpointed, you can take appropriate steps toward remediation. (See “Pinpoint the Cause of the Complaint” on page 24 for examples of root causes.)

3) Treat the Problem. Evaluate your retrofit options to solve acoustic problem areas. “Acoustic ceiling panels are often the first line of defense,” says Marshall. “When seeking to control the transmission of sound from one space to another, a high level of sound containment, or Ceiling Attenuation Class (CAC), is required.”

Also check the NRC (Noise Reduction Coefficient) rating of existing panels. Older panels could have low NRC ratings of only 0.50 to 0.70. Gary Madaras, Acoustics Specialist at ROCKFON, says buildings in the U.S. require that open office areas have acoustic ceilings with a minimum NRC value of 0.90 over 100% of the area.

If an open plenum is the visual preference or it is necessary to avoid interference with lighting, air distribution or fire suppression, the solution may be clouds, baffles or islands. “Ceiling clouds are a great way to concentrate absorption in areas where it is most needed,” says Hutmacher.

If your problem is less about sound absorption and more about sound blocking, you will face complaints about speech privacy. “All walls and ceilings need to be sealed up tight,” says Ingersoll. “As little as a 1% opening can let in 50% of outside noise. You also need to make sure there is sufficient mass in the walls and ceilings to effectively block noise transfer, as well as look out for flanking paths where sound can escape,” he says.

Mass loaded vinyl products can be added to walls instead of drywall to help increase speech privacy. It would also be wise to reconsider the office layout and limit any sound pathways between workstations with strategically placed partitions.

A quieter space isn’t always the solution because it can lead to conversations being overheard. Marshall suggests using an electronic speech privacy system that introduces an acceptable amount of specifically tuned background noise into the space to increase speech privacy. “Sound masking is a good option,” says Hutmacher, “but it requires a certain reverberation in time and space. I have visited many spaces where sound masking was introduced into a loud and reverberant space, and it actually made things worse.”
Vibrations from external sources like rooftop mechanical equipment may require more extensive measures. “In general, with vibrations down from the roof, you can install a 2-inch static deflection spring isolation system, and you will probably need seismic controls in place to stay within seismic codes,” says Spencer.

4) Survey for Satisfaction. The problem isn’t solved until the complaints stop rolling in. “Facility managers should conduct a post-remediation survey of the occupants in the affected areas. This can bring the project to a successful close,” says Madaras.

KEEP YOUR EAR TO THE GROUND
Stay up to date on trends and emerging options through research and visiting websites for acoustical consultants and organizations.

“The best thing I can recommend is for people to educate themselves on acoustics. Read articles, talk to people who have done it before, reach out to facility managers who have tackled similar projects, and seek out experts for advice,” says Ingersoll.

Don’t be afraid to think outside the box, and don’t settle for a compromise if you have a unique vision for your space.

“There are many interesting products out there beyond acoustical ceiling panels,” says Pieleanu. For example, you can use an acoustical plaster treatment which looks like drywall but is sound absorptive. There are micro-perforated wood systems, and many forms and flavors of clouds – there are options out there.”

Jenna M. Aker is a contributing editor for BUILDINGS.

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