Story at a glance:
- Acoustic design starts with understanding the noise reduction coefficient.
- Some techniques for managing acoustics include adding materials such as acoustic panels or steel decking.
Implementation of acoustic design principles in architecture can mitigate frustrations caused by external noise pollution and competing internal noises within a space.
Acoustical treatments need to satisfy the needs of the people residing within the space. For example, large, open office spaces with meeting areas may need ceiling panels that absorb sound or private meeting space to work without worrying about external noise infiltration.
A basic understanding of acoustic design principles and testing methods will give you the confidence to ensure the environmental goals of your project.
Here are six acoustic design principles to consider.
1. Understand the Noise Reduction Coefficient (NRC) rating.
The noise reduction coefficient, or NRC, is a measure of a material’s ability to reflect or absorb sound through its effectiveness in a consistent square footage of absorption. This is expressed in a value between 0.00 and 1.00, with 0.00 indicating that sound is reflected and 1.00 indicating sound absorption. Thicker elements with 3D properties or products with exposed edges can achieve values higher than 1.00 because of the additional surface area.
NRC can be a reliable indicator for a material in a space, but it is also very variable. Different materials can have different NRC depending on how it was installed.
John Johnston of Arktura detailed some important steps to take when choosing to purchase a material for reducing its NRC.
“The NRC rating can help you choose the right material for your job, but only if it is an accurate, true rating,” said Johnston in a previous article from gb&d. “There are three things to consider when you are making a purchasing decision.
First, ask about the NRC rating of multiple products that interest you. The rating should differ from product to product. If it does not, then consider this a caution sign.
Second, ask how your planned installation may change the ratings and discuss your needs with the manufacturer. They should advise you on how the NRC may vary with your installation and make personalized recommendations.
Third, request the laboratory testing report to understand how the product was installed, and to confirm the results match the design and size you are considering.
Lastly, if you feel you are not getting the information you need to make this complex decision. You can always request or engage in third-party testing or work with an acoustician to better understand the truth behind NRC.”
2. Add acoustic panels.
The installation of wall panels is key to mitigating sound refraction, echoing, and reverberation that can affect the listening experience. Primacoustic Product Manager Juan Carlos Bolomey talked about the effects of these and more in a previous story for gb&d.
“A room will resonate at a natural frequency, which tends to be at the lower end of the spectrum, depending on its size,” says Bolomey. “But voices in the lower range can actually activate those frequencies–what’s called a resonant code–and cause the room to sound boomy.”
FSorb, a polyester acoustic wall and ceiling panel, has developed one of the most cost-effective, durable, environmentally friendly solutions out there, according to FSorb CEO Doug Bixel. “With the trend for open ceilings and a lack of physical barriers or walls, acoustical treatments need to satisfy the needs of the people residing within the space,” Bixel wrote in a previous feature for gb&d. “In an office setting, it is common for teams to work on a particular project for a period of time. These teams are often situated with another team next to them. Their ability to be heard within their own team and not be distracted by the adjoining team is critical. As I examined this trend, I found that ceiling materials can be placed directly overhead of these noisy areas in patterns that diffuse and block the sound coming from the neighboring team.
This situational acoustic design approach, where the panels are placed in targeted, noisy areas, can create a nice break in sound from one team’s space to the next. The point is to simply absorb the sound where the noise source is.
By positioning acoustical screens between working spaces and common spaces, a physical barrier can also come into play. Acoustical screens with negative space patterns cut into them provide great absorption from both sides while still allowing light to flow through. They can be suspended on a track system so that they can separate spaces where users can change the feel by simply rearranging panels.”
3. Consider how you insulate for sound.
Sound insulation is essential for comfort, energy-efficiency, and even regulatory requirements. It’s important to understand noise from its origin when choosing a suitable sound insulation product. For noise insulation in closed spaces, dense and closed-cell materials are more preferable, while lighter materials are important for noise absorption.
AcoustiCORK’s products dissipate vibration energy into heat in each vibration cycle, resulting in low amplification at resonance in a wide range of frequencies and load-bearing capabilities.
Soundproofing is also possible with products like National Gypsum’s SoundBreak family of products, which stop noise from bleeding through to other rooms without the need for any prior demolition.
4. Incorporate acoustic zoning.
The idea behind acoustic zoning is to address a diverse range of acoustic needs for a successful working, learning, or living environment. Design adjacencies and details should be capable of supporting a full spectrum of sound–from quiet, meditative library areas to collaborative hubs.
Some of the best ways to incorporate this is using sound-absorbing materials, air gap technologies, best practice wall construction, and laminated/insulated glass enclosure solutions.
5. Design for privacy with flexible options
In large, open office areas, it can become impossible to complete tasks that require some degree of privacy, like making confidential phone calls or meeting in small groups. An important acoustic design principle for office spaces is to allow flexibility and have areas where privacy can be obtained.
The company SnapCab has taken this issue and has developed potential solutions in the form of the SnapCab Focus, Meet 4 and Meet 6. The SnapCab Focus is an acoustically controlled single-person workspace. The SnapCab Meet 4 and Meet 6 are workspaces ideal for small team meetings of four and six people respectively, as well as breakaway sessions.
6. Consider steel decking.
Acoustical steel decks also elevate efficiency and sustainability, according to the experts at New Millennium Building Systems.
The case for sustainable design using structural steel building systems is readily understood—steel is North America’s most recycled material. There is a consistent recycled supply chain and steel decking has post-consumer recycled content that can exceed 70%. But that’s only half the story.
Design teams can maximize efficiency by calling for a long-span acoustical steel deck. By increasing deck span, fewer structural members are required. This leads to fewer materials, less fabrication, less installation time, and less waste. It’s a holistic approach to sustainable design.