The trend toward lower or no partitions in open offices, intended as a way to foster collaboration, has a price: more exposure to noise.
In 2019, flooring company Interface Inc. surveyed more than 2,000 office workers in the United States, United Kingdom and Australia; 70% of respondents said noise negatively impacted their concentration, productivity and creativity.
The biggest offenders? Co-workers’ conversations, ringing phones and a feeling of not having enough sound privacy.
Acoustic comfort has grown in importance over the years. Today, it is prioritized by building rating systems such as LEED, WELL and the Collaborative for High Performance Schools. Besides offices, acoustics can also be an issue in schools, conference rooms, fitness facilities, courtrooms, libraries and performance venues.
To address it, there are a range of options, from surface materials to noise-reducing shades to sound-absorbing panels. Recognizing that luminaires are installed throughout most occupied spaces, generally above the line of sight, manufacturers such as Eureka Lighting, Focal Point and Signify developed another option: acoustic luminaires. While still relatively new and emerging among a limited number of suppliers, manufacturers believe the market will grow.
These luminaires can be surface-mounted, recessed or suspended and provide general lighting while integrating a soft or porous material, such as felt, foam, recycled polyester or wool, that offers sound absorption and a differentiating aesthetic. The majority use felt integrated as panels on the luminaire’s exterior, wrapped around the frame or serving as the housing or shade.
This approach allows specification of a broad range of colors that can be coordinated with specialty felt acoustic ceiling systems—which may be available from the same manufacturer—and contribute to a distinctive interior design.
For electrical contractors, they install similarly to standard luminaires, though there are some special considerations related to cleaning and handling. If the luminaire is part of a larger ceiling installation, some coordination with the ceiling contractor may be needed. Color-matching should be confirmed. Substitution is more difficult, requiring verification that the new solution provides the desired acoustic performance.
For electrical contractors that recommend, specify or sell lighting products, acoustic luminaires offer a point of differentiation and potential opportunity, though some training in acoustics is advisable. They might also benefit from working with a supportive manufacturer and developing new relationships with acousticians and ceiling contractors. Here’s a quick, basic primer.
Sound can be reflected, transmitted and absorbed. Acoustic management involves “ABC”—absorb, block or cover up. Acoustic luminaires are sound-absorbers aimed at reducing reverberation, or the continuation of sound after its source has stopped. Their effectiveness depends on the type, thickness and surface area of the material. If they use the material as a housing or shade, effectiveness increases.
Sound absorption is expressed in a reduction of reverberation time (RT60), which is the time before a sound decays by 60 decibels. The effectiveness is evaluated through independent laboratory testing, with results published in an ASTM C423 test report and used to generate a noise reduction coefficient (NRC), used for two-dimensional spaces, and sabins, for 3D objects. NRC and sabins can be used for side-by-side product comparisons and to determine the acoustic effect of product installation in a space. The latter part can be complex, as the number of luminaires, mounting height and spacing can all alter sound absorption.
If an acoustician isn’t assigned to the project, the manufacturer should provide layout and calculation support. It’s important to note here that, regardless of certain claims, acoustic luminaires can help reduce noise but are not a panacea. Their effectiveness depends on their application in a space and the space’s characteristics.
Two additional considerations are lighting performance and aesthetics. The luminaire’s primary role is illumination, so lighting performance should be prioritized.
As far as aesthetics go, the luminaire may have a distinctive, decorative appearance and be offered as part of a ceiling system that in turn may be a prominent design feature. Also part of aesthetics is color. Even with standard colors, mismatching may occur, so it may be beneficial to stick with a single manufacturer for a space. If an architect or designer is attached to the project, they may need to approve the acoustic material and ensure color matching and coordination.
Acoustic luminaires show that lighting is everywhere all the time, providing real estate for a functional footprint beyond illumination. In this case, manufacturers have carved out a developing market for lights that contribute to acoustic comfort.
Reblogged from: Craig DiLouie, https://www.ecmag.com/section/lighting/silent-light-improving-acoustic-comfort-revolutionary-luminaires
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