New Acoustical Options in Specialty and Seamless Ceiling Systems
EDUCATION CASE STUDY: EXPOSED STRUCTURE ACOUSTICAL CEILINGS
Project: Temple University School of Architecture
Location: Philadelphia
Architect: NELSON
Ceiling: Direct-attach acoustical panels
The Project: Originally built in 2009, Temple University’s School of Architecture building houses a myriad of lecture halls, classrooms, studios, and conference rooms. The design features large open interior spaces with an exposed structure for the ceiling that reveals the building’s open-web steel joists and metal roof deck.
The Challenge: The acoustics in the facility were exhibiting excessively high reverberation times, negatively affecting students’ ability to hear and understand their instructors. Acoustical testing confirmed that reverberation times averaged nearly 2.30 seconds—three times longer than the recommended 0.60 seconds for these types of spaces.
The Solution: Consultant Graham Everhart of Metropolitan Acoustics in Philadelphia explains how his team created acoustical models to develop remedial acoustic recommendations. “Our recommendation was to incorporate acoustically absorptive materials on the available surfaces,” he states, “and in most spaces, that was the ceiling.” The consultants worked in collaboration with NELSON, the architectural firm responsible for the project. “Considering the amount of hard surfaces, it was easy to see why sound bounced around so quickly, making it difficult for students to learn and work in the spaces,” notes Scott Winger, AIA, technical director for NELSON.
Direct-attach acoustical panels were chosen for the classrooms and studios. “Cementitious wood fiber and other selected panels perform in a similar manner acoustically. We went with the tectum panels because they were rugged and better suited for these types of spaces,” Winger states. The 1½-inch-thick tectum direct-attach panels have an NRC of 0.80 and were installed directly to the deck. To reduce reverberation time and improve speech intelligibility, the design team chose a fiberglass second type of ceiling panel for the lecture halls and other presentation spaces. Featuring a NRC of 0.90, the panels were installed directly to the deck with a 4- to 6-inch offset. Acoustical testing after the installation validated the choice of ceiling treatments. Reverberation time was reduced an average of 56 percent in the eight spaces that were tested.
The Results: According to Winger, both the students and faculty have noticed the difference. “By installing the panels between the metal joists, we were able to maintain the intended look and feel of the exposed structure while dramatically reducing the reverberation time.”
Seamless Ceiling Systems
If a seamless ceiling—that is, one without any exposed grid—is desired in a commercial space, the default approach is to use a suspended gypsum drywall ceiling. While that solves the appearance issue, it doesn’t solve the acoustical issues since drywall is a hard and sound-reflective surface. That means if sound absorption is needed, then something else needs to be done to compensate for the reflectivity in the space.
As an alternative, seamless acoustical mineral fiber panels are available that can be suspended into a space and then finished to provide the desired seamless appearance comparable to gypsum drywall. This is achieved by using seaming tapes and compounds specifically made for this type of product. The surface is then finished similarly to drywall using acoustically transparent paint to achieve the look of a smooth, acoustical finish. Most significant to our discussion, the mineral fiber panels also provide acoustical performance that is much better than gypsum drywall in many situations. With a higher degree of sound absorption, the spaces where it is used can have reduced reverberation, improved speech intelligibility, and less noise transfer through the ceiling to other spaces.
As a mineral fiber product, seamless ceilings can carry the same sustainability traits as other sustainable ceiling products. These can include contributions to LEED v4, including the latest Materials and Resources credits. They may also have environmental product declarations (EPDs), which indicate the environmental impact of the products, and/or health product declarations (HPDs), which identify the ingredients in the products. If they are free of Red List chemicals per The Living Building Challenge 3.0, they can also carry a Declare label, which is an easy reference means of identifying the basic ingredients of a product. All of these can allow the use of the products to contribute to the Living Building Challenge and/or to the WELL Building Standard. Finally, some may meet California Department of Public Health (CDPH) low-emissions standards.
OFFICE CASE STUDY: SEAMLESS ACOUSTICAL CEILING SYSTEM
Project: Armstrong World Industries Commons Building Lobby
Location: Lancaster, Pennysylvania
Ceiling: Seamless Acoustical Ceiling System
The Project: The lobby of the Commons Building on the campus of Armstrong World Industries is a busy thoroughfare housing the corporate cafeteria, fitness center, meeting rooms, and an adjacent call center. The lobby finishes are all hard surfaces with window walls, resilient flooring, exposed metal deck, and a drywall ceiling cloud. The average ambient background noise levels were measured at 48 dB, with a reverberation time of 1.5 seconds, exceeding ASHRAE acoustical guidelines for background noise in this type of space. Not only did sound build up within the active lobby, but Armstrong facilities personnel were getting complaints about noise intruding into adjacent meeting rooms.
The Challenge: Operations Manager Karen Spina remarks on the noise problem. “While we want to highly encourage users to interact in the lobby, we also want all of our guests in our private dining room and meeting rooms to enjoy the privacy of those spaces.” Armstrong, as the building owner, wanted to maintain a seamless drywall look but needed to address these noise complaints. Sean Browne, senior principal scientist at Armstrong, says, “Creating and maintaining an appropriate acoustical environment in a space is a critical piece of architectural design. Any area where people interact and communicate needs to maintain low ambient background noise and low reverberation time to preserve speech intelligibility, and this lobby is no different.”
The Solution: To solve the problem, a seamless acoustical ceiling system was installed comprised of mineral fiber acoustical panels suspended using a drywall suspension grid. The edges of the system were sealed with joint compound and the installation was spray finished with acoustically transparent paint.
The seamless acoustical ceiling system provides the monolithic appearance of drywall with the sound absorption of traditional ceiling panels. This type of ceiling system can reduce sound reflectance and reverberation up to 75 percent more than typical drywall. Regarding selecting the seamless system for this space, Browne says, “We wanted to pair comfortable acoustical control with the need for a somewhat lively, energetic space. We didn’t want to create a ‘dead’ acoustical space with too much treatment, but we wanted to address the high background noise. The system we ended up using provided the best acoustical treatment to maintain the smooth drywall visual appearance and lively personality of the space. It also added the acoustical absorption needed to reduce the background noise and the reverberation to improve speech communication and contain the sound from intruding into other areas of the building.”
With the new seamless acoustical ceiling installed, the ambient background noise level in the Commons lobby was reduced to 44 dB, which now meets the ASHRAE guideline. In addition, with the 33 percent reverberation reduction to 1.0 second, speech intelligibility has been drastically improved. Lastly, because the seamless ceiling cloud also blocks sound, the intruding sound into the adjacent meeting rooms has been reduced. The seamless acoustical drywall panels were finished with the same tools and materials typical to standard drywall installations. The seamless acoustical mineral fiber panels were tapered on all four sides and finished with the same tools and materials typical to standard drywall installations.
The Results: When asked about the difference between the new seamless acoustical ceiling system versus the traditional drywall, Spina says, “Visually, no one can tell the difference, but acoustically, everyone can tell the difference. The difference really is very dramatic when you compare and contrast the two systems. Noise was a noticeable problem with the previous drywall ceiling installation. With the seamless acoustical ceiling installation, we have noticed an improvement in user commentary about the privacy of their meeting spaces.”
Conclusion
Design professionals don’t have to sacrifice design vision for great acoustics. Instead, we can now use specialty products that didn’t exist before, including geometric shapes, low- and high-relief textures, acoustical wood grain ceilings, metal ceilings, exposed structure solutions, and even acoustical seamless ceilings. All of these current options mean that ceilings can be visually appealing while providing great acoustics.
Peter J. Arsenault, FAIA, NCARB, LEED AP, is a nationally known architect, consultant, continuing education presenter, and prolific author advancing building performance through better design. www.pjaarch.com, www.linkedin.com/in/pjaarch
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