New Acoustical Options in Specialty and Seamless Ceiling Systems

Designing for acoustics no longer means sacrificing aesthetics

By Peter J. Arsenault, FAIA, NCARB, LEED AP

Many architects and specifiers mistakenly believe that when choosing specialty ceilings to achieve a particular design vision, they must sacrifice good acoustical performance for aesthetics or sustainability. In fact, that is no longer the case since there are new products that offer excellent acoustical performance as well as extensive design options and sustainability. This is welcome news since poor architectural acoustics can be annoying or distracting such that they can impede concentration, comprehension, confidentiality, healing, or learning. By contrast, strong acoustical design can reduce unwanted noise and create useful, inspiring, and helpful interior spaces. This course will provide an awareness of some current options available to combine design excellence with good acoustics while helping to create better, more effective, and more sustainable building projects.

Acoustics Fundamentals Overview

Acoustics is the scientific study of sound in all its forms, and architectural acoustics is specifically related to the interactions of sound both within and between architectural spaces. Professionals, specialists, and scientists have studied sound in terms of its generation, transmission through space and objects, and reception by people. In all cases, sound radiates outward from the source, of which there are many, both inside and outside of buildings. Sound is typically characterized by its loudness and frequency content, such that loudness is measured in decibels (dB) and frequency is measured in Hertz (Hz).

The sound as heard within a space will be a combination of direct sound from the sources and sound reflected off the various surfaces within the space. Highly reflective surfaces will redirect sound without significant changes except for direction. In large, very ‘hard’ rooms, those reflections can result in long delay times for arrival at the listener, causing echoes. On the other hand, highly sound-absorptive surfaces will diminish the reflected sound waves and reduce reverberation and echoes. Based on these different interactions between sound and spaces (i.e., room size and shape and the acoustic treatments within or between spaces), people can experience different levels of speech intelligibility, speech privacy, or unwanted sound intrusion. Hence, good acoustical design for a given space is a matter of finding the right combination of sound absorption and sound attenuation (blocking) using several well-developed tools to balance the acoustic characteristics within that space. (See sidebar.)

While the science-based study of architectural acoustics has developed to a rather sophisticated level, the good news is that acoustical materials and products have also advanced based on that science. Since the product manufacturers provide all of the needed testing and report the results, architects, interior designers, and acoustical consultants can now make better informed, more holistic decisions about many of the materials and products used within a space. This is particularly true when it comes to ceilings, which are a significant surface in the acoustical characteristics of virtually all spaces. Selecting those materials based on the needs of different types of spaces is also important and has similarly been studied and investigated. A brief overview of some of the more common architectural building types where acoustics is a particular concern follows.

Workplace Environments

Good acoustic design in today’s office or workplace environments addresses both rooms for quiet concentration and spaces for energetic collaboration. Locations where speech privacy is required, such as a private office or small conference room, need strong sound absorption and sound blocking for good all-around acoustical performance. Designing these rooms with ceilings that achieve NRC values of 0.70 or higher and a CAC value of at least 35 provides the highest level of acoustical privacy and performance. On the other hand, open collaboration spaces need strong sound absorption and sound blocking to prevent undue sound reverberations and transfer of sound to adjacent spaces. Acoustical ceiling treatments with NRC values of 0.70 work for spaces where this is a priority. Spaces where less sound absorption is required but sound blocking is needed to maintain privacy between adjacent areas can use products with somewhat lower NRC values on the order of 0.60–0.65.

Health-Care Environments

Health-care environments are most successful when they are designed to create a calming atmosphere that may also connect patients with nature. Therefore, good acoustic design in health-care environments must address the need for quiet spaces for healing while also addressing the other often active work and public spaces in the building. Spaces with excessive noise, such as in corridors, busy nurses’ stations, and chaotic treatment rooms negatively affect patients, but they also hamper interactions between health-care professionals and staff. Therefore, spaces dedicated to patient healing require superior sound absorption and sound blocking in order to help keep noise levels down and prevent disruption from adjacent spaces. These spaces should have ceilings with an NRC value of at least 0.70 and a CAC value of 35 or higher. Other areas, such as nurses’ stations, where private conversations and critical information transfer take place should have high-absorption ceilings that keep RT levels down to help with background noise leakage and speech intelligibility. Ceilings with a NRC of at least 0.70 are best for this type of environment. Similarly, public spaces in health-care settings should have ceilings with an NRC of at least 0.80.

Educational Environments

Good acoustical design in education spaces promotes high speech intelligibility for understanding, learning, and effective collaboration. Excessive reverberation inhibits student understanding and increases teacher vocal strain. Studies indicate that students typically hear only three out of every four words in the classroom, missing 25 percent of what is said. This issue can be addressed by meeting the recommended reverberation time for instructional spaces at 0.6 seconds using high-performing ceilings with NRC values of 0.70 or higher.

It is popular to design open, multipurpose spaces in many schools that may change from cafeterias to auditoriums to gymnasiums depending on the daily need. However, each of these uses require different acoustical performance in order to be effective. Sound absorption is key in this situation and can be accomplished with ceilings that obtain high NRC values—specifically, NRC values should not be lower than 0.60 in these types of spaces. If sound transmission to adjacent spaces is a concern, then selecting treatments with an NRC 0.70 and a CAC of 35 or higher is recommended.

With all of the foregoing as a basis for acoustical performance, let’s now turn our attention to the other design aspects of ceilings. Specifically, we will look at some of the innovative and appealing ceiling types that provide both great design options and acoustical performance. We will also look briefly at their sustainability characteristics and examine their use through case study examples.

Specialty Acoustical Ceiling Tile

Most design professionals are accustomed to the familiar suspended, white-colored acoustical ceiling tile systems that have been common in many 2-by-4-foot and 2-by-2-foot patterns for years. These are no longer the only good acoustic choices. Instead, there are new panel shapes and colors available that can be combined into innovative geometric ceiling patterns to create or enhance exceptional design schemes. Different sizes and shapes can be combined in different patterns and colors (both bold and subtle) using special installation components that accommodate creative freedom. Further, lighting and HVAC diffusers have become available through certain manufacturers that coordinate and fit into a variety of alternative patterns, including narrow linear, triangular, and other shapes. These new panels may be used as insets or borders in additional to full ceiling installations.

The acoustical properties of these specialty tile systems are comparable to the acoustical properties of conventional acoustical ceiling tiles in that they can vary based on the product selected. Nonetheless, manufacturers do provide a range of choices in this regard too, so it’s likely that a particular design and acoustical performance criteria can be matched up. At least one manufacturer helps narrow down the selection process by indicating categories of performance as “best, better, and good.”

Specialty acoustical ceiling tiles meet many other typical performance needs too. Attributes and characteristics related to building concerns such as fire ratings, light reflectance, and seismic resistance are readily obtained and can be specified accordingly. From an operations standpoint, they also provide characteristics related to durability, cleanability, mold/mildew resistance, and humidity/sag resistance. Many of these play directly into the sustainability attributes of such ceilings, as does the use of recycled content, and materials that are listed in environmental and health product declarations. Accordingly, many of these specialty ceiling tile systems can contribute to green building programs, such as LEED, Living Building Challenge (Declare), and Well Building Standard.

Metal Acoustical Ceilings

Using metal for ceilings has been a successful design solution when a particular aesthetic is sought out or extreme durability is required. Specifically, the flexibility of the material means that it can be fashioned into metal ceiling tiles in curves, clouds, panels, and planks in standard, custom, or even one-of-a-kind looks. They are available in some new 3-D shapes and torsion spring shapes as well. As such, they can create a strong visual impact or simply add a very sleek look to well-designed interior.

In addition to their good looks, metal ceilings are extremely durable and typically unaffected by many of the potential harmful effects that can be part of commercial building operations. They can be specified in a natural or painted finish, which can be selected as much for performance as appearance. Hence they are used in areas where high durability or high degrees of cleanliness are needed in addition to locations that have specific design needs.

Along with this durability and design flexibility, metal ceilings can also deliver strong acoustic performance. This is commonly achieved through a range of choices in perforation patterns in the metal. Since metal ceilings will be naturally sound reflective, the perforations allow some fine tuning in the amount of sound reflection compared to sound absorption. To aid in the absorption, acoustic fiber, mesh, or fleece can be applied on the back side of the metal tile to soak up sound and reduce echoes as needed. The size and amount of perforations coupled with the type and amount of acoustic backing determine the NRC rating and manufacturers can provide a full range of details and choices.

Metal ceilings meet other design criteria too. They are durable and very cleanable as already noted, but they can also provide high light reflectance that can help in daylighting of interior spaces. They provide great fire resistance and do not provide any organic base for mold and mildew to grow. All of these attributes help with their overall sustainability capabilities and allow them to contribute to green building rating programs. Most metal products are made from substantial amounts of recycled material as well, meaning that their embodied energy can actually be very low compared to other materials.

Wood Acoustical Ceilings

For some design schemes, the intent may be to use natural materials or bring a sense of nature indoors. Using exposed, finished wood for ceilings has been a popular solution for meeting those goals. However, creating a full ceiling out of custom millwork may not suit a construction budget, so turning to manufactured ceiling system that use either solid wood or wood veneer often proves to be a more cost-efficient and versatile solution.

Wood ceiling systems are available in a truly wide variety of types and options. At its simplest, wooden tiles with solid, coffered, or slatted configurations can be set in suspended ceiling grids. For a more continuous look, wood panels in a variety of widths and shapes can be installed. Those panels can have a solid appearance or a pattern that incorporates diffused slats, grilles, or other treatments in linear or radial patterns. Fully three-dimensional shapes are also possible, including curved floating panels or geometric shapes that protrude and recess across a ceiling plane in the fashion of ceiling clouds and canopies. In some cases, the wood products extend from the ceiling down onto a wall surface or fascia area as well, creating a continuous enveloping of the space characterized by the warmth of the natural wood. While many of these solutions can be done using standard products, it is also possible to have fully custom shapes, patterns, and styles produced. In all cases, the exact species of wood and its finished coloration can be specified to suit an overall design scheme by selecting from a wide range of standard and custom color options, including real wood veneers and exotic species. It is even possible to extend the look of a wood ceiling system to an exterior soffit or overhang for a continuous look between indoors and out.

Wood is often considered an ideal acoustical surface, but that varies depending on the type of wood, the use of the space, and other factors. The advantage of a manufactured wood ceiling system is that it can be produced to suit the specific acoustical needs of a room or space by using micro-perforated ceiling and wall panel surfaces. With this approach, panels appear to be nonperforated from a normal viewing distance but in fact have small perforations (on the order of 0.55 millimeter) to help control sound absorption and reverberation. Acoustic fleece can be factory attached to the back of these micro-perforated panels along with the option of acoustic insulation to provide a range of NRC values up to 0.80 for ceilings. Micro-perforated panels can be flat or curved and use a full range of wood species and finishing options.

From a sustainability perspective, wood is a renewable resource that is recognized by most green building rating systems for its comparatively low environmental impact and embodied energy. For true sustainability, the wood used should come from a sustainably managed forest with a certified chain of custody from forest to construction site as provided through independent organizations, such as the Forest Stewardship Council (FSC) or others. Manufacturers of wood ceiling systems offer such products. The sustainability aspects of wood ceiling systems can make a significant contribution to LEED credits or other green building rating systems.

Exposed Structure Acoustical Ceilings

Sometimes the design intent is to leave the roof or deck structure exposed and simply paint it. While that works visually for many buildings and is consistent with the overall design intent, it can have unwanted acoustical consequences, including decreased productivity and less-engaged employees, inhibiting students’ ability to learn or leaving patrons struggling to hear and be heard. In these cases, an acoustical treatment can provide a reduction in noise levels in such spaces. Such treatment can take the form of absorptive mineral fiber or fiberglass panels that are often sprayed the color of the deck so they are virtually unseen. These same treatments can also be used in I-beams and trusses. In other cases, treatment can take the form of suspended clouds and canopies or vertical baffles and blades.

The difference between the addition of acoustical treatments compared to the absence of them can be dramatic in spaces with exposed structures. Depending on the need, products are available that provide sound absorption between 0.75 and 1.00 NRC. Manufacturing partners can run reverberation time reports and recommend square-foot coverage of these absorptive elements to reduce reverberation times. This allows designers to achieve the best of both worlds by providing the right look and less noise in open ceiling spaces.

From a sustainability standpoint, all of the product options for exposed structures use the same materials as other systems already discussed. Therefore, they carry all of the same positive sustainability traits as the ones already noted.

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.

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