The role of metal ceilings in commercial buildings continues to grow for a number of reasons. One major reason is their aesthetics. Metal ceilings impart a sleek, high-tech look to a space, a visual that appeals to many architects, designers, and building owners.
Another is metal’s service life. A metal ceiling panel will generally outlast a traditional non-metal panel, especially in areas where access to the plenum is frequent. Humidity and impact resistance, as well as a durability and low maintenance, are additional considerations when choosing metal.
Yet another reason is the concern for a space’s Indoor Environmental Quality (IEQ) and the acoustical control that metal ceilings can provide. In order to realize the acoustic benefits, however, the panels must be perforated. Perforated panels can be supplied with either a sound-absorbent fleece or a variety of infill and/or liner panels behind the perforations.
Perforation Patterns Vary
Perforations vary in size and pattern depending on aesthetic appeal and acoustical needs. Today, it is possible to have perforated panels with holes that are so small, they are essentially invisible.
For example, the holes in MetalWorks Extra Microperforated ceilings from Lancaster, Pa.-based Armstrong measure only seven-tenths of a millimeter in diameter. Yet, when backed with an acoustical fleece, they allow the ceiling panels to achieve a Noise Reduction Coefficient (NRC) of 0.65, meaning the panels absorb 65 percent of the sound that strikes them. When backed with a fiberglass infill, the NRC increases to 0.70.
A metal ceiling with microperforations that measure 1.5-mm in diameter achieves an NRC of 0.65 when backed with an acoustical fleece, and 0.90 when backed with a fiberglass infill. To provide design flexibility along with acoustic control, microperforations are offered in a number of Armstrong Metal-Works ceilings.
Plenty of Choices
When selecting metal ceilings, there are three general categories of perforated ceilings to consider when aesthetics and acoustics are needed for a space:
Highly perforated These ceilings are mainly open (open cell ceilings, mesh ceilings, etc.) or have a perforation area greater than 20 percent of the ceiling area. The relatively large perforations are available in a wide variety of patterns and shapes, including circles, squares, diamonds, bars, and slats. Since the panels are essentially transparent to sound, acoustical performance is solely dependent upon the acoustic treatment placed behind the ceiling panel. These ceilings are frequently found in retail applications, especially boutique environments, and hospitality installations such as restaurants. They are also used in many types of high ceiling applications such as gymnasiums. Because there is so much open area, use of a black acoustical backer is recommended.
Typically perforated These ceilings have an open area less than 20 percent. The perforations are predominantly circular in shape, although other shapes are available. These ceilings are the most commonly used in commercial applications, including office buildings, health care facilities, and educational buildings. If the acoustical goal is to lower the sound of occupant voices, choose a panel that has an open area as close to 20 percent as possible. In addition, the smaller the perforation, the better.
Minimally perforated These ceilings have an open area less than 2 percent, but can still provide good acoustical performance if properly designed and backed with an appropriate infill. Minimally perforated ceiling panels can be installed in a wide variety of applications to reduce occupant sound level and/or the background noise created by an HVAC system. Visually, the perforations can hardly be seen and give the appearance of an unperforated ceiling. Consequently, if a visible perforation pattern is aesthetically desired in the ceiling, select one of the other choices above.
Assistance Available
The increasing popularity of metal ceiling systems has resulted in the need for more collaboration between architect and ceiling manufacturer, especially in the case of custom installations.
To meet this need, Armstrong has created the Architectural Specialties Group, a consultative design service that provides project management for a ceiling system from concept to completion. It is comprised of specialists in both architecture and engineering whose mission is to partner with architects and interior designers in the implementation of signature ceilings.
Kenneth P. Roy, Ph. D., is senior principal research scientist for acoustic technologies for Armstrong Building Products in Lancaster, Pa. To learn more about metal ceiling systems, visit www.armstrong.com/metalworks. To contact the Architectural Specialties Group, call (877) 276-7876 and select options 1-1-4.
