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Ceilings Can Aid Green Efforts: Light Reflectance And Acoustics
OTHER PARTS OF THIS ARTICLEPt. 1: Five Ways to be Green With Ceilings, SoundmaskingPt. 2: This PagePt. 3: Ceilings Showcase: New Products
There are two other ways that ceilings can aid green efforts: light reflectance and acoustics.
4. Light Reflectance
The ceiling isn't the first place most facility managers look for energy savings, but it can play a role in making a space more energy efficient. A ceiling with a high light reflectance will bounce a higher percentage of the light that strikes it back into the space below. That's important whether the light source is a fixture or the sun. Either way, a more light-reflective ceiling can help reduce the amount of electricity used to illuminate a space.
"In the last 10 years we have spent time developing a high reflectance coating so that you need less lighting and less energy, and that goes on the face of the tiles," Zucco says. Mark Joseph, senior manager, integrated marketing, USG, says this technology can reduce the number of light fixtures needed in a space.
Armstrong also produces light reflecting tile, with its Optima line having a rating of 90 percent reflectance, says Snader.
Ceiling system manufacturers are branching out to make related products. For example, Kuperus says that Hunter Douglas has created a light shelf that works hand in hand with the ceiling to distribute daylight into the interior of a space. A traditional light shelf, a horizontal, reflecting surface, is placed in the window plane, explains Kuperus, either inside or outside the building. Hunter's system, which works with any kind of window, has a wave-like design that is intended to spread and diffuse light over a larger ceiling surface. "The wavy surface gives more than one angle of reflectance," says Kuperus.
5. Indoor Environmental Quality
Acoustical design is an element in an overall green design, and acoustic properties of tiles are an important piece in controlling noise in a building — one element of indoor environmental quality. But green interior designs can sometimes create additional problems for acoustical engineers as they try to control sound.
The problem comes when ceilings are eliminated in favor of an open-plenum approach. While that strategy does reduce the use of materials, it also introduces acoustical problems.
In the ABC equation for improving acoustics — absorb sound, block sound, and cover sound — ceiling tiles play the largest role in absorbing sound, explains Niklas Moeller, vice president of K.R. Moeller Associates. "It is the largest unbroken, absorptive surface," he says.
Moeller notes that studies show that acoustics in open-plenum buildings "are not great," and that while people prefer a green design, they complain about the noise factor. Building owners and operators have "a misperception that they can rely on one or two [of the ABCs], but you need all three," Moeller says. "Sound masking does not help with absorption. It controls background sound to help cover up noises in spaces that otherwise have library-like ambient conditions." Absorption, on the other hand, reduces volume level.
Green design isn't the only reason that office spaces are more acoustically challenging than in the past. Design strategies like lower partitions between workers, less space between workers and open work areas with conference tables, in addition to the elimination of the ceiling, all create a more noisy work environment, says David Smith, director of business and channel strategy at Lencore.
Soundmasking system manufacturers say that LEED credits have not paid sufficient attention to acoustics. The U.S. Green Building Council has recently turned to acoustics, however, with Pilot Credit 24, which "is earmarked for speech privacy and implementing a sound-masking system," says Jody Jacobs, marketing director, Lencore.
Sound masking can help cover up noise, says Smith, "and make the space a lot more comfortable." In the absence of one of the ABCs, the others have to step up to solve the noise problem.
"You need all three, but in the absence of one, you have to pay attention to the other elements," Jacob says.
Taking the ceiling out of an interior space design creates other issues, says Jacobs, which will affect how her company installs sound masking. "When it's set above the acoustical ceiling tile, it's different than when it's exposed, so we need to be able to tune sound masking for both conditions." The sound needs to be contoured so that it is comfortable and pleasing and affords workers speech privacy.
A ceiling also plays a role in hiding speakers and wires, says Moeller. If there is no ceiling, the appearance of sound masking speakers and electronic components becomes a consideration.
Ceiling companies have developed products to help absorb sound in open-plenum offices. These products, which are available in a variety of shapes, may be suspended ceiling products designed to be installed over parts of a space or may be mounted directly on the deck.
Maryellen Lo Bosco is an Asheville, N.C.-based freelance writer who covers facility management and technology. She is a contributing editor for Building Operating Management.