As walls have come down in offices to create open-concept spaces, the trend has brought welcome change, such as encouraging collaboration, but it also means that the old ways of managing noise no longer work. Distraction and a lack of privacy are real concerns that must be addressed in the acoustic design of today’s buildings.
With the popularity of open-concept spaces and use of sound-reflective and sustainable materials, facility managers and designers are looking to the ceiling for noise control. However, the notion that dual-purpose or multi-functional panels can both absorb and block sound effectively has raised confusion about the primary role of ceilings.
In reality, acoustic ceilings are good at sound absorption because they are porous, and in open spaces, the general rule is: the higher the absorption rating, the better. Modular acoustic ceilings do not have enough mass to block sound between private rooms, and penetrations for lights and air devices let sound leak through. Walls are more effective at blocking noise transfer between rooms because of their mass and solidity.
Controlling noise in today’s open building designs begins with effective noise absorption. Acoustic ceiling panels hold the potential to absorb the lion’s share of noise generated in spaces, preventing widespread disturbances and lack of productivity. This explains why the WELL Building Standard 2016 requires the ceiling in open offices to have a noise reduction coefficient (NRC) of 0.90 or higher.
Enclosed spaces, such as meeting rooms, demand noise absorption too. The maximum permissible reverberation times are decreasing in building standards and guidelines, demanding high-performing ceilings. Where low-performing ceilings are installed, the walls and floor may require additional absorption, which adds avoidable costs.
In the past, for example, a conference room with carpeting and acoustic wall panels may have only required an NRC of 0.60 for the ceiling. If the carpeting and wall panels are removed, the ceiling now needs an NRC of 0.90 to maintain the same reverberation time. To achieve successful acoustic experiences, focus on the high absorption ratings of ceiling panels.
Dual-purpose or multi-functional ceiling panels that attempt to both absorb and block sound sacrifice absorption performance for higher blocking performance. Increasing density and mass for improved sound blocking capacity decreases the porosity and open pore structure needed to absorb sound. Yet the higher blocking performance that these panels can provide is not high enough to be effective because the standards are based on the blocking levels of much heavier walls. So, if a product is able to absorb sound effectively, it cannot also block an adequate amount of noise to meet the requirements in the standards.
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