Green building is undoubtedly one of the leading trends in architecture and design today. Unfortunately, its relationship with acoustics has been – and, in many respects, continues to be – rather poor.
Today, I’d like to talk about one aspect of sustainable design that can significantly impact a space’s acoustical performance: daylighting. Improving its penetration into a space is a key feature of green design. It’s not only desirable for energy savings, but also because access to natural light and outdoor views have been shown to make people feel better while they’re at work.
So, what’s the drawback?
First, allowing natural light to penetrate more deeply into a space generally calls for a more open design with fewer, and lower, partitions. As I’ve mentioned in previous posts, the elimination of these physical barriers – or lowering them beyond an effective height – comes at a steep acoustical price.
Rather than sacrifice daylighting or noise control, a simple solution is to use solid, absorptive workstation partitions to the highest point acceptable for daylighting and then top them with a transparent panel in order to raise them above seated head height. The transparent portion will be reflective, so it isn’t ideal acoustically speaking, but it’s better than nothing!
Second, the suspended ceiling is often eliminated in order to raise the ceiling height, which allows direct and reflected light to penetrate more deeply into the space. But removing the acoustical ceiling tiles also deprives the workplace of the majority of its absorptive material, which raises the reverberation time (echo), overall sound levels and the distance over which speech and noise travel. Unless absorption is added via some other method – such as panels mounted on a portion of the deck – acoustical performance will suffer.
Third, daylighting typically calls for narrower footplates in order to ensure that more occupants are close to a source of daylight. The result is similar to the ‘bowling alley’ effect of long hallways – sounds bounce between the exterior wall and windows and the core. And more people work within closer proximity to a reflective wall. The larger, squarer footplates of traditional buildings allowed noises to decay in volume prior to reflection, but to the extent that these shapes are no longer possible, designers should try to balance the effect of narrow spaces by ensuring there are sufficient internal partitions, absorption and sound masking.
In the end, designers don’t need to – and shouldn’t – make a choice between daylighting and good acoustical performance. One of my favorite quotes comes from a 2007 Fast Company interview with Jan Barowitz, who said, “You could make a building that’s very energy-efficient by not having any windows in it and having only one elevator, but this is not a building that people are going to want to work in.” Same goes for a space with poor acoustics. A green building can’t simply mean one that wastes minimal resources. It also has to be a space in which employees can thrive and productivity can soar – and that calls for noise control and speech privacy.
Cheers,
Niklas