The International Well Building Institute is reflecting the finding of numerous studies when it notes that excessive noise “can hinder productivity, focus, memory retention and mental arithmetic”. Not everyone considers, however, that the answer could lie in the ceiling.
Acoustics is a complicated subject, but in an office environment, the most significant consideration is that hard surfaces reflect sound while softer surfaces absorb it. Hence the ubiquity of office carpets and fabric-covered screening.
The inclusion of such materials helps – although in our new, super-clean, wipe-down world they are likely to be a lot less popular – but is seldom sufficient on its own to mitigate intrusive noise.
The geometry of most open plan offices, on the other hand, means that the ceiling will generally provide the most significant surface area. Sound tends to go up and then bounce down from the ceiling, so controlling the reflection of sound will make a huge difference. Essentially, the objective is to turn that huge surface area into a sound-absorbing plane.
The surprise for many is that metal ceilings can do just that. SAS’ range of metal ceiling tiles, rafts and baffles have been designed to provide high levels of both sound absorption and sound insulation.
Metal ceilings are seldom solid surfaces and it is the combination of perforations in the metal tiles with acoustic infills behind the panel that provides for effective acoustic control.
Perforated metal ceilings can appear to be a solid surface because they reflect most of the light incident on them, and designers choose them for this sleek monolithic appearance. Careful specification of the size and number of perforations, however, together with the depth of acoustic infills, allows this ceiling system to provide sound absorption as good or better than other commonly specified materials.
SAS has developed a deep understanding of acoustic principles, using acoustic modelling and in-house test facilities. The result is the ability to demonstrate Class A absorption with a surface that is 97% metal.
In addition to the perforated area, the size of the tile will also have an impact on the ceiling’s acoustic performance. Larger tiles, for example, can flex more and so provide greater sound absorption at lower frequencies.
Similarly, the depth of the ceiling void is another factor. Most SAS systems are laboratory tested using a 400mm ceiling void. As the void-depth is increased so too is the ceiling’s ability to absorb lower frequency sounds.
Where a suspended ceiling cannot be used because the soffit is designed to be exposed, then suspended rafts and baffles provide a practical and aesthetically appealing option. The large surface area and exposed edges of the double-sided baffles provide the excellent acoustic performance, although the ability of baffles to absorb low frequency sound is generally less than that of a suspended ceiling.
SAS’ advanced acoustic modelling and testing is used to develop high-performance products such as the System 610 raft. This unique geometric design combines intriguing contemporary aesthetic with more sound absorption than any comparable product. It’s a great demonstration of the fact that effective acoustic control does not limit design possibilities.