ACOUSTICS at Large

Q: Is Articulation Class (AC) a rating that has gone by the wayside or is it still relevant?

by Keith Peterson

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recently had the pleasure of giving a presentation on acoustics for the Emerging Leaders group. There were several good questions that were asked after the presentation. Kyle Larson the chair of the meeting had a question that struck me as being quite relevant to current office design. He asked me if AC (Articulation Class) is a rating that has gone by the wayside or if it is still relevant? As I first considered this, I responded that it has gone by the wayside, and I really don’t see it much. This is true, but that raises the question: Should we be using it more? AC is a single number value for evaluating ceiling systems for privacy in an open office plan. It is basically telling us how much speech is absorbed and not reflected into other areas of the space by the ceiling system. Open office floor plans continue to be very popular in today’s architecture. It is a more cost effective office design, using less materials to be built, reducing on equipment costs through sharing, and requiring less utilities through natural light and decreased heating zones. Open offices also contribute to teamwork and employee recognition; the ease of communication

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WINTER 2015 | Acoustical INTERIOR CONSTRUCTION

reduces the need for formal meetings and leads to increased productivity. However in my opinion, the major disadvantage to the open office plan is speech privacy. Speech privacy is important for confidentiality, and even if it is not confidential, intelligible speech that is unwanted is a distraction. For example, right now I am on my computer, using its dictation software to compose this article. I am speaking very loudly and in a robotic type rhythm, so the computer can transcribe my words accurately. Think about trying to do this in an open office environment. I would certainly be conscientious about who is listening and if I am disturbing others. These are factors that should be considered by the designers when they are putting together the programming for these spaces. The goal in an open office plan is for speech to not be intelligible when coming from other areas of the space. If the listener can’t understand what is being said, then it is not as distracting, and the concern for confidentiality has been addressed. I hope this gives you a better understanding about