The level of noise for the type of work that is supposed to happen in offices today is an issue. In some open-plan offices, noise ranges from 60 to 65 decibels. That may seem minor compared to a busy highway that generates 85 decibels or a refrigerator that hums along at 40, but it can make cognitively demanding work difficult. Recognizing this, the German Association of Engineers has set noise standards in their country for various types of work. While 70 decibels is acceptable for simple or mainly transactional office work, 55 decibels is the requirement for what the association terms “mainly intellectual work.” They identify this as work characterized by high complexity and demanding creative thinking, decision-making, solving problems and effectively communicating—precisely the kind of knowledge work that, when performed well, puts leading enterprises ahead.
The recommended noise level for intellectual work pertains to participating in discussions and meetings as well as working solo. In fact, the association recommends the same limit on noise for a doctor performing surgery as for office workers doing intellectual work, alone or together.
“There is plenty of research that shows that the most destructive sound of all is other people’s conversations.”
The noise level of 60-65 decibels that’s common in some open-plan offices is not only too loud for concentration, it can also impede effective collaboration by causing speech interference. As Babisch explains it, the sound level of speech is about 60 decibels if people talk to one another, in normal tones without raising their voices, at a distance of about one meter (3 ¼ feet). This means any other noise within that same range—someone else talking nearby, for instance—can cause speech interference, so not all the words may be fully heard. “Nevertheless,” he says, “a sentence may be understood because of cortical processing. This, however, is an active process that may cause reaction leading to adverse effects in the longer run of chronic noise exposure.”
In other words, in noisy environments with poor acoustics, workers can as easily get stressed by trying to hear others as by trying not to hear others—a lose/lose proposition.
The solution, says Treasure, is a variety of workplace environments, each designed with consciousness of sound for the task and the people using the spaces. Work environments need to be designed not just for appearance, but also for experience in all the senses, especially hearing.
“Consciousness of sound is a new tool to design with,” says Treasure. “Good acoustics can make environments more productive.”
Solving for noise in workplaces isn’t easy. Four walls and a door don’t necessarily make for good acoustics, because sound, like water, can spread through the smallest gap. Within any environment, sound can be either sealed, absorbed or masked. Each method has advantages and disadvantages that should be carefully weighed, because controlling sound within acceptable levels of tolerance has become a design imperative and an Interface important metric for the overall effectiveness of a space.