Hand dryers as loud as road drills
The news stories have rightly complained about how loud these devices are inside the washrooms. But I have another gripe to add to that. In offices, pubs and restaurants, the unpleasant howling noise of the hand dryer has become an unpleasant signature sound as I try to work or enjoy a meal with friends. The horrible noise escapes from the washrooms and pollutes the rest of the building.
How can we reduce the noise from hand dryers?
It isn’t easy. One solution might be to change the frequency at which these dryers create noise. Years ago in offices the noise of people typing on mechanical typewriters was unbearable. This was solved by making the typewriters create noise at a lower frequency where our ears are less sensitive. This made the clattering sound of the typewriters appear to be quieter and less disruptive to speech.
However good the design of the hand dryers, they will still make noise. A complete solution has to consider my area of research, Architectural Acoustics. To stop so much noise leaking out of the washroom, architects should consider the layout of the room so that when someone open the doors, there is no direct line of sight from the dryers to the room immediately outside. Forcing sound to bend around corners will quieten it. For this to be effective, however, acoustic absorption needs to be added to the walls and ceiling of the washroom, to stop sound rattling around and building up to a louder noise Most acoustic absorption is fluffy stuff which is fine for the ceiling, but it gets damaged by water and isn’t hygienic for washroom walls. However there are washable absorbents, such as coustone, which was developed many decades ago at the Acoustics Research Centre at Salford University.
Of course there is another way of not causing the noise pollution, ignore the dryers and just wipe your hands on your jeans.