Why Quieter Hand Dryers are Important
The noise from older designs of hand dryers can easily escape from bathrooms and create a disturbance in the surrounding areas. In offices and schools, this can affect concentration and disturb work while in restaurants and other hospitality venues, it can negatively affect customer enjoyment. In industrial and high traffic areas, unwanted additional noise can be a health and safety risk.
Why are hand dryers so noisy?
Older hand dryers use warm air that is blown over a heating element to help water evaporate from the user’s hands as they rub them together after washing. The design of evaporative hand dryers means that they can create as much as 87dB of noise when in use – that’s the equivalent of heavy traffic nearby.
The reason why older hand dryers make so much noise is because of the way they work. For air to be warmed enough to allow it to evaporate water into steam, it needs to move relatively slowly over the heating element. Because the air is moving slowly, a larger nozzle is required to allow sufficient air to flow to make a difference.
A wide nozzle means that the air coming out of the hand dryer is highly turbulent, moving in multiple directions and carrying the noise with it. The size of the nozzle also means that there is nothing between the fan and motor that can reduce the noise levels.
As a result of the combination of turbulence moving a lot of air and significant amounts of noise from the motor, the overall outcome is sound that can penetrate through walls and leak easily into surrounding areas.