Reduced Hand Dryer Noise
Conventional hand dryers can emit up to 83dB of sound when in use. This is the equivalent of the traffic noise that you would hear when standing next to a busy road. The combination of low and high frequency sound from a hand dryer can easily pass through walls and doors into surrounding areas and has even been linked with causing hearing problems for younger children who may be closer to the source of the noise.
Why hand dryers make so much noise
The design of a conventional warm air hand dryer produces a great deal of noise. There are two main causes of this noise:
- The sound of the fan and motor
- The turbulence caused by the airflow from the nozzle
These two factors combine to generate an unpleasant sound that can be extremely disturbing and may put some people with noise sensitivity off using the dryer altogether.
Fan noise from hand dryers
The design of a warm air hand dryer requires a relatively large nozzle to be used. This allows air to move slowly enough to pick up warmth from the heating element so that it can cause water to evaporate. Unfortunately, the size of the nozzle means that there is nothing between the fan system and the outside of the dryer, so all the noise of the motor and fan can be heard. The motor and fan noises tend to be quite high frequency which can be unpleasant in the area immediately around the dryer.
While it is possible to install some sound proofing on the sides of the dryer, this has very little impact on the amount of noise released overall.
The wide nozzle of a warm air hand dryer also creates a turbulent flow of air out of the dryer. Turbulence can be useful in terms of slowing the movement of air and allowing it to stream around the user’s hands, however the effect of multiple streams of air moving at different speeds and colliding with each other causes a whooshing or booming noise.
The lower frequency noises from air turbulence are more likely to escape through walls and into the surrounding area where they can affect the concentration of people working nearby or disturb people in a restaurant or bar setting.