What can you do to make hand dryers quieter?
In modern buildings, bathrooms are positioned where they are needed, and this means that noise from hand dryers can leak out into the surrounding area which can disturb people nearby. Thankfully, modern hand dryer design reduces these problems in a number of ways.
Reducing Air Turbulence
Hand dryers make noise in multiple ways, but the blast of turbulent air from the nozzle is the loudest and most distracting for people nearby.
Conventional hand dryer models feature a wide nozzle and blow air from an exposed fan over a heating element. Warm air from the nozzle flows unevenly over the user’s hands causing water to evaporate. In this type of airflow, air moves at different speeds depending on where it passed over the fan, and this, coupled with the large diameter of the nozzle means that there is excessive turbulence in the airflow.
In a turbulent flow of air, multiple soundwaves are created and bounce across each other to create a wide spectrum of noises that can penetrate through walls and into surrounding areas.
In modern jet hand dryers such as the Mitsubishi Electric Wave i01, airflow is directed through a narrow slot nozzle. This creates a more even laminar flow of air with little turbulence. As a result, the multiple overlapping frequencies are not present, and the sound is naturally lower.