Noise Reduction Techniques for Hand Dryers

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Reducing Noise from Hand dryers in your workplace

Whether you are in a restaurant, school, office, or factory, unwanted noise can be, at best, distracting, and at worst, a health and safety hazard. Taking steps to reduce the amount of excess noise in a building is important. Loud noises from old fashioned warm air hand dryers in bathrooms can easily escape into the surroundings, and disturb people.

What causes Hand Dryer Noise

Conventional hand dryers cause unwanted noise in several ways. The majority of noise is created by the turbulent airflow from the nozzle, and there is additional noise from the fan and motor assembly.

The way a warm air hand dryer works relies on hot air being blown unevenly over the users hands. The turbulence of the airflow helps to create conditions that allow water to evaporate and be carried away from the skin. However, this turbulent air creates noise across a wide frequency spectrum that can be very loud. Traditional hand dryers operate at a level around 85dB because of their design. This is the noise equivalent of heavy traffic heard from the side of a busy road!

Modern jet hand dryers such as the Mitsubishi Electric Wave u02 use a high speed jet of cleanly flowing air to blow water off the skin surface. This means that there are fewer competing frequencies and less harmonic distortion in the sound, and as a result, the amount of noise is reduced significantly to around 57dB – about the level you would experience in a normal conversation.

Better Placement Can reduce Noise

The design of your bathrooms can amplify the sound from hand dryers and help it to escape into the surrounding rooms.

Hard walls are reverberant, which means that they create echoes and cause a situation where noise “surrounds” the user. This can be an unpleasant experience for many people. Ideally you should avoid placing hand dryers directly opposite a wall that can reflect sound back at the user. The installation of sound absorption in ceilings and the avoidance of right angles during construction can help to prevent echo chamber effects.

Similarly, you should avoid placing hand dryers in a location that directly faces the doorway to the bathroom as this creates an easy escape route which can be extremely distracting to people in the surrounding area who will have waves of unwanted noise each time the bathroom doors are opened. Ideally, a bathroom vestibule or a “J” shaped entrance to the bathroom should be used to create a sound trap.

Could your choice of hand dryer affect noise levels?

The biggest change you can make to bathrooms to reduce noise levels in the surrounding areas is to choose a quieter model. Jet hand dryers such as the Mitsubishi Electric Wave i01 have been designed to be quieter in use.

Not only does their jet design reduce the amount of sound they produce, but they also work more quickly, taking as little as 9 seconds to work fully compared to older designs which may have taken more than 35 seconds to dry the user’s hands. This means that any disturbance is much shorter lived and creates less distraction.

Find Out More

If you want to reduce unwanted noise from your bathrooms, we can help. To find out more about the Mitsubishi Electric Wave range of low noise hand dryers and please contact us to arrange a demo.

Wave i01
Wave u02