The noise from super-fast hand driers, common in public toilets, has the same impact on the human ear as that of a road drill at close range and can cause problems for people with hyperacute hearing, research has found.
Sound researchers at Goldsmiths, University of London have found that the noise from high-speed hand dryers caused discomfort for people with hyperacute hearing – a condition characterised by oversensitivity to certain frequency ranges of sound and common for those on the autistic spectrum. This can cause stress and lead to people affected avoiding the public spaces they are found in.
The researchers also found the dryers caused discomfort for elderly dementia sufferers, affected the navigation of visually-impaired people and even forced hearing aid users to turn their devices off when entering public toilets.
Led by Dr John Levack Drever, senior lecturer in composition and head of the Unit for Sound Practice Research at Goldsmiths, the research project consisted of a range of studies including product acoustic testing, environmental acoustics and noise assessment, and interviews with members of the public.
Studies undertaken by Dr Drever and his team in toilets and in spaces resembling the typical box shape of a public toilet found that the decibels reached by hand dryers could reach 11 times more than that recorded in the product-testing lab. This was in stark contrast to the advertised sound levels of the hand dryers.
“Brutally invasive” annoyance
Dr Drever explained: “Manufacturers tend to test hand dryers in ultra-absorbent acoustic laboratories which is perhaps why actual sound levels are so much higher than those advertised. With these results in mind, it is no surprise the high-speed hand dryer is increasingly perceived as an annoyance and brutally invasive within such personal and sensitive spaces.
“From this initial study it is evident that ‘ultra-rapid’ cold air hand dryers are loud, and this loudness is vastly amplified in the highly reverberant and reflective small toilet. A wide range of vulnerable subgroups are been seriously affected by hand dryer noise, resulting in unwelcome stress in this sensitive space, and in extreme cases people are being excluded from public spaces, the workplace and schools.
“To solve these issues, we propose that engineers, sound artists and users come together to look at the acoustic space in which these dryers are found and tune the products accordingly to enhance the listening experience and minimise the discomfort that is caused to a whole range of people.”
The next phase of this project will see the commissioning of a range of users to compose and in turn propose new favourable sound design possibilities.