Nora Louise Keegan, a 13 year old Canadian has generated great publicity with her recent article in Pediatrics & Child Health (Children who say hand dryers ‘hurt my ears’ are correct: A real-world study examining the loudness of automated hand dryers in public places).
She conducted a rigorous study to measure the peak loudness of dryers at two distances from the wall, both with and without hands in the dryer’s air flow. She measured the sounds at different heights, corresponding to the ear canal height of younger and older kids and of adult men and women.
I encourage you to read the article. It is brief and well-written.
When I saw the write-up in the Washington Post, I immediately remembered writing about this very issue back in 2013 (when the author was about 7 and starting to develop an interest in the topic).
In my post (Hand hygiene and hearing loss. Avoiding the tradeoff) I wrote:
I’m not so fond of the Excel Xlerator. Sure it’s powerful, but it’s also incredibly noisy. I have sensitive ears, and I’m not embarrassed to admit that when I’m exposed to a loud sound I cover my ears with my hands. But of course if I’m drying my hands I can’t use them to protect from the noise. The Xlerator is loud enough that I suspect it’s a threat to hearing. At the very least it’s so annoying that I bet some people skip hand washing to avoid using it. My gym has one of these beasts and after being bothered by it for a while I decided to research the noise level.
I didn’t do any original research but I found a paper by Jeffrey Fullerton and a colleague from an acoustical consulting firm and corresponded with Jeff about the subject. He told me that the airstream is a major factor in the noise level and advised me to lower my hands a foot or so below the nozzle , which helps make things quieter. This is the approach I use to this day, with some success –although sometimes the sensor doesn’t see my hands and it does take a bit longer to dry.
The new research by Keegan quantifies the difference made by placing hands in the airflow and also identified the Xlerator as the number one bad boy.
When I read the article I circled back to my original sources. The article I cited is gone (maybe the firm snuffed it when the author moved on) but the Acoustical Society of America still has a summary on its site.
My favorite tidbit is that there is (was?) a noise reduction nozzle for the Xlerator. Presumably the manufacturer understood there was a problem.
I’ve never seen one of these in use. Have you?