Hand dryer
A hand dryer is an appliance for drying the hands after hand washing. It is mostly used in public toilets .
variants
Traditional hand dryers work with a hot air blower and cause the moisture on the hands to evaporate . They are also called warm air hand dryers. It takes about 45 seconds for 90% of the moisture to evaporate.
Jet hand dryers are equipped with a powerful fan (mostly cold air) that blow the water off the hands and evaporate the remaining moisture. The drying time can thus be reduced to around ten seconds.
hygiene
A 2015 study by a research team led by microbiologist Keith Redway from the University of Westminster on behalf of the Association of Pulp Manufacturers (ETS) found that jet hand dryers spread “microdroplets” over a distance of up to 1.5 meters around the device. In addition, in a series of tests with yeast (which artificially contaminated the hands of the test subjects) with the jet hand dryer, an average of 67 yeast colonies were found at a distance of 20 cm from the device, compared to 6.5 when using paper towels. Another study comes to similar results.
The sucked in air must be filtered , otherwise pathogens and bacteria from the ambient air will be brought onto the hands.
Web links
- Konrad Lischka: Technology annoyance hand dryers - And the finger dryer rushes forever , Spiegel Online, October 9, 2008.
Individual evidence
- ^ European Tissue Symposium (ETS): A comparative study of three different hand drying methods: paper towel, warm air dryer, jet air dryer. Keith Redway & Shameem Fawdar, University of Westminster, November 2008.
- ↑ Roberto Berardi, Chairman of the ETS, on the risks of hand washing: “The microdrops are the problem” , Reinigungs Markt, 8/2015, pp. 14-15.
- ↑ University of Westminster study identifies single use towels as most hygienic way to dry hands. University of Westminster, News, April 8, 2015.
- ↑ Spektrum der Wissenschaft 2/2015, " Warm-air hand dryers are bacteria centrifuges ", p. 7 with reference to EL Best, P. Parnell, MH Wilcox " Microbiological comparison of hand-drying methods: the potential for contamination of the environment, user, and bystander "in Journal of Hospital Infection, December 2014, Volume 88, Issue 4, Pages 199-206
- ↑ Hartig / Zenner: Comment on meat hygiene law, 1991, page 39