FEATURE PAPER OR PLASTIC?
New research looking into hand hygiene and the optimal drying methods has reignited the age old debate of paper towels or automatic hand dryers. Keen to find out more, Tomorrow’s Cleaning Editor Matt Waring talked to the man behind the latest study, Keith Redway of the University of Westminster, to find out more.
Little over a year ago, I found myself caught in the middle of a conflict between the European Tissue Symposium (ETS) and Dyson. The creators of the Airblade jet air hand dryers were fairly miffed with some research funded by the ETS that examined the various ways in which people dry their hands in the washroom, and the risks associated with said methods.
The initial research, conducted by Professor Mark Wilcox at the University of Leeds, found that jet air dryers, and to a lesser extent warm air dryers, spread more germs and bacteria around a washroom than their paper counterparts, thus increasing the risk of infection or contamination, particularly in delicate environments such as hospitals, food preparation areas and care homes, where the presence of germs is highly undesirable.
This study came under a lot of criticism from those in the jet air dryer market, with some standout arguments claiming that the research was ‘really targeted’, ‘full of holes’ and ‘looking to prove something’. These claims were only exacerbated by the fact that the research was funded by the ETS itself, which some claimed only added to the ‘targeted’ approach.
However, this year, some new, independent research, conducted by microbiologists Keith Redway and Dr. Patrick Kimmitt at the University of Westminster, added further credence to the growing school of thought that suggests paper towels are the most hygienic and effective hand-drying method in washrooms, particularly when it comes to minimising the spread of viruses.
With Keith Redway in attendance at last month’s ISSA/Interclean show in Amsterdam to present his findings in a special talk entitled ‘Washroom
54 | Tomorrow’s Cleaning June 2016
Hygiene: The dispersal of viruses by different hand-drying methods’, we saw it as the perfect opportunity to catch up with him and find out just what this latest study shows.
Keith is something of an authority on the subject of research into washroom hygiene practices, having conducted several studies dating back to 1984 at the University of Westminster, where he worked as a medical microbiologist and is currently an ‘emeritus fellow’. These studies have ranged from examining the various hand drying methods (as with the latest research), to more observational examinations, looking at washroom behaviour in general.
And throughout his studies, Keith has noticed a consistent trend in his findings. “I’d say in every study we’ve done, every test – with colleagues, not just me alone – paper or textile towels have always come out the best.”
Keith worked with Mark Wilcox and the team at the University of Leeds during the 2015 study, which used lemon juice and yeast as markers to measure the dispersal of liquids and bacteria using the three main drying methods, and they found that, particularly with people who didn’t wash their hands properly, there was a larger risk of bacteria and water being spread across the washroom with the powerful jet air dryers, in no small part due to the air speeds at which they operate.
Following on from the 2015 study, Keith and his team at the University of Westminster set up a new study looking at how the drying systems affected the spread of viruses. In this case, a harmless virus was used, but as Keith explained: “it was a model to demonstrate the potential of different hand drying devices to disperse viruses on the hands into the air, and to see how far it is spread.”
And the results were quite illuminating. “When we looked at how far the viruses travel, with the yeast model we picked it up one and a half metres away, but a virus model is more sensitive, so we were picking it up three metres away, which is quite a distance. This was a lot more with a jet air dryer than a warm air dryer, and unsurprisingly because there is less air disturbance, paper performed a lot better.
“We also looked at dispersal at different heights, and for this we had a figure board, split into different height zones, which was 0.4 metres away from the different dryers, which is the average figure in some public toilets in London when they’ve got banks for them. So what we were illustrating is how much viral contamination we’re going to pick up if you’re standing near one of them when someone else is using them.
“We found that the highest concentration of contamination, particularly with the jet air dryers, was in the middle region, between 0.6 and 1.2 metres, and one of the slightly worrying things about this is that is about the height of a child when they’re standing next to it with their parents, so it’d blow straight into their face. And this risk is increased if they haven’t washed their hands properly if they’re in a rush.”
The final aspect of the study was to test how long the viruses remained in the air after drying took place. Again, the results were particularly eye-opening, as Keith explained: “We sampled the air over a 15-minute period after it had been used to find out how much virus was still in the air, and with jet air dryers, obviously it drops off, but there is still a significant amount in the air, even after 15 minutes.
“So that means if someone hadn’t washed their hands properly and they’ve got norovirus on them, or rotovirus, or if there is an influenza
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