Hand drying is more important than you’d think
We all know how important it is to wash our hands.
But what most of us don’t know is wet hands are more likely to spread bacteria than dry hands. That’s what this Mayo Foundation for Medical Education and Research paper opened with in 2012. ‘The transmission of bacteria is more likely to occur from wet skin than from dry skin’ were the article’s first 15 words – and the paper was a review of 12 other papers on hand drying, so you’d like to think the researchers were well informed.
It’s something worth bearing in mind. We’ve all been guilty of lathering up, scrubbing away, rinsing… and then walking off with dripping wet hands. It’s an innocent blunder. But it’s one that spreads germs and infection.
5 methods of hand drying
Wet hands are more likely to spread diseases. So the traditional shaking-off of excess water, or even the 5-second-trouser-rub, isn’t advised.
Particularly in areas where germs can spread quickly and become dangerous – think schools, restaurants, bars and hospitals – proper hand drying is important.
There are now more than a few methods available.
- Initially, shaking and waving were the only options
- Then came paper towels
- Paper towels were closely followed by rolling cloth (the tea towel-like cloth that loops back on itself)
- The first hot air hand dryers were a real breakthrough
- Most recently, the introduction of high speed hand dryers and blade hand dryers have cut hand drying times considerably... and are greener as a result
Each hand drying method has its own merits and drawbacks – some more so than others. So the real question is: given all available hand drying methods, which is the best way to dry your hands?
Shaking and waving
Shaking dry was the only hand drying option when washing hands was first popularised. Before the likes of Ignaz Semmelweis championed hand-washing, doctors were known to perform surgeries after autopsies without washing their hands in between.
Semmelweis (and others like him) had a hard time convincing the world of the benefits of washing hands, let alone drying them.
Today, just as a small handful of people exit public bathrooms without washing their hands, some people exit public bathrooms with dripping digits. They are the shakers and wavers. The drip-dryers. The dissidents.
The advantages of shaking dry
On the plus side, when relying on nature to dry your hands, you don’t necessarily need to touch anything. Bathroom surfaces often harbour pathogens and bacteria. Limiting what you touch in a public bathroom is a good idea.
Shaking and waving means you don’t need to touch anything – and are less likely to pick up bacteria from tainted bathroom surfaces as a result.
The disadvantages of shaking dry
But the minuses outweigh the plusses.
Wet hands pass on bacteria. This is common knowledge in the hygiene industry, but the University of Auckland’s Department of Medicine offer conclusive research on the subject nonetheless. Here’s an excerpt from one of their papers:
‘When samples of skin, food and utilities were touched with wet, undried hands, microbial numbers in the order of 68000, 31000 and 1900 respectively translocated to these representative surfaces... A 10 s cloth towel-20 s air towel protocol reduced the bacterial numbers translocating to skin, food and utilities on touch contact to 140, 655 and 28 respectively and achieved a 99.8, 94 and 99% reduction in the level of bacterial translocation associated with wet hands.’
In human-speak, the above simply says touching things like food or other people passes on more bacteria when hands are wet than when hands are dry. Shaking and waving leaves hands wet for longer.
When it comes to hygiene, shaking and waving is a poor method of hand drying.
The humble paper towel, easily one of the least technologically advanced hand drying methods, is still in use today. And it’s surprisingly effective.
The advantages of drying hands with paper towels
The big advantage here is speed. Users can dry their hands very quickly with paper towels, often while on the move.
Some researchers speculate that the friction paper towels generate helps to remove bacteria, but the academic world is divided on the subject.
The disadvantages of drying hands with paper towels
Hygiene-wise, paper towels do a good job of removing bacteria from hands. But they don’t kill bacteria. They just transfer it from hands onto a towel. And where do the towels end up?
In the best case scenario, they’ll end up in a sealed bin, in which a mountain of pathogens will get to know each other. Ideally, bins will be emptied quickly by attentive staff – but that’s not always what happens. And that’s the best case scenario.
Worst case? They end up on the floor, or in unwitting users’ pockets like some sort of inadvertent chemical weapon, safely tucked away for unleashing on demand.
Two further drawbacks of paper towels are both their cost and their carbon footprint. In a 2009 food safety bulletin by HACCP Australia, amenities manager Simon Evans is quoted as saying ‘using paper towels was costing £18,000 per annum’. It’s a big expense. And then there’s the environmental impact.
‘571,230,000 pounds of paper towels are used by Americans every year’ says Joe Smith at the beginning of his TedX talk on the subject. And then he corrects himself – to say the number is actually 13 billion.
In pretty much every case (reports Slate’s The Green Lantern) electric dryers are greener than paper towels.
Rolling cloth is perhaps the rarest seen hand drying method these days. It’s similar to drying with paper towels – only the cloth is reusable. Users tug a length of cloth free from its casing and, in doing so, feed some of the cloth back into its casing. They then use the newly exposed cloth to dry their hands.
The advantages of rolling cloth
As is the case with paper towels, hand drying with rolling cloth is quick. Rolling cloth can dry hands in just a few short seconds. It requires no electricity and is easy to fit.
The disadvantages of rolling cloth
The disadvantages of rolling cloth probably explain why they’re so rarely used in hand drying these days. The big disadvantage is simply maintenance. For rolling cloth to remain hygienic, the cloth usually needs to be cleaned multiple times a day. As anyone who has ever used rolling cloth (or, more likely decided against using rolling cloth when confronted with the option) will testify, these things are rarely cleaned as frequently as required.
That then means they’re not only storing bacteria, but often passing bacteria on to the brave people who use them.
It’s difficult to say which is worse: rolling cloth or shaking and waving. Both can be concerning when it comes to hygiene.
Hot air hand dryers
Hot air hand dryers are the hand dryers that seem to plod along at their own pace. Compared to high speed hand dryers, they’re in no real hurry to rid hands of moisture. Instead, work through evaporation: they heat excess water so excess water evaporates from hands.
The advantages of hot air hand dryers
Hot air hand dryers are more effective than shaking. In fact, when used correctly, they can dry hands just as well as paper towels. Plus, with innovations like automatic sensors, you don’t actually need to touch any bathroom surfaces to use them. The drawbacks?
And the drawbacks...
The primary drawback of hot air hand dryers is that people rarely use them correctly. These machines take around 45 seconds to dry hands effectively. To put that into context, researchers once studied how long people typically spend on hand drying.
Males, they found, spent just 17 seconds using hot air hand dryers. Females? 13.3 seconds.
In both cases, it’s a safe bet people were walking away from restrooms with wet hands – and passing pathogens on to whatever they then touched.
High speed hand dryers and blade hand dryers
When it comes to hand drying, high speed and blade hand dryers are the latest innovations on the market. The Kangarillo 2 is a good example of a high speed hand dryer – its air speeds top 245mph, about 110m/s.
Blade hand dryers such as the Gorillo Pro use similar technology but go further. Blades treat hands with a concentrated ‘blade’ of air that whips away moisture. Instead of relying solely on evaporation, the innovations blast moisture from the skin.
The advantages of high speed hand dryers
High speed hand dryers have been built to overcome the problems associated with traditional methods of hand drying. The biggest advantage is probably speed – the latest models can dry hands in as little as 8 seconds.
Automatic sensors mean you don’t need to touch anything to activate them.
At the very cutting edge of hand drying lies the Sterillo, the only hand dryer that pro-actively removes germs and even unpleasant smells from bathrooms.
And, because they work so quickly, they’re both more economical and greener than non high speed counterparts.
The disadvantages of high speed hand dryers
Some studies suggest high speed hand dryers shoot germs into the air, although the validity of such claims has been questioned. Blade hand dryers that actively collect the water they blast from hands are designed to combat such problems (again, look at the Gorillo Pro’s smart mechanisms for an example).
The best method of hand drying available today
All things considered, when it comes to hand drying, we’d recommend using a high speed or blade hand dryer to do so.
The combination of quick drying speeds, hygiene, low running costs, low maintenance costs and a reduced carbon footprint make today’s high speed hand dryers (and the high speed blades), in our opinion, the best choice. Of course, in public washrooms, you don’t always have the choice.
If you do find yourself faced with a hot air hand dryer, be sure to use it for the requisite 45-or-so seconds it takes to dry your hands.
And if you have the option of paper towels?
The hand dryer is probably better for the planet. But, if it’s a choice between paper towels and shaking dry, then pick up the paper.
Wet hands are like a public bus for bad bacteria. Germs and pathogens happily ride along.
Hand drying is an important and overlooked step in personal hygiene. Whatever it takes, get those hands dry!