27th May 2019

The Paper Towel Versus Hand Dryer Germ Debate (Part Three)

Part Three:

This article finalises our three-part investigation into the germ debate between paper towels and hand dryers.

To go back and read the first parts choose Are Hand Dryers Hygienic? (part 1) or Are Hand Dryers Hygienic? (part 2)

How does the number of bacteria found on everyday equipment measure up to that found on petri dishes?

At the office

Another thing to consider when looking at research regarding hand dryers is that the amount of bacteria found were so significantly less than everyday items, such as those found in the office we come into regular contact with.

Millions of bacteria per square millimeter are found on everyday items.

To put this in perspective, research by EMLab P&K, highlighted by CBT Nuggets found that there are:

4,620,000 bacteria units per square inch on an ID badge
3,543,000 bacteria units per square inch on an office keyboard
1,600,082 bacteria units per square inch on a mobile phone

Out of this, 42% were bacteria that cause strep and staph infections and 21% were bacteria resistant to antibiotics, whose group includes MRSA.

Interestingly, in the section “Should you believe everything you read about hand dryers and germs?” the study looked at germs in a hospital visitor's toilet. The samples were selective and its sample size was 15.5 square inch with an average of just 163 bacteria units around hand dryer and floor.

It was a bigger sample area, with significantly fewer bacteria than the everyday office equipment.

University computer keyboards

Study: Microbial contamination of computer keyboards in a university setting

“Overall, a greater number of microorganisms was detected on the keyboards of the multiple-user computers, with an average of 20.1 colonies per square centimeters, whereas the single-user keyboards had an average of 4.5 colonies per square centimeters.

Forty-seven percent of multiple-user keyboards were found to harbor Staphylococcus aureus, compared with only 20% of the single-user keyboards.

Of particular interest was the isolation of bacteria belonging to of the Enterobactericeae family, including Escherichia coli from one keyboard, as well as Enterococcus faecalis, which is indicative of fecal contamination.

Conclusion: In summary, this study has demonstrated that microbial contamination of multiple-user computer keyboards may be a common mechanism of transfer of potentially pathogenic bacteria among users.”

Student mobile phones

Study: High level bacterial contamination of secondary school students’ mobile phones

Results “found a high median bacterial count on secondary school students’ mobile phones (10.5 CFU/cm2). Potentially pathogenic microbes (Staphylococcus aureus, Acinetobacter spp., Pseudomonas spp., Bacillus cereus and Neisseria flavescens) were found”

Fact: The most important aspect of hand hygiene is actually washing the hands in the right manner, for the correct duration. This ensures germs are actually removed from the hands using the best substances for the job, soap and water.

Then ensuring that the hands become completely dry, whatever the method of drying is the next essential step.

This is so you don’t leave your hands open to pathogens that thrive on wet environments as you leave the washroom and on other equipment you come into contact with.

The history of hand dryer hygiene

Below is a summary of the historical timeline of how hand dryers have developed their hygienic properties:

Commercial, warm air hand dryers were under constant testing as it is thought they were a breeding ground for bacteria
High speed hand dryers were introduced, without heater elements, which are quicker at drying hands, therefore diminishing wet hands (the breading ground of germs). Antimicrobial materials were also used in the making of the hand dryers
The HEPA filter was invented, which filtered the air being sucked into the hand dryer of dirt and bacteria, making sure clean air is blown over the hands
New technology has been added to the HEPA filtered hand dryer to actively clean the filter. It is noted that if a HEPA filter is not maintained and serviced regularly, dirt can build up and render the filter ineffective.
We are currently looking at a number of new technologies that specifically draw the air from a sterilised source.

The Advances in Hand Dryer Technology

It is important when answering a question like “Are Hand Dryers Hygienic?” to make the distinction between traditional commercial hand dryers and the new energy efficient hand dryers.

Also, within the new breed there is the distinction between blade hand dryers, hybrid hand dryers and hands under hand dryers.

Traditional commercial hot air hand dryers

These are the type of hand dryers that typically have a motor with an RPM (revolutions per minute) of between 2000 and 7500.

The airflow is a vehicle for warm air to be passed over the hands, thus evaporating the moisture. These types of hand dryers typically have a dry time of between 20 and 50 seconds.

The paper towel industry argues that hand dryers were unhygienic as they essentially suck in dust and dirt, are not regularly cleaned inside and then heat up bacteria and blow it onto the users’ hands.

There have been many studies into this, although the extent of bacteria protection has varied considerably depending on who commissioned the test.

There were also counter studies that showed if the airflow was heated enough, this was enough to kill the bacteria rather than multiply it.

The other argument was that hand dryers were ineffective and therefore the user didn’t tend to dry their hands completely.

This again was true and wet hands have been demonstrated to carry more pathogens than dry hands.

All in all, traditional hand dryers were cheaper, more eco-friendly, required less servicing and kept washrooms tidier, but certainly were not as effective or hygiene.

The new breed of hand dryers

One type of new dryer is the high-speed version. Hands are dried on air speed, instead of heat. The first of these was the Xlerator.

Then came the Airforce hand dryer from World Dryer. This had no heater element and had antibacterial plastics and a filter to prevent the unit from clogging up with dirt.

Even earlier, Mitsubishi Electric launched a completely new concept ‘the blade hand dryer’ called the Jet Towel.

The Jet Towel was available in a non-heated version and dust and dirt was filtered creating a cleaner dry.

Dyson developed and marketed their own clean air, high-speed hand dryer, the Airblade, which gained NSF approval. The Mitsubishi Electric Jet Towel Slim and Jet Towel Smart are now both NSF certified. They also have an antibacterial resin injected into their plastic parts.

Other hand dryer manufacturers have incorporated HEPA filters and antibacterial surface protection and some have even innovated further.

The issue is that not many hand dryer manufacturers can afford to pay the large NSF fees to officially get tested and certified with NSF. We believe a similar, more affordable approval needs to become available.

You can see that modern hand dryers have come a long way from the dirty, unhygienic warm air versions.

Hand dryers are now hygienic, fast-drying, environmentally friendly and help maintain cleaner facilities.

In summary

Modern hand dryers and paper towels are a very effective way of drying hands. This is a vital part of hand hygiene as wet hands are a perfect breeding ground to pick up bacteria from surfaces, doors, office equipment etc.

The method of choice should be determined by noise level, energy efficiency and cost. The modern hand dryer can provide substantial environmental improvements and cost savings.

Because of the concerns, paper towel manufacturers have about the increased use of hand dryers, some scientific studies were commissioned to put some doubt in the public regarding the hygiene aspect of hand dryers.
The scientific literature varies in its conclusions, sometimes dependent upon who commissioned the study. Those that state there are concerns with hand dryer hygiene look to have used biased methodology and the interpretation of results are sometimes biased towards promoting paper towel hygiene above hand dryer hygiene.

The media have been fed these poorly constructed and biasedly interpreted studies and written scaremongering headlines to entice the reader and influence public opinion. Most of the articles concluded that there is nothing to worry about and that any bacteria found is harmless.

Paper towels and their dispensers are not free from bacteria, proven by the scientific literature. As per hand dryers, these pose no threat to public health.
Bacteria is all around us, including potential pathogens. These live in their millions in very small areas on some surfaces. A healthy immune system is more than capable of dealing with these.
Hand dryers now include HEPA filters and antibacterial resin in their materials. This is to enhance the hygiene of a washroom, not to correct public health issues that the media would have you believe. The hand dryer is a hygienic piece of equipment and the extra innovations enhance this.
The key message for hand hygiene is to make sure the hands are correctly washed and then thoroughly dried, whatever the method of choice.

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For more information or for help in finding your ideal hand dryer, please call us on 1300 HANDRY or (+61) 1300 426 379, use our contact us page or email us at info@intelligenthanddryers.com.au.

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Are Hand Dryers Hygienic? (Part 3)