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A hand dryer is an
electric Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by ...
machine which might make use of a
heating element A heating element converts electrical energy into heat through the process of Joule heating. Electric current through the element encounters resistance, resulting in heating of the element. Unlike the Peltier effect, this process is indepen ...
and an air blower to dry the hands after
hand washing Hand washing (or handwashing), also known as hand hygiene, is the act of cleaning one's hands with soap or handwash and water to remove viruses/bacteria/microorganisms, dirt, grease, or other harmful and unwanted substances stuck to the hands ...
. It is commonly used in
public toilets A public toilet, restroom, public bathroom or washroom is a room or small building with toilets (or urinals) and sinks for use by the general public. The facilities are available to customers, travelers, employees of a business, school pupils ...
as a cost-effective alternative to
paper towel A paper towel is an absorbent, disposable towel made from paper. In Britain, paper towels for kitchen use are also known as kitchen rolls, kitchen paper, or kitchen towels. For home use, paper towels are usually sold in a roll of Perforation, pe ...
s. It may either operate with the push of a
button A button is a fastener that joins two pieces of fabric together by slipping through a loop or by sliding through a buttonhole. In modern clothing and fashion design, buttons are commonly made of plastic but also may be made of metal, wood, o ...
or automatically using a
sensor A sensor is a device that produces an output signal for the purpose of sensing a physical phenomenon. In the broadest definition, a sensor is a device, module, machine, or subsystem that detects events or changes in its environment and sends ...
.


History

The earliest hand dryer was patented on June 13, 1922 by R.B. Hibbard, D. J. Watrous and J.G. Bassett as a "Dryer Machine" for the Airdry Corporation of Groton New York. This machine was sold as a built in model or freestanding floor unit that consisted of an inverted blower (much like a handheld blow dryer) that was controlled by a floor pedal. Known as "Airdry The Electric Towel", these units were used in restrooms, barbershops and factories. Airdry Corporation moved to Chicago and San Francisco in 1924 to centralize their distribution. The hand dryer was later popularized in 1948 by George Clemens, who founded World Dryer and invented the Model A, World Dryer’s flagship model. In 1993,
Mitsubishi Electric , established on 15 January 1921, is a Japanese multinational electronics and electrical equipment manufacturing company headquartered in Tokyo, Japan. It is one of the core companies of Mitsubishi. The products from MELCO include elevators an ...
introduced a new type of hand dryer "Jet Towel"( :ja:ジェットタオル) that blows jets of air on both sides of the hand, pushing the water off rather than evaporating it.


Costs

Hand dryers have been popular with industries for their apparent economies. According to manufacturers, hand dryers can cut costs by as much as 99.5% (for example a company may spend $2340.00 per year on paper towels, where as the hand dryer expenditure would be as low as $14.00 per year - this will vary according to the cost of paper towels and electricity). They require very little maintenance compared to paper towels, which must be replaced. An added benefit is the removal of the paper waste. Hand dryers represent a larger initial investment, so those responsible for
facility management Facility management or facilities management (FM) is a professional management discipline focused on the efficient and effective delivery of logistics and other support services related to real property and buildings. It encompasses multiple disc ...
must do a careful cost analysis to determine whether they are cost effective in their building. Costs are always relative to the kWh cost that the facility is charged by its provider. In the UK, this will typically be around 10-12p, the only way to compare costs accurately is to work out the rated energy consumption and divide it by the number of drys the hand dryer is capable of performing back to back in 1 hour, this will give the energy consumption per dry. The world's lowest energy hand dryer uses just 1 watt-hour per dry and is rated at 0.24 kW.


Effect on environment

Due to the reduction in litter and waste in comparison with paper towels, which cannot be recycled, hand dryers are claimed to be better for the environment. By eliminating the need for paper towels, hand dryer manufacturers estimate that over 5 billion paper towels from over 200,000 trees per year can be saved. Another study shows that whereas the majority of the environmental impact of a hand dryer occurs during its use, the environmental impact of paper towels is predominantly in the material production and manufacturing stages. It is estimated that hand dryers use 5% less energy than paper towels in the first year, and 20% less over five years.The Straight Dope: What's better for the environment, electric hand dryers or paper towels?
/ref> A World Dryer study of 102 hand dryers installed in public schools in Topeka, Kansas, claimed an annual savings of 34.5 tons of solid waste, 690,000 gallons of water, and 587 trees; another World Dryer study of 153 hand dryers in the Iowa state capitol showed an annual savings of 10.5 tons of solid waste and 176 trees. However, a Dutch study published in March 1995 indicated that there was environmental parity between hand dryers and paper towels as hand drying methods when all factors were taken into consideration.


Hygiene and health

The World Health Organization (WHO) and the Centers for Disease Control and Prevention both stress the importance of frequent and thorough hand washing followed by their complete drying as a means to stop the spread of bacteria. Bacteria transmit more easily from wet skin than from dry skin. WHO recommends that everyone “frequently clean
heir Inheritance is the practice of receiving private property, titles, debts, entitlements, privileges, rights, and obligations upon the death of an individual. The rules of inheritance differ among societies and have changed over time. Offic ...
hands…” and “dry
hem A hem in sewing is a garment finishing method, where the edge of a piece of cloth is folded and sewn to prevent unravelling of the fabric and to adjust the length of the piece in garments, such as at the end of the sleeve or the bottom of the g ...
thoroughly by using paper towels or a warm air dryer.” The Centers for Disease Control and Prevention report that, “Both lean towels or air hand dryersare effective ways to dry hands.” A study in 2020 found that hand dryers and paper towels were both found to be equally hygienic hand-drying solutions. Other research suggests paper towels are much more hygienic than the electric hand dryers found in many
public toilets A public toilet, restroom, public bathroom or washroom is a room or small building with toilets (or urinals) and sinks for use by the general public. The facilities are available to customers, travelers, employees of a business, school pupils ...
. A review in 2012 concluded that "From a hygiene standpoint, paper towels are superior to air dryers; therefore, paper towels should be recommended for use in locations in which hygiene is paramount, such as hospitals and clinics." In 2008, a study was conducted by the University of Westminster, London, and sponsored by the paper-towel industry the European Tissue Symposium, to compare the levels of hygiene offered by paper towels, warm-air hand dryers and the more modern jet-air hand dryers. The key findings were: *After washing and drying hands with the warm-air dryer, the total number of bacteria was found to increase on average on the finger pads by 194% and on the palms by 254%. *Drying with the jet-air dryer resulted in an increase on average of the total number of bacteria on the finger pads by 42% and on the palms by 15%. *After washing and drying hands with a paper towel, the total number of bacteria was reduced on average on the finger pads by up to 76% and on the palms by up to 77%. The scientists also carried out tests to establish whether there was the potential for cross contamination of other public toilet users and the public toilet environment as a result of each type of drying method. They found that: *The jet-air dryer, which blows air out of the unit at claimed speeds of , was capable of blowing micro-organisms from the hands and the unit and potentially contaminating other users and the environment up to 2 metres away. *Use of a warm-air hand dryer spread micro-organisms up to 0.25 metres from the dryer. *Paper towels showed no significant spread of micro-organisms. In a study conducted by TÜV Produkt und Umwelt GmBH from May 2004 - February 2005, different hand drying methods were evaluated. The following changes in the bacterial count after drying the hands were observed: Another paper found that air dryers dispersed marker bacteria in a radius of three feet (one metre) and onto the investigator's
laboratory coat A white coat, also known as a laboratory coat or lab coat, is a knee-length overcoat or smock worn by professionals in the medical field or by those involved in laboratory work. The coat protects their street clothes and also serves as a simple ...
. Another study found that hot air dryers had the capacity to increase the bacterial count on the skin, and that paper towel drying decreased skin bacterial count. This is corroborated by another study which found that the mechanical action of paper towel drying removed bacteria, something air dryers cannot do. Doctors at the University of Ottawa claim that "the blowing of warm air may lead to an accelerated dehydration of the skin surface, thereby affecting the viability" of the microorganisms, and that the warm air may "penetrate all the crevices in the skin, whereas absorbent towels may not reach such areas, even though the skin appears dryer". The European Tissue Symposium, a trade body, has produced a position statement on the hygiene standards of different hand drying systems. This summarises some of the scientific research undertaken. Dyson (creators of the
Dyson Airblade Dyson Airblade is an electric hand dryer made by the Wiltshire, UK based company Dyson, found in public bathrooms across the United Kingdom. It was introduced in the United Kingdom in 2006 and in the United States in late 2007. In 2013 the Airbla ...
dryer) have countered the claims presented, suggesting that the results were intentionally falsified.


Noise

Many people object to the loud noise that hand dryers make. Typically, installed hand dryers make over 80
decibel The decibel (symbol: dB) is a relative unit of measurement equal to one tenth of a bel (B). It expresses the ratio of two values of a power or root-power quantity on a logarithmic scale. Two signals whose levels differ by one decibel have a ...
s of sound at a
distance Distance is a numerical or occasionally qualitative measurement of how far apart objects or points are. In physics or everyday usage, distance may refer to a physical length or an estimation based on other criteria (e.g. "two counties over"). ...
of while in operation. It is much louder for the user and may exceed safety limits for children whose ears are at the height of the device. Some units, however, are designed to be quieter at the cost of drying speed.


Reception

Research conducted in 2008 indicated that European consumers much prefer hand towels over hand dryers in public washrooms. 63% of respondents said paper towels were their preferred drying method, while just 28% preferred a hand dryer. Respondents overwhelmingly considered paper towels to offer faster hand drying than electric hand dryers (68% vs 14%). On the whole they also considered paper towels to be the most hygienic form of hand drying in public washrooms (53% vs 44%).Intermetra, June 2008 - User's preferences in hand drying systems
/ref>


See also

*
Towel A towel is a piece of absorbent cloth or paper used for drying or wiping a surface. Towels draw moisture through direct contact. In households, several types of towels are used, such as hand towels, bath towels, and kitchen towels. Paper towels ...
*
Paper towel A paper towel is an absorbent, disposable towel made from paper. In Britain, paper towels for kitchen use are also known as kitchen rolls, kitchen paper, or kitchen towels. For home use, paper towels are usually sold in a roll of Perforation, pe ...


References

{{DEFAULTSORT:Hand Dryer Public toilets Personal hygiene products forest conservation water conservation American inventions 20th-century inventions