Hands Up, or Hands Down?

There is more to effective restroom design and user-friendliness, including opportunities for better ergonomics based on advances in accessory and fixture designs. The recent introduction of products such as hand dryers that allow for a hands-down positioning, for example, opens the door to several advantages in user comfort and experience.

Traditionally, electric warm-air and high-velocity hand dryers are wall-hung units that blow down on the user's hands. These appliances can be mounted at a variety of heights, so the user's hands are at approximately shoulder height or at or below waist height, or at a position somewhere in between. Novel air-knife product designs, however, allow the user to put their hands over and into a visually defined hand-drying zone. The accessory is designed to allow for water to move downward on the hands, and the air-knife has the “scraping” action that moves water in addition to the typical evaporative effect.

Other ergonomic concepts include high-speed units that allow for horizontal hand insertion, where air blows down and back from vents on two sides. It mimics the position used for handwashing. This can be a comfortable position for a majority of the population, who can dry hands without bending over or bending their knees. However the design must consider the needs of wheelchair users, younger users and other special-needs occupants, who may need or prefer a lower mounting height.

Hand positioning and the direction of air movement are considered in this combined hand-washing and -drying system. The washing and drying zone is visually defined, and water is pushed downward on the hands via a “scraping” effect of the air-knife output in addition to the typical evaporative effect. Image courtesy of Dyson Inc.

Following on this notion of mimicking handwashing is the recently introduced combination hand dryer and touchless water faucet, where the accommodations for user's sink and drying needs are integrated in one system. In this case, excess water drips into the sink. In terms of resources, the pairing of two needs provides a one-to-one supply—every sink has a dryer—so redundancy is not an issue of user-friendliness. The concept also provides immediate access and reduces required user movements, which is a benefit for mobility-impaired users. The idea also improves hygiene in a number of ways; the most obvious example is that a wheelchair user will not have to touch his or her wheel handrails between washing and drying.

This concept meets several tests of user-friendliness as outlined above: Access, proper height, redundancy and standardization, as well as reducing required user movement. In terms of visibility, the system design must make it clear that it performs the dual function. The solution in some cases is to automate the function using hands-free sensor technology. This allows the user to have a single-location, hands-free washing experience: a sensor faucet and automatic soap dispenser, for example, followed by immediate warm air operation in the same target area as the washing.

Acoustics and Other Factors

There are other usability and comfort issues that impact user-friendliness and positive restroom experience that go beyond the physical and cognitive dimensions of ergonomics. One is the design effectiveness of restroom accessories, hardware and fixtures, which vary widely in terms of quality, value, cost-benefit, and life-cycle performance. Field experience often informs the procurement practices of many commercial and institutional end-users. Architects can supplement these practices with a thorough analysis of key accessory design variables.

One of those is accessory acoustics. In general, noise levels in restrooms have increased over the last decades, with more powerful exhaust fans, flush valves, hand dryers, and even seemingly innocuous features, such as roll towel dispenser levers, faucet aerators, and automatic soap dispenser pumps. The cumulative noise in a restroom with multiple users can detract considerably from user enjoyment—and the likelihood of proper hygiene. Yet in many codes and standards, restrooms are dismissed as “acoustically insensitive” environments.

At the same time, acoustic comfort is an IEQ issue and a LEED credit in some situations. It is also recognized as a serious consideration in all types of facilities, and potentially a code issue or health concern when very-high-frequency or loud electrical equipment is used. Clearly, says one maker of acoustical surfacing products, “Architectural design and building acoustics have a significant correlation when it comes to human satisfaction, learning, and productivity … and all factors of acoustics that should be considered in architectural design.”⁸

For the special case of high-speed hand dryers, studies of acoustics have shown that the “acoustic readings of high-speed hand dryers can be akin to the noise of a road drill at close range,” says John Levack Drever, a faculty member at Goldsmiths, University of London, and author of Sanitary Ambiance: The Noise Effects of High-Speed Hand Dryers.⁹ The noise is invasive and an annoyance—a technical term the World Health Organization says has direct effects on various activities, including “interference with conversation, mental concentration, rest or recreation.”¹⁰ There are other more pernicious effects, says Drever, for the elderly, dementia sufferers, the visually and hearing impaired, and children with autism spectrum disorders. Users with misaphonia and hyperacusis have heightened sensitivity to sounds in certain frequencies; for them exposure can be painful.