Sustainable Hand Drying and Life-Cycle Assessment
Health, IEQ and Comfort
| Hand Dryers and the ADA |
| A few general rules for hand dryers are worth considering in the early phases of product selection. Automatic dryers with no-touch operation are ideal, according to P.B. Gast & Sons, a janitorial and maintenance services provider in Grand Rapids, Michigan. Otherwise, start buttons should protrude from the dryer in a contrasting color. They should be operable with one hand and with no more than 5 pounds of force. For a restroom with a single dryer, the appliance should be 38 to 40 inches above the finished floor, with a minimum of 30 by 48 inches of clear floor space centered on the unit, so that wheelchairs can approach easily from both the left and right sides. For a restroom where two or more dryers are installed, one dryer should be installed so that the start button is 38 to 40 inches above the finished floor; others may be positioned at 41 to 48 inces. Again, alternate the layout for left-handed and right-handed wheelchair approaches.11 |
Of course, there's more to sustainability than life-cycle performance based on resources consumed, greenhouse gases emitted, and total energy draw. Several of these are referenced in the NSF standard P335, while others require scrutiny by the project team or client group. These considerations relate to IEQ (indoor environmental quality), such as acoustics and indoor-air quality, as well as building resources such as maintenance energy and occupant productivity and health. Key examples include:
Acoustics. Electric products make mechanical noise, of course, as opposed to a simple C-fold towel dispenser. The NSF P335 establishes a maximum decibel (dBA) rating, which some electric dryers meet. Are all high-speed air dryers noisier than conventional warm-air dryers? No, says a survey conducted by Acentech and published by the Acoustical Society of America. The report shows that some electric dryers have a dBA of about 84, well within the NSF protocol values. The reported that sound levels from other high-speed dryers are about 30 to 50 percent louder than the older models. Placing a user's hands within a high-speed air stream may create higher sound levels in some dryer models, with values varying between 95 dBA and 100 dBA. Special noise-reduction nozzles are available to cut noise up to about half, but those can increase the dry time by 2 or 3 seconds, changing their energy use and GWP.
ADA and adaptive, universal design. Restroom designs have changed fundamentally since the Americans with Disabilities Act (ADA) became law in 1990. Today, there is a movement to include more aspects of accessible and universal design into green building standards. The ADA was amended in 2008 and 2010 with important rules for hand dryers and towel dispensers; for example, ADA-compliant dryers may not protrude from the wall more than 4 inches. In general, mounting heights should present the device's operating features between 38 inches and 48 inches above the finished floor to allow forward reach by people in wheelchairs, where the nozzle is on the underside of the dryer. It's different for hands-in models: Hands-in type dryers must be installed with the bottom edge not higher than 27 inches off the ground to meet the ADA's cane detection requirement. As a side note, some designers and end-users have praised the hands-in dryers because they eliminate water being blown off hands and onto the wheelchair user.
| Tracking a Key Dryer Standard |
In 2007, NSF International developed a protocol that provides for evaluation and testing of commercial hand dryers. According to HIS Inc., the standard was developed to certify that commercial electric dryers actually dry the users’ hands hygienically. At the time, NSF sought to address the reasons behind the user preference for paper towels. The main reasons? About 70 percent said they take too long to dry hands, and about half said the appliances don’t dry hands Today, the protocol NSF P335 - Hygienic Commercial Hand Dryers, is seen as a useful public measure for the health and sanitary value of hand dryers. Among the primary definitions of “hygienic hand drying” are:
If the hand dryer meets these requirements, they qualify to have the circular NSF logo visible on the appliance body or nameplate. Later, NSF International announced compliant and certified dryers meeting NSF P335. The first company to be granted use of the NSF mark was Dyson Ltd., a U.K. manufacturer with a certified product.
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To maintain the certification, qualifying manufacturers must be audited and participate in product testing. User comfort and ergonomics. Beyond the prescriptive ADA rules, sustainable design values user comfort and good ergonomics as part of high-performance facility. With the 2009 version of LEED, the U.S. Green Building Council introduced a possible ergonomiccredit for existing and new work spaces through the Innovation in Design Process category. By definition, this should include restroom design considerations, as LEED extends the credit for “a comprehensive ergonomics strategy that will have a positive impact on human health and comfort when performing daily activity for at least 75 percent of Full Time Equivalent building users.”12
Personal hygiene and public health. Some studies have compared the hygiene benefits of drying methods on individual subjects or larger end-user populations. High-speed dryers using HEPA filtration are shown to capture at least 99.97 percent of bacteria from the air drying hands, which the NSF protocol uses to define “hygienic.” Studies by independent groups offer varied insights: One by the Bradford University Infection Group published in the Journal of Applied Microbiology concludes that microbial counts on hands decrease when dried properly, and that hands-in, high-speed dryers with HEPA filtration are the most hygienic electric types. Another study by the University of Westminster13 measured bacteria counts near and within about 6 feet of dryers and towel dispensers; electric dryers were shown to move bacteria longer distances. Related hygiene concerns include the issues of messiness from paper towels, both perceived (overflowing trash bins) and real (disease transmission due to user behaviors).
Maintenance and operations. Various considerations affecting the client's satisfaction with restroom performance also link to sustainability measures. Among the most important is energy use, which affects facility ROI as well as its meeting the Energy & Atmosphere (EA) credits for energy performance. In addition, the Materials & Resources (MR) credits reward the sensible purchasing of “ongoing consumables” (MR Credits 1.1 - 1.3) and proper waste management (MR Credits 7.1 – 7.2).
Beyond these impacts on building occupants listed here, there are more that depend on the user base and the objectives of the architect and client. The most important consideration may be that the restroom is full of environmental implications. One of the most important to consider is the choice of a hand dryer versus a paper towel dispenser. Others include day-to-day maintenance concerns, such as the frustrations faced by facility managers who see their low-flow toilets clogged by paper towels. By eliminating hard-to-flush paper, the buildings reduce water use better and solve such operational headaches.
Equipment seems to take the brunt of the concern, when the data clearly show that paper manufacture and waste can be the most environmentally damaging of any restroom challenge. Coverage in the media and information from manufacturers with a vested interest in the topic may not always provide adequate guidance. However a rigorous analysis of the existing data in recently published LCAs can help point to a better way to operate America's 20 million away-from-home restrooms.
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Dyson is about developing new technology and making things work better. Environmentally responsible engineering is efficient engineering. Doing more with less. Creating machines that consume less energy and are made of fewer raw materials, but are better performing. Their function-led approach to design supports this aim. www.dysonairblade.com |
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