Sustainable Hand Drying and Life-Cycle Assessment

Innovative product designs boost building life cycle
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In the public sector, there are few guidelines to help specifiers. Equipment in many buildings can have U.S. EPA Energy Star ratings, but not hand dryers. In 2010, the short-term project funding through the American Recovery and Reinvestment Act (ARRA) stated an official federal preference for procuring products verified to be at least 25 percent more energy efficient than typical or alternative specifications.

In addition, the health impacts of various hand-drying methods are poorly understood and often left to an architect's personal preferences—a weak way to extrapolate against the diverse user bases in university buildings, hospitals or a baseball stadium. One challenge is that Ann Arbor, Michigan-based standards organization NSF International, The Public Health and Safety Company (formerly known as the National Sanitation Foundation), provides only limited standards guidance for hand dryers. One valuable but narrow standard is the protocol NSF P335 – Hygienic Commercial Hand Dryers. (See “A Key Dryer Standard.”2)

Still, linking hand dryer performance to user effectiveness, energy efficiency, acoustical comfort, and even public health is left largely to the architect to determine.

For example, the amount of time it takes for the appliance to dry the user's hands has a useful NSF benchmark: If it takes less than 15 seconds using air filtered by high-efficiency particle arrestor (HEPA) media, the product may qualify to bear the NSF seal. Yet the definition of what “dry” means is inconveniently left open. So while some manufacturers agree that “dry” means a measure of 0.1 grams of water total remaining on the user's hands, which is used for the P335 Protocol, this is by no means a universal assumption—which can make some LCA studies hard to compare. (See sidebar on the next page.)

Ergonomics and user-friendliness are important considerations in restroom design, as is the usability of the hand-drying method by people in wheelchairs.

Photo © Bruce Damonte

 

Another challenge is that ergonomics and user-friendliness are not fully assessed by the protocol. In addition to speed of drying, the standard P335 considers the cleanability of the appliance, noise levels while operating, resistance to causing user burns, water disinfection capability, and whether or not the product allows for hands-free operation.

It's a good checklist, but it leaves out usability by people in wheelchairs, for example, or the discomfort associated with product use by seniors. With about 35 million U.S. citizens over aged 65 or over and with 54.5 million that have some disability, according to Boston's Institute for Human Centered Design (IHCD)—and with future LEED versions to include universal design such as the recent Pilot Credit 34, Design for Adaptability—the notion of user-friendliness has become central to green design as well as public Health, Safety and Welfare (HSW).

Most important, the protocol is all about hygiene. NSF P335 is not designed to present comparative data on using hand dryers—hygienic or not—over paper towels. Put simply, the protocol won't give a life-cycle argument for the environmental benefits of the selection.

LCA Studies for Hand Drying

“In the absence of comparable, full data informing our selection of a building material or appliance, we like to see thorough life-cycle assessments that help us and our clients understand any long-term environmental gains possible through our design choices,” says Jay Brotman, AIA, LEED AP, a partner with New Haven, Conn.-based architecture and art firm, Svigals + Partners. Fortunately, LCA studies have been undertaken for this product category—in the MasterFormat division 10 2000, Interior Specialties, under 10 28 40 for hand dryers as well as for alternatives including paper towel and cotton roll towels. However, the assessments start with different assumptions so architects can't easily compare the results apples-to-apples. Some LCA results only compare standard warm-air dryers to paper towels or one electric dryer type against another, while other studies only assessed cotton roll towels vs paper towels.

A number of the studies comply with an accepted standard for life-cycle assessments, such as the International Organization for Standardization's ISO 14040 and 14044 LCA standards, but most do not. Examples of those adhering to the ISO standards include an analysis of cloth and paper towels by a European textile trade group, a study of various folded and roll towel products for the paper producer Kimberly-Clark, and LCAs of multiple or single electric dryers by their respective manufacturers.

With all these life-cycle studies on the market, how can architects glean useful, equivalent data for making a good choice and specification?

One recent meta-study by a Boston-area research university has put all these LCA studies side by side, using ISO-based LCA methods to ensure a consistent basis of comparison. According to the authors of the mid-2011 analysis, titled Life-Cycle Assessment of Hand-Drying Systems,3 four steps were needed to compile and evaluate all of the industry data:

  1. Establish the “functional unit under consideration, and regional and temporal boundaries of the assessment.” In this case, the functional unit is a single pair of dry hands.
  2. Undertake an inventory analysis, which “entails the quantification of energy, water, and material resource requirements, and emissions to air, land, and water for all unit processes within the life cycle.”
  3. Assess impacts to understand “the human and ecological effects of the resource consumption and emissions to the environment associated with the life cycle.”
  4. Interpret the results “within the context of the limitations, uncertainty, and assumptions in the inventory data and scope.”

The research team at the Cambridge, Mass.-based Materials Systems Laboratory (MSL) recorded, interpreted and compared data for seven hand-drying systems: cotton roll towels; virgin content paper towels; 100 percent recycled paper towels; a typical warm-air, hands-under electric dryer; a high-speed, hands-under dryer; and two high-speed, hands-in dryers, one in a plastic finish and the other in an aluminum housing.

Cambridge, Mass.-based Materials Systems Laboratory has compared data for seven hand-drying systems. One of the comparisons is based on GWP, or global warming potential, based on CO2 equivalents required for each option.

Source: Materials Systems Laboratory

Using LCA for Product Analysis

Life-cycle assessment (LCA) is a scientific means for analyzing the environmental impact of a single building product or a group of functionally comparable alternatives. Various technologies with the same purpose can be directly compared, such as two complete cladding systems.

The main benefit of LCA is that it considers whole product systems for a detailed and balanced comparison of their total environmental footprint. This means they must cover: constituent materials; manufacture and production methods; base material and product transport; use-phase properties; and disposal and reuse options.

Assumptions in LCAs are made for particular situations and justified through clearly stated variables. These may include manufacturing location, product usage scenarios as well as recyclability of constituent materials or product components.

Most important, an LCA must consider the environmental impact in a holistic way, reviewing everything from resource use and ecosystem quality to global warming potential (GWP) and potential human health impacts.

GWP, expressed as CO2 equivalents, is a well-accepted metric that uses measured carbon dioxide equivalent totals to compare the environmental impacts of like products or materials.

International standards are employed to help ensure that the LCAs are rigorous and comparable to others. Two of those, ISO 14040 and ISO 14044, have been created to standardize the functional units compared and the system boundaries for the product under consideration. To make direct comparisons between two dissimilar LCA studies, the architect or green building consultant must ensure that the justified functional unit and set of system boundaries are consistent among the LCAs across all potential scenarios.

The LCAs should also provide for how changes to important variables might affect the overall outcome.

 

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Originally published in Architectural Record
Originally published in September 2012

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