WaterSense:
A consensus-based, common sense approach

for high-efficiency Showerheads

By Stephanie Tanner, EPA, and Sally Remedios, Delta Faucet Co.

WaterSense, a partnership program sponsored by the U.S. Environmental Protection Agency (EPA), seeks to protect the future of our nation's water supply by promoting water efficiency and transforming the market for water-efficient products, services and practices.

Raising consumer awareness about the need for high-efficiency showerheads and helping transform the marketplace for such products are high priorities for EPA. Studies have shown that showers accounts for approximately 17 percent of indoor water use -third overall behind clothes washers and toilets. Even a modest increase in efficiency has the potential to save billions of gallons of water each year. Once a specification is finalized, showerheads will round out the suite of WaterSense-labeled residential bathroom plumbing fixtures.

WaterSense specification development

To earn the WaterSense label, a product must not only save water but also perform its intended functions - within its intended system - as well as, or better than, the average products on the market. Showerheads will be no exception. The difficulty often lies, however, in developing specification criteria that can be used to effectively evaluate a product's water savings and performance. For this reason, EPA relies on industry and other interested parties that have direct experience with the manufacture, installation, maintenance or use of the product to help define the important performance attributes and the test methods for evaluating those attributes.

EPA's WaterSense specification development process offers multiple opportunities to gain this input. This process involves the following:

• Technical analysis and market research. EPA carefully evaluates a product's water savings potential, performance attributes, potential system impacts, environmental and economic impacts, available performance evaluation methods and any data gaps that may exist.
• Notice of intent to develop a specification (NOI). At this stage, EPA relays the outstanding technical issues to industry and other interested parties, requests data or research to answer any remaining questions and seeks input on the development of performance evaluation methods. EPA also evaluates and attempts to resolve any unintended or negative impacts that the product could have on its system or the health and safety of consumers.
• Draft specification. EPA releases the draft specification for public comment only after it has received input from industry and other interested parties on the outstanding technical issues and is confident that its data needs can be fulfilled. At this point, evaluation methods are clearly defined and stakeholder input focuses on fine tuning the performance requirements and establishing appropriate performance levels.
• EPA's objectives through this open specification development process are to ensure that it considers the issues that are important to a variety of stakeholders, that specifications are vetted technically and that the final specification criteria are transparent.

Water-efficient showerheads

EPA initiated research on showerheads in 2006. At the same time, the American Society of Mechanical Engineers (ASME) and the Canadian Standards Association (CSA) established a Joint Harmonization Task Force to evaluate showerhead efficiency and performance, with the intent of developing new performance standards. This task force is open to public participation and comprises showerhead manufacturers, water and energy utilities, testing laboratories, consultants and other water-efficiency and conservation specialists. It is the force behind North American plumbing standards related to showerheads, and its representatives possess years of experience related to showerhead performance, water efficiency and health and safety issues.

WaterSense became actively involved with the task force in early 2007 and has agreed to collaborate on the specification development process for showerheads. With this collaboration, WaterSense seeks to engage a variety of industry experts and to work through the existing consensus-based process established in the United States for developing standards and specifications for plumbing fixtures and fittings.

EPA published its NOI to develop a specification for high-efficiency showerheads in August 2007. In its notice, WaterSense identifies its goal with respect to water efficiency to label products that are about 20 percent more water-efficient than average comparable products on the market. The benchmark for showerheads, as specified in the Energy Policy Act of 1992, is a maximum water use of 2.5 gallons per minute (gpm) when measured at a flowing pressure of 80 pounds per square inch (psi), as determined through testing in accordance with the ASME A112.18.1 standard.

To achieve its water efficiency goal, EPA intends to specify a new lower maximum flow rate for high-efficiency showerheads. A showerhead's efficiency cannot be specified, however, without carefully considering potential impacts on consumer satisfaction or performance, including potential health and safety issues, once it is installed in the plumbing system.

Health and safety concerns

Of particular concern is the potential for increasing the risk of thermal shock or scalding as shower flow rates are reduced. Thermal shock or scalding can be caused when a hot or cold water-using device is activated while the shower is running. Water is diverted away from the shower, causing a pressure drop in either the hot or cold water supply line to the shower. As a consequence, the balance of hot and cold water is shifted either to a hotter or colder temperature mix. This sudden change in temperature can either cause a user to have an abrupt physical reaction that could result in an injury or fall or, if the temperature increase is severe enough, scalding can occur. Because more efficient fittings use lower volumes of water than standard fittings, they are more sensitive to changes in water pressure. As a consequence, temperature change may be amplified when the same amount of water is diverted from the shower.

To mitigate the risks of temperature-related shower injuries, most U.S. plumbing codes require showers to be outfitted with individual automatic-compensating valves that comply with either the American Society of Sanitary Engineers (ASSE) 10162 or ASME A112.18.1/CSA B125.1 standards. An automatic-compensating mixing valve is a device that is installed as part of the shower's flow control (not as part of the showerhead) that helps to regulate water temperature, either through balancing the incoming hot and cold water pressures or through controlling the mixed outlet temperature with a thermostatic element that can maintain water temperature to within +/- 3.6 F.

Despite advances in plumbing codes and mixing valve technology, there are at least two scenarios under which the thermal shock and scalding risks must still be carefully evaluated. First, automatic-compensating mixing valves are currently only required to be tested and certified at a flow rate of 2.5 gpm. When these devices are outfitted in conjunction with a showerhead that has a lower flow rate, there may not be adequate assurance that the valve is sensitive enough to provide the required protection. Second, not all homes are equipped with an automatic-compensating mixing valve. This is of particular concern for showerhead retrofits in homes built prior to the mid-1990s.

As a part of the development of criteria for high-efficiency showerheads, WaterSense and the task force are actively evaluating the link between flow rate and temperature deviations associated with pressure and temperature changes. The task force has gathered and presented data to compare the temperature profiles that result from a drop in hot and cold water pressure for both conventional and high-efficiency showerheads under two scenarios: 1) installation with various types of auto-compensating mixing valves (thermostatic, pressure balancing or combination) designed for a flow rate of 2.5 gpm and 2) installation without the protection of an auto-compensating mixing valve. The task force will fully evaluate the data before it recommends a maximum flow rate designation for high-efficiency showerheads.

In addition to relying on the expertise of the task force to fully understand and assess the impact of showerhead flow rate on consumer health and safety issues, EPA would like to work with the Joint Harmonization Task Force, comprising members of ASME, ASSE, and CSA, that is considering updates to address the performance of automatic-compensating mixing valves with high-efficiency showerheads. Such updates could alleviate potential risks associated with the installation of high-efficiency showerheads in new construction or in retrofit installations when mixing valves are also replaced with a device with the same flow rating as the showerhead.

Performance is critical

Establishing performance-based criteria for WaterSense labeled showerheads is critical to ensuring user satisfaction and maintaining the integrity of the WaterSense label. However, there are currently no universally agreed-upon testing protocols for performance or measures that adequately define user satisfaction. EPA's research and initial discussions with the task force identified a number of potential attributes that can be used to define a showerhead's performance, including: the ability to remove soap and shampoo, comfort of the shower spray, distribution of water over the body, temperature drop as the distance from the showerhead increases, noise and variation of flow rate with changes in water pressure.

The challenge is translating these, or any other performance attributes, into meaningful specification criteria; this involves filling two major data gaps. First, the attributes must be converted into measurable parameters that can be tested in a laboratory under reproducible test conditions that will yield repeatable results. Second, the attributes must be correlated with user satisfaction. These two factors are inextricably linked and are further complicated for showerheads because the criteria must be delicately balanced so that it is robust enough to weed out poor performing products but expansive enough to satisfy a broad range of consumer preferences.

With the laboratory testing and user satisfaction in mind, the task force has narrowed the list of recommended key performance attributes to the following:

• Pressure compensation
• Spray pattern (or water distribution)
• Effectiveness (or showerhead force and wetting capabilities)

Work is already under way to develop test protocols to verify these performance attributes in the laboratory, and the results are encouraging. Once the test protocols are fully developed, the next step is to conduct a series of comparative tests with the same set of showerheads at multiple manufacturers' laboratories. This evaluation will test the reproducibility of the methods and the repeatability of the results.

Simultaneously, select members of the task force are also conducting consumer testing to determine whether there is a uniform preference or - more importantly - a uniform dislike of certain showerhead attributes and to determine whether the performance attributes identified above adequately encapsulate and define user satisfaction. If the consumer testing provides conclusive results, the task force plans to correlate these attributes against the test protocols and utilize the output values to establish performance levels in a specification.

Common sense makes WaterSense

For all product specifications, EPA's intent is to establish an open process that facilitates the involvement of industry and other interested parties and fosters the development of technically sound and transparent specification criteria. EPA also must carefully balance its water efficiency goals with considerations of the impact of the product both on consumer satisfaction and on the system in which the product is ultimately installed. Collaborating with the ASME/CSA Joint Harmonization Task Force on showerheads serves both of these objectives for the WaterSense program.

As a result of this cooperative relationship, industry is vested in the WaterSense specification development process and has taken the lead on the development of showerhead efficiency and performance criteria, test protocols and evaluation of health and safety issues. EPA, in turn, is confident that this process will result in a widely accepted specification that meets the WaterSense water efficiency and performance goals. This common sense, consensus-based specification development process for showerheads is vital to the development of a quality specification and may serve as a model for working with future industries to ensure consumer confidence in WaterSense labeled products.

Stephanie Tanner is the product development coordinator for the U.S. Environmental Protection Agency's WaterSense ®program. She is responsible for all technical aspects of the development of labeled products, including setting efficiency and performance criteria as well as managing the certification process. Prior to EPA, she managed a water-efficiency program for federal facilities and wrote a number of guides to water efficiency for federal facilities. Ms. Tanner holds a B.S. in Marine Engineering from the Merchant Marine Academy and a Master of Engineering Management from the George Washington University.

Sally Remedios joined Delta Faucet Co. in 1995. She was previously employed by the Canadian Standards Association (CSA) with roles in its standards, certification and quality programs. Remedios's responsibilities include standards development, with positions on the ASME and CSA standards committees for plumbing products. There she has been involved in harmonizing the national consensus standards between the United States and Canada. Remedios is a registered professional engineer in the province of Ontario, Canada. She can be reached at sar@deltafaucet.com.