High on Efficiency, Low on Water Usage

April 1, 2008

Low-consumption flush valves are an easy-to-use, cost-effective technology that will significantly lower water usage


Water-efficient flushing technologies have come a long way in terms of enabling facilities to save water. Even more good news: Low-consumption flush valves, including those with dual-flush functionality, are an easy-to-use, cost-effective flushing technology that will immediately and significantly lower water usage in your buildings.

Efficiently Functional
As plumbing products that use less and less water continue to emerge, including 1.0 gallon-per-flush (gpf) water closets and urinals utilizing only 1 pint of water to flush, specifiers are showing greater interest in low-consumption fixtures — as long as they perform effectively. While no official definition has yet emerged in an approved standard, high-efficiency urinal (HEU) and high-efficiency toilet (HET) products are already impacting purchase decisions.

The New York City-based American Society of Mechanical Engineers (ASME) Intl. will likely provide those definitions when it next updates the ASME A.112.19.2 standard. For now, HEUs and HETs can be defined as follows:

  • An HET is a toilet that meets the current performance requirements outlined in ASME A.112.19.2, but does so by either flushing at a maximum of 1.28 gpf/4.8 Lpf or by deploying a dual-flush device, which, based on a typical 2:1 liquid/solid use ratio, averages a total flush volume of 1.28 gpf. The U.S. EPA's WaterSense label is offered to HETs that are certified by independent laboratory testing to meet rigorous criteria for performance and efficiency. Only HETs that receive third-party certification earn the WaterSense label.
  • An HEU is a urinal that performs to current ASME A.112.19.2 performance standards while using no more than 0.5 gpf/1.9 Lpf to flush. This is a reduction from the current standard of 1.0 gpf/3.8 Lpf as required by the Energy Policy Act of 1992. By this definition, waterfree urinals are categorized as HEUs. For urinals, there are no WaterSense labels given by the EPA.

Double the Chance to Save
Dual-flush flushometers are rising in popularity, partly because they easily meet HET performance standards as proven by independent testing. The public is increasingly interested in doing its part for the environment, and building owners largely support that — as long as it's economically feasible.

Dual-flush functionality for toilets is a win-win: Restroom users can choose a reduced or regular flush, depending on need, and the reduction in water consumption results in lower water and wastewater utility bills. Dual-flush functionality typically saves about a half-gallon of water in its reduced flush cycle, and can be manually or electronically activated.

Once you've decided that you want dual-flush functionality in your restrooms, the fixture choice then becomes manual or electronic. In smaller buildings, it may be more advantageous to install manual dual-flush flushometers in restrooms because they have a regular set of users. These users are more familiar with (and conscientious about) the facility, which means they are more likely to learn how to manually operate a dual-flush flushometer to its full potential. In a large commercial building with a transient population, however, it's more difficult to train users on proper fixture usage. For these restrooms, electronic dual-flush flushometers, which automatically initiate the appropriate flush cycle depending on the amount of time the user remains in the sensor range, are ideal.

Dual-flush functionality can be purchased as separate retrofit conversion kits or as part of complete flush-valve systems. A manual retrofit kit consists of a dual-flush handle that replaces a regular flush handle. An electronic kit includes an electronic assembly body that installs in place of the existing valve body.

Because you can't count on restroom visitors to use water responsibly, taking advantage of today's water-efficient products that reduce water consumption automatically is one of the best ways to ensure water savings.

Evaluate the Savings of Water-Efficient Plumbing
Most building owners are open to water-efficient products — if they come out on top financially. But, when does it make better sense to replace higher-water-consuming water closets and urinals with more efficient models? Each facilities professional should do his/her homework to determine usage and the potential savings of installing HETs and HEUs.

John Watson is director of technical services at Franklin Park, IL-based Sloan Valve Co.

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