As plumbing products continue to become more water-efficient, including 1.0-gpf water closets and urinals utilizing only 1 pint of water to flush, there's greater interest in low-consumption fixtures. The American Society of Mechanical Engineers is expected to soon bring more clarity to some of these low-consumption flushing terms by defining them in applicable standards.
John Watson, director of technical services for plumbing manufacturer Sloan Valve Company and a member of the ASME A112.19.2 Working Group, said no “official” definition has yet emerged in an approved consensus standard for high-efficiency urinals (HEU) and high-efficiency toilets (HET).
ASME will, however, likely provide those definitions when it next updates the ASME A.112.19.2 standard. For now, an HEU can be defined as a urinal that performs to the current ASME A.112.19.2 performance standards while using no more than 0.5 gpf. This is a reduction from the current standard of 1.0 gpf as required by the Energy Policy Act of 1992. By this definition, water-free urinals are categorized as HEUs.
An HET is a water closet 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 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 while achieving a MaP test score of removing at least 350 grams of waste.
“Dual-flush flushometers are rising in popularity,” Watson said, “partly because they easily meet HET performance standards.”
In smaller buildings, Watson said, 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,” he said.
Sloan includes signage with its UPPERCUT dual-flush flushometers, which can be affixed near the flush valve to quickly educate users on its usage and benefits. Proper operation by even a fraction of the users can equate to significant water savings.
Plus, as dual-flush flush valves become more common, restroom users will just intuitively know how to operate them — much in the same way they learned to adapt to sensor-operated flushometers when they first emerged on the market.
Large commercial or institutional buildings with a transient population, or restrooms in high-traffic areas such as airports, entertainment venues and shopping malls, may gain greater efficiencies from automatic operation.
“For these restrooms, it makes sense to install the new electronic dual-flush flushometers, which automatically initiate the appropriate flush cycle, depending on the amount of time the user remains in the sensor range,” Watson said.