Faucet Fixtures Introduction
Residential and Non-Residential Faucet Fixtures
Flow Rate Maximums
In the past, faucets were not a primary focus of water efficiency advocates, given that the Energy Policy Act of 1992 (EPAct 92) and subsequent EPAct actions limited faucet flows to 2.2 gpm (8.3 L) (at 60 psi). In the mid-1990s, however, the U.S. model plumbing codes and the U.S. standard (ANSI standard ASME A112.18.1) further reduced that maximum flow rate to 0.5-gpm (1.9 L) for public (non-residential) applications.
The 0.5 gpm standard for non-residential applications is frequently neglected by design professionals and building owners as many people are simply unaware of this standard and the implementing plumbing codes. Some believe that the maximum flow rate for faucets in non-residential applications is still the EPAct rate of 2.2 gallons per minute (8.3 L), but this is untrue. Unfortunately, this myth has taken hold and gotten serious traction among design professionals, specifiers, plumbing contractors, and building owners. The result of this confusion has been and continues to be the illegal installation of non-compliant faucets in some new commercial projects.
Background and Definitions
EPAct 92 and subsequent rulings by the U.S. Department of Energy (DOE) set the maximum lavatory faucet flow rate at 2.2-gallons per minute (8.3 Lpm) when measured at 60 pounds per square inch (4.2 Kg/cm) of flowing water pressure. However, the governing standard and test procedure (as established by the DOE) for faucets was and continues to be the ANSI national standard, ASME A112.18.1/CSA B125.1. As noted above, this standard was changed to reflect a lower maximum flow rate of 0.5-gallons per minute (1.9 Lpm) for all “public” applications.
All of the major plumbing codes have adopted ASME A112.18.1 by reference.
Public vs. Private Applications
“Public” applications are defined in those implementing codes as all applications that are not defined as “private”. The codes (Uniform Plumbing Code, International Plumbing Code, and the National Standard Plumbing Code) each define “private” as inclusive only of fixtures in residences, hotel/motel guest rooms, and private rooms in hospitals. All other applications are deemed as within the “public” category and subject to a 0.5-gallons per minute (1.9 Lpm) maximum for lavatory faucets. This includes such applications as single-tenant and multi-tenant office buildings, schools, gymnasiums, manufacturing facilities, public buildings (including even those where the general public is denied access), bars, restaurants, retail stores, and any other type of building that does not fall within the “private” definition.
Metering faucets for public applications are subject to the same codes and standards as other faucets, all of which set the maximum water use at 0.25 gallons per cycle (.94 L). That is, the “on-off” cycle (or time during which the faucet is on) cannot result in a total volume in excess of 0.25 gallons (.94 L) of water. It is important to note that metering faucets are NOT subject to a maximum flow rate. Hence, if a cycle is 15 seconds, that then means the flow rate can be as high as 1.0 gpm (3.8 Lpm). A 20% reduction (to a total volume per cycle of 0.2 gallons – 0.76 litres) may be achieved by shortening the cycle to 12 seconds at 1.0-gpm (3.8 Lpm), leaving sufficient water for washing one's hands.
In 2006, the U.S. Environmental Protection Agency launched WaterSense, its voluntary partnership program focused on water use efficiency. In 2007, WaterSense released its final specification for residential lavatory faucets. Certification of lavatory faucets and earning the WaterSense label requires conformance with a rigorous set of performance requirements. Those requirements are detailed in the WaterSense faucet specification and include three significant elements: (1) a maximum flow rate of 1.5 gpm (5.7 Lpm) at a flowing pressure of 60 psi (2) a minimum flow rate of 0.8 gpm (3.0 Lpm) at 20 psi (3) prohibition of instructions on how to circumvent the maximum flow rate. A more complete discussion of the specification and its background, go here.
Currently, over 2,800 faucets and aerators have been independently tested and found to comply with the WaterSense specification, entitling them to be labeled with the WaterSense logo. An up-to-date listing of those qualified products may be found at the EPA WaterSense website.
Do Sensor-Activated Commercial Faucets Save Water?
Before beginning this discussion, it is important to note that the growth of the "touchless restroom" has been in large part due to the concern for hygiene and health, since fixtures do not need to be touched with the hand in order to activate flow. In the past several years, the commercial side of faucets has been a topic of much conversation, if not research. Most water efficiency practitioners readily acknowledge that sensor-operated flush valves (for commercial toilet and urinal fixtures) save no water. In fact, they would quickly say that these devices waste water by flushing more frequently than necessary! But, what about faucets?
Hillsborough County Florida
Concluding in 2009, Veritec Consulting, Inc. and Koeller and Company conducted an extensive fixture replacement study in a major commercial office building wherein manually activated faucets and flush valves were replaced with sensor-activated units. This study took place over a two-year time period, was comprised of 4 phases, and used dataloggers to determine what changes in water consumption resulted from such replacements.
After an extensive period of baseline measurement (pre-monitoring), the study analysis showed that the replacement of manually operated commercial lavatory faucets with sensor-activated faucets resulted in a 30 percent increase in water consumption. Similarly, replacement of manual toilet flush valves with sensor-activated units saw water use increase by 54 percent. For urinals, water use dropped by a small amount.
Gauley and Koeller (2010) Sensor-Operated Plumbing Fixtures, Do They Save Water?
Millennium Dome Report on Water Efficiency-“Watercycle” (2002)
Thames Water’s “Watercycle” project at the Millennium Dome in London was one of the largest in-building recycling schemes in Europe, designed to supply up to 130,000 gallons per day (500 m3) of reclaimed water for toilet and urinal flushing. It catered to over 6 million visitors in the year 2000. Overall, 55% of the water demand at the Dome was met by reclaimed water. The Dome was also the site of one of the most comprehensive studies ever carried out of water conservation in a public environment, evaluating a range of water efficient appliances and researching visitor perceptions of reclaimed water.
Of particular interest is Figure 6 in the report which shows washroom water use for handwashing and compares infrared sensor-operated faucets with “push top” (cycling) faucets and conventional swivel top faucets. It confirms that infrared sensors on the faucets create a waste of water when compared to conventional manually operated fixtures. Another major finding of the study was the importance of a water efficient aerator on sensor faucets. When people open a conventional faucet, they very seldom turn it on all the way. The study shows that on the average, a users open the faucet to a flow rate of some 1.0 to 1.5 gallons per minute. By contrast, sensor faucets open the valve all the way. If a 2.2 gpm aerator is on the faucet , the flow will be 2.2 gallons per minute, but if a 0.5 gpm aerator is used, the flow will be only 0.5 gpm.
Hills, S. et. al. (2002) The Millenium Dome Watercycle Experiment - to Evaluate Water Efficiency
ASHRAE Field Study
Another study that compared manually operated faucets with sensor-activated faucets was published in 2002 by ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.). While not the main focus of the study, (which was titled “Field Test of a Photovoltaic Water Heater”), Tables 3 and 4 provide data needed for the comparisons.
Fanney, A.H. (2002) Field Test of a Photovoltaic Water Heater
“Hands-free” Faucet Valves
Two manufacturers have introduced devices that enable the end-user (home or office) to open and close a faucet valve “hands-free” with the foot. Go to these websites for more information on the pedal valve and foot faucet products: