There's been a lot of talk recently about the auto-control / metering faucet requirement in LEED via the "Water Use Reduction Additional Guidance" document. I understand the requirements per the document (and the 12 second allotment for autocontrols going back to the earliest versions of LEED), but I'm hoping someone can help me understand why both the low-tech "push button" type metering faucets as well as the high-tech "auto-sensor" faucets that are only on when your hands are under them are now grouped together under "metering."
It seems to me that these two types of "metering faucets" are very different. In the first case with the low-tech "push button" type, where the user pushes a button and the water is on for a specific amount of time until the metering fixture turns it off, there is always a set amount of water being used. If the user feels that one "push" isn't enough, they have to push it again and the water will continue running until the end of the cycle -- whether or not the user needs it that full amount of time. With the “auto-sensor” faucets there are also two types – those that once triggered act just like the “push button” type and stay on until the time runs out, and the high-tech version that are only on when they sense hands underneath them. For the later case, if the faucets are only on when hands are underneath them, they will be saving more water than the ones that are on for a set amount of time.
I understand that 12 sec is the “minimum allowed for good handwashing,” but it seems to me that there should still be a further differentiation between metering faucets that use a set amount of water every time and high-tech faucets that really only use water when demanded. I would think the high-tech faucets use less water than any other type of faucet, metering or otherwise, and should be recognized in LEED accordingly.
R Jones
74 thumbs up
January 8, 2013 - 6:00 am
With the battery sensor faucets could they / should they be considered in the LEED template using their GPM figure rather than GPC? the auto sensor taps typically run so long as their is movement in front of the sensor. Moving your hands away is pretty much the same as manually shutting the faucet off rather than the automatic push down button.
Also with the flow rates in BREEAM we use a 2/3rds of the flow rate figure for a normal tap based on the fact that people will not typically turn the faucet on fully when hand washing. Any possible justification for this in LEED?
Michelle Teague
Architect, LEED ConsultantPolk Stanley Wilcox Architects
39 thumbs up
April 1, 2013 - 2:05 pm
I absolutely agree with you on the inappropriatene grouping of automatic sensor faucets with metered faucets and then applying reduced duration time to both. In researching and documenting this credit for a few projects in LEED v2 and LEED 2009 I've found the following four types of faucets which are not accurately reflected in the LEED form calculations.
Sensor activated, variable duration per user (runs until user removes hands)
Sensor activated, metered output (starts running when it senses a user, then runs for a preset amount of time or flow quantity)
Manual activated, metered output (pushbutton, run for preset amount of time or flow quantity)
Manual activated, variable duration per user (i.e. regular leverset faucet)
LEED Users note that 12 seconds is NOT the recommended time for hand washing and shouldn't be used as an ideal duration of use setting for any kind of faucet.
The US centers for disease control recommends 20 seconds for good handwashing practice.
http://www.cdc.gov/handwashing/
For history on the length of duration see the LEED v2 Reference Guide, Credit 3, Calculations example p104 "Occupants in this example are assumed to use lavatories for each restroom use for 15 seconds", then later in example on p105 "Motion sensors and electronic controls are used on lavatories, sinks, and water closets. These devices are estimated to reduce lavatory and sink use duration by 20% but do not reduce the flow of water closets. These fixtures' duration data have been correspondingly adjusted form 15 seconds to 12 seconds."
The shortcut to combine faucet types and reduced duration multipliers in the programming of the LEED form was not a good move.
Jean Marais
b.i.g. Bechtold DesignBuilder Expert832 thumbs up
October 15, 2013 - 10:42 am
Observation: At gas station toilets in Germany, I have not found a single gas-station toilet faucet which was not set on the minimum setting of 5 seconds (I always check)...I know that these come out of the factory with a default setting of 15 seconds (every datasheet I've seen). This means they have been adjusted (to save costs) to the minimum. Whether that means people are pushing the button once, twice or three times, or more...I can't say, but I do reckon that they are put on the minimum setting and that this saves water more than the default setting of 15 seconds. So the setting saves money (the proof is in the pudding). Are we being rewarded for settings below 12 seconds? No.
The "12 seconds" for good handwashing comes from somewhere. And that we want to promote water savings, but not at the detriment of public hygien...that is the why for the "no".
I don't use 12 seconds, not even at a normal faucet...why? I wash only with the liquid soap (no hand wetting neccessary) at my leisure and then promptly wash the soap and dirt away once done. 5 seconds, no problem. Very, very seldomly do I see a public restroom with solid soap.
I would have no issue if the 12 sec limit was revised to 5 sec.