We are having a little trouble with the flow fixture table calculations. We specified Sloan automatic sensing faucets. According to the Additional Guidance document 8/16/10 we're supposed to list this as a "metering faucet" type and calculate the gpc per the manufacturer's data. I assumed that the fixture would adjust to a 20 second run time, which is the Centers for Disease Control recommended handwash time and calculates out to 0.17gpc. Compared to the 0.25gpc typical from LEED guide table 4 we would get savings. However, the plumbing engineer and I have checked with Sloan and they say their controls for the autosensing faucet only go down to 1 minute, not 20 seconds, so the faucet will shut off a) after the user removes their hands or b) after 1 minute. So do we use user behavior patterns (average person keeps their hands under the faucet for 12 seconds, gpc = 0.5*12sec/60sec = 0.1gpc? I am curious how you arrived at the 0.17gpc value for the Toto fixture? I see on toto's faucet info they use 10 sec cycles. If the hands are still under after 10 sec does it begin another cycle?
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John Drigot
Design/LEED SpecialistThe Neenan Company
185 thumbs up
August 22, 2011 - 5:16 pm
Michelle,
I too have been digging into this for a LEED school project. I just got off the phone with a Zurn technical representative and he set me straight on their AquaSense faucet, 6915-F. Similiar to the Sloan faucet it turns off when the user removes their hands. What is different though is the maximium length of cycle, 30 seconds. This still doesn't help me as I try to get down to a .08 GPC. In the past I specified a .35 gpm aerator with a 12 second duration to arrive at .07 GPC. This time I am trying to find a 10 second duration, minimum required by ADA, and use a .5 gpm aerator. All my research thus far points me away from sensor to metered type faucets. I am going to contact Toto and see what I can learn about their faucets. I'll let you know what I find. Can anyone else chime in on this one??
Emmanuel Pauwels
OwnerGreen Living Projects
137 thumbs up
January 13, 2012 - 5:21 am
I have a similar issue on a project with a sensor. But the faucet does not turn off automatically, only when the hands are removed. Would we be able to make an assumption about how long someone needs to wash his hands or can we only use a faucet that turns off automatically after a certain time and use that time instead?
Nadia Ayala
Architect / LEED AP BD+CKILTIK Consultoría
52 thumbs up
March 7, 2012 - 2:41 pm
Hello,
My case is similar as well. Faucet only works when hands are placed below and are touching a valve. It's similar to the system in this image: goo.gl/xzTO5 and the actual product we're using is the one described in this video (go to http://www.youtube.com/watch?v=gz0GEObnnKA 0:45 to 1:00) it is manually, not electronically controlled though.
Any thoughts?
Nadia Ayala
Architect / LEED AP BD+CKILTIK Consultoría
52 thumbs up
March 22, 2012 - 11:29 am
LEED User staff, any hints on my previous question?
Thank you.
Amy Rider
Sustainability ManagerKEMA Services
161 thumbs up
March 22, 2012 - 1:11 pm
It seems to me that a non-metered (with no maximum running time) sensor faucet/lav should be treated like a standard fixture since it operates like one with different controls. As such I would report flow rates using the LEED assumptions for run times.
Nadia Ayala
Architect / LEED AP BD+CKILTIK Consultoría
52 thumbs up
March 22, 2012 - 1:18 pm
Thank you Amy!
Gabriele E. Bibee
Architectural InternClark Nexsen Architecture & Engineering
6 thumbs up
May 23, 2012 - 4:10 pm
LEED Water Use Reducation Additional Guidance, Version 6, does not recommend autocontrol faucets with durations less than 12 seconds, "as shorter intervals are insufficient for typical hand washing".