The Water Use Reduction Additional Guidance document states that "When using an autocontrol faucet with metering control or automatic fixture sensor, please select the Metering Lavatory fixture in the Fixture Type pull-down menu of the Flow Fixture Data table."
I have a client that is considering a sensor activated faucet with a 0.5 GPM flow rate. When the product senses activity it allows water to flow. Water will continue to flow until the hands are removed or until 2 minutes - the time out limit. It would seem more appropriate to use 0.5 GPM as the flow rate instead of a metered amount, since the water stays on essentially the whole time a person is washing their hands. If I had to use the meter type, then wouldn't I have to use 2 minutes as the default duration when calculating the flow per cycle?
Sam Farmer
Green Fields13 thumbs up
January 7, 2014 - 12:09 pm
I believe you would use the 12 sec default run time. For your 0.5 gpm faucet, you would have a resulting 0.1 gpc total consumption per use - 0.5 gpm X (12sec / 60) = 0.1 gpc. Hope that helps!
Gary Soe
Sr EngineerTOTO USA Inc
June 5, 2015 - 2:03 pm
Hi there,
Does this calculation with 12sec default run method still apply to V.4? Thanks
Carlie Bullock-Jones
PrincipalEcoworks Studio
LEEDuser Expert
220 thumbs up
June 9, 2015 - 12:59 pm
Hello Gary,
No, for v4 duration-based savings from autocontrol faucets with automatic fixture sensors or metering controls are no longer allowed in the design case. Studies have shown that autocontrol faucets do not save water because users frequently reactivate the faucet after initial use or stop washing before the cycle ends.
Gary Soe
Sr EngineerTOTO USA Inc
June 9, 2015 - 1:20 pm
Noted. Thank you, Carlie. May I also ask if you can direct me where to find the studies showing the water saving? Thanks.
Carlie Bullock-Jones
PrincipalEcoworks Studio
LEEDuser Expert
220 thumbs up
June 9, 2015 - 1:28 pm
Hi Gary - this was simply noted in the v4 Reference Guide...no studies were cited.