It appears that the metering faucet calculation providing a Gallons per Cycle option for flow rate has been removed from LEED 2012 Water efficiency prerequisite and Indoor water use calculation.
Is it assumed that faucet flow rate restriction is the only method to save flowing water, not restricting the meter time?
We understand the recent research, (see link) but is this conclusive enough to limit water efficiency to flow and not not consider duration?
http://allianceforwaterefficiency.org/WorkArea/linkit.aspx?LinkIdentifie...
Tristan Roberts
RepresentativeVermont House of Representatives
LEEDuser Expert
11478 thumbs up
March 2, 2012 - 1:33 pm
Jeremy, there are other experts around here who know more on the topic than me, but I don't think this represents a change from LEED 2009, in which limiting duration is not accepted for WE. Just FYI.
Jeremy Cressman
VP GM Commercial Business UnitAmerican Standard Brands
21 thumbs up
March 2, 2012 - 4:27 pm
I may be wrong, but in LEED 2009 NC I believe that in the Flow Fixture Data Table, the "metering" drop-downs for type with gallons per cycle unit do exactly that -- recongnize a savings based on not only flow but duration and flow.
If you utilize a .5gpm flow faucet vs. the .5 gpm baseline, then there is no contribution to savings. But if you use a .5gpm faucet at 12 second cycle, the gpc is .10 vs. a .25gpc baseline. Big difference.
If this has changed recently, I am not aware.
http://www.usgbc.org/ShowFile.aspx?DocumentID=6493
Melissa Wrolstad
Senior Project ManagerCodeGreen Solutions
228 thumbs up
March 9, 2012 - 5:30 pm
In the LEED v2009 Requirements table of baseline flow rates / flush rates, it lists 0.25gpc as a faucet baseline.
A 0.5GPM faucet with a 10-sec timer = 0.083gpc which is ~67% water savings for all commercial faucet flow. This has a HUGE impact on overall water savings calculations.
If this option is removed from the LEED system (they have removed the 0.25gpc baseline from the Requirements section) - it will have a significant impact on projects. It will vary depending on the type of project - but for the typical office it will result in an overall drop of water-savings of about 10% (which is 2 tiers of LEED points).
Along those lines - a funny thing about this "metering" approach is that if you have a 0.5GPM faucet that automatically turns off when you take your hands away - there is no way to quantify any water savings in the LEED template. I was hoping they would address this in v2012 - however it is not addressed in the current third draft.
Susann Geithner
PrincipalEmerald Built Environments
1297 thumbs up
March 20, 2012 - 4:46 pm
I think metered and automatic faucets should be treated equally with a reduced cycled compared to manual. It's a pretty simple reason. If I open the faucet and close it, that's time the faucet runs and I'm not washing my hands, were as if i hold my hands underneath the faucet I start washing hands the very first millisecond. You can also make a similar argument as for taking a shower. Turn of the shower while you are applying the soap. same can be done with an automatic faucet.
So yes definitely add some back in. I suggest to give a fixed discount for any automatic faucets if metered or just automatic. So instead of 30 sec for the manual do 20 sec for all automatic.