On LEED Online and in the Reference Guide one use of a lavatory faucet is 15 seconds. In the Water Use Reduction Additional Guidance (updated July 14, 2011) page 3, the duration of a lavatory faucet is 30 seconds. All my projects were registered earlier than July, which duration should I use? Can I use 15 seconds? The precertification comments state that I should use the Additional Guidance (but not what version).
I have also been wondering why a private lavatory faucet has 2.2 GPM for the baseline, while public lavatory faucets have 0.5 GPM. Why is there such a big difference? Why is one allowed to have much bigger flows in private faucets? They look the same and are used in basically the same way.
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John Drigot
Design/LEED SpecialistThe Neenan Company
185 thumbs up
January 4, 2012 - 1:45 pm
Maria,
The .5 GPM for public lavatory faucets used to be 1.5 GPM way back in NC v2.2. It was updated to .5 GPM based on the American Society of Mechanical Engineers standard. This standard was incorporated into the national Uniform Plumbing Code and International Plumbing Code. Follow this link to learn a little more about the history - http://www.allianceforwaterefficiency.org/Faucet_Fixtures_Introduction.aspx
In terms of duration of a lavatory faucet I see that Table 3a. Non-residential Default Fixture Uses by Occupancy Type was updated by addenda on 2/2/2011. So if you registered your project before 2/2/11 you have the option of using the 30 second duration (12 seconds if autocontrol). Projects registered after 2/2/2011 must use the updated duration times.
Hope this helps.
Maria Porter
Sustainability specialistSkanska Sweden
271 thumbs up
January 13, 2012 - 4:19 am
Thank you John
I hadn’t realized that 0.5 GPM is code in the US. In my country the common belief is that water is something we don’t have to save because we have lots of it. Which I don’t think is a good way of seeing it. It still costs a lot of energy to heat and to treat after it’s been used. Swedish code states that flows should be 0.2 l/s (3.17 GPM). I have now however started opening the eyes of my building owners telling them that we can reduce flows significantly, especially in commercial projects. They are very interested. And I am currently testing different taps in our own office bathrooms to see with own eyes how low we can go and still keep a good comfort for our users.
I have a project that for CS is registered early and can use 15 seconds in the calculation. But now I am also doing a CI certification for the tenant in the same building and they are registered later and have to choose 30 seconds. In CI a large part of the credits are dependent on WE. So I really have to think twice already in the CS-project so that the CI-project don’t have to change anything later.