NC 2009 WEp1: Water Use Reduction—20% Reduction

Nadav Malin replied President, BuildingGreen, LLC Aug 11 2009

Great info here. I'm curious whether your dual-flushA type of water-saving toilet that gives a choice of flushes depending on the type of waste — solid or liquid. WC is based on a residential 1.6/0.8 gpf or commercial 1.6/1.1 gpf rates.

Dave Intner replied Firmitas Architecture & Planning Sep 16 2009

I believe that you can get better savings with lavatory faucets if they are metering faucets (manual-on, auto-off as most new public lavs are nowadays); the standard given there is 0.25 gallons per cycle. Toto faucets, as an example, use 0.09 gallons in a 10-second cycle.

Tristan Roberts replied Editor – LEEDuser, BuildingGreen, LLC Sep 16 2009

Do you have any data or calculations on this, Dave, or anyone? Published studies have tended to show that fixtures with sensors use more water on average than those without.

Brenden McEneaney replied Green Building Program Advisor, City of Santa Monica Sep 17 2009

It is certainly more challenging, but it also can strongly depend on your occupant types. In a hotel project, you'll find that showers dominate water use (at least, the water use that's considered in LEED...). If you've got a lot of students/visitors, waterless urinals have a more significant contribution.

1.5 or 1.6 gpm showerheads are out there and are good.

For a typical office building, you might also go to the 1.0 gpf pressure-assist toilets. That makes 3.0 gal/day for female users vs. 3.2 with regular dual flush or 3.8 for commercial dual-flushA type of water-saving toilet that gives a choice of flushes depending on the type of waste — solid or liquid.. But it's still not 40% at the fixture level so you need to make up for it with the urinals.

I wonder where the occupant usage rate data originally came from. It seems like this might be an area for future research by USGBC to test and verify these assumptions, since they are the foundation for the indoor water usage estimates.

Dave Intner replied Firmitas Architecture & Planning Sep 24 2009

Tristan- I don't have any calculations, but the Toto product data sheet is available here: http://admin.totousa.com/Product%20Downloads/SS-00420,%20TEL3%285%29GS,%... . As I found out after a recent punch-list walk, the .09 gp/cy model is no longer available; its replacement model is a 0.17 g/cy. I should note that I have no particular affinity for Toto; it's just the only one I've found so far (in my admittedly limited research) that quantifies both flow rate and gallons per cycle on its data sheet. I'm sure there are many others.

I'd be curious to see the studies you reference about fixtures with sensors using more water (can you post some links?); if true, then it would appear the USGBC has it backwards by encouraging a preference for metering faucets in the new credit requirements.

Jean Marais replied b.i.g. bechtold INGENIEURGESELLSCHAFT MBH Sep 29 2009

I also made some rudimentary calcs and get to 20,8% possible savings using some German industry water saving features. This let's me believe that other than having a grey water system or using non-convensional means, getting to 30% is not possible. Almost like it should fall into Exemplary PerformanceIn LEED, certain credits have established thresholds beyond basic credit achievement. Meeting these thresholds can earn additional points through Innovation in Design (ID) or Innovation in Operations (IO) points. As a general rule of thumb, ID credits for exemplary performance are awarded for doubling the credit requirements and/or achieving the next incremental percentage threshold. However, this rule varies on a case by case basis, so check the credit requirements., i.e. more than high performance.

Seema Pandya replied Senior Consultant, YRG sustainability Aug 13 2009

I would start by defining your user groups and what fixtures they will be using.
For example, if you have 100 patient rooms and all of them have the same type of sink and a private restroom fixtures, you could define the patients as one user group. You would then run the use calculations for each fixture in that user group at the conventional EPAct rates.

* 50 men using the toilet 3 times a day x 1.6g/f (this would change to 2 urinal uses and 1 toilet uses if your design case had a urinal)

* 50 women using the toilet 3 times a day x 1.6g/f

* 100 people washing their hand in the sink every time they used the restroom 3 times a day x 0.5 g/l

Another user group would might be the nurse station, etc. You would run the base case water uses for each user group.

Mara Baum replied Sustainability Coordinator, Anshen + Allen Architects Oct 15 2009

Although I haven't seen the v3 credit template for this (are samples available for download?), if it is similar to v2.2, then patients are considered residents; staff (nurses, doctors, etc.) are considered FTEs and family are considered transient visitors. This gives the standard fixture use rates. Challenge 1 is that FTEs can be very hard to pin down for a single building that is a part of a larger hospital campus, and that family numbers are just estimates. Challenge 2 is that staff wash their hands many, many times more than the basic LEED rates; there are estimates of up to 12x per hour -- yes, hour -- though I think that is high for most circumstances. Challenge 3 is that some regions have flow rates dictated by code that are different than the EPAct rates. Challenge 4 is that any product with aeration is prohibited for infection control purposes; only laminar flow products are permissible, and there are fewer of them available. Challenge 5 is that very low flow faucets (like the ones required) can potentially take a long time to get to hot, depending on how the hot water loop is set up -- this is a big problem for surgeons and others. (These are just a few of the challenges... are you excited yet?) A lot of hospital projects have shied away from this v2.2 credit given the challenges, but that won't be an option any more. Good luck.

Mara Baum replied Sustainability Coordinator, Anshen + Allen Architects Oct 15 2009

p.s. I gave a webinar for H2E on plumbing fixture selection for healthcare in 2008 -- you can download the slides from http://www.h2e-online.org/teleconferences/ConferenceDetails.cfm?Date=200... (scroll down)

Sherry Bonelli replied LEED Project Manager/Consultant, BudSprout LLC -- SucceedAtLEED.com Jan 05 2010

Hi...

For anyone who's interested, I have posted a PDF of WEP 1 Credit Teamplate on my site so you can see what information is contained on the template:

http://succeedatleed.com/?page_id=307

Good luck!

Sherry Bonelli, LEED Green Associate
www.SucceedAtLEED.com

Briana Sprague replied LEED Review Team Leader, NSF International Feb 15 2010

I still have issues about Mara's 2nd challenge from above: "Challenge 2 is that staff wash their hands many, many times more than the basic LEED rates; there are estimates of up to 12x per hour -- yes, hour -- though I think that is high for most circumstances."

In NCv2.2 CIR dated 2/1/0/09, exam room sinks were designated as process usage. This issue is not addressed in the LEED-BD&C 2009 Ref. Guide (maybe I am missing it) and the CIR not longer applies.

What do we do with the exam sink usage for the 2009 rating systems?

Thanks!
Briana

Mara Baum replied Sustainability Coordinator, Anshen + Allen Architects Feb 15 2010

Briana, I'm not sure which you have an issue with: that staff wash their hands so many times, or how to deal with the sinks that they use in LEED. The first issue is definitely debatable, and depends a lot on individual facility culture. In theory, staff are required to wash hands between patients, and they often see up to 12 patients per hour. However, some facilities push gels in liu of washes (lots of opinionated backstory here...), and at others the patient count may be lower.

As for how to qualify the sinks used for handwashing, I think it depends on the circumstances. In theory, any sink in a hospital outside of public or staff restrooms could be considered clinical. However, in many buildings the bulk of those sinks are only or mostly used for handwashing, over and over again. In v 2.2, I had heard of projects that included sinks only or primarily meant for handwashing in the LEED calcs -- for example, sinks between corridors and patient rooms. Exam room sinks, which are often used for many things, would (as the CIR states) be considered process. All of these areas are somewhat gray, and I can definitely agree with arguments on both sides, depending on the situation.

As for LEED 2009, I don't think any of us can do much other than guess, though I definitely encourage anyone who hears more to share their interpretations with the LEED User community.

Keith Amann, YRG sustainability replied Consultant, YRG sustainability Sep 21 2009

Jean, this question is referring to WEc2 "Innovative Wastewater Technologies," where the baseline only includes water closets and urinals. Therefore, you would not need to adjust flow rates and durations of sinks and showers. The following shows the correct calculations for the baseline case of WEc2 with 100 occupants and default of 260 annual work days:
1. Water Closet (male)- 1 daily use x 1.6 gpf x 50 occupants= 80 gallons
2. Water closet (female)- 3 daily use x 1.6 gpf x 50 occupants= 240 gallons
3. Urinals- 2 daily use x 1.0 gpf x 50 occupants= 100 gallons

80 + 240 + 100= 420 gallons per day x 260 days/year= 109,200 gallons/year

Joshua Radoff replied Principal, LEEDuser Primary Author, YRG sustainability Sep 17 2009

Ivy,
Where are you seeing this regional credit threshold? Is this something that is zip code specific? If so, what zip?

Josh

Joel Ann Todd replied Independent Consultant Oct 08 2009

Which rating system and region (zip code)?

Nadav Malin replied President, BuildingGreen, LLC Sep 29 2009

If you're using LEED-NC then you're right, there is no credit for reducing cooling water use (although there is precedent for getting innovations points for it in previous versions of LEED-NC). I believe that NC doesn't address this simply because in the early days of LEED we were unable to establish a fair baseline from which to compare a project's design and award points.

But you say that this is an existing museum--does that mean it's apply for EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems. certification? In that case, there is WE Credit 4: Cooling Tower Water Management, which includes a point for minimizing water use and another for using a nonpotable waterNonpotable water: does not meet EPA's drinking water quality standards and is not approved for human consumption by the state or local authorities having jurisdiction. Water that is unsafe or unpalatable to drink because it contains pollutants, contaminants, minerals, or infective agents. supply.

Joel McKellar replied Research, LS3P ASSOCIATES LTD. Feb 15 2010

You can likely submit credit from the EB systems for an ID point in LEED-NC or CS and it's not covered elsewhere.

Bill Swanson replied Oct 06 2009

You could always try for an innovation design credit. Just document the water savings is equivalant to this credit. Potable saved is potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. saved. I doubt the review team will reject it if your numbers add up.

Bill Swanson replied Oct 06 2009

See my first post for some estimates. You don't need a template to calculate the values. But if you want to use one then just modify the v2.2 template.

Tristan Roberts replied Editor – LEEDuser, BuildingGreen, LLC Dec 03 2009

Wagner, the USGBC document Shannon references below answers your question, I believe. To quote from the last page of it:

"When using a metering (or autocontrol) faucet, please select the Metering Lavatory fixture in the Fixture Type pull-down menu of the Table. Flow Fixture Data.

"The Baseline case flow rate for a metering faucet is .25 gallons per cycle (gpc). Since the flow rate is measured in gallons per cycle, the duration is not necessary. The “Installed” flow rate must also be entered in gallons per cycle."

Dave Intner replied Firmitas Architecture & Planning Dec 09 2009

Thanks for posting this link, Shannon; I had been somewhat vexed as to how USGBC intended for us address metering faucets, and this helps clear it up quite a bit.

Mara Baum replied Sustainability Coordinator, Anshen + Allen Architects Feb 15 2010

Most of the people who spend time in student housing are people who actually live there, so the transient number is likely to be relatively low. I would speak to the college or university housing office to try to pin down an estimated number. Be up front about this issue, the discussion with the housing office and all assumptions or other ways of thinking in the credit template narrative. In many circumstances guessing transient numbers is an exercise in estimation -- just be honest about it.

Bill Swanson replied Feb 26 2010

Yes, at 60 psi. I remember reading a CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide asking about gpm at different psi for some multistory dorm building. The response was that you had to use the gpm value at a standard psi for all fixtures which I think was 60 psi.

Bill Swanson replied Feb 26 2010

here's the wording of the actual CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide ruling.

8/27/2004 - Ruling
[Note: this ruling was revised on 9/1/04.]

The underlying assumptions used for calculating projected water use savings should remain consistent between the baseline and design case. Supply water pressure varies across the United States and within individual buildings (as you note in your inquiry). Flow rates at 80 psi are used for the calculations in this credit for consistency and to reward use of efficient fixtures. It is recommended that all projects use the flow rates reported by the manufacturer at 80 psi for comparison with the Energy Policy Act of 1992 flow rates. If you wish to use on-site tests to report the most accurate volume of water use, you must be consistent throughout all fixtures and test both baseline and design fixtures. It is not acceptable to use flow rates at 80 psi for some fixtures and actual flow rates for other fixtures. Measurement can also be used to account for the benefits of whole-building strategies, e.g., flow restrictors at the water service entrance.

Jean Marais replied b.i.g. bechtold INGENIEURGESELLSCHAFT MBH Mar 02 2010

I didn't check your math, but recently also spec'ed a metering faucet for 0.125 GPC which I rounded to 0.13. It could be that the baseline GPC of 0.25 is based on a much more realistic cycle time of 15 seconds or 12 seconds with autocontrol. 5 seconds is about 33% of 15 seconds.

Andrea Traber replied Director, Sustainable Buildings and Operations, KEMA Mar 05 2010

I wish I did have insight as to why the baseline methodology was changed to GPC, and I concur that you have in fact discovered a significant gap for this fixture type, we have too. One suggestion is to leverage your contact with your assigned review team, provided that your project is registered, and ask them to clarify the methodology, and ask if they are aware of the intent of the GPC calcs. Additional contact with USGBC LEED staff may be helpful. Yet another reason the CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide process needs to come back!

Andrea Traber replied Director, Sustainable Buildings and Operations, KEMA Mar 09 2010

I inquired with GBCI and this issue has been identified as needing investigation. It will be presented to the WE TAGLEED Technical Advisory Group (TAG): Subcommittees that consist of industry experts who assist in developing credit interpretations and technical improvements to the LEED system., though I'm not sure of timing. The thinking is that there is a discrepancy in the baseline calculation methodology. Stay tuned and I will post if a clarification is announced.

Hannah Pham replied Mar 09 2010

Dave makes a great point and there is definately a discrepancy here! The .25 GPC baseline for metered faucets, when converted to GPM, equals 1.5 GPM (three times the baseline for public lavs). Perhaps the assumption is that, if the faucet doesn't shut off automatically, people will leave it running three times as long, therefore using three times as much water. I seriously doubt the accuracy of this type of assumption. As Tristan commented above, "Published studies have tended to show that fixtures with sensors use more water on average than those without." At least, if there is no conclusive evidence to the contrary, the baseline GPM should be the same for metered and non-metered faucets. This would also avoid a lot of confusion.

Tristan Roberts replied Editor – LEEDuser, BuildingGreen, LLC Mar 12 2010

We heard from TAGLEED Technical Advisory Group (TAG): Subcommittees that consist of industry experts who assist in developing credit interpretations and technical improvements to the LEED system. support staff on this question. They have been hearing the same question from several sources but don't have a ready answer. They also noted that based on the TAG's current schedule and workload, we may be in for a waiting game.

Dave Intner replied Firmitas Architecture & Planning Mar 12 2010

Shoot, that's a bummer they have it on the back burner. Depending on how they rule on this, it could be a six point swing for our project; possibly more. I wonder if submitting a formal CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide would expedite it.

There is precedent within LEED for multiple analysis paths leading to different outcomes; for example, EAc1.1 (Lighting Power Density) in LEED CI 2009 allows you to use either a Space-by-Space Method or an overall Building Area Method. Same fixtures, same floor area, but potentially different results due to varying baselines.

Just sayin'.

Neil Rosen replied Project Director, North Shore LIJ Health System Mar 17 2010

As an example, Zurn makes it, its not on their standard sheet but just spec it with plain end, flow control in base of spout and that you want 0.5 gpm.

Dave Intner replied Firmitas Architecture & Planning Mar 17 2010

That would be helpful to us, too, if you could point us to a couple, Neil. We have had similar trouble finding them at that flow rate.