NC 2009 WEc3: Water Use Reduction

The pressure should be the same with less water. I don't think there should be any issues with using 1 gpm aerators.

I was just filling out the form too and noticed the same change. Although it now defaults at 30 seconds, the form does allow you to change the number of seconds back to 15 if that helps. I wouldn't consider this alternative compliance and just submit normally.

OK, but the case is that, except metering faucet where we can take data from cutsheet, we have to put default value which "might be modifed for special circumstances".
Do you think that requirements change during construction process might be considered as special circumstances?

Valentin,

This is a new edition to the WEp1 v4 of the credit. I believe your assumption is correct. As long as the pre-rinse spray value is 1.6 gpm or below it complies with the requirement. The actual consumption does not appear to be taken in to account in the calculation.

Hi Jeremy,

I agree that this appears to be a huge oversight in LEED Online v2009. The template, as you said, does not take into account rainwater or graywater1. Defined by the Uniform Plumbing Code (UPC) in its Appendix G, titled "Gray water Systems for Single-Family Dwellings," as "untreated household wastewater which has not come into contact with toilet waste. Grey water includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washer and laundry tubs. It shall not include wastewater from kitchen sinks or dishwashers." 2. The International Plumbing Code (IPC) defines graywater in its Appendix C, titled "Graywater Recycling Systems," as "wastewater discharged from lavatories, bathtubs, showers, clothes washers, and laundry sinks." Some states and local authorities allow kitchen sink wastewater to be included in graywater. Other differences with the UPC and IPC definitions can probably be found in state and local codes. Project teams should comply with the graywater definitions as established by the authority having jurisdiction in their areas. utilization even though the reference manual clearly states: "Efforts to increase rainwater harvesting, increasing graywater use, and decrease the demand on local water aquifers may support the following credits: EW Credit 3: Water Use Reduction."

My recommendation would be to submit a technical question through the 'feedback' link under the Credit Information tab as well as sending an email via the contact tab at gbci.org. In your question, I'd spell out your utilization of rainwater, the quantities harvested, what fixtures the non-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. is used in, etc. It may even be viable to send them a completed v2.2 template to demonstrate the savings achieved and why you are looking for the same opportunity to demonstrate savings achieved on the v2009 template. The drawback to this is that it may take up to 4-6 weeks to get a response; and there's no guarantee that the response will be of any help.

If time is an issue, it may be a gamble, but you could try using the alternative compliance approach and submit an excel spreadsheet that mimics the v2009 template, but adds in the missing rainwater/graywater non-potable source water table from the v2.2 template.

Hope this helps. Good luck!

I just read down, and saw this under another comment regarding graywater1. Defined by the Uniform Plumbing Code (UPC) in its Appendix G, titled "Gray water Systems for Single-Family Dwellings," as "untreated household wastewater which has not come into contact with toilet waste. Grey water includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washer and laundry tubs. It shall not include wastewater from kitchen sinks or dishwashers." 2. The International Plumbing Code (IPC) defines graywater in its Appendix C, titled "Graywater Recycling Systems," as "wastewater discharged from lavatories, bathtubs, showers, clothes washers, and laundry sinks." Some states and local authorities allow kitchen sink wastewater to be included in graywater. Other differences with the UPC and IPC definitions can probably be found in state and local codes. Project teams should comply with the graywater definitions as established by the authority having jurisdiction in their areas. use... Under the Resource Tab above, there is a technical document entitled: LEED 2009 Water Use Reduction: Additional Guidance. On page 4, it provides guidance for calculating non-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. use. You'll still need to use the alternative compliance path as I suggested in my comment above, but there at least is a method for it.

William, thank you! That document needs to find its way into the reference guide IMO. Thank goodness for LEEDUser!

Also, it seems that the intents for WEc2 and WEc3 need to be refined a little more. They overlap in some ways, which isn't ideal. Maybe they could be modeled after EAc1 and EAc2 where one deals only with efficiency, and the other with on-site generation and use. I think that aquifer recharge is already pretty much covered by SSc6.1 and SSc6.2. Just my two cents.

There currently is no explicit guidance on how to calculate visitors for residential components of a project, and from past experience, this has not been included in the water use calculations. If you did want to include visitors as part of the residential component, I assume you could estimate the number of transients / visitors and propose an estimated usage but it seems like this can be excluded altogether. Have you checked with GBCI?

Nicolas, it seems you an use any 2.5GPM showerhead at 80psi for your testing. There aren't any LEED accredited showerheads, so you don't have to worry about that.

I was actually looking for the answer to the very same question. I found the answer in the USGBC's Water User Reduction Additional Guidance. On page 4 under Non-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. Use Calculations it recommends using the Alternative Compliance Path section of the Submittal Template. This does not automatically change your calculated water savings but I imagine that with proper calculations and documentation they will award you (and us) this credit.
Good luck!

Yes. That's correct. Because it's assumed that the tenant than just meets Epact 1992 not improves it by 20%. You will have to have some improvement with fixtures installed in the building. Keep in mind just because the tenant installs them all, doesn't mean you would not consider them in the calculation.

Susan, sorry that you didn't get a reply on this question. Did you make a decision on what to do here?

I realized that the gender of the patient is irrelevent because the patient bathroom does not have a urinal in it. Then I developed a spreadsheet that bases staffing off bed count which was the key to engaging the hospital staff as they think that way. We went with a 24 hour calculations for everyone one which further simplified who is in what category. We will upload the back up spreadsheet when we submit next month. It took some time but eventually we were able to streamline this process.

According to Kohler, a blow-out water closet is one that has a non-siphonic trapway at the rear of the bowl, and integral flushing rim and jet. Since the water closet you referenced has “siphon-jet flush action” I would assume that it is not considered a blow-out water closet and would use 1.6 gpf as its baseline flush rate.

My guess is someone wrote a manual for the reviewers to follow and they're following the wording of this manual that we don't have access to.

I'm figuring as much, but it doesn't seem right that they can change the rules mid-stream. Plus, it's not even accounted for in LEED 2009. Very frustrating. Each time I think I have the credits figured out and "this time we will get it through on the first try", they seem to change the rules.

I've suggested to USGBC that they look at this issue and consider putting out an addenda so that everyone is on the same page.

The gender ratio being defensible for the life of the building is actually from 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 Ruling dated 9/14/2006, "Also, you should be sure to use a 50/50 male/female ratio unless there is strong evidence of an alternate ratio for the projected life of the building."

The "strong evidence" aspect is apparently at the reviewer's discretion, and I have seen them rule both ways. To futher complicate things there are quite a few new reviewers undergoing training right now, so more fluctations between past and more recent reviews should be expected for awhile.

Tristan - I have two questions:
1) If our building is designed TO CODE with an 80/20 ratio, it would not seem to make sense to use a 50/50 ratio. The evidence for the particular facility I am trying to get certified right now is in the fixtures themselves: 2 women's toilet total, 4 men's toilets plus 4 men's urinals - for a total of 8 fixtures. These facilities have long histories (30 years plus) of operating at these ratios. Should we simply explain this in better detail to the reviewers? Again, it doesn't seem to make sense for the calculations to use a 50/50 ratio when that is not what the building is designed for or how it will be used "for the life of the building".
2) I can understand, perhaps, changing the rules with an Addenda for v3.0 (2009), but should not all v2.2 projects be held to the same standards? We have three projects that have used ratios other than 50/50 and these earned the points with no problem - exact same type of facilities. I plan to cite those certified projects in my reply to the reviewers. This has worked for other clarifications.

Thank you,
Kris

How well did you explain the permanance of the fixtures in the given ratio in your submittal? If it were up to me I'd say you have enough evidence, provided it's properly explained. I'm not GBCI, though, so I can't speak for how they see it.

I'm curious what kinds of obstacles you're facing in getting water use below the baseline. Theoretically you can replace all the fixtures and fittings necessary to get you there. What's the case you'd make for a looser requirement here?

Also, maybe I'm forgetting something obvious, but does LEED require a different baseline for projects subject to CA Title 24?

Tristan,
My intent may not have been clear. We are not facing obstacles getting water use reduction below baseline. My hope, however, was to show 'real world' savings. Where the reference guide baseline assumes reduction from 1.6 gpf to 1.28, we will be reducing from 3.0 to 1.28. Significantly lower draw on municipal resources.
We have a number of complications which make some other credits very hard to achieve ( historically significant building with large single pane operable windows which must remain), any assist here would increase our desired compliance.
LEED does not require a different baseline for CA Title 24 projects.

My gut reaction is that you won't be able to successfully argue this. ItsSeems to fall in the category of doing a great job making a big reduction, but it's not something that LEED gives extra credit for.

Think about it from a LEED policy perspective, and how difficult it would be to draw a clear line between projects deserving of extra credit for this kind of situation, and projects not deserving. LEED solves this by creating a single benchmark for what it considers a reasonable conventional baseline.

You may be able to get extra credit through RPc1, if this is an applicable credit, and through synergies with WEc2.

Other thoughts?

Tristan,
Fair enough. I do understand it must be difficult to try to find an acceptable template for all project types. In a project where we are being both innovative and historically reverential, situations arise where doing the right thing is sometimes rewarded big, other times not so much.
Thanks for your time reviewing this.
Rick

Rick, seems this is one of the obstacles of LEED (real world vs. base case). Unfortunately there's no way to "prove" that you have 3gpf fixtures, and they are not going to send someone to check every renovation project out there. Thus the reliance on a standard as Tristan mentions above.

After the shower runs out, can you immediately push it again for another cycle? Or is there a delay during which you can't push it?

The reason I ask is that without this kind of thing, there's no guarantee of reduced shower time.

Hi Tristan

Yes. Unfortunately the valves do cycle immediately when engaged. This is typical for a spring activated valve. And no a reduction in run time cannot be guaranteed.

On a similar note if an infrared sensor was used is there a precedence from previous projects to reduce the run time in the calculation? If not then I would assume spring activated would be evaluated on a similar basis.

I haven't heard of such a precedent, no. Perhaps with infrared sensors it would be possible to include a delay that would actually encourage people to get out of the shower—in which case perhaps a reduction could be justified. I don't see it being justified for the spring-activated valve.

Tristan

I agree...it was a bit of a long shot. I also reviewed this with another consultant who does a lot of recreational facilites and he has also not heard of an precedents.

Thanks.

Deborah

Nobody seems to be replying to these threads which is disapointing.

Your question seems similar to mine below in that it is not covered under any descriptions on how to achieve the credits in any of the LEED literature.

I agree with what you are proposing but the only means to verify if it will be acceptable is probably to post 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. Of course I would anticipate that you will get an ambiguous answer and that final approval or rejection would be based on the acutal audit.

I would be surprised if this credit was awarded based only on the water metering system you describe. While research may show a 20% reduction from this kind of system it still relies on behavior rather than the efficiency of the installed fixtures.

The metering system is still a great idea, I just don't think it will be sufficient to prove compliance with this prerequisite, especially since you'd be hard pressed to prove actual savings in a new building.

I would start by reading this USGBC document, which clarifies a lot of common questions about calculations for this credit. Post back here if you still have questions after reviewing it.

There is a documentation approach to Gallons Per Cycle: if the sensor faucet is equipped with a .5gpm aerator, and the metering cycle is 10 seconds, the flow is .08gpc v. the baseline of .25gpc provided.

This can be calculated by .5gpm / 60 seconds * 10 seconds = .08333 gallons used in each 10 second meter. This selection would contribute a 66% savings towards your case versus baseline and can be a major factor in the entire building's water efficiency calculation.

Metering faucets and sensor-operated metering faucets will have fixed metering timing (or adjustable) depending on model and operation. Choose a suitable duration and flow rate.

Hi,
I also can`t find precise explanation related to flow rate. With the metering faucet it`s clear. But am I correct that if flow rate of my public lavatory faucet (without metering and sensor) is 5l/min (1.32 gallon) the calculations are: 1.32 gpm * 15 sec / 60 sec = 0.33 gpc ? Or gpc is used only for metering faucet and in the row with baseline (public lavatory faucet) 0.5 I should write 1.32 (and we are not taing to account duration) ?

Thanks

Isn't there a difference between a metering faucet and a sensor operated faucet? This seems different to me that the method under LEED v2.x Under that guidance we were able to assume the design case was 12 sec versus 15 sec for the baseline. But I don't know about this version of LEED documentation. Can we specify 12 seconds on a sensor operated faucet and show water savings that way? Is it described in the USGBC guidance document somewhere that I am not finding?

Jonathan, see USGBC's additional water guidance document. It specifies that savings is based on gallons per cycle, so reduced duration does not help with the credit.

The documentation for this credit is mostly populated from the LEED Online form for WEp1. When you're documenting WEp1 in the LEED Online form, you have he opportunity at the beginning to define "Fixture Groups," which could correspond to different usage types like those in your project.

I have a similar project type with split occupancies of office/retail on one floor and residential multi-family on three floors. My question is relative to calculating transients for the residential component. Appendix A in the LEED reference manual provides guidance for calculating FTEFull-time equivalent (FTE) represents a regular building occupant who spends 8 hours a day (40 hours a week) in the project building. Part-time or overtime occupants have FTE values based on their hours per day divided by 8 (or hours per week divided by 40). Transient Occupants can be reported as either daily totals or as part of the FTE. Residential occupancy should be estimated based on the number and size of units. Core and Shell projects should refer to the default occupancy table in the Reference Guide appendix. All occupant assumptions must be consistent across all credits in all categories. and transients for various occupancy types, but nothing for residential/multi-family. Because we couldn't find any guidance initially on the residential floors, we assumed one visitor per residential unit. Is there any rule of thumb for calculating transients for multi-family projects?

Additionally, in the preliminary review comments, the reviewer suggested that "transients of the building should be removed from the calculations associated with these fixtures [residential] since they do not have access to these fixtures." This does not seem right as a visitor to a residential tenant would likely use the tenant's restroom, and not go down to the first floor to use the public restrooms. Thoughts?

William, I agree with your logic and I don't know of any other resources for residential transients.

Have you learned more since you posted this?

You are right in that process waterProcess water is used for industrial processes and building systems such as cooling towers, boilers, and chillers. It can also refer to water used in operational processes, such as dishwashing, clothes washing, and ice making. savings can not apply directly to WEc3, but it can contribute to an ID point. If we maintain credit interpretations from LEED NC, you need to be able to prove that process water savings represent at least 5% of the base building water use as defined by WEc3. I think it's a reasonable assumption to thing that you can get an additional point if you can prove a savings in excess of 45% with both regulated and process water included.

Save the template from WEc3 as a pdf and upload it as a document for the IDc1 credit. You still have to fill out the IDc1 Template. The Intent is the same as WEc3, the Requirement is to exceed the exemplary credit threshold, and the Approach is the approach that you took to achieve your water efficiencies.

Yep, sounds like you got it right with the three FTEFull-time equivalent (FTE) represents a regular building occupant who spends 8 hours a day (40 hours a week) in the project building. Part-time or overtime occupants have FTE values based on their hours per day divided by 8 (or hours per week divided by 40). Transient Occupants can be reported as either daily totals or as part of the FTE. Residential occupancy should be estimated based on the number and size of units. Core and Shell projects should refer to the default occupancy table in the Reference Guide appendix. All occupant assumptions must be consistent across all credits in all categories.'s. No word on LEED for Healthcare—waiting on the next public comment period.

This should have a preview option. I forget some things.

I'd like to add the question about usage rates as well to this.

The LRG has water use calculations which indicate fixture usage rates based on residential standard calculation methodology presented in the LEED-NC v2.2 Reference Guide, Third Edition on page 142.

So, would guests count toward a Residential occupancy (same usage rate essentially as a home, i.g. there at morning and night)? Unless special conditions exist, projects should assume a 50/50 male/female ratio and an average of 5 fixture uses per day for residential usage.

Any thoughts are appreciated.

I would calculate hotel guests as residents, and yes, they should definitely have an assumed 50/50 male/female usage. This is always true unless there is a very specific and provable reason otherwise, which I can't really foresee for a hotel. You would also have FTEs (hotel employees) and transients (visitors + those who come for events, conferences, etc.) These would all be calculated separately in the WEc3 template. You will have to work with your client and design team to determine how many transients are appropriate based on event spaces and other hotel practices.

Thanks Mara, that's what we suspected after looking thru LRG BD+C (we are analyzing this for NCv2.2). But, still, for SS4.2 should different FTE be applied vs WEc3? As 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 v2.1 SSc4.2 6/20/2008 where the guests belong in transient calculations.

There is limited guidance from the USGBC on this matter. Inpatients are considered to be residents; outpatients are transients.

Calculating transients is often an exercise in estimation, and this is especially true for healthcare, because so many of the staff are mobile -- e.g. doctors on rounds who may pop into a building for just a few minutes or maintenance personnel who work in one building periodically but may have a permanent home in a different building. This type of occupant is usually a transient, although you should use common sense to determine your approach. You should work with your client to estimate these numbers, as well as outpatients and typical visitors per inpatient. They will probably hate this! Start with everything you know about the building, then and ask questions as specific as possible. For example, a desk in an office building often represents 1 FTE... but it could represent 3 in a hospital nurse station... even if the desk is used only two individuals, because shifts are often 12 hours.

I have not found the LEED for Healthcare draft (now quite old) to be useful on this topic, as it's something that is more likely to be addressed in a reference guide.

thanks!