NC v2.2 WEc3.1–3.2: Water Use Reduction

Select Alternative Compliance and upload your own unprotected Excel sheet that does the calculations. Make sure to include a narrative that explains in detail how your Excel sheet works.

William, first question—what rating system are you using? Just checking since this seems like a CS question that's posted in the NC-v2.2 forum.

Tristan, this project is pursuing a LEED NC certification. It is a 4-story project. Three stories are completely fit out, and the lower level is split - partial occupancy for management office and amenity spaces, with the remainder (approx 13,000sf) being shell space for future retail and/or office upfit.

The future tenants of the shelled space will not have access to the restrooms in the remainder of the building, and therrefore will be required to fit out their own facilities within their space(s). The owner intends to require the future tenants to pursue LEED CI for their respective upfits via green lease, and we have written guidelines providing maximum allowable flow rates, and recommended fixtures.

As LEED NC is a whole building rating system, I cannot technically exclude the shelled volume and must account for it in our calculations with the rest of the building. My question is how do I go about accomodating that future occupancy within my calculations? Am I required to assume they will upfit their restrooms using baseline fixtures, or can I use the maximum allowable flow rates that we've provided in the tenant guidelines, provided that the owner submits a letter attesting that they will hold the tenant to those flow rates within the lease agreement?

William, I think the best guidance on this is from CS Appendix 4 in the 2009 BD&C LEED reference guide. Yes, it's 2009 and yes it's CS, but I think the prescription there is perfectly logical for your situation.

Assume that tenant fixtures will be equivalent to the baseline, unless you're claiming savings in which case those must be supported by tenant sales and/or lease requirements.

Does that make sense?

Yes, that makes sense. But, if I understand Appendix 4 correctly, we would have to provide a copy of a lease agreement in order to claim savings? Would a signed letter from the owner stating that they will enforce those requirements through a binding tenant lease be sufficient for our needs to claim savings, or must we literally have a copy of the agreement?

William, I don't know. I would think that the letter would work, but the leases would be more ironclad.

If you find out what works, let us know.

There is currently no tenant in place yet. The owner, being a non-profit, opted not to pay legal fees to generate a draft lease agreement until they have a prospective tenant lined up. So, we moved forward by submitting a signed letter from the owner attesting to enforcing requirements through a binding lease, as well as highly detailed tenant upfit guidelines. Fingers crossed...

I'm anticipating we'll receive award notification sometime mid-September. I'll post here what the determination is.

David - though I agree with your line of thinking, it is conceivable that there may be other visitors/transients to the building aside from the students. If you refer to the table in Appendix A in the reference manual, you can calculate transient occupancies for schools with the following formula:

# transients = gross square footageSum of the floor areas of the spaces within the building including basements, mezzanine and intermediate-floored tiers, and penthouses with headroom height of 7.5 ft or greater. It is measured from the exterior faces of exterior walls or from the centerline of walls separating buildings, but excluding covered walkways, open roofed-over areas, porches and similar spaces, pipe trenches, exterior terraces or steps, chimneys, roof overhangs, and similar features. / 150

So, if you had a 50,000sf facility, your total transient occupancy would be 50,000 / 150 = 333. (189 students plus 144 additional visitors/transients)

Thanks for your reply. Do you think that would solve their request for daily average building occupants? From my submitted template and attached calculations, they probably can't conclude or differentiate between students and "other" visitors becuase I included them as one in the same.

I can't speak to a higher-ed facility submitted under LEED NC, but under LEED for Schools the template clearly delineates between 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., Students, and Average Visitors.

My recommendation would be to provide a narrative that spells out the number of staff and students, and provides the calculation for transients. Refer to the table in Appendix 1 in your narrative so there's no question where your trnasient calculation came from.

On a side note, in my original response, I said the transient number included the student occupancy. The more I think about it, the transients may be in addition to the student population given that the LEED Schools template makes the delineation.

Yes, our facility willl be different than a k-12 type, it is more of a traching lab building where 1-2 classes/day may be brought in. Regarding the student vs. transient discussion, my confusion is in the template where you can list 1.) the FTEs, 2.) a student/visitor, 3.) customers, 4.) resident, and 5.) Other. So to me if they are not full-time they are calculated as a transient (at least in the template). That is why I wondered if the "daily building average" was including the transients into the FTE but the template surely is not set up that way to calculate your water usage, i think you are probably correct in stating that a narrative would help.

Yes, if you meet both criteria you'll qualify for two ID credits.

GBCI just denied my project a 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. ID credit because the project had also been awarded the WEc3 40% reduction ID credit. This conflicts with your interpretation. The review comment states: "The project has already achieved 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. of WEc3. Only one exemplary performance point is available for each credit." The comment further states: "Innovation in Design credits are not awarded when the strategy aids in the achievement of an existing credit." I may appeal this. Does anyone have a good idea how to justify it? Or has anyone actually achieved two ID credits for WEc3? Thank you!

I would agree with their comment "Innovation in Design credits are not awarded when the strategy aids in the achievement of an existing credit"; however 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. consuming fixtures DO NOT contribute to the achievement of WE Credit #3.2.

On page #393 of the LEED NC ver2.2 reference guide it states that "no single strategy is eligible for more than one point". It does not say that only one 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. point is available for each credit.

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. usage and process water usage are,in my opinion, two completely seperate items. LEED NC ver2.2 does not include a credit strictly dedicated to process water consumption. However the LEED 2009 rating systems include a credit specifically for process / cooling tower water. Furthermore, BOTH the Water Use Reduction & Process Water Use Reduction credits of LEED 2009 allow project teams exemplary performance. Since ver2.2 does not specifically include a credit for process water usage it must lump it into the Water Use Reduction credit.

I disagree with the LEED reviewer and argue that project teams should not be penalized for "incompletions" of older rating systems.

I brought my soap box to LEEDuser today. :)
Hopefully you achieve success when interacting with the GBCI on this issue.
-Dave

Lauren, I am not looking at the Reference Guide right now, but my guess is that they are asking you to demonstrate a combined reduction of 10%.

Have you figured this out since you posted the question?

Angie -
There's a link at the bottom of this page to the 2009 page where Mara discusses this in a few places. It sounds like you'll want to look into using fixture groups to differentiate between guest and staff water use. Also, look for the place to enter "Total number of residents" in PI form 3 - it's on page 3 after the FTE and Occupancy tables.

Veronica, I just played around with the template a bit and it seems like if you vary the percentage of male bathrooms that have urinals, it changes the water use, even if you are not changing anything about daily uses, etc. So yes, it takes it into account.

Melissa, would this be a better post for the CS WEc3 forum?

Sorry Tristan, I believe that my initial question did not contain sufficient detail.

My project is an NC v2.2 project consisting of a residential tower with a core and shell space (approximately 22% of total GSF) that is most likely going to be built out into a museum. The residential tower and core and shell space core bathrooms have different types of plumbing fixtures. We are having difficulties with:

1.) Figuring out how to use the v2.2 LEED Online Template with multiple fixture and occupant types, AND
2.) Estimating number of transients for the core and shell space since there is not a type listed in “Table 1. Default Occupancy Numbers” in the LEED BD+C Reference Guide, Core & Shell Appendix 1.

Can we use the NC v2009 template in lieu of the v2.2 LEED Online Template, since it will let us easily incorporate multiple occupant and fixture types? AND, since this core and shell space is a portion of a primarily residential New Construction project, is the CS WEc3 forum the best place for us to track down an answer to the initial inquiry of how to estimate the number of transients and FTEs for a core and shell space that will most likely end up being museum space?

Melissa, in terms of using the 2009 form I would ask GBCI if this is okay. It seems to make sense but I would ask in this situation.

Relative to estimating transients and FTEs, that's a difficult question. It seems unusual to build a C&S space for a museum without having some idea who the tenant will be. If you do have some idea, can you look at existing museum space that is similar and estimate from that?

There are so many different kinds of museums, it would seem hard to have a general rule for this.

I believe you can address this by setting up fixture usage groups identifying the varying fixture groups and their anticipated usage. Make sense?

I'm confused. I have a similar issue on a project. Can I for example, nominate 2 of 4 unisex WC's for men and count them without urinals or can I disregard them entirely?

Beckham, I don't know what you mean about disregarding them (what?) entirely.

If the WC's are unisex and will be marked as unisex then I don't see how you can count them as being just for men in your calcs.

Hi Tristan,
Can you use fixture groups with the 2.2 template? I asked for clarification from our review team and they are saying we should base the percentage on the number of restrooms accessible for males. For example, we have 6 multi-accommodation restrooms for males and 22 unisex restrooms therefore we only have 21% of male restrooms with urinals. This means we loose all of our water reduction points! I'm going to ask if we can base it on number of fixtures instead. Something to be aware of on projects with significant numbers of unisex toilets. If anyone has any other experience with this, I'd love to hear. Thanks.

Tristan,
Them is the WC's. I'm specifically wondering how I count WCs vs Men's Rooms with Urinals. The template requires a percentage of Men's Rooms with Urinals be input. Am I required to count the Unisex WCs as Men's Rooms without Urinals or can I disregard the Unisex WCs from the equation?

Hi Beckham,
Based on my recent experience with a reviewer, yes: you have to count unisex restrooms as accessible to men. Therefore if you have 5 unisex restrooms without urinals and 5 male restrooms with urinals, you'd have to put in that only 50% of men's restrooms have urinals. The template says that if your project has any urinals, you can not use the dual-flushA type of water-saving toilet that gives a choice of flushes depending on the type of waste — solid or liquid. option for males, which for our project means we loose all of our water points. I'm appealing this with our reviewer and have submitted two separate templates: one for just the percentage of male restrooms with urinals and one for everything else. I then added the two baselines and the two design case water usages and got a percentage from that. I think this is a more accurate reflection of usage and ironically it's almost the same percentage I got without all the number gymnastics. I'm not sure if they're going to accept though. I'll post and update once I hear back. Has anyone seen 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 about this kind of issue? I haven't been able to find one. Thanks

I have just run into the same review comment. We have a theatre with 2 unisex restrooms, 1 male restroom with urinals and 1 female restroom. The reviewer is saying we have 3 male restrooms and therefore only 33% of male restrooms with urinals. We also have dual flush toilets and they are requireing that we call 100% of the male use of the dual flush toilets as full flush. This seems totally skewed to me. We have a 50/50 gender split so half of the time the unisex restrooms will be used by women. This is a double penalty for having unisex restrooms. I guess I can understand calling them male, since they are accessible to males, but then the logic that there is NO half flush use of the dual flush toilets for males makes no sense.

Hi Nancy,
I finally heard back from the GBCI regarding my alternative compliance approach. They spent a long time looking at it apparently and provided the following guidance:

"First of all, please note that the percentage of male restrooms with urinals may be calculated based on the percentage of male fixtures in bathrooms that have urinals versus the total number of fixtures available to male occupants. For example, if your project has 20 male-accessible bathrooms with a total of 100 male fixtures (both urinals and toilets) and the breakdown is 5 bathrooms that contain a collective total of 85 fixtures (mix of toilets and urinals) and 15 bathrooms that contain a collective total of only 15 toilets (with no urinals), the percentage of male restrooms with urinals would be 85% (85 mixed fixtures / 100 total male fixtures). Please take care to include all fixtures that are available to males in your calculations (i.e. any unisex toilets must also be included in the total number of male fixtures in addition to those dedicated solely for male occupants).

In order to claim credit for dual-flushA type of water-saving toilet that gives a choice of flushes depending on the type of waste — solid or liquid. toilets in male restrooms when the project also includes urinals, you must perform a weighted calculation to determine an accurate percentage of males who will be utilizing the dual-flush option versus those that are expected to use only the full-flush option (i.e. those males who will be accessing the urinals). This number must be calculated using the percentage of male restrooms that was determined above. For example, assuming that you have 200 male occupants and that 20% of these occupants will have access to the urinals – these 40 people cannot be assumed to use the low-flush option of the toilet as they will be expected to be utilizing the urinals instead. However, you must calculate the amount of water they will generate using the full-flush option. To do this, you will need to perform the following calculations (numbers used as examples):

• Male Occupants with Urinals:
o Percentage of Male Restrooms with Urinals:
1. Count the total number of male-accessible fixtures: 100 Total Male Fixtures
2. Count the total number of fixtures in only the bathrooms that contain both urinals and toilets: 85 Mixed Bathroom Fixtures
3. Percentage of Male Restrooms = 85 Mixed Bathroom Fixtures / 100 Total Male Fixtures = 85% Male Bathrooms with Urinals
o Breakdown of 200 Male 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. Occupants:
• Males Without Urinals: 200 Male FTE Occupants x 15% Male Restrooms Without Urinals = 30 occupants
• Males With Urinals: 200 Male FTE Occupants x 85% Male Restrooms With Urinals = 170 occupants

2A. Full-Flush Water Use:
a. Males Without Urinals: 30 FTE males-without-urinals x 1 uses/day = 30 uses/day x 1.6 gallons/flush = 48 Full-Flush Gallons/Day
b. Males With Urinals: 170 FTE males-with-urinals x 1 use/day = 170 uses/day x 1.6 gallons/flush = 272 Full-Flush Water Gallons/Day
i. Total Full-Flush Water Use = 48 gallons/day + 272 gallons/day = 320 Full-Flush Water Gallons/Day

2B. Low-Flush Water Use:
a. Males Without Urinals: 30 FTE males-without-urinals x 2 uses/day = 60 uses/day x 1.1 gallons/flush = 66 Low-Flush Gallons/Day
b. Males With Urinals: 0 Low-Flush Gallons/Day as these occupants are assumed to be using Urinals rather than Low-Flush Toilets
ii. Total Low-Flush Water Use = 66 gallons/day + 0 gallons/day = 66 Low-Flush Water Gallons/Day

3. Total Daily Male Water Used: 320 Full-Flush Water Gallons/day + 66 Low-Flow Water Gallons/day = 386 Total Daily Male Water/Day
a. Percentage of Males Using Full-Flush: 320 Full-Flush Water Gallons/Day / 386 Total Daily Male Water/day = 82.90% FTE Males Using Full-Flush
b. Percentage of Males Using Low-Flush: 100% Total Fixture Use – 82.90% Males Using Full-Flush = 17.1% FTE Males Using Low-Flush

Please note that if you have multiple types of occupants within the project such as Transients, Residents, etc, the calculations for Steps 2A and 2B will need to be performed for each individual group based on the group’s total male occupancy, the group’s access to the urinals, and the group’s appropriate usage rates. The Total Water Use found in these steps should include the sum total of each group’s individual water use so that the overall percentage is accurate for each group.

For the urinals, you would still need to use the default of 100% of Males use the Urinals. For the design final review, please provide a copy of this email correspondence to confirm usage of this calculation method, separate calculations documenting the weighted fixture calculations provided in the Template, and a revised Template to show the weighted percentages for the male use of the dual-flush toilets. "

While this helped, I was still confused as to how to calculate the total savings and don't want to do all the calculations separately by hand when it seems that the template can handle it. I therefore replied with a second proposal that I split the occupancy between male restrooms with urinals on one template (using their guidance on percentage of fixtures to determine % of occupants applicable) and then womens and unisex on another. Haven't heard back yet but will let you know what they say. Ironically, the percent water savings was about the same from the split template and the initial version i submitted. It should be more straightforward!

Wow - that is indeed complicated! Thanks for the update it will definitely help me.

1) Yes, I agree.

2) Based on your note that the unequal staffing was not explained in the initial submission, and since your description makes it sounds like the situation meets the threshold the reviewer described, you have a good shot at justifying the unequal ratio and should go for that.

3) From what I have seen from GBCI, fire stations, or at least the dorm part, are considered "residential" for EAc1, i.e. HVAC, because EAc1 references ASHRAE 90.1 in which those dorms are residential.

With WEc3, GBCI is prepared to see a fire station as either residential or commercial depending on the project specifics. One of the factors they look at is shift length, and it sounds like you make a good case that this is more of a "commercial" situation than residential.

Thanks so much, Tristan! Very helpful.

I don't have a hard answer for you, but there's been some ongoing discussion on this same issue on the equivalent LEED NC 2009 page.