NC-2009 WEp1: Water Use Reduction—20% Reduction

  • NC CS Schools CI WEp1 Action Steps Diagram
  • The bar has been raised

    You will not earn this prerequisite using standard fixtures that only comply with the federal EPAct 1992. This prerequisite, first introduced in LEED 2009, raises the bar significantly. All projects must now reduce water use by at least 20% as a prerequisite, whereas earlier versions of LEED awarded a point for a 20% reduction. The baseline against which water savings are measured has also become more demanding. The LEED 2009 baseline for commercial lavatory faucets is 0.5 gallons per minute (gpm), whereas the previous baseline was 2.5 gpm. Note that this prerequisite addresses interior water use only, but can be coupled with other water credits addressing outdoor water use.

    Plan on focusing on efficiency with ultra-low-flow or waterless fixtures, as well as overall conservation with strategies like rainwater capture and graywaterGraywater is untreated household waste water which has not come into contact with toilet waste. Graywater typically includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washer and laundry tubs, though definitions may vary. Some states and local authorities also allow kitchen sink wastewater to be included in graywater. Project teams should comply with the graywater definition established by the authority having jurisdiction in the project area. reuse (these strategies are documented as an alternative compliance path in LEED Online). Careful attention to fixture selection and flow rates can help projects achieve 20% or greater interior water savings  at minimal cost and without compromising comfort.

    Clearly defining Fixture Usage Groups is an important step in achieving this credit. In buildings with toilet facilities that are not accessible to visitors, it is reasonable to exclude visitor numbers from the Fixture Usage Groups. The occupancy values entered in the PI forms should inform, but not necessarily parallel the numbers used for this credit. 

    Follow these key steps

    1. Determine Full Time Equivalent (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.) occupancy and Fixture Usage Groups.
    2. Determine the Baseline Case Water Use Budget for Indoor Water Use.
    3. Choose fixtures and water reduction or reuse strategies. 
    4. Estimate the project’s water usage by creating a Design Case Water Use Budget. 
    5. Use the LEED Online credit form to compare the baseline and design case water budgets to determine the water reduction percentage for the project. 
    6. Complete the LEED Online credit form and upload water fixture cut sheets.

    Sample water use reduction chart for a commercial building.

    In the example illustrated in this bar chart, 21% savings is achieved by looking for savings in the fixtures that use the most volume of water: toilets, urinals, and showers. This example assumes 1.28 gpf toilets, 0.5 gpf urinals, and 2.0 gpm showers. Sinks are a less likely target because baseline use is already very low in many cases.

    Only some water uses are under the LEED scope

    Project teams often assume that if a water fixture or process on their project uses water, then it must fall under the scope of this credit. However, only specific "regulated" fixtures fall under the scope. The following uses, among others, are not within the credit scope. Following efficient practices is a great idea for these uses, but it's simply not covered under the scope here.

    • "Process" water
    • Pot- or bucket-filling sinks
    • Bidets
    • Laboratory sinks
    • Dishwashers and other appliances

    Key guidance from USGBC

    Since LEED 2009 was launched, USGBC has developed and updated a key guidance document for WEp1 calculations: Water Use Reduction Additional Guidance. It provides indispensable guidance for fixture groups, total daily uses calculation, dual flush toilet flow rates, public metering faucet flow rate conversion, 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 alternative compliance path and gender ratio guidance.

    For example, this document provides key guidance on when a non-default male-female gender ratio is appropriate—essentially, modifications to the 50:50 ratio must be shown to apply for the life of the building, with specific exceptions allowed.

  • A question of scope

    As of an addenda issued in May 2011, USGBC has clarified the scope of this prerequisite for addition projects. For additions to existing buildings, only the fixtures within the project scope must be counted for WEp1. To earn points under WEc3, all fixtures necessary to meet the needs of occupants using the addition must be included, including those located within the preexisting building.

  • FAQs for Water Use Reduction

    Will the reviewers accept a spreadsheet as a plumbing fixture schedule in lieu of the plans from the Construction Documents?

    A copy of the plumbing fixture schedule from the project's construction documents, outlining detailed information for each flush and flow fixture specified (including fixture manufacturer, model number and flow rate) helps the review team verify that those fixtures are part of the construction contract. In the absence of such documentation, a copy of project-specific specifications and details or a project-specific contractor’s submittal with manufacturer’s cut sheets highlighting flush and flow rates for each fixture specified can be provided.

    In LEED review comments I've been referred to the Water Use Reduction Additional Guidance document. I didn't know this was a required reference document.

    USGBC originally created this guidance document to address common questions project teams encountered when documenting WE credits. The calculations in these forms are fairly complex and are generally not addressed in the reference guide. The guidance document is intended to guide the user through the process of filling out the form, but is not intended to create any new requirements.

    Should I include bar sinks? What about mop sinks or janitor sinks? Swimming pools? Safety showers? Bidets? Tub spouts?

    If the bar sinks installed have a similar usage pattern and are similar fixture type as for those in kitchens then these should be included.

    Mop sinks, janitor sinks, swimming pools, bidets, and safety showers are considered 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. and are not included. Consider only the showerhead and not the tub spout.

    Additionally, commercial kitchen sinks and bar sinks including pot sinks, prep sinks, wash down, and cleaning sinks are considered process water and are not included.

    However, pre-rise spay valves must be considered. If your project is registered after the 11/1/2011 addenda release then the pre-rinse spray valve flow rate must be 1.6 gpm or less in order to comply with the prerequisite. If your project has a pre-rinse spray valve that has a higher flow rate than 1.6 gpm, then the project is not in compliance and the pre-rinse spray valve would need to be revised in order to be eligible for LEED certification.

    We provided showers to comply with the alternative transportation credit. Should they be considered in WEp1 calculations?

    Yes. Once you enter the project occupancy the WEp1 form calculates the default daily FTE shower uses.

    If those fixtures are outside the LEED Project Boundary, they should only be included if your project is LEED-CI, however.

    Can you explain the 12-second duration for metering faucets?

    This duration is intended to prevent LEED projects from claiming credit for reducing the duration below 12 seconds; durations less than 12 seconds are not permitted for LEED calculations as shorter intervals are insufficient for typical hand washing

    Can I use a nonpotable water source to contribute to WEp1 compliance?

    Yes. Although the focus is water efficiency of the installed fixtures, onsite sources of nonpotable water such as captured rainwater, graywaterGraywater is untreated household waste water which has not come into contact with toilet waste. Graywater typically includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washer and laundry tubs, though definitions may vary. Some states and local authorities also allow kitchen sink wastewater to be included in graywater. Project teams should comply with the graywater definition established by the authority having jurisdiction in the project area., air conditioner condensate, cooling tower bleed off water, etc., can be applied via an alternative compliance path. Refer to the Water Use Reduction Additional Guidance document for further information.

    Our project does not have any eligible water fixtures in the project boundary. Can we comply with WEp1?

    Yes, per LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. #10214: "A project without eligible water fixtures in the LEED-NC project boundary is exempt from WEp1. Should such a project wish to pursue points under WE Credit 3, they may do so by evaluating WEc3 performance based upon all of the fixtures that are necessary to meet the needs of the project occupants, even if they are located outside the project boundary."

    We are having trouble finding EPAct-compliant fixtures. Is that a problem?

    Not for individual fixtures. You only have to meet the LEED requirements for your fixtures as a group.

    Where can I find a clear meaning of "public" and "private" as relevant to lavatory faucets?

    Private usePrivate use applies to plumbing fixtures in residences, apartments, and dormitories, to private (non-public) bathrooms in transient lodging facilities (hotels and motels), and to private bathrooms in hospitals and nursing facilities. applies to plumbing fixtures in residences, apartments, and dormitories, to private (non-public) bathrooms in transient lodgingLodging are facilities that provide overnight accommodations to customers or guests, including hotels, motels, inns and resorts. facilities (hotels and motels), and to private bathrooms in hospitals and nursing facilities. Any fixtures that are not in one of those more residential-focused situations are considered to be public fixtures.

    Our project is a factory with historically a 95% male workforce. The restroom design accounts for this. Can I argue that the male/female gender ratio is different than 50/50?

    GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC). provides very little leeway for non-standard gender ratios, even in a case just like you describe. Even a 10% bump toward women to account for possible future trends was not deemed sufficient. GBCI is only granting exceptions if a nonstandard gender ratio can be verified for the lifespan of the building.

    Are shower duration controls an acceptable water-saving strategy?

    LEED assumes a baseline of 300 seconds for a shower, and LEEDuser has heard of review comments rejecting controls that would shorten this duration for the design case. 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 or LEED Interpretation would likely be needed to make a case.

    Can I include process water savings in order to earn an Exemplary Performance point?

    Yes—refer to LEED Interpretation #5819, issued 8/31/2004 and modified 4/1/13 to apply to NC-v2.2 and NC-v2009 projects. Quoting the relevant text from LI #5819: “A whole building approach to process water must be used (including washing machines, dish washers, drinking fountains, cooling towers, etc.) The project must demonstrate a process water savings that is equal to or greater than 10% of the regulated water usage as calculated in WEc3. The project should obtain information on the average amount of water use for each type of equipment to determine an appropriate baseline and demonstrate that the increased efficiency compared to the baseline exceeds the 10% WEc3 threshold. Required submittals for this innovation would include: 1) A narrative explaining what strategies were used and how the baseline was developed. 2) Calculations demonstrating performance compared to the baseline. 3) Cut sheets showing water usage of equipment used.”

    NC projects have also had success using Schools WEc4 as an ID credit. Also see LEED Interpretations #808 (issued 7/8/2004) and #5752 (issued 5/13/2005) for some history on this issue. You can also earn an EP point for 45% savings under the Water Use Reduction credit, but it appears, based on the most recent ruling, that the 45% savings should be based on regulated (non-process) fixtures alone.

Legend

  • Best Practices
  • Gotcha
  • Action Steps
  • Cost Tip

Pre-Design

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  • Check local codes and incentives for water-saving opportunities and restrictions. Rebates are common, as are plumbing codes restricting some water-savings technologies such as waterless urinals, graywater reuse, on-site wastewater treatment and reuse, rainwater harvesting, composting toilets, and other strategies.


  • Graywater and rainwater collection systems may offer the potential for non-potable water to be used in interior applications, helping to achieve this prerequisite, and the additional water-reduction credit.


  • Perform a Water Balance Study for the entire project to make informed decisions about where to focus water savings efforts. Look for all water sources on the site, such as stormwater, graywater, and onsite water, and note opportunities for using that water for interior water use and or irrigation. 


  • Calculating outdoor water use is not required for this prerequisite . However, understanding how indoor water use compares to outdoor water use can help you gauge where to focus reduction efforts for the greatest benefit. Some water saving strategies address both indoor and outdoor water needs holistically. For example, graywater from interior sink fixtures can be collected for landscape irrigation.


  • Graywater used for landscaping cannot be calculated for this prerequisite, but can be counted in WEc1: Water Efficient Landscaping.


  • Are composting toilets an option? While not common, composting toilets can go a long way toward achieving this prerequisite. They affect programming and layout, so consider them early.


  • Consider setting water-reduction goals higher than the 20% reduction required by this prerequisite. Many projects are able to achieve 30%–40% savings with little or no impact on cost. First-time costs for water savings above 20% can be minimal since project teams will already be integrating water-saving techniques for this prerequisite.

Schematic Design

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  • Estimate the project’s baseline water needs and determine the baseline water use budget for indoor water use. This helps determine where the most effective water-saving technologies can be applied.


  • Establish goals for water use reduction and include these goals in the Owner’s Project Requirements (OPR) for EAp1: Fundamental Commissioning. Consider aiming higher than a 20% reduction. Many of the same strategies used for this prerequisite will also apply to WEc2: Innovative Wastewater Technologies and WEc3: Water Use Reduction.


  • Determine the numbers and types of occupants in the building. The water use calculation is based on occupant use and the number of full-time equivalent (FTE) occupants, including employees and visitors, not the number of water fixtures installed.



  • Determine user groups for the various fixtures as not all occupants may be using all the fixtures; for example, employee restrooms and customer toilets in a retail store will have different use patterns.


  • The baseline for commercial lavatory faucets has been changed in LEED 2009 to 0.5 gpm.  The previous baseline for commercial lavatory faucets was 2.5 gpm. Take note of this more stringent requirement compared with earlier versions of LEED.


  • This prerequisite only includes core water uses—bathroom lavatories, water closets, urinals, showers, kitchen faucets and pre-rinse sprays. Janitors’ sinks, pot fillers, and tub faucets can be left out as they are used to fill containers with a fixed water volume regardless of the flow rate. "Kitchen sinks" includes all sinks in public or private buildings that are used with patterns and purposes similar to a sink in a residential kitchen. Break room sinks would be included; commercial kitchen sinks are not included. Lavatory faucets refer to hand-washing sinks, regardless of location, but lab or healthcare sinks with regulated flow rates are excluded. Pot-filling sinks can be excluded.


  • Appliance and process water uses such as clothes washers, dishwashers, cooling tower make-up, and others, do not need to be included in the LEED water reduction calculations.  However, teams do have the option of earning an additional point for reduced appliance and process water as part of an exemplary performance point, building on the 30%–40% water-use reduction for WEc3: Water Use Reduction.


  • Well water and pond water are not considered “reused” water for the purposes of this credit and must count as potable water—so you don’t get credit for substituting them for conventional water sources. Water types that do count as reused are: graywater (lavatory, sink and shower water), rainwater, treated wastewater, air-conditioner condensate, reverse-osmosis reject, and sump-pump water.

Design Development

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  • Select water-efficient fixtures and strategies. Gather information on applicable fixtures including manufacturer, model number, and flush or flow rates.


  • For residential projects, showers typically use more water than any other fixtures due to the duration of use. For commercial projects, toilets and urinals typically use more water. Water-saving strategies should target the most consumptive fixtures to achieve greatest water reductions.


  • Compare the baseline and design case water use budgets to determine the water reduction percentage goals for the project. The LEED Online credit form has a built-in calculator to facilitate this calculation. Repeat this process until final selection of water fixtures and strategies have been made and the project’s water reduction goals are satisfied. 


  • Size graywater and rainwater systems to match non-potable water demand, for needs such as toilet flushing, cooling tower makeup, and irrigation.


  • Untreated rainwater, graywater, and blackwater may corrode plumbing systems, or lead to biological growth. Teams should plan for water treatment, filtration, or using corrosion-resistant materials. The use of seawater for toilet flushing, although very uncommon, can cause similar problems.


  • Plumbing piping must be doubled for interior water fixtures when graywater or rainwater is reused in addition to potable water. This is likely to add upfront costs, while potentially reducing water and sewer charges.


  • Sensors on toilets and faucets are perceived as saving water. However, several studies have shown that while they may offer some hygiene or other operational benefits, they increase water use substantially, due to “phantom flushes” and faucets running longer than needed. If you do choose lavatory sensors, look for models with adjustable flow durations. Although the LEED calculation estimates a standard 30-second use, setting the flow duration to a shorter time interval can help save water. In other words, adjusting the LEED design case calculation to a more accurate (and shorter) flow duration can help you meet the 20% reduction.


  • Aerators are very cost-effective, costing only a few dollars per fixture. Installing an aerator allows you to chose the sink fixtures that are desired and not have to worry if they are low–flow—simply purchase compatible aerators in addition to the fixtures. You can also easily retrofit existing faucets with low-flow aerators.


  • Many commercial toilets can be retrofitted with dual-flush flushometers, costing less than installing new dual-flush toilets. Check with manufacturers for retrofitting compatibility.

Construction Documents

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  • Integrate efficient water fixture specifications into construction and design development documentation.


  • Specify signage for water strategies that may require special instructions for use. This may include occupant signage for operating dual-flush toilets, indicating non-potable water, and operational signage for distinguishing pipes carrying reused water.


  • If reusing graywater or rainwater, ensure that key system components such as treatment and cisterns are not removed during value engineering.


  • Fill out the LEED Online credit form and upload water fixture cut sheets to LEED Online.


  • You must use an Alternative Compliance Path to document savings from a non-potable source in LEED Online. Adjust the design case total water use volume to account for the annual amount of non‐potable water. Then use the adjusted design case total water use to recalculate the percent reduction of water use for all fixtures. Additional documentation or calculations may include but are not limited to plumbing drawings, calculations and system capacity to support quantities provided, and any analysis to confirm the availability of the non‐potable water source.

Construction

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  • The contractor ensures that the correct fixtures have been purchased and any applicable water reuse systems or specified metering systems have been installed. 


  • Make sure supply pipes carrying non-potable water are clearly labeled and color-coded to avoid inadvertent cross-connection with potable water lines.

Operations & Maintenance

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  • Apply for water-reduction incentives and rebates through municipal water authorities.


  • Provide building managers with manuals for all irrigation systems and controls, fixtures and fittings, water-reuse technologies, on-site water treatment systems, and unconventional products.


  • Consider installing permanent water metering for ongoing monitoring of the project’s water use. A sub-metering system can help operations staff detect problems early and facilitate future LEED-EBOM certification.


  • Train cleaning and operations staff to maintain atypical fixtures such as waterless urinals, water sensors and other fixtures.

  • USGBC

    Excerpted from LEED 2009 for New Construction and Major Renovations

    WE Prerequisite 1: Water use reduction

    Required

    Intent

    To increase water efficiency within buildings to reduce the burden on municipal water supply and wastewater systems.

    Requirements

    Employ strategies that in aggregate use 20% less water than the water use baseline calculated for the building (not including irrigation).

    Calculate the baseline according to the commercial and/or residential baselines outlined below1. Calculations are based on estimated occupant usage and must include only the following fixtures and fixture fittings (as applicable to the project scope): water closets, urinals, lavatory faucets, showers, kitchen sink faucets and pre-rinse spray valves. [Europe ACP: Water Use Baseline]

    Commercial Fixtures, Fittings, and Appliances Current Baseline (Imperial Units) Current Baseline (Metric units)
    Commercial Toilets 1.6 gallons per flush (gpf)*

    Except blow-out fixtures: 3.5 (gpf)
    6 liters per flush (lpf)

    Except blow-out fixtures: 13 lpf
    Commercial Urinals 1.0 (gpf) 4 lpf
    Commercial Lavatory (Restroom) Faucets 2.2 gallons per minute (gpm) at 60 pounds per

    square inch (psi), private applications only (hotel

    or motel guest rooms, hospital patient rooms)

    0.5 (gpm) at 60 (psi)** all others except private

    applications

    0.25 gallons per cycle for metering faucets




    8.5 liters per minute (lpm) at 4 bar (58 psi),

    private applications only (hotel or motel guest

    rooms, hospital patient rooms)

    2.0 lpm at 4 bar (58 psi), all others except

    private applications

    1 liter per cycle for metering faucets




    Showerheads 2.5 (gpm) at 80 (psi) per shower stall **** 9.5 lpm at 5 bar (58 psi)
    For projects with commercial pre-rinse spray valves, the flow rate must comply with the asME a112.18.1 standard of 1.6 gpm or less.



    Residential fixtures, fittings, and appliances Current baseline (imperial units) Current baseline (metric units)
    Residential toilets 1.6 (gpf)*** 6 liters per flush (lpf)

    Except blow-out fixtures: 13 lpf
    Residential lavatory (bathroom) faucets 2.2 (gpm) at 60 psi 4 lpm

    8.5 lpm at 4 bar (58 psi), private applications only

    (hotel or motel guest rooms, hospital patient rooms)

    2.0 lpm at 4 bar (58 psi), all others except private

    applications

    1 liter per cycle for metering faucets




    Residential kitchen faucet
    Residential showerheads 2.5 (gpm) at 80 (psi) per shower stall**** flow rate ≤ 6.1 lpm

    (no pressure specified; no performance requirement)
    * EPAct1992 standard for toilets applies to both commercial and residential models.

    ** in addition to Epact requirements, the american society of Mechanical Engineers standard for public lavatory faucets is 0.5 gpm at 60 psi (2.0 lpm at 4 bar (58 psi)) (asME a112.18.1-2005). this maximum has been incorporated into the national uniform plumbing Code and the international plumbing Code.

    *** EPAct 1992 standard for toilets applies to both commercial and residential models.

    **** residential shower compartment (stall) in dwelling units: the total allowable flow rate from all flowing showerheads at any given time, including rain systems, waterfalls, bodysprays, bodyspas and jets, must be limited to the allowable showerhead flow rate as specified above (2.5 gpm) per shower compartment, where the floor area of the shower compartment is less than 2,500 square inches (1.5 square meters). for each increment of 2,500 square inches (1.5 square meters) of floor area thereafter or part thereof, an additional showerhead with total allowable flow rate from all flowing devices equal to or less than the allowable flow rate as specified above must be allowed. Exception: showers that emit recirculated 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. originating from within the shower compartment while operating are allowed to exceed the maximum as long as the total potable water flow does not exceed the flow rate as specified above.





    The following fixtures, fittings and appliances are outside the scope of the water use reduction calculation:

    • Commercial Steam Cookers
    • Commercial Dishwashers
    • Automatic Commercial Ice Makers
    • Commercial (family-sized) Clothes Washers
    • Residential Clothes Washers
    • Standard and Compact Residential Dishwashers

    Alternative Compliance Paths (ACPs)

    Europe ACP: Water Use Baseline

    Projects in Europe may use the values defined by European Standards.

    Potential Technologies & Strategies

    WaterSense-certified fixtures and fixture fittings should be used where available. Use high-efficiency fixtures (e.g., water closets and urinals) and dry fixtures, such as toilets attached to composting systems, to reduce water demand. Consider using alternative on-site sources of water (e.g., rainwater, stormwater, and air conditioner condensate) and graywaterGraywater is untreated household waste water which has not come into contact with toilet waste. Graywater typically includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washer and laundry tubs, though definitions may vary. Some states and local authorities also allow kitchen sink wastewater to be included in graywater. Project teams should comply with the graywater definition established by the authority having jurisdiction in the project area. for nonpotable applications such as custodial uses and toilet and urinal flushing. The quality of any alternative source of water used must be taken into consideration based on its application or use.

Technical Guides

Energy Policy Act of 1992 and amendments

Pages 62-69 of this legislation set federal standards for plumbing fixtures.


Energy Policy Act of 2005

The Energy Policy Act (EPA) addresses energy production in the United States. One example, the Act provides loan guarantees for entities that develop or use innovative technologies that avoid the by-production of greenhouse gases.


LEED 2009 Water Use Reduction: Additional Guidance

This document from USGBC offers guidelines to help you properly set up fixture usage groups in the LEED Online credit form, avoiding common mistakes associated with the water-efficiency prerequisite and credit.

Web Tools

WATERGY version 3.0

WATERGY is a spreadsheet model that uses water/energy relationship assumptions to analyze the potential of water savings and associated energy savings.


EPA Water Information links

This website offers links to state and regional water information.


Water Studies

This site provides a number of studies related to water.

Organizations

Alliance For Water Efficiency

AWE advocates for water-efficient products and programs and provides information related to water conservation.


EPA Office of Water

The Office of Water coordinates EPA's efforts to protect drinking water, oceans, watersheds and other aquatic ecosystems.


American Rainwater Catchment Systems Association

This organization promotes rainwater catchment in the U.S.


Oasis Grey Water Policy Center

Oasis Design, a maker of graywaterGraywater is untreated household waste water which has not come into contact with toilet waste. Graywater typically includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washer and laundry tubs, though definitions may vary. Some states and local authorities also allow kitchen sink wastewater to be included in graywater. Project teams should comply with the graywater definition established by the authority having jurisdiction in the project area. systems, maintains this compilation of graywater laws and other resources on the regulation of graywater use.

WEp1 LEED Online Form

This sample form for WEp1 is from a real project whose name was changed on the form. (Note that WEp1 was achieved for this project even though this sample displays that the form was not completed.)

Product Cut Sheets

Carefully research products and examine cut sheets to find fixtures and fittings meeting the credit requirements, as shown in these examples.

LEED Online Forms: NC-2009 WE

Sample LEED Online forms for all rating systems and versions are available on the USGBC website.

Design Submittal

PencilDocumentation for this credit can be part of a Design Phase submittal.

750 Comments

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Heather Appell LEED Project Manager SEQUIL Systems, Inc.
Jul 13 2016
LEEDuser Member
110 Thumbs Up

Fire Station water calculations

Project Location: United States

I am currently working on a Fire Station that has a total of 18 employees. However, each shift is 24 hours long and it's 6 employees per shift. Do I consider all BOH fixtures as residential and treat the 6 employees as residents? Also, more than likely, is it fair to say that 75% are male employees and 25% female due to the fact that most firemen are males? Thanks in advance!

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Kath Williams LEED Fellow 2011, Principal, Kath Williams + Associates Jul 13 2016 LEEDuser Member 2015 Thumbs Up

In two fire station projects we have worked on in the past, the fixtures were not permitted to be residential. Also, the employees should be 50/50 male/female. LEED does not look at current demographics but 50 to 100 years when there may be more female fire fighters than men! Even projects now with 100% male users are not permitted to be figured as such because that can change...and rapidly!

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Jens Apel Jul 14 2016 LEEDuser Member 1296 Thumbs Up

From the logic in the Ref.Guide with 8-hours day per 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. I think you would have 6 employees counting as 18 FTE.

Post a Reply
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Todd Bundren Director of Sustainabilty - Architectural Project Manager Lawrence Group
Jun 29 2016
LEEDuser Member
1773 Thumbs Up

Daily Use of sink in Dorm Lobby

Project Location: United States

Hello,

We are currently responding to initial preliminary advise and getting ready to resubmit our responses for a dorm building. However, we are uncertain as to how to evaluate daily usage for one of our sinks. We have a large open entry lobby/lounge that contains a counter with a single sink for when/if there are any gatherings in this space. This sink would most likely not be used on a daily basis by every resident and/or guests and could go days without any use. Is there a best way to calculate overall daily usage for this sink?

Thanks in advance!

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0
Vibha Pai Student University of Cincinnati
Jun 25 2016
Guest
49 Thumbs Up

Master's Research Survey

Project Location: United States

I am conducting a survey in affiliation with University of Cincinnati for my Master's thesis which would take just 10-15 minutes of your time. By answering the questions that are relevant to your experience, would help me in giving my research the required depth in understanding the achievability of the credit points in the Material and Resource category of LEED v2009 and v2013.

The following is the link to complete the web based questionnaire.
https://www.surveymonkey.com/r/XR3ZVZN
Thank you in advance for your time!

Post a Reply
0
0
Vibha Pai Student University of Cincinnati
Jun 25 2016
Guest
49 Thumbs Up

Master's Research Survey

Project Location: United States

I am conducting a survey in affiliation with University of Cincinnati for my Master's thesis which would take just 10-15 minutes of your time. By answering the questions that are relevant to your experience, you would help me in giving my research the required depth in understanding the achievability of the credit points in the Material and Resource category of LEED v2009 and v2013.

The following is the link to complete the web based questionnaire.
https://www.surveymonkey.com/r/XR3ZVZN
Thank you in advance for your time!

Post a Reply
0
0
James Lee
Jun 24 2016
Guest
19 Thumbs Up

Different gpm in the same fixtures types

Hi,

I am working on luxury condominium with amenity deck. And in the amenity deck, the public restrooms, staff's lavatories have two kinds of faucets with different gpm, such like one faucet has 1 gpm and the other one has 1.5 gpm.

In this case, can I make them as average like 1.25 gpm OR follow the worst case scenario (pick up the fixture with the largest gpm (1.5 gpm))?

Please provide me advice.

Thanks,

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deborah lucking associate fentress architects
Jun 22 2016
LEEDuser Member
2397 Thumbs Up

Occupants / users of public park

Project Location: United States

Our project includes the creation of a park, and construction of a pavilion with restrooms for park users.
The challenge - how do we calculate the number of FTEs using these restrooms?

Anyone has any ideas/experience with this?

thanks!

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Gerren Wagner Energy Opportunities Jun 22 2016 Guest 175 Thumbs Up

I hate to follow a question with a question, but my first thought is how many FTEs are you assuming for your project? Based on MPR 5, (http://www.usgbc.org/node/1731546?return=/credits/new-construction/v2009...) the project must have a minimum of 1 FTE calculated as an annual average. Are there staff at the park on a regular basis?

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Charles Nepps Charles Nepps Consulting Jun 22 2016 LEEDuser Member 1235 Thumbs Up

If the park is open to the general public, in addition the other project 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, then standard practice is to write a narrative explaining what you expect the usage to be...it will just be a guess, but as long as your numbers are well reasoned, it should be accepted. You could take into consideration factors such as population density of the surrounding community, proximity of schools, is the park likely to be in the travel path of people going shopping, are there factors that would draw people to the park in it's own right etc. consideration.

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Charles Nepps Charles Nepps Consulting Jun 22 2016 LEEDuser Member 1235 Thumbs Up

If the park is open to the general public, in addition the other project 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, then standard practice is to write a narrative explaining what you expect the usage to be...it will just be a guess, but as long as your numbers are well reasoned, it should be accepted. You could take into consideration factors such as population density of the surrounding community, proximity of schools, is the park likely to be in the travel path of people going shopping, are there factors that would draw people to the park in it's own right etc. consideration.
I would increase your "transient" number, by what ever you estimate the number of park visitors to be, assuming of course the park pavilion fixture flow rates are the same as the rest of the project.

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deborah lucking associate, fentress architects Jun 22 2016 LEEDuser Member 2397 Thumbs Up

Thanks, Charles. We did find some studies of park usage and could be applied to our project.

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VICTOR MORENO TECHNICAL DIRECTOR ISOLANA AHORRO ENERGÉTICO SL
Jun 18 2016
Guest
369 Thumbs Up

WEp1 calculator gender

Project Location: Spain

In v2009 WEp1 calculator, the toilet is divided by gender (male and female.

If the % male-female is 50%-50%, it might point to 50% in "percent of occupants" cell each. Or the excel applies the % gender automatically.

Thanks

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sebastian castañeda students students
Jun 17 2016
Guest
9 Thumbs Up

Unisex Toilet

Project Location: Peru

We are working on LEED NC 2009 for a new 9 stories building. There is one unisex toilet at each office level. How I determine the number of people will use those toilets? And How I enter the information of this unisex toilet in the calculator?

Other questions in the calculator we have to indicate the percent of males expected to use restrooms with urinals, in this case, I have to considerer as male toilet the sum of the Male toilet + Unisex toilet, and then determine the percentage?

I hope you can help me.

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Charles Nepps Charles Nepps Consulting Jun 18 2016 LEEDuser Member 1235 Thumbs Up

It's important to remember that the water consumption calcs have nothing to do with number of fixtures, just the type (flow rate) of fixtures and the occupancy. In other words it does not matter if some of the toilets are designated unisex, because the calculator assumes a certain amount fixture usage by the 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, regardless if there is a single restroom or 100 restrooms. Now if the faucets and/or toilets in the unisex facilities have a different flow rate than in the gender specific facilities, it can make a difference, otherwise you don't really need to worry about it.

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Carlie Bullock-Jones, LEED Fellow, WELL AP Principal, Ecoworks Studio Jun 18 2016 LEEDuser Expert 3336 Thumbs Up

The calculator automatically assumes that 100% of male occupants will use restrooms that contain urinals so your default Total Daily Uses for water closets and urinals must be adjusted/modified accordingly. Include a narrative and supporting daily use calculations to explain the anticipated urinal usage for your project.

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Charles Nepps Charles Nepps Consulting Jun 18 2016 LEEDuser Member 1235 Thumbs Up

Carlie, I may be reading more into the original question than was there, but I'm assuming each floor of the building has gender specific restrooms, in addition to 1 Unisex restroom. The calculator assume a certain number of uses per occupant, per fixture; for example, (just looking at 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), it assumes women will use the toilet 3x and men 1x, per day, in addition to men using urinals 2x per day. Given a 50/50 gender split of FTE, the only possible variance in water usage would be "men who use the Unisex restroom toilet, instead of a urinal". In lieu of any actual data, attempting to assign a number to that usage would have to be a complete guess and really quite meaningless. It would be interesting to have those Unisex restrooms sub-metered to see how how usage compares to the default assumptions, as this will probably be a more common practice on future projects.

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Carlie Bullock-Jones, LEED Fellow, WELL AP Principal, Ecoworks Studio Jun 19 2016 LEEDuser Expert 3336 Thumbs Up

Hi Charles,

Correct, the only variance would be men who utilize the unisex restroom instead of a urinal; and agree that without actual usage data assigning a number is really just a general guess. However, it will likely be questioned during the review if the use of the unisex toilets are not accounted for in some way.

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Charles Nepps Charles Nepps Consulting Jun 20 2016 LEEDuser Member 1235 Thumbs Up

I agree it is probably a good idea to acknowledge that the unisex restrooms are include in the project, but I still would not assign any additional water usage to them, assuming of course the fixture flow rates are the same as the other toilets/lavs on the project. Though I completely appreciate that the water usage could be significant, 6x more for an efficient urinal vs standard toilet, I still see no fair or accurate way to anticipate that usage. The possible additional water is in the noise, so to speak; you can no more assign a value to it than you can to men who will always opt to use a toilet over a urinal, or men who use a toilet when no urinal is free. I also wonder if the “unisex” toilets are in reality “accessible toilets” and this is how the project is meeting the handicapped access requirements? How the toilets are signed, will also have an impact on who chooses to use them.

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Sheryl Swartzle Sustainability Specialist, TLC Engineering for Architecture Jul 22 2016 LEEDuser Member 1063 Thumbs Up

My experience has been in not assigning % of
male usage to unisex bathroom will result in a reviewer comment.

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Muriel Alvarez LEED Green Associate Samconsult S.A.
Jun 01 2016
LEEDuser Member
5 Thumbs Up

WEp1 calculator

Project Location: Uruguay

Dear
Since I have a problem with BETA version for WEp1, the form did not calculated the percentage correctly, I´ve decided to use the v06 form calculator, well... the problem here is I can not enable the macros to work accurately. How I can enable macros or do you have any idea about how to work with different group when some of the them work 312 days and other 240 day per year... Thank you .

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Kath Williams LEED Fellow 2011, Principal Kath Williams + Associates
May 11 2016
LEEDuser Member
2015 Thumbs Up

Existing fixture upgrades

Project Location: United States

Project is new addition to building. Only one 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. sink will be installed in new addition. According to LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. #10214, we'll meet prerequisite 1 but we understand if we punch through to existing building and upgrade the adjacent shower and restrooms, we can qualify for points under WEc3. The question--For WE calculations do we use existing fixtures as baseline with upgraded fixtures as design case? There will be significant improvement.

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Michelle Schwarting Robinson Re:Vision Architecture May 11 2016 LEEDuser Member 1392 Thumbs Up

You'll need to us the baseline rates from the LEED Ref. Guide. Sadly no extra credit for replacing water hogs. (Although if you get the whole existing building (assuming it's a pretty big existing building) to retrofit all the restrooms (beyond the ones the addition occupants will use), you could potentially get extra credit if it's enough other restrooms... But again the baseline would be from the LEED Ref. Guide...)

BTW, just remember that older drain lines don't necessarily slope as much as they should so make sure you have some water flowing down those pipes (be it from the final urinal farthest from the drain/main having flush as opposed to waterless or some water in all, etc...)

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Wyatt Suddarth Mechanical EIT HDR Architecture, Inc.
Apr 01 2016
Guest
5 Thumbs Up

Pre-Rinse Spray Valves in Laboratories

Project Location: United States

I have several pre-rinse spray valves that were specified by an external laboratory consultant in a college laboratory building that do not appear to meet the requirement of being less than or equal to 1.6 gpm. There seems to be a slight discrepancy between the online form and the physical reference guide. In the reference guide, it states "Commercial pre-rinse spray valves (for food service applications)", but the online form says all pre-rinse spray valves. The pre-rinse spray valves would not be used for food service applications, so we are trying to decide if we need to make the external lab consultant re-specify pre-rinse spray valves that meet the requirement of 1.6 gpm. Thoughts/interpretations?

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Lewis Hewton Cundall May 17 2016 Guest 703 Thumbs Up

My understanding is that lab fixtures are process use and can be excluded from the calculations.

The credit benchmarks have been established using residential/commercial uses only.

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Christian Kaltreider
Apr 01 2016
Guest
76 Thumbs Up

Hourly Data for Rainwater Harvesting Calculation

Project Location: United States

Hello,

I need to do a rainwater harvesting analysis for our building. I am clear on how to do the analysis...but I am having some trouble finding the hourly precipitation data I need in spreadsheet format. What data do others use, and where do you find it? Is it freely available, or does it have to be purchased?

Thanks!

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Michelle Schwarting Robinson Re:Vision Architecture Apr 01 2016 LEEDuser Member 1392 Thumbs Up

Check NOAA for weather data. Here's the link for the hourly rainfall data:
https://www.ncdc.noaa.gov/data-access/quick-links#h-precip
(I believe it's free, but it can take a little time to get the data (a few minutes or up to a day).)

I have to admit I haven't had to do these calcs in quite a while, but do you really need to use HOURLY precipitation data or would daily be enough detail? I would imagine with hourly data, you'd then struggle to define at what time each day the various fixtures would be using the rainwater that's collected, and that basing it on daily rainfall data would be detailed enough, perhaps looking at a few different historical years... (But again, I haven't done these calcs in a while, and off hand I don't recall if LEED perhaps require them to be done on an hourly basis...)

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Christian Kaltreider Apr 04 2016 Guest 76 Thumbs Up

Thanks for the response. I did end up using free NOAA data, though it took some time to get it into a workable format.

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VICTOR MORENO TECHNICAL DIRECTOR ISOLANA AHORRO ENERGÉTICO SL
Mar 31 2016
Guest
369 Thumbs Up

Faucet in cleaning room

Project Location: Spain

Should I include the faucets placed in a cleaning room?
It are used for cleaning of the building.
Thanks

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Michelle Schwarting Robinson Re:Vision Architecture Mar 31 2016 LEEDuser Member 1392 Thumbs Up

If the sink is in the janitor's closet and its purpose is to fill buckets for cleaning, then you do not have to include it. (Putting a lower flow rate aerator on that faucet would only extend the amount of time it would take to fill the bucket, because the water's being collected for a certain amount of water and not for serving a purpose, like washing something, in the sink itself.) That said, if it's in there for the janitor to wash their hands after cleaning, then I'd say you should include it. But if the purpose is for filling buckets, then you can exclude it.

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Christian Kaltreider
Mar 29 2016
Guest
76 Thumbs Up

Metered Faucet: Max GPC or Flow Rate x Duration?

Project Location: United States

Hello,
My project will use metering handwash faucets at the lavatories. The flow rate is 0.5 gpm. According to USGBC's additional guidance document, I should use 0.25 gallons per cycle (gpc) as the baseline. For the proposed case, I understand that I am to multiply my flow rate (0.5 gpm) times 12 seconds/60 to get my equivalent gpc. That comes out to 0.1 gpc for the proposed case. However, the cut sheet for my faucet, while stating the 0.5 gpm flow rate, also clearly states in bold "Total flow not to exceed 0.25 gallons per handle activation."
Does this mean that I have to use 0.25 gpc for my proposed case, or can I still use the 0.1 gpc that I calculated earlier?

Thanks!

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Michelle Schwarting Robinson Re:Vision Architecture Mar 29 2016 LEEDuser Member 1392 Thumbs Up

You can use the 0.1 gpc you calculated.

(That statement on the cut sheet is because the max. allowable flow for a metering faucet is 0.25 gpc by law (hence why it's the baseline for water calcs), so they're just stating it to show the faucet complies with the law.)

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Christian Kaltreider Mar 29 2016 Guest 76 Thumbs Up

Got it, that makes sense. Thanks!

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Annalise Reichert Project Manager stok
Mar 01 2016
Guest
366 Thumbs Up

Multi-Flow Showerhead

I am working on a project that plans to install a shower head with three flow options: 0.5 GPM-1.0 GPM -1.5 GPM. How do we account for multi-flow showerheads on the WEp1 form? This circumstance was not accounted for in the WEp1 Additional Guidance documentation.

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Carlie Bullock-Jones, LEED Fellow, WELL AP Principal, Ecoworks Studio Mar 02 2016 LEEDuser Expert 3336 Thumbs Up

Unless the fixture can be installed to limit water use and guarantee one of the lower flow rates, I would recommend using the 1.5 GPM (worst case scenario) in the calculations.

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Nena Elise
Feb 25 2016
LEEDuser Member
4740 Thumbs Up

lavatory faucet in a dormitory

Hello,

I am working on a Co-ed dormitory were all of the bathrooms will be residential with the exception of two single occupancy bathrooms on the ground floor. These bathrooms will are located in a common area for the dorm directly across from the reception desk. There isn't a 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. for this building because all of the employees will also be residents within the building. Students will need key cards to enter the building, but it should be expected that there will be some transients from other students coming in to visit friends. My question is, do the single occupancy bathroom lavatory faucets need to be classified as public or residential? On one hand, the building is secured and not open to the public, but on the other hand students may let other students in and they may use those bathrooms. Any help would be greatly appreciated.

Thanks,

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Michelle Schwarting Robinson Re:Vision Architecture Mar 29 2016 LEEDuser Member 1392 Thumbs Up

I think it would be safer to classify them as public. You'll want to assign usage groups -- it seems like it could be reasonable to assign all the visitors to one usage group who use those two bathrooms and then assign all the residents to another usage group who use the residential bathrooms.

(Is your reception desk staffed by an 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.? If so, they would also use that bathroom.)

If the LEED Reviewer wants you to change it, they'll let you know. But I imagine the contribution of those two visitor bathrooms won't be very much compared to the residents, so likely it won't impact your water calcs too much...

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Karen Elliott LEED AP ID+C & BD+C Ecoteric Ltd
Jan 27 2016
LEEDuser Member
21 Thumbs Up

FTE for campus or for building

Project Location: United Kingdom

We have a manufacturing campus and are assessing a new office block within that campus. Within this block there are large toilet and shower facilities that will be used by everyone on the entire site. Therefore I have calculated the 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. for the entire site. This has been submitted for preliminary review and GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC). had no issue with that. Since that review the client informs me of a new project within the campus that they would like to use LEED on.

The people who will be using the second building are already included within the FTE of the first building, as they will be using the facilities within the offices. Therefore when we come to calculate the FTE of the second building for Wep1, I was going to put the actual staff number. My worry is that we are double counting the toilet and showers facilities over 2 projects and if that will cause an issue? But understand that we need to include actual facilities used for start getting credits?

Any help is much appreciated.

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Karen Elliott LEED AP ID+C & BD+C Ecoteric Ltd
Jan 27 2016
LEEDuser Member
21 Thumbs Up

FTE for campus or for building

Project Location: United Kingdom

We have a manufacturing campus and are assessing a new office block within that campus. Within this block there are large toilet and shower facilities that will be used by everyone on the entire site. Therefore I have calculated the 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. for the entire site. This has been submitted for preliminary review and GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC). had no issue with that. Since that review the client informs me of a new project within the campus that they would like to use LEED on.

The people who will be using the second building are already included within the FTE of the first building, as they will be using the facilities within the offices. Therefore when we come to calculate the FTE of the second building for Wep1, I was going to put the actual staff number. My worry is that we are double counting the toilet and showers facilities over 2 projects and if that will cause an issue? But understand that we need to include actual facilities used for start getting credits?

Any help is much appreciated.

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Melissa Merryweather Director, Green Consult-Asia Jan 29 2016 LEEDuser Member 3037 Thumbs Up

I've had a similar issue with a factory that we had certified several years ago. The office was in one certification package, a key factory building in another. The canteen in the office serves the entire factory so we had water use crossover in two projects. The fact is that you can't have a LEED building with no toilet facilities, yet the actual water use in the your office building project must be based on the total 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. as you calculated it. So there is a peculiar overlap in your case but it is what it is. WEp1/WEc3 water use for your new project is calculated with your new building's FTE only. Since the toilet block is existing, and since its not regularly occupied, it is only a feature of the Wep1 / WeC3 credits and no others but you'll need to include it in the building plan set. ( best to highlight the area). What I'm not sure is whether or not you need to include the toilet block in the total GFA of the building and include as "existing building" in the Pf2 form. I think you must but best to check. I believe you could put these figures into a narrative at the bottom of the form (I often have non-regular projects and narratives seem to work well), but you could also just contact the reviewers directly and ask them.

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Karen Elliott LEED AP ID+C & BD+C Ecoteric Ltd
Jan 27 2016
LEEDuser Member
21 Thumbs Up

FTE for campus or for building

Project Location: United Kingdom

We have a manufacturing campus and are assessing a new office block within that campus. Within this block there are large toilet and shower facilities that will be used by everyone on the entire site. Therefore I have calculated the 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. for the entire site. This has been submitted for preliminary review and GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC). had no issue with that. Since that review the client informs me of a new project within the campus that they would like to use LEED on.

The people who will be using the second building are already included within the FTE of the first building, as they will be using the facilities within the offices. Therefore when we come to calculate the FTE of the second building for Wep1, I was going to put the actual staff number. My worry is that we are double counting the toilet and showers facilities over 2 projects and if that will cause an issue? But understand that we need to include actual facilities used for start getting credits?

Any help is much appreciated.

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CATALINA CABALLERO SUSTAINABILITY COORDINATOR JALRW Eng. Group Inc.
Dec 29 2015
LEEDuser Member
4501 Thumbs Up

Existing and new fixtures

I have a facility that will be LEED NCv2009 certified and is part existing and partly new. The existing fixtures include 2 showerheads, 10 WC, 2 Urinals, 8 Lavatories, however the new addition includes 6 showers, 4 lavatories and 4 WC. In the water efficiency calculation, should I set 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. to use existing fixtures and then FTE to use new fixtures? then set visitors to use existing fixtures and then visitors to use new fixtures? or should I set the calculation to adjust the usage proportional to the ratio of existing to new fixtures.?

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Charles Nepps Charles Nepps Consulting Dec 29 2015 LEEDuser Member 1235 Thumbs Up

If the flow rates of the new and old fixtures are the same, and all 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. have access to all fixtures, then there is no need to separate the existing from the new. If the existing fixtures are less efficient than the new fixtures, then setting the flow rate in the calculator based on a weighted average of the fixtures, would be appropriate. For example if your existing WC`s are 2 gpf and the new WC's are 1.5 gpf then the weighted average would be: ((10*2) + 4*1.5))/ 14 or 1.86 gpf average.

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CATALINA CABALLERO SUSTAINABILITY COORDINATOR JALRW Eng. Group Inc.
Dec 29 2015
LEEDuser Member
4501 Thumbs Up

gym facility showers

I'm working on a community center that pretty much works as a facility. they will have new high efficiency showers that are accessible to all members (80 people per day), however the water efficiency calculator on the template only calculates consumption by the FTEs which are about 10. Should adjust the usage times on the shower by the members in order to demonstrate savings?

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Carlie Bullock-Jones, LEED Fellow, WELL AP Principal, Ecoworks Studio Dec 30 2015 LEEDuser Expert 3336 Thumbs Up

Hi Catalina,

Based on the project type (community center facility with showers accessible to all members) it seems reasonable to include some visitor shower use. In the WEp1 Form calculator I would create an additional fixture group just for the visitor shower use (however you will likely need to list these 80 visitors in the 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. column in order for the Form to calculate this fixture group). I would provide a narrative explaining your methodology and rationale for including the visitor shower use.

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Aswin M Conserve Consultants Private Limited
Dec 24 2015
Guest
83 Thumbs Up

Water Consumption Outside LEED Boundary

Project Location: India

We have a garment factory project that has a Main block and two toilet blocks (separately for Men & Women).
The Main block has cutting & sewing sections only and the occupants of the Main block only will be utilizing the Toilet blocks built next to the main block.
But the Main block and Toilet blocks has no structural connectivity, (but only via a passage at outdoors), hence only Main block is to be registered under Single Building certification.

The major consumption of water for the Project is only in the Toilet blocks.

If the Project with Main block alone be registered under LEED New Construction 2009 (Single Building Certification), how to calculate & meet the water use baseline (Water closets, lavatory fixtures) of the project where majority of water consumption is in the Toilet blocks only which is outside the LEED Boundary.

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Melissa Merryweather Director, Green Consult-Asia Dec 26 2015 LEEDuser Member 3037 Thumbs Up

Hi Aswin

In fact you can include the toilet blocks in the project --LEED doesn't consider a toilet block such as the one you are describing to be "occupied" (I've done several garment factory projects) and the walkways and grounds around the toilet block really should be in the boundary as well. Only in the case that the toilet blocks are really buildings in their own right are they needing a separate certification. So best to re-draw the boundary and include them. Otherwise you should register the project and ask your review team what to do (using the on-line feature), since your reviewer would have a preference as to how you deal with it.

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Carlie Bullock-Jones, LEED Fellow, WELL AP Principal, Ecoworks Studio Dec 30 2015 LEEDuser Expert 3336 Thumbs Up

Agree with Melissa here… all fixtures used by project occupants should be included in the water calculation and the toilet blocks as described should be included within the LEED Project Boundary.

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Aswin M Conserve Consultants Private Limited Dec 31 2015 Guest 83 Thumbs Up

Thanks Melissa & Carlie for your suggestions!.. Appreciate your support!..

As per your advice, on including the toilet block into my LEED Boundary, should we account the Toilet block area also into my project built up area for LEED certification?
And also should we consider the Toilet block for all the credit calculations such as roof areaRoof area is the area of the uppermost surface of the building which covers enclosed Gross Floor Area, as measured when projected onto a flat, horizontal surface (i.e. as seen in Roof Plan view). ‘Roofs’, or portions of roofs, covering unenclosed areas (e.g. roofs over porches and open covered parking structures) are not included in the areas used to evaluate compliance with SSc7.2, though they may be applicable to SSc7.1., LPDLighting power density (LPD) is the amount of electric lighting, usually measured in watts per square foot, being used to illuminate a given space. lighting calculations, material calculations, etc.

How to include the health faucet in the Water Use calculations, which is not listed in the LEED Water Use Reduction Calculator.

Thanks in Advance!.

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Melissa Merryweather Director, Green Consult-Asia Dec 31 2015 LEEDuser Member 3037 Thumbs Up

Hi Aswin, yes you should include that block in all the other calculations. However I'm not sure what you are asking about in your last question, I'm unfamiliar with a "health" faucet. Please explain!

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Aswin M Conserve Consultants Private Limited Dec 31 2015 Guest 83 Thumbs Up

Hello Melissa!. Thanks again!.

I meant Bidet Shower as the health faucet which shall be used in the Toilets for cleaning. Clarify on how to calculate the water use calculation for the bidet shower.

As per your earlier advice, since Toilet block alone cannot be certified separately, how about the blocks like STP room,Pump room & Guard room which are separated from the Main building be considered as per LEED.
Should those blocks also to be included in the LEED boundary and to meet all the prerequisite & credit calculations.

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Melissa Merryweather Director, Green Consult-Asia Dec 31 2015 LEEDuser Member 3037 Thumbs Up

Dear Aswin, this is not counted. Bidet shower is a bit like a service sink or bath tap, it makes no sense to have low-flow, but I think the actual reason it is not mentioned in the LEED manual is that it is not a typical feature of US sanitary ware. Potentially, as LEED becomes more international, it could be that like the kitchen spray there will be an upper flow limit rather than having it included in calculations or omitted altogether. For now we don't count it.

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Aswin M Conserve Consultants Private Limited Dec 31 2015 Guest 83 Thumbs Up

Melissa, Thanks for your insight on the Bidet shower.

Can you help me in the below clarification also.
As per your earlier advice, since Toilet block alone cannot be certified separately, its included in LEED boundary. How about the blocks like STP room,Pump room & Guard room which are separated from the Main building be considered as per LEED.
Should those blocks also to be included in the LEED boundary and to meet all the prerequisite & credit calculations.

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Melissa Merryweather Director, Green Consult-Asia Jan 03 2016 LEEDuser Member 3037 Thumbs Up

Yes that's right. For instance Guard room is probably less than 10m2 which means that it can be excluded from energy modelling and outdoor air calculations, but you can include in SS and MR credits. STP room and pump room unlikely to have 1 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. so the same applies. Download the MPR document since it lays it out clearly.

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JAMES MARK CHAN PROJECT MECH/F.P. ENGINEER WM ENGINEERING SERVICES, LLC
Dec 11 2015
LEEDuser Member
12 Thumbs Up

PERCENTAGE OF MALE USING URINAL

is there any guidance about percentage of male expected to use urinal.

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Charles Nepps Charles Nepps Consulting Dec 11 2015 LEEDuser Member 1235 Thumbs Up

Yes, this is covered in the LEED Reference Guide for Green Building Design and Construction in the WE credit section.

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Carlie Bullock-Jones, LEED Fellow, WELL AP Principal, Ecoworks Studio Dec 30 2015 LEEDuser Expert 3336 Thumbs Up

Hi James,

Default Fixture Uses are outlined within WEp1 Table 2 of the BD+C Reference Guide (e.g. Male FTEs utilize urinals twice daily) and these values should be used in the calculations for this credit unless special circumstances warrant modifications.

However, if your project does not contain urinals in every male (including unisex) restroom, then the default Total Daily Uses for water closets and urinals must be adjusted in the form accordingly. You will need to provide a narrative and supporting daily use calculations to explain the anticipated urinal usage based on your project parameters.

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JAMES MARK CHAN PROJECT MECH/F.P. ENGINEER WM ENGINEERING SERVICES, LLC
Dec 10 2015
LEEDuser Member
12 Thumbs Up

Water Saving thru the use of urinal

Does adding more urinals have an impact on water saving compare with lesser urinal.

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Charles Nepps Charles Nepps Consulting Dec 11 2015 LEEDuser Member 1235 Thumbs Up

Water usage is calculated based on occupancy (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.) so adding more fixtures does not impact the usage number, but adding more FTE's would.

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Francis McNulty OCSC
Dec 09 2015
LEEDuser Member
100 Thumbs Up

PSI for faucets and showers

Hi,

Can anyone please advise on the following;

Do shower flow rates need to be calculated at 80 psi and installed at 80 psi?

The same for for faucets, do flow rates need to be calculated at 60 psi and then installed at 60 psi?

Thank you.

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Carlie Bullock-Jones, LEED Fellow, WELL AP Principal, Ecoworks Studio Dec 30 2015 LEEDuser Expert 3336 Thumbs Up

Hi Francis,

The psi (based on 60 psi for lavs and 80 psi for showers) is how the industry/manufacturers calculate the GPM flow rate for their fixtures. The calculations must be performed using GPM rates based on these pressures, but there is no pressure requirement for installation.

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Susannah Goddard
Nov 04 2015
Guest
318 Thumbs Up

Water Use Reduction Calculator

Project Location: United Kingdom

I'm hoping to run by our approach to achieving WEp1 by some experienced LEED APs in the hope to reassuring myself that our approach is acceptable before submitting to USGBC at appeal. Excuse the ignorance- LEED is pretty new to us!

We've had this credit knocked back by the USGBC previously partly due to incorrectly defining Fixture Groups. I now understand that Fixture Groups should be defined by the facilities which the group has access to. As such I believe we should have 2 groups (football academy)- footballers/staff and visitors (transients). On this basis, I have created 2 tabs within the Water Use Reduction Calculator.

On each of the two tabs in the Water Use Reduction Calculator we intend to complete the Flush and Flow tables with details of the fittings installed. There is a requirement to enter the percentage of occupants with access to the fixture. Is this percentage of users within that User Group, or total building users (i.e. all tabs)? I'm concerned about double counting.

Other than that the Calculator tool seems fairly straightforward and a good means of demonstrating compliance I hope!

If anyone with experience of this credit is able to comment on our approach it would be much appreciated!

Many thanks,

Susie

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Nov 27 2015 LEEDuser Moderator

Susie, I'm going to answer off the cuff without looking at the form, but my memory is that the % is within that user group.

I think if you play around with the numbers in the calculator, you'll see them change in ways that will also confirm your approach.

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Renee Shirey
Oct 13 2015
LEEDuser Member
3733 Thumbs Up

Male occupant usage w/ family rstrm next to gang rstrms

Project Location: United States

Since the default assumption is that 100% of male occupants will use a restroom with a urinal, how do you calculate the usage when there is a family toilet (without a urinal) next to the large gang restroom? My guess is that a certain % of the male (and female) population is assumed to use the family toilet in lieu of the gang restroom. However, what would that percentage be? Any ideas of where I could derive an idea of that percentage?

Although the family toilet is ADA accessible, there is also an ADA toilet stall in each of the gang restrooms, so I can't use the ADA calculation to determine the % of people requiring the usage of the family toilet. Any guidance/ideas would be appreciated! Thanks.

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Carlie Bullock-Jones, LEED Fellow, WELL AP Principal, Ecoworks Studio Dec 30 2015 LEEDuser Expert 3336 Thumbs Up

Hi Renee,

If your project does not contain urinals in every male (including unisex) restroom, then the default Total Daily Uses for water closets and urinals must be adjusted in the form accordingly. You will need to provide a narrative and supporting daily use calculations to explain the anticipated urinal usage based on your project parameters. We have calculated the percentage based on the overall fixture counts in the project.

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CATALINA CABALLERO SUSTAINABILITY COORDINATOR JALRW Eng. Group Inc.
Oct 12 2015
LEEDuser Member
4501 Thumbs Up

Addition Project

when I have an addition project do I have to demonstrate compliance for the new addition and renovated areas or does it have to be applied to all areas? (existing to remain, renovated and new) We are creating an addition that is around 30% of the existing area including a few restrooms, but most of the restrooms are in the existing to remain area. Since only the new area will include high efficiency fixtures Im not sure if we will be able to meet the 20% efficiency requirement.

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Nov 27 2015 LEEDuser Moderator

Catalina, if the LEED project is the whole space and not just the addition, then you have to demonstrate compliance for the whole space, as with all LEED-NC credits.

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deborah lucking associate fentress architects
Sep 30 2015
LEEDuser Member
2397 Thumbs Up

Accounting for shower use by non-occupants

Project Location: United States

Ours is a campus project where FTEs from a number of buildings have access to showers and lockers in a separate "clubhouse" building. The clubhouse has a much lower staff number than the other buildings. How do we account for the "visitors" use of the showers? Are they transients? Part-time occupants - just for the 20 minutes they are in the locker rooms?
(I posted this question on the EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating systems. page as well.)

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Carlie Bullock-Jones, LEED Fellow, WELL AP Principal, Ecoworks Studio Jan 04 2016 LEEDuser Expert 3336 Thumbs Up

Hi Deborah,

Since students/visitors are not anticipated to utilize the shower the Form is set up to automatically not include any daily uses from this occupancy type. However, based on the project scope (campus clubhouse where showers and lockers will be used by students) it seems reasonable to include some student shower use.

In the WEp1 Form calculator I would create an additional fixture group just for the student shower use (however you will likely need to list these students in the 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. column in order for the Form to calculate this fixture group). I would provide a narrative explaining your methodology and rationale for including the student shower use.

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Susannah Goddard
Sep 29 2015
Guest
318 Thumbs Up

WEp1 Credit Resources - Water Use Reduction Calculator

Project Location: United Kingdom

I have just come across the Water Use Reduction Calculator tool in the credit tools for WEp1. Do most people use this to demonstrate compliance? It looks to make the WEp1 process a lot more straight forward...

The instructions say to complete the Water Use Reduction Calculator, upload to LEED Online, and complete any related summary fields in the LEED credit form with results from the calculator. I can't see which are "summary fields" though- can I avoid completing the WEp1 credit form in its entirety if I upload the Water Use Reduction Calculator?

Many thanks,

Susie

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