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 graywaterUntreated household waste water which has not come into contact with toilet waste. Graywater includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washers and laundry tubs. It must not include waste water from kitchen sinks or dishwashers (Uniform Plumbing Code, Appendix G, Gray Water Systems for Single-Family Dwellings); waste water discharged from lavatories, bathtubs, showers, clothes washers and laundry sinks (International Plumbing Code, Appendix C, Gray Water Recycling Systems). Some states and local authorities allow kitchen sink wastewater to be included in graywater. Other differences can likely be found in state and local codes. Project teams should comply with the graywater definition established by the authority having jurisdiction in the project area. reuse The reemployment of materials in the same or a related capacity as their original application, thus extending the lifetime of materials that would otherwise be discarded. Reuse includes the recovery and reemployment of materials recovered from existing building or construction sites. Also known as salvage.(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 waterWater that meets or exceeds U.S. Environmental Protection Agency drinking water quality standards (or a local equivalent outside the U.S.) 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, graywaterUntreated household waste water which has not come into contact with toilet waste. Graywater includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washers and laundry tubs. It must not include waste water from kitchen sinks or dishwashers (Uniform Plumbing Code, Appendix G, Gray Water Systems for Single-Family Dwellings); waste water discharged from lavatories, bathtubs, showers, clothes washers and laundry sinks (International Plumbing Code, Appendix C, Gray Water Recycling Systems). Some states and local authorities allow kitchen sink wastewater to be included in graywater. Other differences can likely be found in state and local codes. 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 graywaterUntreated household waste water which has not come into contact with toilet waste. Graywater includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washers and laundry tubs. It must not include waste water from kitchen sinks or dishwashers (Uniform Plumbing Code, Appendix G, Gray Water Systems for Single-Family Dwellings); waste water discharged from lavatories, bathtubs, showers, clothes washers and laundry sinks (International Plumbing Code, Appendix C, Gray Water Recycling Systems). Some states and local authorities allow kitchen sink wastewater to be included in graywater. Other differences can likely be found in state and local codes. 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 graywaterUntreated household waste water which has not come into contact with toilet waste. Graywater includes used water from bathtubs, showers, bathroom wash basins, and water from clothes-washers and laundry tubs. It must not include waste water from kitchen sinks or dishwashers (Uniform Plumbing Code, Appendix G, Gray Water Systems for Single-Family Dwellings); waste water discharged from lavatories, bathtubs, showers, clothes washers and laundry sinks (International Plumbing Code, Appendix C, Gray Water Recycling Systems). Some states and local authorities allow kitchen sink wastewater to be included in graywater. Other differences can likely be found in state and local codes. 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.

791 Comments

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VICTOR MORENO TECHNICAL DIRECTOR ISOLANA AHORRO ENERGÉTICO SL
Feb 13 2017
Guest
490 Thumbs Up

Freatics water

Hello.
In our LEED Project, the water used for Urinals and WC is recovered of the subsoil (freatics water). So, in Water Use Reduction Calculator, i have indicated the total non-potable waterWater that meets or exceeds U.S. Environmental Protection Agency drinking water quality standards (or a local equivalent outside the U.S.) and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. supply to rest of Annual design water consumption.
In preliminary review, the reviewer ask us if the recovered water is used only for WC and Urinals or if this water has other purposes.

Is possible to achive compliance with this strategy?
Thanks

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Charles Nepps Charles Nepps Consulting Feb 13 2017 LEEDuser Member 1753 Thumbs Up

One of the goals of water reduction is to decrease the demand on local water supplies including aquifers (Phreatic water). I'm guessing the Reviewer wants to know if the phreatic water is used as part of the domestic water supply in your region, if so, it would not count as an offset for this credit.

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VICTOR MORENO TECHNICAL DIRECTOR , ISOLANA AHORRO ENERGÉTICO SL Feb 13 2017 Guest 490 Thumbs Up

Thank you Charles.

In my region phreatic water does not used for domestic water. This systems was designed for the project to reduced the water supply for municipal water supply.

If I answer to reviewer that the water is only for domestic water supply, he can understand that this design is normal for our community?

Thanks

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Charles Nepps Charles Nepps Consulting Feb 13 2017 LEEDuser Member 1753 Thumbs Up

It's difficult to say. If I understand you correctly, your project has drilled a well onsite to reduce the municipal water consumption. Despite the fact that aquifers are not the primary source of water in the region, it could still be problematic if enough developers started to tap into them for the same reason. Would it be possible for you to post the exact wording of the reviewer's comment?

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VICTOR MORENO TECHNICAL DIRECTOR , ISOLANA AHORRO ENERGÉTICO SL Feb 14 2017 Guest 490 Thumbs Up

Hi, the reviewer´s comment is: "It is not clear that the sub-soil groundwater is an acceptable source of 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.. Provide a detailed narrative, at a minimum, to describe how the water is collected, and to clarify whether the water is collected for the sole purpose of supplying water to the domestic water fixtures, or if the collection of the water is necessary for other reasons. See the Water Use Reduction Additional Guidance, updated October 17, 2016, for additional guidance on acceptable sources of nonpotable water for this prerequisite." The Water Use Reduction Additional Guidance 10-17-2016 v9_0 indicate: "Sources of non-potable water that do not apply to the Water Efficiency credits include water discharged from an open loop geothermal system as indicated in LI 2545, untreated water sourced from naturally occurring surface water bodies, such as streams, rivers, and lakes, and well water as indicated in LI 10013 and LI 456." Our project treat the water (Chlorination) of the wells before using to toilets and urinals. Is this an allowable casuistry for LEED? Thanks

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Charles Nepps Charles Nepps Consulting Feb 14 2017 LEEDuser Member 1753 Thumbs Up

I think the key comment is: "clarify whether the water is collected for the sole purpose of supplying water to the domestic water fixtures, or if the collection of the water is necessary for other reasons."
So, for example, if you were recovering ground water that was being pumped to keep the buildings basement dry (dewatering water), to use for flush fixtures, that would be ok, but if you drill wells specifically to supply water to the flush fixtures, that would not be acceptable. The response to LI 10013 states ground water "does not meet the intent of the WE credits. Although the local groundwater may not be suitable for drinking straight out of the ground, it still represents an important source of potable waterWater that meets or exceeds U.S. Environmental Protection Agency drinking water quality standards (or a local equivalent outside the U.S.) and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems.. Applicable internationally."

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Aru Sau
Feb 06 2017
Guest
111 Thumbs Up

Eye Wash Basins in a Lab

Project Location: United States

Would a Eye Wash Basin in a Laboratory be considered as 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 should not be included in the credit calculation? These eye wash basins are in particular labs in the buildings not inside the restrooms.

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Carlie Bullock-Jones, LEED Fellow, WELL AP Principal, Ecoworks Studio Feb 06 2017 LEEDuser Expert 3656 Thumbs Up

Correct, and eye wash basin would be 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 is not included in the prereq/credit as a regulated fixture.

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Jean Marais b.i.g. Bechtold DesignBuilder Expert Feb 07 2017 LEEDuser Member 10961 Thumbs Up

Similaraly we're not gonna look at emergancy power, because hopefully there are not going to be any emergancies.

Carlie, in the EU we're moving toward sanitary systems that do a lot of automated flushing (also of non-regulated fixtures such as this) as well as using venturi flow dividers to keep the systems free of stagnation and germs. Such systems will display a leaching effect on water resourses similar to that of "stand-by" power usage in electrical devises. Is this something LEED is going to have to adress in future?

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Guillermo Brunzini
Jan 13 2017
Guest
6 Thumbs Up

Use of bidets in an office bathroom for NC 2009 project

As farFloor-area ratio is the density of nonresidential land use, exclusive of parking, measured as the total nonresidential building floor area divided by the total buildable land area available for nonresidential structures. For example, on a site with 10,000 square feet (930 square meters) of buildable land area, an FAR of 1.0 would be 10,000 square feet (930 square meters) of building floor area. On the same site, an FAR of 1.5 would be 15,000 square feet (1395 square meters), an FAR of 2.0 would be 20,000 square feet (1860 square meters), and an FAR of 0.5 would be 5,000 square feet (465 square meters). as I know, bidets 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. fixtures, so do not need be included in the water saving calculation, is that correct?
I would appreciate any confirmation or comment in that respect.

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Tristan Roberts LEED AP BD+C, Executive Editor – LEEDuser, BuildingGreen, Inc. Jan 15 2017 LEEDuser Moderator

That's correct. They are not regulated fixtures.

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Angel Vega Project Manager
Dec 14 2016
Guest
17 Thumbs Up

Kitchen Faucets

Project Location: Spain

The building I am trying to obtain the certification for, is a museum. It has two rooms with faucets for the cleaning staff. Are these faucets into the objetive of reduction?
Additionally, do the faucets of the kitchens (we have five different kitchens and 3 of them are not commercial because are aimed to private activities promoted by the property), pre-rinse and sink faucets a baseline of 1.6 gpm? Anyway, for the kitchens, the facets are not in the objetive of efficiency and we just have to check the objetive of 1.6 gpm, am I in a good way?
Thanks in advance

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Gerren Wagner Energy Opportunities Dec 20 2016 Guest 211 Thumbs Up

Hi, Angel,

Fixtures for cleaning staff (i.e., housekeeping or janitor sinks) and commercial kitchens are not applicable to WEp1/c3 and should not be included in the calculations. The kitchen sink faucets that should be included are those typically found in staff break rooms, conference rooms, etc.

Suerte!
Gerren

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Michelle Reott LEED AP® BD+C, ID+C, O+M, Managing Principal, Earthly Ideas LLC, a LEED® Proven Provider™ Dec 20 2016 LEEDuser Expert 12847 Thumbs Up

Gerren and Angel - I just wanted to note that pre-rinse spray valves from commercial kitchens are required to be included for projects registered after 11/1/2011.

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John Krutko Sr Project Manager Osborn Engineering
Dec 08 2016
LEEDuser Member
24 Thumbs Up

Water Use Reduction Baseline for Renovation

My office is working on a school renovation registered under LEED v2009 NC. I am wondering what the baseline water usage is for new plumbing fixtures replacing fixtures that were installed in the 1980s. Example, is 1.6 GPF for water closets still the baseline or would the baseline be what the original fixtures being replaced is?

Thanks

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Carlie Bullock-Jones, LEED Fellow, WELL AP Principal, Ecoworks Studio Dec 08 2016 LEEDuser Expert 3656 Thumbs Up

Hello John,

Yes, the baseline flow rate for water closets is 1.6 GPF. Projects must utilize the baseline flow rates outlined in the LEED 2009 BD+C Reference Guide (and not the flow rates for the current fixtures installed).

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Neshat Sakeena Sustainability Consultant Ramboll
Dec 05 2016
LEEDuser Member
78 Thumbs Up

Reference for the Total Daily Uses numbers

Hello,

I was just wondering if anyone knows the reference or basis of the numbers used in Table 2. Default Fixture Uses, by Occupancy Type in the LEED manual? Example; The default for residential occupants is 5 uses per day of water closet and lavatory faucet, 1 shower, and 4 kitchen sink uses.

Cheers,
Neshat Sakeena

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Charles Nepps Charles Nepps Consulting Dec 05 2016 LEEDuser Member 1753 Thumbs Up

I think it's just a best guess of typical household fixture usage in the U.S. On the commercial side they assume 3 WC visits per day, per occupant, so maybe that is the base daytime usage and then you add a morning & evening visit to the WC to get to 5? ) The numbers were derived (somehow) just to create a basis for comparison. Regardless of the number of actual uses, what's important is the water savings your project achieves over the baseline.

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Neshat Sakeena Sustainability Consultant, Ramboll Dec 05 2016 LEEDuser Member 78 Thumbs Up

Thanks for your response Charles. I am actually trying to overlap MEP water demand calculations with the LEED Water calculations for a Hotel project. The MEP water demand calculations are almost twice of that of LEED water baseline (IPCInternational Plumbing Code/UPCUniform Plumbing Code) numbers. Thus my interest in reference standard (if any) for the Default fixture uses. I understand water demand calculations also account for a safety factor but 50% discrepancy is too high.

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Charles Nepps Charles Nepps Consulting Dec 05 2016 LEEDuser Member 1753 Thumbs Up

Are you just comparing fixture usage in both cases? Remember LEED (v2009) doesn't address things like dishwashers, clothes washers, bathtub usage, 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., etc.

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Jean Marais b.i.g. Bechtold DesignBuilder Expert Dec 06 2016 LEEDuser Member 10961 Thumbs Up

From memory the rates and uses per day are from the IPCInternational Plumbing Code (international plumbing code).

In MEP design both anual usage and peak (or design) rates are considered. The designer needs to size equipment (pumps, filters, pipe dimensions) to deal with peak demand rates that are subject to ratios of concurrent usage, AND caluculate the annual water usage based on daily usage.

The two are however not the same.

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Neshat Sakeena Sustainability Consultant Ramboll
Dec 05 2016
LEEDuser Member
78 Thumbs Up

Reference for the Total Daily Uses numbers

Hello,

I was just wondering if anyone knows the reference or basis of the numbers used in Table 2. Default Fixture Uses, by Occupancy Type in the LEED manual? Example; The default for residential occupants is 5 uses per day of water closet and lavatory faucet, 1 shower, and 4 kitchen sink uses.

Cheers,
Neshat Sakeena

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Jean Marais b.i.g. Bechtold DesignBuilder Expert Dec 06 2016 LEEDuser Member 10961 Thumbs Up

From memory the rates and uses per day are from the IPCInternational Plumbing Code (international plumbing code).

In MEP design both anual usage and peak (or design) rates are considered. The designer needs to size equipment (pumps, filters, pipe dimensions) to deal with peak demand rates that are subject to ratios of concurrent usage, AND caluculate the annual water usage based on daily usage.

The two are however not the same.

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Erin Holdenried Sustainable Design Manager AECOM
Nov 29 2016
LEEDuser Member
405 Thumbs Up

tested flush and flow rates

I have a major renovation project that has existing plumbing fixtures that will remain. These fixtures have been tested, however, the water pressure at the project site is well below the Energy Policy Act of 1992 water pressure test rates. It appears that the water pressure requirement is only applicable to non-metered flow fixtures? So test results from the toilets, urinals, and metered lavatories can be used, correct? But, there is one pantry faucet that is not metered and the showers are not metered. How can I account for these fixtures in the water calculations? I don't see LI #829 (http://www.usgbc.org/content/li-829) as an applicable option. The client is not going to purchase, install, and test "baseline" fixtures at the project for LEED water efficiency calculations. Any advice would be greatly appreciated!

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Michelle Reott LEED AP® BD+C, ID+C, O+M, Managing Principal Earthly Ideas LLC, a LEED® Proven Provider™
Nov 15 2016
LEEDuser Expert
12847 Thumbs Up

v09 Water Use Reduction Additional Guidance available

Project Location: United States

As part of the October 2016 LEED addenda update (http://www.usgbc.org/articles/leed-addenda-update-october-2016), USGBC updated the Water User Reduction Guidance document to Version 9 (http://www.usgbc.org/resources/water-use-reduction-additional-guidance). While it is touted to utilize new guidance related to applying on-site alternative water sources (like campus or municipally reclaimed treated wastewater and seawater) to credit achievement (WEp1 must be achieved through project fixture and fitting efficiency measures alone), it also contains help for those using the Water Use Reduction Calculator that was part of the v06 forms release.

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Erin Holdenried Sustainable Design Manager AECOM
Nov 10 2016
LEEDuser Member
405 Thumbs Up

testing of existing plumbing fixtures

Project Location: Vietnam

We have a project that is undergoing major renovation and most of the existing plumbing fixtures will me maintained, and their flush and flow rates have been tested under the 0.9 bar municipal-supplied water pressure. However, the baseline rates for lavatories requires testing at 4 bar water pressure, and showers require 5 bar. How can the project compare its water usage to the baseline? Has anyone encountered this issue on a project?

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deborah lucking associate fentress architects
Sep 01 2016
LEEDuser Member
3261 Thumbs Up

Use of showers by "transients"

We have a campus project where one of the buildings contains showers and changing rooms for the entire campus.

In spite of our explanations of the function of these showers, the LEED Reviewer states "The calculations for WEp1 are only attributed to the LEED project building, and therefore should only include 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.
and transient occupancy of the LEED project." Meaning, we suppose that transients should not be counted in the shower usage.

This is like saying that showers in a health club are only used by the club employees....Does anyone have an argument that has worked?

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Melissa Merryweather Director, Green Consult-Asia Sep 01 2016 LEEDuser Member 3581 Thumbs Up

I think this is a clear example where different reviewers have given different answers--or where answers have changed over time. We had a certified project where over 20,000 workers from other parts of the factory came to our certified facility for lunch. We submitted this as transient usage, explained it and it was accepted. If not the water use shown in Energy Star records after certification would have been exceeded by 5 times. I think our way of recording it had to be correct and was glad when the reviewer agreed.

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deborah lucking associate, fentress architects Sep 15 2016 LEEDuser Member 3261 Thumbs Up

Our project has 69 FTEs and 12 showers (6 male, 6 female). Would seem a tad excessive to argue that only FTEs use the showers. The biggest irony of course, is that if we had attempted SSc4.2 for the campus, we would have to account for use of those showers by the entire campus FTE population.

I am beyond frustrated.

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Michelle Rosenberger Partner, ArchEcology, LLC Sep 15 2016 LEEDuser Member 8880 Thumbs Up

Hi Deborah,
I've done lots of YMCA projects that have a similar shower issue in that there are lots of transient users. I've always declared a percentage of them as users and explained with no issues. The showers were in the building and used for the building users entirely.

I also have projects where showers were not in the project scope for my users. In that case, WEpr1 doesn't show the showers at all. Only WEcr3 includes them. Is that what the Reviewer is trying to say perhaps? That the shower use for WEpr1 should only be building users, but the shower use on WEcr3 would include the transients? Just a thought. Otherwise I don't understand.

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deborah lucking associate, fentress architects Sep 15 2016 LEEDuser Member 3261 Thumbs Up

Michelle,
I was going to ask the Reviewer if he/she was referring to your second point (about WEp1 and WEc3 having different users).
This one particular project has been a real test of patience - the project is simple, but we kept getting stuck on definitions and interpretations.
Will apprise this group once I get some sensible clarity.
Thanks for the suggestions!

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Anastasia Makarenko EcoStandard
Aug 11 2016
Guest
419 Thumbs Up

n/a

Dear all,
our project is being certified under LEED v3 NC.
at the Preliminary Design Review Stage we've divided users into occupant groups in accordance with their functionality - office workers, kitchen staff, reception workers etc. We've received Technical advice from reviewers stating that our approach to defining occupant groups is wrong and that we need to revise the form to ensure that fixture groups have been defined to reflect the various occupant groups within the project that use a specific set of flush and flow fixtures.
All users of the building have access to all fixtures in certified building, so the usage patter is the same for all users. But there are some users who have different working schedule - most of them work 247 days/year and there are security guards who works 365 days/year. So we've divided occupants into two fixture usage groups - one group is for General staff/users who works 247 days per year (513 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.
per day). And other group is for security staff who works 365 days per year (4 FTE per day). Does our approach (dividing occupants into two groups) seem reasonable?
We have other solution - count security FTEs as if they've worked 247 days per year:
(4*365)/247=5,9 FTE = 6 FTE

How do you think, what approach is better?
Thank you all in advance.

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Charles Nepps Charles Nepps Consulting Aug 11 2016 LEEDuser Member 1753 Thumbs Up

In the past on mixed use office/retail projects I have defined the user groups based on work schedule; "retail" & "office", since retail workers have a different schedule than office workers. Never had an issue with this approach.

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Anastasia Makarenko EcoStandard Aug 12 2016 Guest 419 Thumbs Up

Thank you very much, Charles.
Hope we will get approval for our approach.

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Heather Appell LEED Project Manager SEQUIL Systems, Inc.
Jul 13 2016
LEEDuser Member
142 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 2305 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 1455 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.

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Todd Bundren Director of Sustainabilty - Architectural Project Manager Lawrence Group
Jun 29 2016
LEEDuser Member
2114 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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Vibha Pai Student University of Cincinnati
Jun 25 2016
Guest
459 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!

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Vibha Pai Student University of Cincinnati
Jun 25 2016
Guest
459 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!

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James Lee
Jun 24 2016
Guest
36 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
3261 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 211 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 1753 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 1753 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 3261 Thumbs Up

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

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deborah lucking associate, fentress architects Sep 01 2016 LEEDuser Member 3261 Thumbs Up

Wanted to give an update on how we determined the number of park users. We followed Charles' advice to use population density, and managed to find a report on percentage of park users relative to the distance of such residents from the parks themselves.
As to Gerren's question, the pavilion includes a retail component, so there are FTEs associated with the building.
Thanks to all for the help!

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VICTOR MORENO TECHNICAL DIRECTOR ISOLANA AHORRO ENERGÉTICO SL
Jun 18 2016
Guest
490 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
39 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 1753 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 3656 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 1753 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 3656 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 1753 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 1200 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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Charles Nepps Charles Nepps Consulting Sep 21 2016 LEEDuser Member 1753 Thumbs Up

Just wanted to revisit this question as we have, as predicted by Sheryl, just received a reviewer comment, on a project with unisex toilets, that we must assume a certain percentage of male usage. In our particular case the toilets are actually "accessible"; there is one per floor, in addition to the gender specific restrooms. The flush rate of the toilet in the "accessible" room is identical to the flush rate of the toilets in the gender specific rooms. It just seems to me any "male usage" number we assign would be random and would not increase the accuracy of the estimated water consumption. If we were to create a group specifically for the usage of these toilets, we could base it on a estimated percentage 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.
that require an accessible toilet, and tie it to a government statistics of percentage of disable persons in the community as a whole, however we've never been required to do that on projects where the accessible toilets were integrated into the gender specific restrooms. If we take "need" out of the equation and just create a group, "people who prefer private restrooms", that number would be completely fabricated and in my mind, meaningless. I realize the easiest thing to do is throw some number out there and get on with life, but part of me really would like to challenge the reviewer's assumption that making up a number somehow improves the accuracy of the estimate.

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deborah lucking associate, fentress architects Sep 21 2016 LEEDuser Member 3261 Thumbs Up

Charles,
kudos to you for wanting to get to a rational basis for these assumptions.
Have been down this road before (i.e. trying to arrive at some reasonable/sensible approach, with the LEED reviewer), and it's like Waiting for Godot.
Good luck to you, sir!

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Michelle Rosenberger Partner, ArchEcology, LLC Sep 21 2016 LEEDuser Member 8880 Thumbs Up

Hi Charles,
I'm with Deborah on this. You are in a no win situation. We've been through this many times. You need a number of male users that you can "assign" to these restrooms. Come up with something that seems reasonable to take the minor hit for lack of urinal use, gnash your teeth and then move on.

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Renee Shirey Sep 21 2016 LEEDuser Member 4137 Thumbs Up

In lieu of USGBC providing guidance on % of occupants to assign to a unisex toilet, you need to provide a number and back it up. In a narrative, acknowledge that there is no USGBC guidance on the matter, so for your calculations you used the following reasoning to justify the % of men possibly using the unisex toilet for the purposes of calculating water usage. If it is a location where it is just office workers, and not a situation where there would be families (dad taking kids into family toilet, as an example) then maybe try using the % of transgender people (per some statistic for your country, or a statistic for another country if that info is not available). This at least gives you SOMETHING to go by, and that you have taken usage of the unisex toilet into consideration.

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Charles Nepps Charles Nepps Consulting Sep 21 2016 LEEDuser Member 1753 Thumbs Up

Thanks for the replies; good to know I'm not alone in this! I guess I feel because the USGBC doesn't offer guidance, and reviewers have essentially been asking projects to make something up, it actually somewhat damages the LEED brand. The simple reality is that I have considered the possible male usage and have reasoned that, in a system which is already making very broad assumptions about people's bathroom habits, adding more random data isn't helpful....not sure if that would make a winning narrative though. )

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Lewis Hewton Cundall Sep 21 2016 Guest 869 Thumbs Up

I totally agree with Charles! Reviewers - please remember we are trying to benchmark consumption, not predict actual consumption.

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Muriel Alvarez LEED Green Associate Samconsult S.A.
Jun 01 2016
LEEDuser Member
19 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
2305 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 Robinson Schwarting Re:Vision Architecture May 11 2016 Guest 1613 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
13 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 869 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
142 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 Robinson Schwarting Re:Vision Architecture Apr 01 2016 Guest 1613 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 142 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
490 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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