EBOM-2009 WEc4: Cooling Tower Water Management

  • EBOM_WEc4_Type3_CoolingTower diagram
  • A high-impact strategy

    Because of the sheer magnitude of water used to operate a cooling tower, implementing a successful water management program and automatic controls can have a much greater overall impact on your building’s water efficiency than retrofitting indoor plumbing fixtures. Depending on your local water rates, it can also bring your project significant cost savings.

    Two very different credit options

    This credit has two sides, with two separate points available. WEc4.1: Chemical Management addresses chemical management for cooling towers and is highly achievable for any project that has a cooling tower.

    WEc4.2: 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. Sources involves using non-potable water in your cooling tower—this option is rarely attempted due to the challenges associated with retrofitting an existing cooling tower to use non-potable water sources.

    Cooling towerCooling towers chill buildings by evaporating water. A 100-ton chiller evaporates about three gallons of water per minute (11 lpm), with additional water loss from drift and blowdown. In a typical office building, HVAC equipment accounts for about a third of total water use. Photo – Advance Cooling Towers

    WEc4.1: Chemical Management

    Implementing a professional water management program effectively manages the chemicals used to treat the cooling tower makeup water and controls outbreaks of harmful biological organisms, such as Legionella pneumophilaLegionella pneumophila is a waterborne bacterium that causes Legionnaire's disease. It grows in slow-moving or still warm water and can be found in plumbing, showerheads, and water storage tanks. Outbreaks of Legionella pneumonia have been attributed to evaporative condensers and cooling towers., the bacterium that causes Legionnaires’ disease.

    This option does not require that your water management plan meet any specific environmental standards or thresholds—only that you have a detailed plan that is written specifically to optimize water management in your cooling tower. 

    Costs associated with WEc4.1 are minimal, especially if automatic bleed-offBleed-off, or blowdown, is the release of a portion of the recirculating water from a cooling tower; this water carries dissolved solids that can cause mineral buildup. controls are already installed on your cooling tower. Work with your management contractor to successfully integrate the LEED requirements into contract language and ongoing operational procedures.

    Follow these two requirements for WEc4.1:

    • In cooperation with your cooling tower management contractor, implement a water management plan that clearly defines processes and procedures for chemical management, bleed-off, biological controlBiological control is the use of chemical or physical water treatments to inhibit bacterial growth in cooling towers., and staff training. Your existing contract may meet the LEED requirements with little or no modification, but make sure that it thoroughly addresses each of the requirements. If the contract only provides partial information, it may be necessary for you to develop a separate document.
    • Install and maintain a conductivity meterA device that measures the amount of nutrients and salt in water. Also know as a EC meter. and controls that automatically adjust the bleed-off rates and minimize the buildup of dissolved solids as the water evaporates.

    WEc4.2: Non-Potable Water Sources

    WEc4.2 addresses the use of non-potable water in your cooling tower. Non-potable water can be used as cooling tower makeup water if it is treated to eliminate the introduction of biological contaminants. Available sources of non-potable water range from HVAC condensate to collected stormwater to desalinated ocean water. Naturally occurring surface and groundwater do not qualify as appropriate non-potable sources for the purposes of this credit.

    Costs associated with WEc4.2 will probably be substantial if you’re not already using non-potable water in your cooling tower. Retrofitting a cooling tower to use non-potable water can be very difficult and costly, due in part to the amount of water treatment needed and also to the sheer amount of reclaimed or captured non-potable water required to effectively operate a cooling tower.

    Water use bar chart by building typeDepending on building type, HVAC can represent a huge portion of overall use. Source – Awwa Research Foundation

    Consider these questions when approaching this credit

    • Does your building have a cooling tower? Sometimes project teams mistakenly believe that if they don’t have a cooling tower, they can qualify because they’re avoiding the environmental impacts of having one. You must have a cooling tower to qualify for this credit.
    • What sort of controllability and automation currently exist?
    • Can the cooling tower be retrofitted to use non-potable water? 
    • Are rebates available through your water utility for cooling tower improvements or retrofits?
    • What is your current contractor arrangement for cooling tower management? Will the existing contract need to be amended to meet the LEED criteria for the water management plan?
    • To what extent does onsite staff perform cooling tower management duties? What training do they receive?

Legend

  • Best Practices
  • Gotcha
  • Action Steps
  • Cost Tip

Before the Performance Period

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  • Do you have a cooling tower? If not, your project is not eligible for this credit, even if you realize environmental benefits from not having one.


  • Decide whether you will explore WEc4.1, which involves chemical management and is very attainable, and/or WEc4.2, which involves using non-potable water in the cooling tower and requires substantial investment if you don’t have a system already in place. You may also choose to pursue both options. See below for more details on each option. Each option is worth one point, and pursuing both options will yield two points.


  • WEc4.1: Chemical Management


  • Implement a water-management plan for the cooling tower that addresses the following areas:

    • Chemical treatment—Describe the chemicals and procedures used to treat cooling tower water to an appropriate quality.
    • Bleed-off—Describe the procedures and appropriate set points for effective use of a conductivity meter and controls to automatically adjust the bleed rate of cooling tower water. Proper automatic adjustment of the bleed rate will help maintain proper concentrations and conserve water.
    • Biological control—Describe the biocides and procedures used to control biological contamination, including Legionella pneumophila, the bacterium that causes Legionnaires’ disease.
    • Staff training—Describe the regular training program or opportunities available to onsite staff with cooling tower management duties.

  • This option does not require that your water management plan meet any particular environmental standards or thresholds, but only that you have a detailed plan that is written specifically for your cooling tower in order to optimize water management.


  • Work with your existing cooling tower management contractor to develop a written water management plan. Existing contract language may meet some or all of the plan criteria. Carefully compare the contract and existing procedural documents with the plan criteria described in the LEED Reference Guide, developing additional detail as needed in order to meet the requirements. Submitting the contract alone as LEED documentation may not provide enough information.


  • Staff training is often a weak point for vendors who otherwise do a good job of documenting their services and procedures for chemical treatment, bleed-off, and biological control. Make sure that you collaborate with your vendor to develop adequate staff training procedures for building staff responsible for daily cooling tower maintenance. Unless cooling tower management is completely outsourced, staff training is required, even if your onsite staff is only performing minor monitoring and inspection duties.


  • Vendors are usually happy to work with you in developing a compliant water management plan and typically offer onsite staff training as part of their services at little to no additional charge.


  • Install and maintain a conductivity meter and automatic controls to adjust the bleed rate and maintain proper concentrations at all times.


  • Automatic control modulates bleed-off to match the actual evaporation rate, which is far more water-efficient than using fixed bleed rates. 


  • Updating your preventive maintenance plan to include regular inspections and maintenance of cooling tower controls is a good practice.


  • There are moderate costs associated with installing a conductivity meter and controls, but this equipment has a payback period ranging from less than one year to as little as two years through reduced water bills, and will immediately help to reduce potable water consumption.


  • Utilities may offer rebates for the use of qualifying conductivity meters and automatic controls.


  • WEc4.2: Non-Potable Water Source Use


  • Retrofit or maintain each onsite cooling tower to use makeup water consisting of at least 50% non-potable water.


  • Non-potable water can be used as cooling tower makeup water if it has been treated to an appropriate quality to eliminate the introduction of biological contaminants. One of the biggest concerns surrounding the use of non-potable water is the increased risk of fouling.


  • Consider the volume of water that is available from non-potable sources compared to demand for the cooling tower and the cost and logistics of reconfiguring current systems.


  • Available sources include but are not limited to the following:

    • Air-conditioning condensate is a good source. Cold condensate is generally cleaner than other potential sources and provides an efficiency advantage compared with other sources.
    • Harvested rainwater or stormwater can be used, especially if the project building has large surfaces that facilitate collection.
    • Graywater may be used if it is treated to an appropriate quality. Consult state or local ordinances to determine whether this is a viable option for your building.
    • Desalinated ocean water may be used if appropriately treated, but the desalinization process is fairly energy-intensive.
    • In some areas, municipal utilities offer a non-potable, reclaimed water supply, or so-called purple-pipe system (often plumbed in purple pipes to clearly differentiate it from potable water).
    • Naturally occurring surface and groundwater do not qualify as appropriate non-potable sources for LEED purposes.

  • Install and maintain submeters to track the amounts of potable and non-potable water used for cooling tower makeup.


  • If you own the submeters, ensure that they are calibrated within the specified manufacturer’s interval, and keep calibration and maintenance logs.


  • Utilities may provide and maintain submeters that can also be used to deduct cooling tower water consumption from sewage bills.


  • Utilities may offer rebates for the use of non-potable cooling tower makeup water.

During the Performance Period

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  • WEc4.1: Chemical Management


  • A narrative describing the conductivity meters, automatic controls, and the setpoints installed on each cooling tower must be included with your documentation. Be sure to include details about specific target concentration rations for each system. A manufacturer cut sheet, photograph, or engineer drawing for each conductivity meter must be supplied as supporting documentation.


  • Ensure that the automatic controls are working properly.


  • Implement a preventive maintenance plan to inspect and maintain cooling tower controls. An effective plan will address the water management plan of the project building in question. Do not submit a water management plan that addresses another building, or that is too general and does not address the specifics of the project building.


  • Be prepared to demonstrate that onsite building staff who are responsible for daily water tower maintenance receive appropriate training, as this is often overlooked.


  • WEc4.2: Non-Potable Water Source Use


  • Track and record monthly consumption of potable and non-potable water used for cooling tower makeup. This will require submetering capability for all cooling tower make-up water.


  • If you are also attempting WEc1: Water Performance Measurement, submetering of cooling tower makeup water will help demonstrate the amount of non-potable water used. In this case, make sure that your onsite staff is taking weekly manual readings of cooling tower submeters to ensure compliance with WEc1 requirements.

  • USGBC

    Excerpted from LEED 2009 for Existing Buildings: Operations & Maintenance

    WE Credit 4: Cooling tower water management

    1-2 points

    Intent

    To reduce 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. consumption for cooling tower or evaporative condenser equipment through effective water management and/or use of nonpotable makeup water.

    Requirements

    WE credit 4.1 (1 point): Chemical management

    Develop and implement a water management plan for the cooling tower or evaporative condenser that addresses chemical treatmentChemical treatment includes the use of biocidal, conditioning, dispersant, and scale-inhibiting chemicals to control biological growth, scale, and corrosion in cooling towers. Alternatives to conventional chemical treatment include ozonation, ionization, and exposure to ultraviolet light., bleed-offBleed-off, or blowdown, is the release of a portion of the recirculating water from a cooling tower; this water carries dissolved solids that can cause mineral buildup., biological controlBiological control is the use of chemical or physical water treatments to inhibit bacterial growth in cooling towers. and staff training as it relates to cooling tower maintenance.

    Improve water efficiency by installing and/or maintaining a conductivity meterA device that measures the amount of nutrients and salt in water. Also know as a EC meter. and automatic controls to adjust the bleed rate and maintain proper concentration at all times.

    AND/OR

    WE credit 4.2 (1 point): Nonpotable water source use

    Use makeup water that consists of at least 50% nonpotable water, such as harvested rainwater, harvested stormwater, air-conditioner condensate, swimming pool filter

    backwash water, cooling tower blowdownBleed-off, or blowdown, is the release of a portion of the recirculating water from a cooling tower; this water carries dissolved solids that can cause mineral buildup., pass-through (once-through) cooling water, recycled treated wastewater from toilet and urinal flushing, foundation drain water, municipally reclaimed water or any other appropriate on-site water source that is not naturally occurring groundwater or surface water.

    Have a measurement program in place that verifies makeup water quantities used from nonpotable sources. Meters must be calibrated within the manufacturer’s recommended interval if the building owner, management organization or tenant owns the meter. Meters owned by third parties (e.g., utilities or governments) are exempt.

    Potential Technologies & Strategies

    Work with a water treatment specialist to develop a water management strategy addressing the appropriate chemical treatmentChemical treatment includes the use of biocidal, conditioning, dispersant, and scale-inhibiting chemicals to control biological growth, scale, and corrosion in cooling towers. Alternatives to conventional chemical treatment include ozonation, ionization, and exposure to ultraviolet light. and bleed-offBleed-off, or blowdown, is the release of a portion of the recirculating water from a cooling tower; this water carries dissolved solids that can cause mineral buildup. to ensure proper concentration levels in the cooling tower. Also, develop a biocide treatment program to avoid biological contamination and the risk of Legionella in the building.

    Identify 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. sources that may be suitable for use in the cooling tower makeup water. Ensure that the water meets the cooling tower manufacturer’s guidelines in terms of water purity and adjust the chemical treatment program accordingly.

Web Tools

U.S. DOE, FEMP, Cooling Tower BMPs

Provides an overview of cooling tower best management practices to improve water efficiency.


U.S. Department of Energy, Federal Energy Management Program, Cooling Tower Operations and Maintenance

This website provides a cooling tower maintenance checklist to ensure optimal performance of cooling towers. 

Publications

ASHRAE Journal, Maintaining Cooling Towers

This article discusses routine preventive maintenance practices and operational measures to optimize cooling tower performance.

LEED Gold Project Documentation

Complete LEED Online documentation for achievement of WEc4.1 on a certified Gold LEED-EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems. 2009 project in Denver, Colorado.

Cooling Tower Water Management Plan Template

Projects can use this template to help develop their plans for water and chemical management for cooling towers.

LEED Online Forms: EBOM-2009 WE

The following links take you to the public, informational versions of the dynamic LEED Online forms for each EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems.-2009 WE credit. You'll need to fill out the live versions of these forms on LEED Online for each credit you hope to earn.

v06 forms:

v05 forms:

These links are posted by LEEDuser with USGBC's permission. USGBC has certain usage restrictions on these forms; for more information, visit LEED Online and click "Sample Forms Download."

61 Comments

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Rajesh Ghorla Mr First Green Consulting Pvt Ltd
Apr 16 2013
Guest
19 Thumbs Up

Non Potable Water Source Use

What QC process can be added to identify variances from Standard Approach and what measures can be take. For example, if the non-potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. source is used for other building systems and sufficient quantities are unavailable for all end uses claimed.

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Jul 31 2013 LEEDuser Moderator

Rajesh, I am not sure I understand your question, but if you are claiming 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. use you should be sure that you have enough supply to meet demand. Use of metering or historical measures can be of help here.

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Vincent Kotwicki
Jan 02 2013
Guest
68 Thumbs Up

Treated seawater for makeup water

The intent of the credit is: "To reduce 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. consumption for cooling tower equipment through effective water management and/or use of nonpotable makeup water."

I have two questions: Can we get a credit for using a beachwell (a well drilled on a beach and drawing seawater) and desalinating this seawater for use in the cooling tower?

And question two: What "potable water" we are talking about? The source (seawater) is nonpotable, but if we desalinate it, it becomes potable.

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Jan 02 2013 LEEDuser Moderator

Vincent, in my opinion, this would meet the definition 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. use. You are making use of a nonpotable water source, and treating it to the standards needed in the building. Other more common nonpotable sources, like 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., would require similar treatment.

The energy required to desalinate the water will count against you in the EA category, of course.

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Vincent Kotwicki Jan 03 2013 Guest 68 Thumbs Up

Tristan, thank you for your elucidating clarification. On energy, we are thinking about wind turbines to keep our head above water in the EA category.

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Wagner Oliveira CTE
Nov 19 2012
Guest
605 Thumbs Up

Drycoolers

We work on a project that has Drycoolers, all water user is non-potable. Since there is no closed loop and make up water this system there no treatment. Can we pursue both 4.1 and 4.2 credits?

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Hannah Bronfman Sustainability Consultant, YR&G Dec 14 2012 LEEDuser Expert 1348 Thumbs Up

Hi Wagner

This is a good question. And I'm not sure if I have a 100% certain answer, but it seems to me that you would be eligible for WEc4.2 because the system in and of itself uses no 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..

As for WEc4.1, I'm inclined to say that your project would not be eligible - the intent of the credit is for water quality (not quantity as in WEc4.2), so you'd need to be using water to achieve it.

You can always try and submit both as I'm assuming the documentation would be similar by submitting an Alternative Compliance Path option. But if you want a more definitive answer, I'd suggest submitting 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.

Thanks

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Julie Klein Principal Confluence Sustainability
Nov 08 2012
Guest
30 Thumbs Up

Applicable credits for chemical free cooling tower maintenance

I am looking at a chemical free cooling tower maintenance system that returns huge water savings. Is there a threshold on the number of credits for one facility component? Assuming meeting WEp1 and meeting the criteria for the following credits, can this system gather credit points for WEc1, WEc2, WEc3, WEc4.1 and/or 4.2 and WEc17 and 18? Any other credits in Innovation or IAQIndoor air quality: The quality and attributes of indoor air affecting the health and comfort building occupants. IAQ encompasses available fresh air, contaminant levels, acoustics and noise levels, lighting quality, and other factors.? thanks...

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Nov 23 2012 LEEDuser Moderator

Julie, check the credit language for those credits posted here, but cooling towers aren't within the scope of several of the credits you list.

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Julie Klein Principal, Confluence Sustainability Nov 24 2012 Guest 30 Thumbs Up

Thanks Tristan - it seems like a stretch for WEc1, WEc2, and WEc3 with some exception within EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems., but in that list are there credits that can absolutely not be achieved through cooling towers?

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Nov 24 2012 LEEDuser Moderator

Julie, please check the credit language for those credits, and the LEEDuser guidance. That will explain it a lot more thoroughly than I can here. Please post specific questions on those credit forums.

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Kevin Krejci
Jun 18 2012
LEEDuser Member
44 Thumbs Up

Using Rainwater for Cooling Tower Make-up

Thinking of doing a feasability study on using rainwater from garage run-off for cooling tower make-up. Has anyone been down this road and is willing to share challenges / successes?

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Sep 03 2012 LEEDuser Moderator

Kevin, any results from your research that you can share?

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Katie Anthony
Mar 27 2012
Guest
157 Thumbs Up

Non-potable river water vs. cooling tower

I am working on certification for a building that doesn't have cooling towers, but uses the adjacent river (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.) for the similar purpose as a cooling tower. The system is not air cooled, it is indeed water cooled, but does not have the requisite towers. By foregoing cooling towers and using the river, the building saves thousands of gallons of potable water a year, which is the intent of this credit.

We plan to pursue the credit using an Alternative Compliance Path, but I'm curious if there are any thoughts out there on our eligibility for WEc4.2?

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Apr 06 2012 LEEDuser Moderator

Katie, I can't speak to the likelihood of this approach being accepted, but I would say it's worth a shot.

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Susan Walter Sr Project Architect, Wilmot/Sanz Apr 06 2012 LEEDuser Expert 14575 Thumbs Up

This is one I've been thinking about and I'm not sure either. If you do divert the river water, you should have protections against harming wildlife and the temperature of the discharge water. You may need to ensure that the return temperature is equal to the entering temperature to avoid shocking the river plants and animals. What happens to the contaminants from the cooling tower? How will you filter the incoming water? If you can account for the full cycle and protect the environment, you have a shot.

Oh, and do a little reading on the formation of the Riverkeepers and their work currently.

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Lili Pan LEED AP BD+C, O+M, Managing Director , L GEES 智利捷达 Oct 14 2013 LEEDuser Member 193 Thumbs Up

Without having a cooling tower, these two credits are not eligible. We had a project using seawater for cooling and got rejected for these two credits.

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Jiri Dobias
Dec 13 2011
LEEDuser Member
1197 Thumbs Up

Air Cooled Units

Does it mean that projects which are using air cooled chillers are not eligible for this credit and therefore are "punished" for using no 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. for chillers?

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Brittany Bliffen Sustainability Manager, YR&G Dec 20 2011 LEEDuser Expert 454 Thumbs Up

HI Jiri,

Unfortunately, it seems that way. If the project does not have cooling towers, then I believe that WEc4 cannot be pursued.

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Glenn Dawson Mr, Majid Al Futtaim Apr 29 2012 LEEDuser Member 24 Thumbs Up

Can we use for Innovation?

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Nov 23 2012 LEEDuser Moderator

Glenn, what's your angle on an innovation point?

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Lili Pan LEED AP BD+C, O+M, Managing Director , L GEES 智利捷达 Oct 14 2013 LEEDuser Member 193 Thumbs Up

I think the only way to get ID credit for using air cooling is to prove your specific air cooling system has very sound sustainable / environmental value which is not addressed by existing points.

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Anshul Chawla Green Building Analyst Environmental Design Solutions
Nov 24 2011
Guest
167 Thumbs Up

Cooling Tower for Back-up Diesel Generators (DG)

The project site has 3 cooling towers of 215 ton capacity each. These cooling towers serve the HVAC system of the building and are operational for 8-10 hrs on all working days. These cooling towers support automatic bleed-offBleed-off, or blowdown, is the release of a portion of the recirculating water from a cooling tower; this water carries dissolved solids that can cause mineral buildup. and meet the credit requirements.

There are 3 small cooling towers of 40 ton capacity each. These are temorary use CT's which are only operational when DG sets are run for power back-up (3-4 hrs/day in peak requirement). Also these cooling towers only serve the DG sets and no other part of the building.

Are the mechanical services cooling towers also to be included in the credit documentation? There is no clarification on this situation in the reference manual. A way forward will be highly appreciated.

Thanks

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Brittany Bliffen Sustainability Manager, YR&G Dec 20 2011 LEEDuser Expert 454 Thumbs Up

Hi Anshul,

I believe that all cooling towers in the building should be included for WEc4, including mechanical services cooling towers.

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Michael Angell
Oct 17 2011
LEEDuser Member
72 Thumbs Up

Pursuing this Credit for New Construction

Would this credit be available as an ID credit under a project going for new construction? Or is there already a like credit that addresses these parameters?

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Brittany Bliffen Sustainability Manager, YR&G Oct 21 2011 LEEDuser Expert 454 Thumbs Up

Hi Micheal,

There is a related credit in the LEED Pilot Credit Library that can be pursued as one of your ID points for a New Construction project. Its called PC 17: WE - Cooling Tower Makeup Water.

Find PC17 and info on how to use the Pilot Credits here:
http://www.usgbc.org/DisplayPage.aspx?CMSPageID=2104

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Jessica Hawley Sustainability Consultant EBI Consulting
Sep 30 2011
LEEDuser Member
865 Thumbs Up

One Conductivity Meter for Multiple towers

On our project building there is only one system meter. All cooling towers are interconnected with a single header which is monitored by the conductivity meterA device that measures the amount of nutrients and salt in water. Also know as a EC meter.. Will this configuration be acceptable for this credit or does USGBC require separate meters for each tower? Thanks for the help!

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Brittany Bliffen Sustainability Manager, YR&G Oct 21 2011 LEEDuser Expert 454 Thumbs Up

From my experience, that should be fine. Anybody else have thoughts?

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David Hubka Director of Operations Transwestern Sustainability Services
Jun 02 2011
LEEDuser Expert
4470 Thumbs Up

Maintenance Staff Training

LEED User offers the following advice for projects that completely outsource their cooling tower management:
"Unless cooling tower management is completely outsourced, staff training is required, even if your onsite staff is only performing minor monitoring and inspection duties."
Our project completely outsources the cooling tower management however the technical advice of the LEED review team requires us to provide details on staff training as it relates to cooling tower maintenance.
Please advise.

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nadav malin Jun 27 2011 LEEDuser Member 89 Thumbs Up

Hi David,

In this situation I would provide information on the training available to whoever it is on your team who contracts with and oversees the work done by the outside maintenance contractor.

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Scott Bowman Owner, Integrated Design + Energy Advisors, LLC Jun 29 2011 LEEDuser Expert 5679 Thumbs Up

Another idea would be to ask what training the vendor provides to its clients. Often, the person maintaining the chemical treatmentChemical treatment includes the use of biocidal, conditioning, dispersant, and scale-inhibiting chemicals to control biological growth, scale, and corrosion in cooling towers. Alternatives to conventional chemical treatment include ozonation, ionization, and exposure to ultraviolet light. will work with the client to understand what they are to do between their visits and when to call if there is a problem, etc. I think that is "training" but not as formal.

My guess is USGBC is interested in the long term performance of the treatment system, to make sure it is performing at the level intended.

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Asa Posner Senior Sustainability Consultant, Sustainable Investment Group (SIG) Aug 09 2011 LEEDuser Member 923 Thumbs Up

To document training for a building with partially outsourced maintenance, we submitted training certificates from the specialist to the on-site engineers noting dates within the performance period. However, the credit is pending, "more details on the duration, frequency, and subjects of staff training as it relates to cooling tower maintenance."
Be sure you include all those variables in your written plan.

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Anderson Benite
Apr 11 2011
LEEDuser Member
987 Thumbs Up

WE 4.1 TEMPLATE

In our project the towers has the following water cooling consumption during the Performance Period:

Potable: KGALI 52.16 (4% of total)
Non Potable: KGALI 346.71 (96% of total)
TOTAL: 398.87

In my opinion we are using 96% of 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., but the template displays the following data:

Total cooling tower meter coverage (must Be 100%) (%) = 100

Estimated total cooling tower water use nonpotable During performance period (KGALI) = 102.2336
Estimated total cooling tower water use potable During performance period (KGALI) = 360.5784
Estimated total cooling tower water use During performance period (KGALI) = 462,812
Estimated total annual cooling tower water use (KGALI) = 1,397.04
Percent 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. use for cooling tower equipment:% = 77.91%

I think something is wrong. Can anyone help me?

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Apr 23 2011 LEEDuser Moderator

Anderson, first I would note that it's the WEc4.2 form that you're referring to.

Second, I think the issue you're having is the "Meter Coverage(% of Total
Cooling Towers)" entry. I put in 100% for both numbers, potable and nonpotable, and got the correct output. Perhaps you have different numbers entered there.

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Jean Marais b.i.g. Bechtold DesignBuilder Expert
Feb 07 2011
LEEDuser Member
8571 Thumbs Up

non-Cooling tower thinking

How does the line of thought go that balances out not using cooling towers (e.g. air cooled chillers)? Is it bad to not use a cooling tower? is it good? does it balance out in the energy points? What's the general idea here?

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Feb 07 2011 LEEDuser Moderator

Jean, that's a complex question. I would say it has a lot to do with the building, its size and heating/cooling loads, efficiency of relevant equipment, etc.

If you don't have a cooling tower you're not eligible for these two points, but I wouldn't let that influence design and operation decisions.

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Scott Bowman Owner, Integrated Design + Energy Advisors, LLC Feb 08 2011 LEEDuser Expert 5679 Thumbs Up

This is a massive generalization, but when chillers are the selected system, smaller chillers will be better air cooled, and larger chillers better water cooled. There are all sorts of other factors like load profile, because air cooled (which are often screw or scroll compressors) have very good part load performance, where centrifugal chillers tend to have better full load performance for base loading.

So,it really all depends on the project, and should be examined carefully during the energy modeling early in the project. There are other options when you have a water cooled system such as heat recovery chillers and water-side economizerAn economizer is a device used to make building systems more energy efficient. Examples include HVAC enthalpy controls, which are based on humidity and temperature. too.

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Jean Marais b.i.g. Bechtold DesignBuilder Expert Feb 09 2011 LEEDuser Member 8571 Thumbs Up

I know what you're saying...I've read loads of articles in ASHRAE journal, basically all saying that the efficiencies of Chilling Equipment should really be modelled and not read out of the back of ASHRAE 90.1, exactly because, as you say, the environmental loads, outdoor humidity, size, part loading and many other factors hugely impact on it's efficiency.

I've also read articles testing air cooled and water cooled solutions on specific and divers problems trying to extrapolate trends...basically saying that "well, it depends".

That's why I first felt like this existing building was unduelly penalized for having air cooled chillers.

I'm not going to try and fuddle in a cooling tower where it doesn't fit, don't worry. I just know that there is usually reason behind these things from the USGBC. It could be as simple as that the majority of chillers in the USA are water cooled and this water (probably potable) is being thrown away. I remember how shocked I was to here how late the USA was at bringing in laws forbidding (controlling) the use of potable ground water for cooling in power plants (mostly also cooling towers). It was like 40% of 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. was used in cooling towers in power plants, even right next to the see. Water is obviously way to cheep.

Thanks for the input.

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Scott Bowman Owner, Integrated Design + Energy Advisors, LLC Feb 09 2011 LEEDuser Expert 5679 Thumbs Up

Yes, we just did a large rainwater capture project, and in preparing for a presentation, I learned that one of the major users of fresh water (not always treated, but definately non-salt) was power plants, and many were once-through!

In general, if the chiller is in good shape, it would be rare that switching a water cooled unit for the air cooled unit would pay back economically...there are many more energy efficiency measures that should be tried first.

I do think water is too cheap, and it does not take into account the social and infrastructure cost to a city, such as urban areas with combined storm and sewer systems. But that is a different thread. One thing we seem to include in more projects is rainwater capture for cooling tower makeup, which can help reduce chemical treatmentChemical treatment includes the use of biocidal, conditioning, dispersant, and scale-inhibiting chemicals to control biological growth, scale, and corrosion in cooling towers. Alternatives to conventional chemical treatment include ozonation, ionization, and exposure to ultraviolet light. costs. So, sometimes it is good to look at smaller systems even if you cannot support a large system for flushing.

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Scott Bowman Owner Integrated Design + Energy Advisors, LLC
Dec 14 2010
LEEDuser Expert
5679 Thumbs Up

District Energy Application?

I know that the guide for EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems. and District Energy is coming, but we are doing a feasibility study right now and would like some feedback on any thoughts about a central plant in an university setting.

We have a university campus that has a central plant which meters the make up water and has a significant chemical control system. Can individual EBOM projects take advantage of these aspects of the central plant as long as they are documented in the same manner as if they were in the building?

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Jan 11 2011 LEEDuser Moderator

Scott, you may be aware of this, but the DES guide for EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems. came out about two weeks ago and is on the USGBC site. I would check that for the guidance you need.

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Scott Bowman Owner, Integrated Design + Energy Advisors, LLC Jan 11 2011 LEEDuser Expert 5679 Thumbs Up

Tristan;

I did see that, and opened it with great excitment, but alas, it only covers EA credits! So this is still an open question. However, as you read that document, I have to believe that applying credits to a DES where appropriate, with documentation of course, should be accepted.

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Alexa Stone ecoPreserve: Building Sustainability Apr 06 2011 LEEDuser Member 2340 Thumbs Up

Tristan and Scott,
I tried to answer the answer myself with your comments above BUT.... if we currently utilize our local utilities' DES for purchased chilled water, can we pursue this credit by working with the utility on their chemical management?

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Scott Bowman Owner, Integrated Design + Energy Advisors, LLC Apr 06 2011 LEEDuser Expert 5679 Thumbs Up

At this point we just do not know. The project we have that may pursue this is very long term and no decision has been made, so we may not know for a while.

My opinion, and it is only that, is if your provider can provide documentation that the comply with credit, then that should pass through to anyone that uses that service.

Hopefuly USGBC will clarify at some point, or someone will try it and report it here!

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Norma Lehman Director of Sustainability, The Beck Group Mar 18 2014 LEEDuser Member 1577 Thumbs Up

Any update on using the central plant to achieve compliance for an individual building in a university campus setting?

We are working on an EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems. project located on a college campus and are wondering if we can achieve this credit by documenting the reduction in water consumption at the central plant. We do not have cooling towers at the building level; everything is located at the university's central plant.

Any insight would be very helpful, thank you!

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Norma Lehman Director of Sustainability, The Beck Group Mar 31 2014 LEEDuser Member 1577 Thumbs Up

All, i just received guidance on this from my LEED coach:

Yes, project teams may pursue WEc4.1 and take credit for a building-owned cooling tower on campus that meets the credit requirements, even though it is not within the LEED project boundary. Note that all cooling towers that serve the project building must be accounted for.

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Trista Little Sustainability Manager, YR&G Apr 08 2014 LEEDuser Expert 1587 Thumbs Up

Hi Norma, I recommend checking out the Campus Guidance document for additional info - http://www.usgbc.org/resources/campus-guidance

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S Sundararaj
Nov 22 2010
Guest
1061 Thumbs Up

Required toolkit for Water Management Plan

My project building uses only treated water for cooling tower. The conductivity meterA device that measures the amount of nutrients and salt in water. Also know as a EC meter. installed is automatically controlling the bleed off rates. However to document the credit requirement, I am in search of a sample "Water Management Plan". If anyone can help i would really appreciate it. Thank you in advance.

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Jan 21 2011 LEEDuser Moderator

S, this is fairly uncharted territory. USGBC hasn't offered guidelines on what they're looking for. I am, however, looking for a sample and will post it here if I get it.

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S Sundararaj Jan 31 2011 Guest 1061 Thumbs Up

Oh well thank you Mr.Tristan!

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Ashley Miele President J&A Associates Engineers and Managers
Sep 23 2010
Guest
239 Thumbs Up

Zero Blowdown Technology for Cooling Towers - No Chemicals

I am a professional environmental engineer that just started specializing in a cooling tower water conservation technology. Similar to the discussion previously this technology softens the water without the addition of chemicals and prevents corrosion and scaling allowing the cycles of concentrationConcentration ratio is the ratio of the level of dissolved solids in the recirculating water to the level found in the entering makeup water. A higher concentration ratio results from a lower bleed-off rate; increasing the ratio above a certain point, however, leads to scaling, and water savings diminish after a certain level. This ratio is also called the cycles of concentration. Cycles refers to the number of times dissolved minerals in the water are concentrated compared with makeup water, not to water flow over the tower or to on-off cycles. to increase.

The technology can get up to 3 LEED credits. It was established a few years ago and will hopefully gain momentum once the news spreads. Cooling tower water is such a significant fresh water user and this technology can make a large impact. Please feel free to contact me if you would like further information.

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Sep 23 2010 LEEDuser Moderator

Ashley, thanks for joining the forum. However, we're generally not wild about people posting here promoting their own services without at least adding some value in terms of tips on earning the credit, lessons learned, probing questions, or sample documentation.

We're also not big fans of general statements about how many credits a technology can get that aren't backed up with specifics. Many such claims are very overblown (no pun intended... you know cooling towers... :).

Care to add some real value here in terms of any of the above?

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Ashley Miele President, J&A Associates Engineers and Managers Sep 28 2010 Guest 239 Thumbs Up

Thanks Tristan, I appreciate your feedback. I am new to the LEEDuser and noticed someone else was interested in this technology from a previous discussion.

I wasn't looking to promote as much as try to get some feedback on this technology and others like it for sustainable solutions to water conservation.

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. Sep 28 2010 LEEDuser Moderator

Cool,  it's good to have you here.

Any hot tips on using this technology to earn WEc4?

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Michael Miller Project Architect Jul 25 2011 Guest 2157 Thumbs Up

I would be interested to hear whether this technology has been submitted for EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems. WEc4. It sounds like the same system we are submitting for an ID point under NC 2.2, referencing the CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide/Interpretation originally submitted for a different non-chemical treatmentChemical treatment includes the use of biocidal, conditioning, dispersant, and scale-inhibiting chemicals to control biological growth, scale, and corrosion in cooling towers. Alternatives to conventional chemical treatment include ozonation, ionization, and exposure to ultraviolet light. system.

The system we are using is a proprietary technology which one case-study article called 'zero liquid discharge'. It eliminates chemical corrosion, scale and biocide treatments, and eliminates regular blow-down. It's an intriguing system, and I'm looking forward to seeing how it performs on our project.

From what I've learned about the system so far, using it for WEc4.1 shouldn't be problematic, though it would require a 'special circumstances' narrative, since this system eliminates the need for some of the requirements of the credit.

However, I don't see how the technology, in and of itself, would have any bearing on WEc4.2 (per the other thread), since the elimination of water used for blow-down is still only a minor portion of the total water used by an evaporative cooling tower, whereas WEc4.2 requires at least 50% of makeup water to be from nonpotable sources.

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John Ida President Urban Works, Inc.
Aug 10 2010
LEEDuser Member
980 Thumbs Up

Conductivity Meter and Auto Controls/No chemical management

Can our team still attempt WEc4.1 with a system that does not require blow-down and does not require chemical treatmentChemical treatment includes the use of biocidal, conditioning, dispersant, and scale-inhibiting chemicals to control biological growth, scale, and corrosion in cooling towers. Alternatives to conventional chemical treatment include ozonation, ionization, and exposure to ultraviolet light. as an alternative compliance method? Here is an excerpt from the plan:

1. Chemical Treatment: The water is pre-treated with a water softener and UV filter; there is no chemical treatment required.
2. Bleed-offBleed-off, or blowdown, is the release of a portion of the recirculating water from a cooling tower; this water carries dissolved solids that can cause mineral buildup./BlowdownBleed-off, or blowdown, is the release of a portion of the recirculating water from a cooling tower; this water carries dissolved solids that can cause mineral buildup.: The cooling tower has no automatic blowdown feature, which wastes water and requires 1,500 gallons of water per day. The blowdown process is used when cleaning with acid or eliminating hard metal or other buildup. Because the water is pretreated, blowdown will not be necessary. Because using the blowdown feature is not necessary, the system saves 1,250 gallons per day.

With no blow-down requirements (except for annual maintenance), there is no need for conductivity meterA device that measures the amount of nutrients and salt in water. Also know as a EC meter./automatic controls. Similarly, the cooling tower water is pre-treated with a water-softener (non-toxic) and a UV light. Overall this method minimizes the amount 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. consumption for cooling tower equipment through effective water management, (as stated by the intent of WEc4.1) but does not meet the requirements for conductivity meters or "chemical" treatment.

Would this system be ineligible for this credit?

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Andrea Traber Director, Sustainable Buildings and Operations, KEMA Aug 23 2010 Guest 601 Thumbs Up

From what you are describing, you are using a very innovative system that would in fact qualify for credit WEc4.1. If any of your makeup water is from a non-potable source you may also be able to qualify for 4.2 and possibly 4.3 as well. It would be great for LEED Users if you could share the system name. Good job!

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Jordan Friedberg
May 10 2010
Guest
502 Thumbs Up

Cooling Towers vs Irrigation

It is my understanding (largely from this site) that if a project does NOT have an irrigation system, it can qualify for the maximum five points under that credit, because the project has reduced the amount of water used in irrigation by 100% over a typical system.

It is also my understanding that a project that does NOT use any water to cool the chillers (they are air cooled), does NOT qualify for any points under this credit, though it has reduced the amount of water used by the cooling tower by 100%.

Why would an absence of a system earn full credit in one instance, and disqualify a project from earning points in another?

Thanks!

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Tristan Roberts LEED AP BD+C, Editorial Director – LEEDuser, BuildingGreen, Inc. May 12 2010 LEEDuser Moderator

You do understand things correctly, and raise a good question. It's kind of like EQc4.3 in earlier versions of LEED-NC, where you could only earn the point if you used carpet, so in some cases teams were adding small areas of carpet just to earn the point. Not exactly productive.

In that case, the credit was changed through 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 and in LEED 2009. LEED-EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems. definitely has some kinks; maybe this issue will be revisited in 2012.

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Jenny Carney Principal, YR&G May 19 2010 LEEDuser Expert 7871 Thumbs Up

Another note on this...you can only earn the irrigation credits if you actually have some amount of vegetation on your site (something to irrigate). An absence of vegetation itself results in the same situation as with the cooling towers - the points are off the table.

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Geraldine Seguela RAIA Architect/Sustainability, Cleveland Clinic Abu Dhabi Nov 19 2012 LEEDuser Member 641 Thumbs Up

Chilled water on our project is provided by a large (80,000 TonR) district cooling plant. Does this credit applies?

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