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Orginated in LEED-EBOM
This is a modified version of the Cooling Tower credits originally in LEED for Existing Buildings: Operations & Maintenance.
Credit Submittals
General
- Register for Pilot Credit(s) here.
- Register a username at LEEDuser.com, and participate in online forum
- Submit feedback survey; supply PDF of your survey/confirmation of completion with credit documentation
Credit Specific
New Construction, Retail – NC, Schools, Core & Shell and Healthcare Projects:
Provide the following:
- A water analysis measuring as a minimum the five control parameters measured in ppmParts per million. or mg/l.
- Verification that sidestream filtration will be provided
- Proof of a meter on both the make-up and discharge from the tower.
- Location of conductivity meterA device that measures the amount of nutrients and salt in water. Also know as a EC meter..
- Diagram showing meter locations, sand filter.
- Drift eliminators specified on the tower achieving efficiencies of 0.2% or greater for counter flow or 0.5% or greater for cross flow systems.
- Narrative describing the water treatment system and the number of cycles which the cooling tower can achieve without exceeding the control parameters. The narrative should also include the predicted acceptable corrosion rates for each pipe material within the condenser water system.
Existing Buildings: Operations & Maintenance Projects:
Provide the following:
- A water analysis measuring as a minimum the five control parameters measured in ppm or mg/l.
- Narrative describing the water treatment system and the number of cycles which the cooling tower can achieve without exceeding the control parameters. The narrative should also include the predicted acceptable corrosion rates for each pipe material within the condenser water system.
Additional Questions
None
USGBC
Excerpted from LEED 2009 for New Construction and Major Renovations
Pilot Credit 17: Cooling Tower Water Use
Intent
To conserve water used for cooling tower makeup while controlling microbes, corrosion, and scale in the condenser water system.
Requirements
NC, CS, Schools, Retail, Data Centers, Warehouse & Distribution Centers, Hospitality, Healthcare, CI, Retail, Hospitality
Equip cooling towers and evaporative condensers with:
- Makeup and 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. meters,
- Conductivity controllers and overflow alarms.
- Efficient drift eliminators that achieve drift reduction to a maximum of 0.2% of the recirculated water volume for counterflow towers and 0.5% of the recirculated water flow for cross-flow towers.
AND
For cooling towered and evaporative condensers, conduct a one-time 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. analysis, measuring at least the following five control parameters listed in Table 1, in ppmParts per million. or mg/l:
Table 1. Maximum concentrations for parameters in condenser water
Calculate the number of cooling tower cycles by dividing the amount of each parameter in the condenser water by the amount in the potable makeup water. The maximum acceptable levels of the parameters in the condenser water are shown in Table 1. Limit cooling tower cycles to avoid exceeding maximum values for any of these parameters.
Table 2. Points for cooling tower cycles
EBOM, Schools, Retail, Data Centers, Hospitality
ESTABLISHMENT
For cooling towered and evaporative condensers, conduct a one-time 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. analysis, measuring at least the following five control parameters listed in Table 1, in ppmParts per million. or mg/l:
Table 1. Maximum concentrations for parameters in condenser water
Calculate the number of cooling tower cycles by dividing the amount of each parameter in the condenser water by the amount in the potable makeup water. The maximum acceptable levels of the parameters in the condenser water are shown in Table 1. Limit cooling tower cycles to avoid exceeding maximum values for any of these parameters.
Table 2. Points for cooling tower cycles
PERFORMANCE
Confirm that the number of cooling tower cycles are up to date.
Potential Technologies & Strategies
Organizations
LEED Pilot Credit Library
The homepage for the LEED Pilot Credit Library. The LEED Pilot Credit Library is intended to facilitate the introduction of new prerequisites and credits to LEED. This process will allow USGBC to test and refine credits through LEED 2009 project evaluations before they are sent through the balloting process for introduction into LEED.
Articles
Foundations of LEED
Background for the LEED Pilot Credit Library is provided in this foundational document.
LEEDuser is produced by BuildingGreen, Inc., with YR&G authoring most of the original content. LEEDuser enjoys ongoing collaboration with USGBC.
24 Comments
Sand Filter
The credit requirement #5 asks for a "diagram showing meter locations, sand filter.:
Is a sand filter required to meet the credit?
A sand filter is not required - here is the newest version of the pilot credit - http://www.usgbc.org/node/2606869?return=/pilotcredits if you registered for the credit befor 1/15/2013 and would prefer to use the older version of the credit, you can just document that there is a side stream filtration system.
Pipe Corrosion Rates
How do you determine the predicted acceptable corrosion rates for each pipe material in the condenser water system?
Providing verification that there will be side stream filtration
Our project is pursuing an ID point for Pilot Credit 17 under the LEED-NCv2009 rating system. In reviewing the requirements, we had submitted an inquiry regarding "verification that there will be side stream filtration" and whether a cutsheet would suffice and if a sand filter is required as part of the side stream filtration system?
GBCI did respond to our inquiry and stated: "1. A cut sheet is a sufficient submittal to verify that side stream filtration is provided in the project.
2. No, a sand filter is not required to be part of the side stream filtration system."
One-Time Potable Water Analysis
When the credit requirements ask for a "one-time" 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. analysis to be conducted, what sort of time-frame is required for this to be completed? If I'm working on an EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems. project, does the analysis have to be completed during the performance period? The credit doesn't necessarily state when the analysis has to be completed, or how long the results are valid until another test would have to completed.
Edward - For EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems. projects, the 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. analysis should be done within the last 5 years (5 years of submitting for certification) - the goal is to get an idea of what type of water the cooling tower is using in terms of dissolved solids, and how that water and system can be optimized, so the analysis doesn't need to be done very frequently in order to get to the result. Here's the EBOM pilot credit language, which mirrors the v4 draft proposal.
LEED HC WEc4.2 vs Pilot Credit 17
A long-term healthcare project I have been working on that was registered under LEEDv2.2 recently got resistance for submitting LEED HC WEc4.2 as an ID credit. Our review came back requiring us to switch to Pilot Credit 17. At this point it is not a big deal since we comply with all of the requirements and it is just the paperwork required to provide the clarification, but can anyone confirm why we got the resistance in the first place and why our original submission was not acceptable? It sounds like everything about the submission was correct; they just wanted us to revise it to Pilot Credit 17. How are project teams supposed to know if a Pilot Credit is more appropriate than a credit from a different rating system?
April, I don't know what kind of "resistance" you got, but here's my best guess: the PC17 language is more up-to-date with where USGBC sees a cooling tower water credit going—the PC17 language is more recent than HC WEc4.2. So perhaps someone thought that as long as you were doing an innovation credit, they might as well have you use this new language that's being piloted, and thus it's a win for the project and a win for LEED development rather than just the former. The requirements are also intended more broadly for BD&C, and not just HC.
This is pure conjecture, mind you, but I think it's plausible.
As a general rule, I would advise teams to consider the Pilot Credit Library as a first place to go when considering innovation credits, because of the feedback that it provides to the LEED development process.
Makes sense. Really the only resistance we got was that the credit was bounced back during review so we had to provide some additional documentation. I think it will be accepted this go-around.
Thanks for your thoughts! I think I will look through the Pilot Credit Library for my next project.
I wonder if it also has something to do with the nature of your project. Is is all new construction or renovation? My other thought was the difference between a v2.2 project and v3. The GBCI often sees renovation projects in hospitals as more aligned with CI or CS than HC as well.
Susan, our project is new construction - healthcare facility. I had heard that you could submit credits approved in newer versions of LEED as ID credits which is why we pursued that one from LEED HC. I was just surprised that we had to re-issue it as a Pilot Credit instead. Again, it wasn't really a big deal since we met all of the requirements either way.
Good thought, though. Some rating systems align better than others.
Sidestream filter?
The credit requirements do not call for a sidestream filter, but the documentation requirements list that we should confirm that a sidestream filter is being provided. Why is that?
You're correct that the credit requirements do not call for a sidstream filter. They are filtration systems alongside the cooling tower that filter a small percentage of the water at a time. They are fairly common on high performance cooling towers, but are not a requirement. Instead, please describe the filtration system utilized or provide a narrative explaining why this system does not include filtration. We're mainly looking to see the process by which the system is protected from corrosion and build-up.
One-time potable water analysis
In the new version of Pilot credit Revised at 1/3/2012 they ask to be done one-time 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. analysis. How do we do if our project already covers 100% makeup water with non-potable water?
Hi Wagner, that's a good question. If the project isn't using any 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 cooling tower makeup, then I think the most appropriate thing would be to do an analysis of your non-potable water source for the same purpose - to show that it can be cycled through multiple times without creating build up or performance problems.
Would that work in your case?
Hi Batya, first of all thanks for your reply.
This does not work in our case, since 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. will be generated only when the building comes into operation.
Hi Wagner, that would make the credit harder to achieve, but assuming that non-potable waterPotable water meets or exceeds EPA's drinking water quality standards and is approved for human consumption by the state or local authorities having jurisdiction; it may be supplied from wells or municipal water systems. is the only source you're planning to use on the cooling tower, I would assume there is some planning or calculation going into the setup. In that case, the documentation could show 1) how much non-potable water you expect to generate for cooling tower use (and what type, it would need to have low dissolved solids) 2) how you plan to deliver it to the system and 3) how you will meet the dissolved solids and 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. as outlined in the credit - perhaps filtration/treatment, or perhaps the source is very pure to begin with.
2009 for Schools
Can this PC17 be used for LEED 2009 for Schools??
Yes, according to the main pilot credit guide from USGBC, LEED for Schools can use PC17.
questions of Install Drift Eliminators and minimum efficiencies
In the pdf download from usgbc.org, one of the credits requirements is 'install drift eliminators that achieve minimum efficiencies of 0.2% for counter-flow systems or 0.5% for cross-flow system'.
Anyone who knows this efficiencies? What doest it mean? And how to calculate or measure?
Thanks very much.
Compared the LEED requirement of drift eliminator the minimum efficiencies are more higher than Chinese standard requirements.
Now what I want to know is how about the average level of drift eliminator in USA.
Another question is about the maximum level of conductivity. The unit of conductivity is μS/ml, however I do some study of this value that the unit is μS/cm. I wonder that it is just a printing mistake or the 'μS/ml' needs to convert to 'μS/cm'.
Thanks and hope for answer.
The credit authors have looked over this credit and believe that the units for conductivity are correct with μS/ml, with ml being equal to cm3. They are also staying with the drift eliminator values listed in the credit. This credit is currently being revised though, and we'll have a new version out in July that may help to clarify.
How long does the monthly monitoring last for?
One of the mentioned requirements is to report results of the amount 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. used, microbiological levels, 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. and corrosion on monthly basis, but for how long after occupancy?
Hi William -
Staff is going to check in with the Water Efficiency TAGLEED Technical Advisory Group (TAG): Subcommittees that consist of industry experts who assist in developing credit interpretations and technical improvements to the LEED system. on this one. For now, show that you have performed the test for a three month period. If you are an NC project, show a contract or some other intent to have ongoing monthly reports.
Does this make sense?
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