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LEED v4
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Water Efficiency
Cooling tower water use

LEED CREDIT

Schools-EBOM-v4 WEc3: Cooling tower water use 2-3 points

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Ashwini Arun

WSP
Sustainability Manager

SPECIAL REPORT

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Credit language

USGBC logo

© Copyright U.S. Green Building Council, Inc. All rights reserved.

Intent

To conserve water used for cooling tower makeup while controlling microbes, corrosion, and scale in the condenser water system.

Requirements

Establishment

For cooling towers and evaporative condensers, conduct a potable water analysis within five years of submission for certification, measuring at least the five control parameters listed in Table 1.

Table 1. Maximum concentrations for parameters in condenser water

Parameter Maximum level
Ca (as CaCO3) 1000 ppm
Total alkalinity 1000 ppm
SiO2 100 ppm
Cl- 250 ppm
Conductivity 2000 µS/cm

ppm = parts per million
µS/cm = micro siemens per centimeter

Calculate the number of cooling tower cycles by dividing the maximum allowed concentration level of each parameter by the actual concentration level of each parameter found in the potable makeup water. Limit cooling tower cycles to avoid exceeding maximum values for any of these parameters.

Table 2. Points for cooling tower cycles

Cooling tower cycles Points (except data centers) Points (data centers)
Maximum number of cycles achieved without exceeding any filtration levels or affecting operation of condenser water system (up to maximum of 10 cycles) 2 2
Achieve a minimum 10 cycles by increasing the level of treatment in condenser or make-up water
OR Achieve the number of cycles for 1 point and use a minimum 20% recycled nonpotable water
3 4
Performance

None

Pilot Alternative Compliance Path available

A pilot alternative compliance path is available for this credit to certain project types without cooling towers. For more information, please visit the Pilot Credit Library

Pilot ACPs:
No Cooling Tower - alternative compliance path (BD+C)
No Cooling Tower - alternative compliance path (O+M)
No Cooling Tower - alternative compliance path (O+M: Data Centers)

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LEEDuser expert

Ashwini Arun

WSP
Sustainability Manager

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USGBC logo

© Copyright U.S. Green Building Council, Inc. All rights reserved.

Intent

To conserve water used for cooling tower makeup while controlling microbes, corrosion, and scale in the condenser water system.

Requirements

Establishment

For cooling towers and evaporative condensers, conduct a potable water analysis within five years of submission for certification, measuring at least the five control parameters listed in Table 1.

Table 1. Maximum concentrations for parameters in condenser water

Parameter Maximum level
Ca (as CaCO3) 1000 ppm
Total alkalinity 1000 ppm
SiO2 100 ppm
Cl- 250 ppm
Conductivity 2000 µS/cm

ppm = parts per million
µS/cm = micro siemens per centimeter

Calculate the number of cooling tower cycles by dividing the maximum allowed concentration level of each parameter by the actual concentration level of each parameter found in the potable makeup water. Limit cooling tower cycles to avoid exceeding maximum values for any of these parameters.

Table 2. Points for cooling tower cycles

Cooling tower cycles Points (except data centers) Points (data centers)
Maximum number of cycles achieved without exceeding any filtration levels or affecting operation of condenser water system (up to maximum of 10 cycles) 2 2
Achieve a minimum 10 cycles by increasing the level of treatment in condenser or make-up water
OR Achieve the number of cycles for 1 point and use a minimum 20% recycled nonpotable water
3 4
Performance

None

Pilot Alternative Compliance Path available

A pilot alternative compliance path is available for this credit to certain project types without cooling towers. For more information, please visit the Pilot Credit Library

Pilot ACPs:
No Cooling Tower - alternative compliance path (BD+C)
No Cooling Tower - alternative compliance path (O+M)
No Cooling Tower - alternative compliance path (O+M: Data Centers)

In the end, LEED is all about documentation. LEEDuser’s Documentation Toolkit, for premium members only, saves you time and helps you avoid mistakes with:

  • Calculators to help assess credit compliance.
  • Tracking spreadsheets for materials purchases.
  • Spreadsheets and forms to give to subs and other team members.
  • Guidance documents on arcane LEED issues.
  • Sample templates to help guide your narratives and LEED Online submissions.
  • Examples of actual submissions from certified LEED projects.

LEEDuser expert

Ashwini Arun

WSP
Sustainability Manager

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