The document summarizes guidelines for water conservation in office buildings. It discusses why water conservation is important, typical water usage in office buildings, potential savings from more efficient practices, and specific tips in areas like bathrooms, heating/cooling, kitchens, cleaning, irrigation, and legislation. Key recommendations include fixing leaks, installing efficient fixtures, properly operating cooling towers, using Florida Friendly landscaping, and following water restrictions.

1. Office Water Conservation
Water Conservation Guidelines
for Office Buildings
Brent M. White
BOMA Engineers Breakfast
May 18, 2010
Tampa City Center
Tampa, FL

2. Water Conservation in
Office Buildings
 Why is water conservation important to
the office building industry?
 Reduces utility bills
 Reduces water treatment costs
 Increase competitiveness
 Extend the life of water using equipment
 Enhances public image
 Improves property value
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3. Office Building Mean Water Use
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4. Office Building Mean Water Use
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5. Water Use Allocation
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6. Seasonal Influences
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7. Potential Water Use Savings
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8. Conducting On-Site Evaluation
 Determine the water use rate for
all equipment and processes.
 Consistency is important
 Major areas to include are:
 Sanitation  Heating / Cooling
 Kitchen  Leak detection
 Office  Water used in products
 Miscellaneous  Alternative water use
 Irrigation  Staff input
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9. Gathering Facility Demographics
 Information to be gathered about a
facility to be audited includes:
 Service address  Number of employees
 Utility contact  Percent male/female
 Title  Full / Part time
 Age of facility  Meter size and count
 Building size  Water source(s)
 Operating hours/days  Billing class / rates
 Shifts per day  4-years of water history
 Cooling Tower size  Cooling Tower conductivity
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10. Water Budget
 A Water Budget Includes:
 Facility Statistics
 Equipment water use ratings
(Existing and Proposed)
 Frequency of use
 Days per year of use
 Estimated / Adjusted use
 Per year
 Estimated savings
 Per year
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11. Water Budget
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12. Indoor Water Saving Tips
 Domestic (Bathrooms)
 Report and repair all leaks
 Replace flush valve diaphragms
 Replace flappers annually
 Replace showerheads
 Replace faucet aerators
 Install waterless urinals
 Replace high-flow toilets
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13. Heating and Cooling
 Heating/Cooling
 Lower tower blowdown
 Use softener on makeup water
 Use efficient ice machines
 Install conductivity meter
 Submeter makeup & blowdown
 Use air cooled AC units
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14. Cooling Tower Schematic
Legend
B: Bleed Off
D: Drift
E: Evaporation
M: Make-up
CR: Concentration
ratio
Water Balance
M = E+B+D
Concentration Ratio
CR = MQuality / BQuality
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15. Concentration Ratios
 For metered towers (gallons)
 CR = M/B, or CR = (B+E)/B
 Example: 250 ton tower – 24 hours
M = 14,400 gallons
B = 5,760 gallons
CR = 14,400 gal / 5,760 gal
CR = 2.5
 Some utilities may provide a credit to
the wastewater charges for evaporative
losses with tower submetering.
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16. Concentration Ratios
 For unmetered towers (gallons)
 Calculation based on the conductivity
concentration ratio (TDS/S)
 CR = [B] / [M]
 Example: Bleed-off conductivity = 1,400 S
Make-up conductivity = 550 S
CR = 1,400 / 550
CR = 2.5
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17. Calculations
 Evaporation:
 Evaporating rate = 2.4 gpm/100 tons of cooling
 E = (2.4 gpm/100 tons) x (250 tons) x 24 hours x (60 min/hr)
 E = 8,640 gallons
 Bleed-Off:
 B = E/ (CR-1)
 B = 8,640 gallons / (2.5 – 1)
 B = 5,760 gallons
 Make-Up:
M=E+B
 M = 8,640 + 5,760
 M = 14,400 gallons
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18. Savings from Increasing Ratios
Concentration Ratios
Concentration Ratios After Adjusting Cycles
Before Adjusting
Cycles 2 3 4 5 6 7 8 9 10 12 15 20
1.5 33% 50% 56% 58% 60% 61% 62% 63% 63% 64% 64% 65%
2 25% 33% 38% 40% 42% 43% 44% 44% 45% 46% 47%
3 11% 17% 20% 22% 24% 25% 25% 27% 29% 30%
4 6% 10% 13% 14% 16% 17% 18% 20% 21%
5 4% 7% 9% 10% 11% 13% 14% 16%
6 3% 5% 6% 7% 9% 11% 12%
7 2% 4% 5% 6% 8% 10%
8 2% 3% 5% 6% 8%
9 . 3% 5% 6%
10 2% 4% 5%
12 2% 4%
15 2%
 Most towers run at 1.5 to 2.5 cycles of concentration
 Cycle of Concentration – How many times the water is
used inside the tower before being bled-off
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19. Water Use –vs Concentration Ratio
Wate r Consumption -v s- Conce ntration Ratio
Water Use Per 100 tons of Cooling (GPD)
Log. (Water Use Per 100 tons of Cooling (GPD))
8000
Approx. Total Water Consumption per 100 Tons of Cooling (GPD)
7500
7000
6500
6000
5500
5000
4500
4000
3500
3000
1 2 3 4 5 6 7 8 9
Concentration Ratio
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20. Calculating Savings
 Increasing the concentration ratio saves water
 CR1 = Ratio before increasing cycles
 CR2 = Ratio after increasing cycles
CR2 – CR1
 Percent conserved = X 100
CR1 (CR2-1)
 Example: CR1 = 2, CR2 = 6
 Percent Conserved = 6 - 2 X 100 = 4/10 = 40%
2(6-1)
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21. Outdoor Water Saving Tips
 Irrigation
 Use Florida Friendly rules
 Use nozzles on hoses
 Use a rain shutoff device
 Install drip irrigation
 Follow water restrictions
 Use reclaimed water
 Audit your system/schedule
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22. Cleaning Water Saving Tips
 General Cleaning
 Use mop water efficiently
 Clean windows as needed
 Calibrate all chemical mixes
 Use dry powders for
carpet cleaning
 Use low-volume pressure
washing
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23. Kitchen Water Saving Tips
 Food-Service
 Report and repair all leaks
 Use air-cooled ice machines
 Install foot pedals on prep sinks
 Use a drip lexan as an ice dump
 Turn on dip wells only as needed
 Defrost frozen food in walk-in
 Reuse last rinse as first rinse
 Install a low-flow pre-rinse spray nozzle
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24. Other Water Savings Tips
 Outdoor recommendations
 Fountain wind speed control system
 Automatically slow down or shut off a
fountain if surrounding wind speeds
are high enough to blow the spray
out of the fountain basin.
 Reduces spray drift that reaches
impervious surfaces.
 Fountains currently restricted to
8-hours of operation per day.
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25. Other Water Savings Tips
 Typically, water pressure from a
utility will average 45 psi
 Depends on elevation and distance from
the water main
 Running a booster pump to increase
pressure can affect the fixture flowrates:
*Fixture flow rate is measured at 35 psi.
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26. Recent Legislation – SB 494
 Ch. 373.62, F.S., Efficient Irrigation
Technology
 Licensed contractors must inspect, repair
 Local ordinance by October 2010
 Variance for “smart irrigation” technology
 Removes grandfather date of May 1, 1991 for
irrigation automatic shutoff devices.
 Ch. 482.1562, F.S., Fertilizer Application
Certification
 Certification by Jan. 2014 for professionals
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27. Recent Legislation – SB 2080
 Ch. 373.185, F.S., Florida-friendly language
 Ch. 373.187, F.S., WMDs must be FFL
 WMD’s should encourage local governments
to enact FFL ordinance language for
development permitted after June 30, 2009
 Ch. 125.568(3),
 Deed restrictions, local codes
may not prohibit or limit FFL
 Workshops were held for public
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28. Phase IV Water Restrictions
 Initial Phase IV restrictions:
 Common areas must be kept at 78 F
 Based upon US DOE standard
 Updated Phase IV restrictions:
 Based on Austin, TX ordinance
 Must have blowdown and makeup meters
 Must have conductivity controllers
 Must run at a minimum of 5 COC’s
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29. Thank You!
For more info:
Brent.White@swfwmd.state.fl.us
1-800-423-1476 ext. 4214