Water Efficiency Flashcards
Water Efficiency Intent
Promote “efficiency first” by looking at reductions in potable water through water efficiency alone, then recognizing the use of non-potable and alternative water sources second.
Water Efficiency Credits
Outdoor Water Use Reduction - 0 Points Required
Indoor Water Use Reduction - 0 Points Required
Building Level Water Metering - 0 Points Required
Outdoor Water Use Reduction - (2) Points Max
Indoor Water Use Reduction - (6) Points Max
Cooling Tower Water Use - (2) Points Max
Water Metering - (1) Point
Water Efficiency Definitions
Potable Water: Meets or exceeds the EPAs standards for drinking water quality and is approved for human consumption for state and local authorities. It may be supplied from wells or municipal plumbing systems.
Process Water: Water that 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.
Graywater: Untreated wastewater that has not come in contact with toilet waste. Includes used water from bathtubs, showers, bathroom sinks, and laundry machines. Does Not include water from kitchen sinks or dishwashers. Governed by the Uniform Plumbing Code.
Blackwater: Wastewater from toilets and urinals.
Tertiary Standards or Tertiary Treatment: The highest form of water treatment, and removes phosphorus and nitrogen from wastewater.
Note: While technologies are available today, and are in use, to treat raw sewage and convert it to drinking water, according to LEED, Tertiary Treatment does Not produce drinking water.
Outdoor Water Use Reduction Prerequisite
Purpose/Requirements/Notes
Purpose: To reduce outdoor water use.
Requirements: 1) Use No Irrigation or 2) Reduce Irrigation by 30% from the baseline, which is determined by the EPA Water Sense Budget Tool.
Notes: Nonvegetated surfaces should be excluded from landscape area calculations. Athletic fields and playgrounds and food gardens may be included or excluded at the project team’s discretion.
Strategies: Drought Tolerant Species Plant Density Irrigation Efficiency Non-Potable Water Reuse
Definitions:
Evapotransporation: Loss of water evaporation
Evapotrasnpiration Rate: Amount of water lost to the air via specific plants in a geographic area, this is the water necessary to grow and or maintain a plant.
Indoor Water Use Reduction Prerequisite
Purpose/Requirements/Notes
Purpose: To reduce indoor water use.
Requirements: Use 20% less water than the baseline. To achieve this, project teams should spcify that all newly installed toilets, urinals, private lavatory faucets, and showerheads be WaterSense labled (or local equivalent for projects outside the US).
Notes: WaterSense is an EPA program that labels fixtures that use about 20% less water than other products on the market.
Fixture Baselines are Based on:
1 Energy Policy Act (EPAct) 1992 and 2005
2 Uniform Plumbing Code
3 International Plumbing Code
Fixtures must use 20% less water than:
Toilet - 1.6 Gallons Per Flush (GPF)
Urinal (Commercial Buildings) - 1 Gallon Per Flush (GPF)
Showerheads - 2.5 Gallons Per Flush (GPF)
Faucets - 2.2 GPM for private/kitche, 0.5 GPM for public
Use Appliances that meet the requirements listed in the table below.
Residential Clothes Washers - Energy Star or Equivalent
COmmercial Clothes Washers - CEE Tier 3A
REsidential Dishwashers - Energy Star or Equivalent
Prerinse Spray Valves - Less than or equal to 1.3 Gallons Per Minutes
Ice Machine - Energy Star or equivalent and use either air-cooled or closed-loop cooling
Water processes must meet the following requirements:
Heat rejection and cooling - No once-through cooling with potable water for any equipment or appliances that reject.
Cooling towers and evaporative condensers - Equip with Makeup water meters, conductivity controllers and overflow alarms, efficient drift eliminators that reduce drift to maximum of .002% of recirculated water volume for counterflow towers and 0.005% of recirculated water flow for cross-flow towers.
Building Level Water Metering
Purpose/Requirements/Notes
Purpose: As the saying goes “you can’t manage what you don’t measure” This prerequisite aims to provide transparency and information to building projects by tracking building water consumption.
Requirements: 1) install permanent water meters in building on grounds and 2) commit to sharing water data with USGBC for 5 years after certification or occupancy, whichever is first.
Outdoor Water Use Reduction
Purpose/Requirements/Notes
Purpose: To reduce outdoor water use more than prerequisite levels.
Requirements: 1) use no irrigation or 2) use reduce irrigation
Notes: Show that option 1 does not require irrigation. Show that option 2 show that irrigation requirements are reduced by at least 50% from baseline in peak watering.
EPAs Water Sense Budget tool should be used to calculate savings.
Strategies: Exeriscape and drought resistant plant species. Alternative water sources should be considered as well as smart watering source technologies.
Non vegetated surfaces and athletic fields, playgrounds, and food gardens are to be used in a similar manner to prerequisite outdoor water use reductions.
Indoor Water Use Reduction
Purpose/Requirements/Notes
Purpose: Reduce Indoor Water Use beyond prerequisite baselines.
Requirements: Incremental higher points until water use is reduced by 25-50%.
25% - 1 points 30% - 2 points 35% - 3 points 40% - 4 points 45% - 5 points 50% - 6 points (Except for hospitality, retail, schools, healthcare)
55% may receive exemplary performance.
WE Calculations: Full Time Equivalent Occupants
Daily Averages: Taken into account all occupants of a given type over a 24 hour day of operation.
Peak Totals: Measured at the moment in a typical 24 hour period when the a given occupant type is at the greatest.
FTE is calculated as below:
FTE Employees = Full time employees + (Sum daily part time employee hours/ 8 hours)
FTE at buildings with irregular occupancy patterns calculation is a shown below:
FTE Employees = Sum all employee hours/8
Part time employees work 20 hours a week.
Regular Building Occupants
Full time employees/staff Part time employees/staff Residents Primary and Secondary School Students Hotel Occupants Inpatients
Visitors
Retail Customers
Outpatients
Volunteers
Higher Education Students
Male Female Ratio
1:1
Women
3 Bathroom trips a day
3 Water Closet Trips a Day
Dual Flush - 1 big button 2 small button
Men
3 Bathroom trips a day
1 Water Closet Tip 2 Urinal Closet Trips
But no water closet trips
Building Level Water Metering
Purpose/Requirements/Notes
Purpose: Find incremental opportunities to save water by metering water use.
Requirements: Go beyond building macro level building water metering and install permanent water meters for two or more subsystems such as irrigation, plumbing fixtures and fitting, domestic hot water, boiler, reclaimed water, or other process water.
