Presentation at the 2011 USGBC Illinois Chapter Credential Maintenance Day by Rob Young and Scott Bowman. Using the LEED Platinum Wellmark BCBS Headquarters in Des Moines, Iowa as a case study, the presenters provide factors related to rainwater capture systems, how LEED credits relate, demonstrate the system from design through start-up, and discusses pros and cons of rainwater capture and flushing systems.

1. USGBC Illinois Chapter
November 1, 2011
Taking Water Efficiency
to the Limit
Presented by:
Scott Bowman, P.E., LEED AP BD+C
Rob Young. P.E.
Slow the Flow

2. Learning Objectives1
• Feasibility factors of a rainwater capture
system
• Evaluate LEED guidelines
• Comprehend system design through
implementation
• Weigh pros and cons of rainwater capture

3. What’s the big deal?

4. What’s the big deal?
• We turn on the
tap and get
water!

5. What’s the big deal?
• But it takes1

6. Why should we care?
• Water is a undervalued resource, at least
in the Midwest
• Potable water use is increasing at 2x the
rate of world population growth
• 100 years ago, we used 10 gallons of
water a day1today we use 100!
• Americans spend $523 on water per year,
and $707 on soda!

7. Why should we care?
• Save some money
• Reduce pollution
• Reduce reliance on aging infrastructure
• Conserve energy

8. Why do we care?
• Freshwater supply in world

9. USGS
Circular
1268

10. USGS Circular 1268

13. Why do we care?
• Energy is used to deliver water
– Pump from source
– Treat to potable standards
– Distribute to use
– Desalination
– Waste water treatment

14. Why do we care?
• Water is linked directly to energy
– Cooling towers of power plants
– Direct cooling of power plants
– Scrubbing of plant discharge
– Oil recovery
– Bio>fuel production
• 8% of freshwater withdraw around the
world is for power plants!

15. Why do we care?
• LEED is often invisible
• Energy efficiency is tough to visualize
• Water use is a common language
• Rainwater capture is a tangible
benefit1you can see it!
• Every project needs a story1

16. LEED and Water Efficiency

17. LEED and Water Efficiency
• Some changes in v2009
• Not a major change in the way credits are
calculated
• New prerequisite
• Baseline has been clarified, making credits
more difficult to achieve
• Values changed, impact similar

18. Breakdown of v2.2

19. Breakdown of v2009

20. WEp1 Reduce by 20%
• First credit of v2.2 is now prerequisite
• This savings was so easy, it is now
mandatory
• Baseline fixtures now defined by table in
the standard
• Baseline lavatories are clearly now 0.5
gpm (rather than 2.5 gpm)
Water Use Reduction

21. WEc2 Innovative
Wastewater Technologies
• Increased to 2 points
• Reduce generation of wastewater
• Reduce potable water use for sewage
conveyance by 50%, or1
• Treat 50% of wastewater on site to tertiary
standards
• Waterless urinals or composting toilets

22. WEc3 30>40% Reduction
• Now three levels up to 40%, first step
gains 2 points, 4 total possible
• Maximize water efficiency in buildings
• May be difficult to reach higher levels with
only fixture selection
• Higher levels will require rainwater capture
Water Use Reduction

23. IDc1 45% Reduction
• Exemplary Performance ID credit
• Adds one more point
• Requires 45% reduction from baseline
• Waterless or ultra low urinals required
• Rainwater or Gray Water
Water Use Reduction

24. Pilot Credits
• PC10 – Sustainable Wastewater
Management
– Focus on innovative systems
– Recovery and treatment
– Reduces Threshold to 25%
• PC17 – Cooling Tower Makeup
– Modification of EBOM credit
– Controlled blowdown and filtration
• PC18 – Appliance and Process Water Use
Reduction
– Modification of LEED for Schools credit
– Minimum performance for different equipment

25. LEED Healthcare
• WEc2 – Measurement and Verification
• WEc4.2 – Cooling Tower Makeup Water
• WEc4.3 – Food Waste Systems
• ID credits can be from different product)

26. LEED 2012?
• WEp1 – Landscape Water Use Reduction
• WEp2 – Minimum Fixture and Fitting
Water Use Reduction
• WEp3 – Appliance and Process Water
Use Reduction [PC18]
• WEc1 – Additional Landscape Water Use
Reduction

27. LEED 2012?
• WEc2 – Additional Fixture and Fitting
Water Use Reduction
• WEc3 – Sustainable Wastewater Systems
[PC10]
• WEc4 – Cooling Tower Makeup Water
[PC17]
• WEc5 – Additional Appliance and Process
Water Reduction

28. Water Efficient Design

29. Water Efficient Design
• Thought process for reducing
water usage.
1) Baseline
(Demographics / Usage)
2) Conserve (Fixture Selection)
3) Generate (Reclaim, store, treat,
and distribute Rainwater,
Graywater, Condensate,
Subsoil Drainage)
FTE’s
Demographics
Usage
Fixture
Types
Human
Waste
Rainwater
Capture
Total
Water
Rainwater
Capture

30. Water Efficient Design
• Usage for a variety of occupants

31. Water Efficient Design
• Once it has been determined
that rainwater capture is
necessary:
– Refine goals.
– Define cistern size.
– Iterate with goals to determine
proper size and type.
– Determine diagrammatical layout,
equipment, and treatment.
Rainwater
Capture
Goals > %
Cistern
Size/Type
Pumps /
Piping
Treatment

32. Demographic Affect
– Note: based on % female occupancy

33. Demographic Affect
– Note: based on % female occupancy

34. Demographic Affect
– Note: based on % female occupancy

35. LEED NC v2.2
WEc2 Calculation

36. LEED
NC v2.2
WEc2
Calculation

37. LEED NC v2.2
WEc2 / WEc3 Calculations
Note that this drops to 43.2%
under LEED v2009!

38. Fixture Selection
• Which fixtures contribute the most?
– Based on WEc3 – total water usage
– Assumes 50/50 gender distribution
Baseline Water
Usage
Percentage
of Total Use
Lowest Possible
Water Usage
Potential for
Savings
Urinals 1.0 22% 0 21.6%
Men's Water Closets 1.6 17% 1.28 3.5%
Women's Water Closets 1.6 52% 1.1/1.6 10.8%
Lavatories 0.5 6% 0.5 0.0%
Sinks 2.5 1% 2.2 0.2%
Mop Basins 2.5 1% 2.5 0.0%
Total 36.1%

39. Fixture Selection
• Lavatories: 0.5 gpm base, 15 second use
– Sensor faucets save additional 20% (12
second use rather than 15 second)
• Sinks: 2.5 gpm base
– Standard 2.2 gpm faucets save 12%.
• Showers: 2.5 gpm base
– Many options available. Beware of
performance!

40. Fixture Selection
• Urinals – 1.0 gpf base
– Waterless Urinals
• Save 100%
– 1/8 gpf urinals
• Save 87.5%
• Sensor only
– 1/2 gpf urinals
• Save 50%
• Manual / Sensor

41. Fixture Selection
• Water Closets – 1.6 gpf base
– Dual Flush
• 1.1 / 1.6 gpf
• Save 21%
• Manual / Sensor
– Low Flow
• 1.28 gpf
• Save 20%
• Manual / Sensor
• Requires special bowl

42. Fixture Selection – Cost
• Lavatories, battery operated
– 2.0 gpm lavatory
• $365
– 0.5 gpm lavatory
• $350

43. Fixture Selection – Cost
• Urinals, battery operated sensors
– 1.0 or 0.5 gpf
• $460
– 1/8 gpf
• $495

44. Fixture Selection – Cost
• Water Closets, battery operated sensors
– Standard Flush – 1.6 gpf
• $395
– Dual Flush – 1.6/1.1 gpf
• $426
– Low Flow – 1.28 gpf
• $400

45. Rainwater Capture Design
• Rainwater Capture – What’s the big deal?

46. Rainwater Capture Design
• Cistern sizing – what’s the big deal?
– Inputs
• Monthly Rainfall – how many events per month?
• Other inputs (subsoil, condensate, site, etc)
• How much water can be captured?
– Roof capture coefficients
– Filter efficiencies
– Outputs
• Daily usage
• Overflow

47. Rainwater Capture Design
• Cistern sizing – what’s the big deal?
– Other uses
• Irrigation (Landscape Architect)
• Stormwater Detention (Civil Engineer)
– The mechanical engineer cannot size cisterns
for these types of systems.
• Conclusion – not just a tank in the ground!

48. Rainwater Capture Design
• Storage is dynamic

49. Rainwater Capture Design
Material List
• Roof Drains
• Pre>Filters
• Cisterns
• Intake Filters
• Pumps
• Final Filters
• Final Treatment
• Day Tank
• Makeup Water
• Level Sensors
• Booster Pumps
• Meters
)following a drop of water

50. Rainwater Capture Design
Pre>Filter Options
Stark Industries JR Smith / RMS –
Vortex Filter

51. Rainwater Capture Design
• Cisterns
– Concrete
• Poured
• Pre>fabricated

52. Rainwater Capture Design
• Cisterns
– Concrete
• Poured
• Pre>fabricated
– Polyethylene

53. Rainwater Capture Design
• Cisterns
– Concrete
• Poured
• Pre>fabricated
– Polyethylene
– Fiberglass

54. Rainwater Capture Design
• Cisterns
– Concrete
• Poured
• Pre>fabricated
– Polyethylene
– Fiberglass
• Intake Filters

55. Rainwater Capture Design
Inside Building
• Pumps
• Final Filters
• Final Treatment
– Ozone
– Chlorination
– High>efficiency filters
– UV

56. Ozone by Nature

57. Ozone by Man

58. Rainwater Capture Design
Distribution
• Day Tank
• Makeup Water
• Level Sensors
• Booster Pumps
• Metering

59. Rainwater Capture Design
Indoor equipment for reclaimed flushing

60. Rainwater Capture Design
• Hydraulic implications
– Adding two sets of pumps
• Reclaim Pumps (cisterns treatment day tank)
• Booster Pumps (to distribute to flush valves)

61. Rainwater Capture Design
• Multiple Levels of Metering
– Main Meter
– Sanitary Add
• Flushing Reclaim
– Sanitary Deduct
• Irrigation Makeup

62. Rainwater Capture Design
• Other types of water to consider for re>use
– Subsoil drainage
– Cooling coil condensate
– Gray water (possibilities exist for 5>25%
savings depending on lavatory and shower
selections)

63. Rainwater Capture Design
• Code implications
– Get the code officials involved early – this is new to
most of them.
• Uniform Plumbing Code – Chapter 16
– No direct connection to any potable water system
– Building and equipment room signage
– Pipe and equipment labeling
– Tank>type water closets

64. Rainwater Capture Practice
• Keeping the Cisterns Clean
– Pre>Filters
– Aeration
– Chlorination
– Natural (Biofilm)

65. Rainwater Capture Design
• Packaged Systems now Available

66. Case Study

67. Wellmark BCBS

68. Wellmark BCBS
• HOK
• RDG Planning & Design
• Snyder Associates
• KJWW Engineering
• The Weitz Company
• Baker Group
• Baker Electric
• The Weidt Group

69. Wellmark BCBS

70. Wellmark BCBS

71. Wellmark BCBS

72. Wellmark BCBS
• Office building
– 603,980 GSF Office Building
• 5 levels above grade
– 500 car below grade parking
• 2 parking levels below grade
• 115,000 GSF roof

73. Wellmark BCBS

74. Wellmark BCBS
• Multipurpose building
– 35,000 GSF fitness center
• 2 levels above grade
– 5,500 GSF Central plant
– 1647 car parking structure
• 10 levels above grade, ½ level below

75. Wellmark BCBS

76. Wellmark BCBS
• 48.2 kBtu/sf/year
– 33.8% better than
ASHRAE 90.1 –
2004 (30.8% cost)
• LEED NC v2.2
Platinum!
– 53 of 69 points
• 5.6 acre urban site

77. Wellmark BCBS
• 2,330 full time equivalents
– Established for LEED and Design purposes
• 70/30 split women to men
• Current Water Modeling:
– 55.8% reduction in human water flushing
– 57.9% reduction in total water use
• 8,000 gallons per day required for flushing
Note that all values related to this project are for design purposes
based on averaged historical data. Actual performance cannot
be confirmed until after final construction and commissioning.

78. LEED WEc3 Distribution
Total Water Use

79. Wellmark BCBS
Total Water Use

80. Wellmark BCBS
• Achieved 7 LEED points related to Water
– SSc6.1 – 1 point
• Stormwater Detention (integrated into system)
– WEc1 – 2 points
• No water use for irrigation
– WEc2 – 1 point
• Greater than 50% reduction in wastewater flushing
– WEc3 – 2 points
• Greater than 30% reduction in water use
– IDc1 – 1 point
• Exemplary performance, Greater than 40% reduction in
water use

81. Wellmark BCBS
• Fixture Selections:
– Sensor lavatories 0.5 gpm
– Sensor low flow urinals 0.5 gpf
– Sensor dual flush toilets 1.6/1.1 gpf (women)
– Sensor toilets 1.6 gpf (men)
• All sensors are battery powered

82. Wellmark BCBS
• Detailed system costs
Fixture QTY Cost % QTY Cost %
Dual Flush water closests 96 $445.00 1.15%
1.6 gpf water closets 49 $425.00 0.56% 145 $425.00 1.67%
0.5 gpf urinals 31 $465.00 0.39% 31 $465.00 0.39%
0.5 gpm lavitories 87 $78.00 0.18% 87 $68.00 0.16%
Total Fixture costs 2.29% 2.22%
Fixture cost difference 0.08%
Wellmark building Baseline building
Plumbing fixture comparison from Percent of Plumbing

83. Wellmark BCBS
• Cistern Size:
– 112,000 gallon Irrigation/Detention
• 52,000 gallons for Detention
• 60,000 gallons for Irrigation
– 60,000 gallon Flushing
• 2 x 3,500 gallon Day Tanks
• 130 gpm Flushing Booster Pump
• 100 gpm Irrigation Booster Pump

84. Wellmark BCBS
• Storm water detention
– Irrigation cistern also used for detention
– Added complexity to keep 52,000 gallons free
for detention

85. Wellmark BCBS
• Wellmark Cisterns

86. Wellmark BCBS

87. Wellmark BCBS
• Lessons Learned
– Possibility of combining rainwater detention
and reclaimed rainwater storage
– Water Purity Standards
• Coliform Bacteria
– Diarrhea/Dysentery Symptoms
• Turbidity Units (NTU)
– Higher risk of gastrointestinal diseases
– Protects bacteria from UV treatment
– Elevations!

88. Rainwater Capture Design
• Lessons Learned
UV Treatment

89. Wellmark BCBS
• Mechanical Site Work
• Piping cost would normally be
in site budget
Material Labor Total
1.07% 0.25% 1.31%
Material Labor Total
0.75% 0.16% 0.91%
2.23%Total cost for site and cistern piping and pre-filters
Mechanical Site Work as Percent of Site
Underground site piping
Vault pre-filters and piping

90. Wellmark BCBS
• Reclaimed Water System Costs
Less than 0.8% Mechanical Budget
Material Labor Total
Reclaim water pumps 0.14% 0.08% 0.22%
Reclaim tank 0.41% 0.07% 0.48%
Pressure booster pump 1.33% 0.06% 1.39%
Meters/solenoid valves 0.06% 0.02% 0.08%
Total 2.17%
Irrigation System Costs as Percent of Plumbing
Material Labor Total
Reclaim water pumps 0.14% 0.08% 0.22%
Final filters 0.11% 0.07% 0.18%
Ozone generator 0.68% 0.06% 0.74%
Reclaim tank 0.41% 0.07% 0.48%
Pressure booster pump 0.51% 0.06% 0.57%
Meters/solenoid valves 0.09% 0.02% 0.11%
Total 2.31%
Flushing System Costs as Percent of Plumbing

91. Wellmark BCBS
• And the grand total is1
Less than 0.5% of Total Construction!
1.90%
0.91%
Flushing system costs 0.41%
Irrigation system costs 0.38%
Plumbing fixture premium 0.01%
Misc piping/labels/valves 0.19%
3.81%
Perecent of Mechanical for Reclaim Water System
Total
Cistern piping/pre-filter cost
Flushing Cistern

92. Wellmark BCBS

93. Wellmark BCBS
• Cost of Saving Water

94. Wellmark BCBS
• Wellmark will1
– Save 7,200 gallons of water a day
– Will not discharge 1,550,000 gallons of
sewage
– Save 2,600,000 gallons of water a year
• Enough to fill four Olympic sized pools
each year

95. Wellmark BCBS
• Or thinking of a standard water cooler1
• 1435 Water Cooler Bottles a Day
• 520,000 Bottles a year!

97. Thank you!
Slow the Flow

98. Credits and Resources
• Virginia Rainwater Harvesting Manual
– www.cabellbrandcenter.org
• Rainwater Management Solutions
– www.rainwatermangement.com
• JR Smith
– www.jrsmith.com
• Wade/Hydromax
– www.hydromax.com
• Stark Environmental
– www.starkenvironmental.com