Jon Burke
2006
Mechanical
Faculty Consultant: Dr. Jelena Srebric
An In-depth Look at a Green Roof
Outline
Jon Burke
2006
Mechanical Option
Consultant: Dr. Jelena Srebric
Building Information
Purpose
Procedure
Results
•First Cost Analysis
•Lifetime Analysis
•Additional Benefits
Conclusions
Existing Conditions
Jon Burke
2006
Mechanical Option
Consultant: Dr. Jelena Srebric
Central Shared Use Facility
FDA’s White Oaks Campus
Silver Spring Maryland
Rendering supplied by Kling
Design Firm: Kling
Civil Firm: Greenhorne & O’mara
Owner: GSA
Existing Conditions
Jon Burke
2006
Mechanical Option
Consultant: Dr. Jelena Srebric
3rd Floor – Library
26,500 sq ft.
VAV System
Cold and Hot water pumped from Central Plant on Campus
Rendering supplied by Kling
Existing Conditions
Jon Burke
2006
Mechanical Option
Consultant: Dr. Jelena Srebric
Purpose
Jon Burke
2006
Mechanical Option
Consultant: Dr. Jelena Srebric
First Cost Analysis
•Material and Labor
•Rainwater Quality
•Structural Support
Lifetime Analysis
•Energy Savings
•Maintenance Costs
GOAL: Find “Benefit”/sf and optimal size
How does size affect project costs and benefits?
Other Benefits
•LEED Rating
•Architectural Value
Procedure
Jon Burke
2006
Mechanical Option
Consultant: Dr. Jelena Srebric
Procedure
Jon Burke
2006
Mechanical Option
Consultant: Dr. Jelena Srebric
Procedure
Jon Burke
2006
Mechanical Option
Consultant: Dr. Jelena Srebric
Procedure
Jon Burke
2006
Mechanical Option
Consultant: Dr. Jelena Srebric
Procedure
Jon Burke
2006
Mechanical Option
Consultant: Dr. Jelena Srebric
Procedure
Jon Burke
2006
Mechanical Option
Consultant: Dr. Jelena Srebric
Procedure
Jon Burke
2006
Mechanical Option
Consultant: Dr. Jelena Srebric
Procedure
Jon Burke
2006
Mechanical Option
Consultant: Dr. Jelena Srebric
Results – First Costs
Jon Burke
2006
Mechanical Option
Consultant: Dr. Jelena Srebric
Materials and Labor
Built-up Flat Roof: $2/sf
Green Roof: $14/sf
COST $12/sf Green Roof
Results – First Costs
Jon Burke
2006
Mechanical Option
Consultant: Dr. Jelena Srebric
Rainwater Runoff Quality
Runoff of Green Roof is Clean
Bio-Retention System
1 I.A. = 3000 sf Filter
Greenhorne & O’mara
Rainwater Quality Control
600
700
800
900
1000
1100
1200
1300
1400
25 30 35 40 45 50 55 60 65 70 75
Green Roof Size (%)
Req
uir
ed S
ize
of
Fil
ter
Sys
tem
(sf
)
$10 /sf of Filter
SAVE 69¢/sf of Green Roof
Jon Burke
2006
Mechanical Option
Consultant: Dr. Jelena Srebric Results – First Costs
Structural Support for 50 psf
1 2 3 4 5 6 7 8 9 9.5 10
A
B
C
MIR
RO
R L
INE1 2 3 4 5 6 7 8 9 9.5 10
A
B
C
MIR
RO
R L
INE
1 2 3 4 5 6 7 8 9 9.5 10
A
B
C
MIR
RO
R L
INE1 2 3 4 5 6 7 8 9 9.5 10
A
B
C
MIR
RO
R L
INE
1 2 3 4 5 6 7 8 9 9.5 10
A
B
C
MIR
RO
R L
INE1 2 3 4 5 6 7 8 9 9.5 10
A
B
C
MIR
RO
R L
INE1 2 3 4 5 6 7 8 9 9.5 10
A
B
C
MIR
RO
R L
INE
1 2 3 4 5 6 7 8 9 9.5 10
A
B
C
MIR
RO
R L
INE1 2 3 4 5 6 7 8 9 9.5 10
A
B
C
MIR
RO
R L
INE
30” Diameter ($1,992) 14” Diameter ($875)24” x 24” ($3,203) 12” x 12” ($1,252)
COST $2.50/sf Green Roof
Jon Burke
2006
Mechanical Option
Consultant: Dr. Jelena Srebric Results – First Costs
Total First Costs
Materials and Labor: $12/sfStructural Impact: $2.50/sfFilter System: -$0.69/sf
Total: $13.80 Additional Cost per Square Foot of Green Roof
Results – Annual Costs
Jon Burke
2006
Mechanical Option
Consultant: Dr. Jelena Srebric
Energy Savings
Energy Savings
100
105
110
115
120
125
130
25 30 35 40 45 50 55 60 65 70 75
Green Roof Size (%)
Pea
k C
oo
lin
g L
oad
(to
ns)
SAVE 21¢/sf Green Roof PER YEAR
Annual Electric Load Reduction•2.15 kWh/sf Green Roof
Peak Cooling Load Reduction•0.6 tons/265 sf Green RoofGSA:
10¢/kWh
Results – Annual Costs
Jon Burke
2006
Mechanical Option
Consultant: Dr. Jelena Srebric
Maintenance CostsBuilt-up Flat Roof Green Roof
Annual Maintenance
Lifetime: 15 yrs
Negligible MaintenanceLifetime: ??
Greening Rooftops for Sustainable Communities. Chicago 2003. Page 280
Results – Other Benefits
Jon Burke
2006
Mechanical Option
Consultant: Dr. Jelena Srebric
LEED Rating
Guaranteed•Credit 6.1: Stormwater Management – 1 point•Credit 7.2: Heat Island Effect – 1 point
Architectural Value
Conclusion
Jon Burke
2006
Mechanical Option
Consultant: Dr. Jelena Srebric
“Energy conservation is the foundation of energy independence.”~Thomas H. Allen (D-ME 1st)
Conclusion
Jon Burke
2006
Mechanical Option
Consultant: Dr. Jelena Srebric
Any Questions?