Environmental Impact of Roofing Systems Written By : Jonathan Dickson, Duncan Rowe, Matthew Bowick and Russell Richmond Presented By : Jonathan Dickson, M. Eng, P. Eng, BSSO, LEED GA Project Engineer at Read Jones Christoffersen Ltd. Building Science and Restoration
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Environmental Impact of Roofing Systems
Written By: Jonathan Dickson, Duncan Rowe, Matthew Bowick and Russell Richmond Presented By: Jonathan Dickson, M. Eng, P. Eng, BSSO, LEED GA Project Engineer at Read Jones Christoffersen Ltd. Building Science and Restoration
Agenda
• Overview of Life-Cycle Assessments (LCAs)
• How to Quantify Environmental Degradation
• LCA Methodology
• Examples
• Discussion of Key Findings
• Next Steps
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Overview of Life-Cycle Assessments
• “Cradle-to-Grave” analysis of a product, system, assembly, etc.
• Important to define “Cradle” and “Grave”. When do we start looking at the products and when do we finish?
• For this assessment the review was broken down into 4 phases:
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Raw Materials
Acquisition and
Manufacture
Construction Operations
and Maintenance
End of Life Disposal
Measuring Environmental Degradation
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Life-Cycle Impact Units of Measurement
Total Primary Energy MJ
Fossil Fuel Consumption MJ
Global Warming Potential kg CO2 eq
Acidification Potential moles of H+ eq
Human Health Criteria kg PM10 eq
Eutrophication Potential kg N eq
Ozone Depletion Potential kg CFC-11 eq
Smog Potential kg O3 eq
Solid Waste kg
Water Use L
LCA Methodology
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Define Scenario • Building Type • Roof Assembly • Insulation Level • Building Location
Calculate Material Quantities Based on User Inputs
Input Material Quantities into Athena IE • Determine environmental effects associated with manufacture, construction and end of life disposal
Model Operations and Maintenance Phase • Using Sefaira modelling software, calculate electricity and natural gas usage based on whole building energy modelling and calculate associated environmental impacts.
Combine Results from all Lifecycle Phases • Determine all 10 LCA environmental indicators
Repeat Process for all 432 Permutations
LCA Methodology
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Define Scenario • Building Type • Roof Assembly • Insulation Level • Building Location
Calculate Material Quantities Based on User Inputs
Input Material Quantities into Athena IE • Determine environmental effects associated with manufacture, construction and end of life disposal
Model Operations and Maintenance Phase • Using Sefaira modelling software, calculate electricity and natural gas usage based on whole building energy modelling and calculate associated environmental impacts.
Combine Results from all Lifecycle Phases • Determine all 10 LCA environmental indicators
LCA Methodology
Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014
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Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014
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Define Scenario • Building Type • Roof Assembly • Insulation Level • Building Location
Calculate Material Quantities Based on User Inputs
Input Material Quantities into Athena IE • Determine environmental effects associated with manufacture, construction and end of life disposal
Model Operations and Maintenance Phase • Using Sefaira modelling software, calculate electricity and natural gas usage based on whole building energy modelling and calculate associated environmental impacts.
Combine Results from all Lifecycle Phases • Determine all 10 LCA environmental indicators
• All 432 permutations input into excel based database accessed by the user using the interface below
• Each permutation tracks 10 environmental indicators
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Example: Montreal Industrial Building with 20-Year Roofs
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Mod-Bit scenarios have lowest embodied CO2eq emissions but BUR has lowest life-cycle CO2eq emissions
Example: Montreal Industrial Building with Realistic Roof Service Lives
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BUR continues to have lowest life-cycle CO2eq emissions
Example: Montreal Industrial Building with Realistic Roof Service Lives and Increased Insulation Levels in TPO and PVC Roofs
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TPO and PVC now have near highest embodied CO2eq emissions but lowest life-cycle CO2eq emissions
Key Findings from Database • Approximately 1-3% of the building life-cycle CO2eq emissions
result from the embodied energy of the roofing system. • Focus should be placed on reducing operational energy usage.
• In Canada, installing black roofs vs. high albedo (white reflective) roofs results in better thermal performance when insulation is at code minimum values
• As insulation is increased beyond code minimum values, the
importance of membrane selection on thermal performance decreases.
• When the insulation is increased to approximately 30% above the code minimum values, the difference in thermal performance attributed to the membranes is negligible.
• The importance of membrane selection on lifecycle CO2eq emissions was found to vary across Canada depending on the energy supply mixes of each city. In Edmonton usage of an exposed black membrane was found to reap a greater benefit than in Montreal with respect to reducing CO2eq emissions;
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Key Findings from Database
• With exception of life-cycle CO2eq emissions, environmental impacts of roofing systems are primarily dependent on manufacture of the roof assembly materials.
• For all cases, the negative environmental implications are minimized as the service lives of the roof assemblies are maximized, indicating that good design, construction, and maintenance remain critical to reducing environmental impact by extending the useful life of roof systems.
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Next Steps
1. Improve accessibility and accuracy of database
2. Allow for custom inputs rather than pre-defined archetypes to improve applicability of results
3. Increase number of roofing assemblies available
4. Verify model to EN 15978 – Assessment of Environmental Performance of Buildings
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Before After
Thank You Questions? What RJC Does
• Structural Engineering • Building Science
• Structural Restoration
• Parking Facility Design
• Sustainable Design
• Audits and Studies • Historic Structures
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Presented By: Jonathan Dickson [email protected] Read Jones Christoffersen