Environmental Impact of Roofing Systemsobec.on.ca/sites/default/uploads/files/members/... · • 6 Roofing Assemblies 1. Conventional BUR 2. Inverted Mod-Bit – Grey Ballast 3. Inverted

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

Buildings for Tomorrow Conference – Toronto Canada - October 28-30, 2014

2 14th Canadian Conference on Building Science and Technology

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:



Raw Materials

Acquisition and

Manufacture

Construction Operations

and Maintenance

End of Life Disposal

Measuring Environmental Degradation



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



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








LCA Methodology



•  6 Building Types 1.  Industrial 2.  Mid-Rise Residential 3.  Mid-Rise Office 4.  Mid-Rise Mixed-Use 5.  High-Rise Office 6.  High-Rise Residential

LCA Methodology








•  6 Roofing Assemblies 1.  Conventional BUR 2.  Inverted Mod-Bit – Grey Ballast 3.  Inverted Mod-Bit – White Ballast 4.  PVC 5.  TPO 6.  Green Roof

•  6 Cities 1.  Vancouver 2.  Calgary 3.  Edmonton 4.  Toronto 5.  Montreal 6.  Halifax

•  2 Insulation Levels 1.  Code 2.  Code + (30% Improvement)

Database and Design Tool

• All 432 permutations input into excel based database accessed by the user using the interface below

• Each permutation tracks 10 environmental indicators



Example: Montreal Industrial Building with 20-Year Roofs



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



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



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;



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.



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



Before After

Thank You Questions? What RJC Does

•  Structural Engineering •  Building Science

•  Structural Restoration

•  Parking Facility Design

•  Sustainable Design

•  Audits and Studies •  Historic Structures



Presented By: Jonathan Dickson [email protected] Read Jones Christoffersen

Documents

Environmental Impact of Roofing Systemsobec.on.ca/sites/default/uploads/files/members/... · • 6 Roofing Assemblies 1. Conventional BUR 2. Inverted Mod-Bit – Grey Ballast 3. Inverted