1. Measuring Sustainability: Life Cycle Assessment
The Greening of the Rooftop
Module 3
Measuring Sustainability:
Life Cycle Assessment

2. Measuring Sustainability
The Greening of the Rooftop
Measuring Sustainability
Sustainability can be defined quantitatively in terms of system life expectancy and the cumulative impact of certain factors or terms in the system:
Impact
Time
Sustainability =
(Impact over Time)
When measuring the relative sustainability of a product or a system, the key questions are:
How long (time) can the product or system last?
What is the cost (impact) to last that long?

3. Life Cycle Assessment (LCA)
What is LCA?
… a scientific approach to evaluating the environmental impact of a product throughout its life cycle.

4. Life Cycle Assessment (LCA)
What is LCA?
Scientific Approach: Based on measurable and predictable attributes
Focused on Impact: What is the net result to the environment?
Throughout the Life Cycle: A “cradle-to-grave”… or “cradle-to-cradle” approach

5. Key LCA Steps Establish the Time Period Describe the Life Cycle System
Life Cycle Assessment
Key LCA Steps
Establish the Time Period
Describe the Life Cycle System
Identify & Measure the Impacts
Assess the Impacts

6. Step 1: Establish the Time Period
Life Cycle Assessment
Step 1: Establish the Time Period
10 Years
15 Years
20 Years
30 Years
39 ½ Years
60 Years
Typical
Commercial Roof Warranty Length
U.S. Taxable Building Depreciation Period
USGBC Life Cycle
Task Force Recommendation

7. Step 2: Describe the Life Cycle System
Life Cycle Assessment
Step 2: Describe the Life Cycle System
Inputs
Processes
Outputs
System Boundary

8. The Product Life Cycle Describing the Life Cycle System Inputs:
Raw Materials
Energy
Processes:
Outputs:
Atmospheric Emissions
Waterborne Waste
Solid Waste
Co-Products
Other Releases
Raw Materials Acquisition
Manufacturing
Transportation & Handling
System Boundary
Installation / Assembly
Operation / Maintenance
Recycling / Waste Mgmt.
Source: Life Cycle Assessment: Principles and Practice. Scientific Applications International Corporation, 2006.

9. Step 3: Measure the Impacts
Life Cycle Assessment
Step 3: Measure the Impacts
Identify Significant Impacts
Establish Meaningful Measures

10. Measuring Environmental Impacts
The TRACI Model
Significant Impact:
Global Warming Potential (GWP)
Ozone Depletion Potential (ODP)
Photochemical Oxidant Potential (PCOP)
Acidification Potential
Eutrification
Health Toxicity (Cancer)
Health Toxicity (Non-Cancer)
Health Toxicity (Air Pollutants)
Eco-Toxicity Potential
Meaningful Measure:
kg CO2 Equivalent
kg CFC Equivalent
kg NOX Equivalent
H+ Moles Equivalent
kg Nitrogen Equivalent
kg Benzene Equivalent
kg Toluene Equivalent
kg: DALYs Equivalent
kg 2,4-D Equivalent
Source: EPA Tool for the Reduction and Assessment of Chemical and other Environmental Impacts (TRACI)

11. Step 4: Assess the Impacts
Life Cycle Assessment
Step 4: Assess the Impacts
Weigh the Impacts
Which impacts are most important in the assessment?
Compare Alternatives
Which alternative provides the optimal benefit?
Look for Improvement Opportunities
How can the impacts be reduced?

12. Life Cycle Assessment LCA Benefits
Avoids Shifting of Impacts
Allows Consideration of Trade-Offs
Promotes Situation-Based Decisions

13. Building Construction Examples:
Life Cycle Assessment LCA Benefits
Building Construction Examples:
Limestone Concrete versus Fly Ash Concrete
(USA)
Plastic Insulation versus Mineral Wool & Cork
(Europe)

14. Life Cycle Assessment LCA Limitations
LCA is Expensive
Requires time & money
LCA is Complex
Difficult to understand & communicate
LCA is Not Absolute
Useful for reference or comparison
Cannot by itself determine cost-effectiveness or practicality

15. Building Construction Example:
Life Cycle Assessment LCA Limitations
Building Construction Example:
Use of Cover Boards in Insulated Roof Assemblies

16. Life Cycle Assessment Current Status of LCA
Part of ISO 14000
“Standard for Environmental Management”
Similar to ISO 9000 “Standard for Quality Management”
Describes how LCA should be used to evaluate products and how the results should be communicated to the consumer

17. Life Cycle Assessment Communicating LCA Data
Environmental Product Declaration (EPD)
ISO method for communicating to the consumer
Growing rapidly in Europe
Driven by global corporations seeking common denominator to simplify product lines

18. Environmental Product Declaration Sample EPD
Polystyrene Board
Manufacturer:
LAPE (Italy)

19. Environmental Product Declaration EPD Detail
Life Cycle Diagram:
Impact Summary:
System Boundary
(In this case, excludes installation, use and final disposal)
Impact
Category
Impact
Measure
Impact
Data

20. Environmental Product Declaration Sample EPD
Steel Roofing System
Manufacturer:
Corus (UK)

21. Environmental Product Declaration EPD Detail
Life Cycle Diagram:
Impact Summary:
System Boundary
(In this case, covers “cradle-to-grave”)
Impact
Category
Impact
Measure
Impact
Data

22. Environmental Product Declaration EPDs Moving to United States
Office Chair
Manufacturer:
Steelcase (USA)

23. Life Cycle Assessment LCA Tools
EPD
EPD
EPD
EPD
EPD
EPD
EPD
EPD
(Environmental Product Declarations)
LCA Database
Project Requirements
Life Cycle Assumptions
LCA Tool
Local Conditions
Impact Weighting
Project Life Cycle Assessment

24. Life Cycle Assessment LCA Tools
Typically web-based or downloadable
Usually sponsored by non-commercial research organizations
Tend to follow a recognized LCA protocol
Draw from life cycle databases for impact information
Combine products and processes to evaluate whole buildings or sub-systems

25. Life Cycle Assessment Emerging LCA Tools
ImpactEstimater (Athena Institute / GBI)
BEES 4.0
(NIST)
GaBi
(Europe)

26. LCA Tools Athena Impact Estimator

27. Athena Impact Estimator Benefits
Based on ISO methodology
Covers “more than 90% of the structural and envelope systems typically used in residential and commercial buildings”
Covers a wide variety of impact sources
Allows for regional variations
Summarizes key impacts
Allows weighting of impacts

28. Athena Impact Estimator Limitations
Not all product data has been peer- reviewed and validated
Some databases may contain significant feedstock and product formulation errors
Database errors may influence overall assessment validity
Most of the product data is generic, based on a composite of different proprietary products
Database may not reflect real differences between different proprietary products and processes

29. LCA Tools Athena Impact Estimator
Free Demo Download Available:
Very Important:
Contains the background reports used to generate the product impact data.

30. LCA Tools BEES
“Building for Environmental & Economic Sustainability”
Sponsored in part by US EPA
Established and maintained by National Institute of Science & Technology (NIST)
Free download available
Peer-reviewed and validated
Limited, but growing product database

31. BEES 4.0 Benefits Comprehensive Model
Validated Weighted
Averages
Provides Overall Weighted Score
Key Impacts
Considers Economic as well as Environmental Factors

32. BEES 4.0 Benefits Validated & Weighted Scoring System
Peer-Reviewed &
Validated Weighted Average
Key Impacts
Simple Graphic Report
Alternative A
Alternative B

33. BEES 4.0 Limitations Limited Product Data
… but peer-reviewed, validated, and growing

34. Free Download Available:
LCA Tools BEES
Free Download Available:

35. LCA Tools In the Future…
US Life Cycle Inventory Database
Joint Athena Foundation / US Government Initiative
Funded in part by EPA, GSA, and DOE
Managed by National Renewable Energy Laboratory (DOE)
Establishing peer-review / validation guidelines
Slowly, but surely expanding the database

36. LCA Tools US Life Cycle Inventory Database
NREL and its partners created the U.S. Life-Cycle Inventory (LCI) Database to help life-cycle assessment (LCA) experts answer their questions about environmental impact. This database provides a cradle-to-grave accounting of the energy and material flows into and out of the environment that are associated with producing a material, component, or assembly. It's an online storeroom of data collected on commonly used materials, products, and processes.

37. Life Cycle Assessment The Future of LCA
ISO will become the global LCA model
ISO has been endorsed as the basic model for managing environmental impacts
Almost all major global companies are seeking ISO registration for their facilities – and this will carry over to their products
Use of LCA tools will become standard for all major construction projects
Integration of LCA tools into LEED will accelerate the process
EPD will be the “New MSDS”
Specifiers may soon require EPDs or similar data for all products

38. LCA & The Roofing Industry Short Term Impact
Confusion Will Reign
ISO 140OO is a standard method – not a standard
Variety of proprietary rating systems may only add to the confusion
Early Adapters May Influence the Rules
Defining system boundaries
Determining product inputs
Determining weighting of impacts

39. LCA & The Roofing Industry Long Term Impact
LCA may favor thinner, stronger products
Lightweight membranes
Lightweight foam insulations
LCA may favor systems that can be installed quickly – and removed / recycled quickly
New attachment technologies
Industry recycling programs

40. Critical Issues Life Cycle Assessment
Do system boundaries include all significant impacts?
Are impacts weighted in regard to relative importance?
Is the service life period realistic?
Is the assessment realistic in terms of planned durability?
Are alternatives compared equitably?

41. Life Cycle Assessment LCA Summary: Key Terms
Life Cycle Period (or Study Period)
Impacts / TRACI
Inputs, Processes, Outputs
System Boundaries
ISO Environmental Management System
Environmental Product Declaration (EPD)
LCA Tools
Life Cycle Inventory Database