The Greening of the Rooftop
Module 3
Measuring Sustainability:
Life Cycle Assessment
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:
Sustainability =
Impact
Time
(Impact over Time)
When measuring the relative sustainability of a
product or a system, the key questions are:
1. How long (time) can the product or system last?
2. What is the cost (impact) to last that long?
Life Cycle Assessment (LCA)
What is LCA?
… a scientific approach to
evaluating the environmental impact
of a product throughout its life cycle.
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
Life Cycle Assessment
Key LCA Steps
1. Establish the Time Period
2. Describe the Life Cycle System
3. Identify & Measure the Impacts
4. Assess the Impacts
Life Cycle Assessment
Step 1: Establish the Time Period
10 Years
Typical
Commercial Roof
Warranty Length
15 Years
20 Years
30 Years
U.S. Taxable Building
Depreciation Period
USGBC Life Cycle
Task Force
Recommendation
39 ½ Years
60 Years
Life Cycle Assessment
Step 2: Describe the Life Cycle System
•
Inputs
•
Processes
•
Outputs
•
System Boundary
Describing the Life Cycle System
The Product Life Cycle
Inputs:
Processes:
Raw
Materials
Raw Materials Acquisition
Atmospheric
Emissions
Manufacturing
Waterborne
Waste
Energy
Transportation & Handling
System
Boundary
Installation / Assembly
Outputs:
Solid Waste
Co-Products
Other Releases
Operation / Maintenance
Recycling / Waste Mgmt.
Source: Life Cycle Assessment: Principles and Practice. Scientific Applications International Corporation, 2006.
Life Cycle Assessment
Step 3: Measure the Impacts
•
Identify Significant Impacts
•
Establish Meaningful Measures
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)
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?
Life Cycle Assessment
LCA Benefits
•
Avoids Shifting of Impacts
•
Allows Consideration of Trade-Offs
•
Promotes Situation-Based Decisions
Life Cycle Assessment
LCA Benefits
Building Construction Examples:
Limestone Concrete versus Fly Ash Concrete
(USA)
Plastic Insulation versus Mineral Wool & Cork
(Europe)
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
Life Cycle Assessment
LCA Limitations
Building Construction Example:
Use of Cover Boards in Insulated Roof
Assemblies
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
Life Cycle Assessment
Communicating LCA Data
Environmental Product Declaration (EPD)
–
ISO 14000 method for communicating to the
consumer
–
Growing rapidly in Europe
–
Driven by global corporations seeking common
denominator to simplify product lines
Environmental Product Declaration
Sample EPD
Product:
Polystyrene Board
Manufacturer:
LAPE (Italy)
Environmental Product Declaration
EPD Detail
Life Cycle Diagram:
System Boundary
(In this case, excludes installation,
use and final disposal)
Impact Summary:
Impact
Category
Impact
Measure
Impact
Data
Environmental Product Declaration
Sample EPD
Product:
Steel Roofing System
Manufacturer:
Corus (UK)
Environmental Product Declaration
EPD Detail
Life Cycle Diagram:
Impact Summary:
System Boundary
Impact
Impact
Category Measure
(In this case, covers “cradle-to-grave”)
Impact
Data
Environmental Product Declaration
EPDs Moving to United States
Product:
Office Chair
Manufacturer:
Steelcase (USA)
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
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
Life Cycle Assessment
Emerging LCA Tools
ImpactEstimater
(Athena Institute / GBI)
BEES 4.0
(NIST)
GaBi
(Europe)
LCA Tools
Athena Impact Estimator
Athena Impact Estimator
Benefits
•
•
•
•
•
•
Based on ISO 14000 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
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
LCA Tools
Athena Impact Estimator
Free Demo Download Available:
Very Important:
Contains the
background
reports used to
generate the
product impact
data.
http://www.athenasmi.ca/tools/impactEstimator/demo/index.html
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
BEES 4.0 Benefits
Comprehensive Model
Validated Weighted
Averages
Provides Overall
Weighted Score
Key Impacts
Considers Economic as
well as Environmental
Factors
BEES 4.0 Benefits
Validated & Weighted Scoring System
Key Impacts
Peer-Reviewed &
Validated Weighted Average
Alternative A
Simple Graphic Report
Alternative B
BEES 4.0 Limitations
Limited Product Data
… but peer-reviewed, validated, and growing
LCA Tools
BEES
Free Download Available:
http://www.bfrl.nist.gov/oae/software/bees/bees.html
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
LCA Tools
US Life Cycle Inventory Database
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.
http://www.nrel.gov/lci
Life Cycle Assessment
The Future of LCA
• ISO 14000 will become the global LCA model
– ISO 14000 has been endorsed as the basic model for managing
environmental impacts
– Almost all major global companies are seeking ISO 14000 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
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
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
Life Cycle Assessment
Critical Issues
• 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?
Life Cycle Assessment
LCA Summary: Key Terms
•
•
•
•
•
•
•
•
Life Cycle Period (or Study Period)
Impacts / TRACI
Inputs, Processes, Outputs
System Boundaries
ISO 14000 Environmental Management System
Environmental Product Declaration (EPD)
LCA Tools
Life Cycle Inventory Database