LCA for Design of Greener Buildings

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Life Cycle Assessment in Green Building Rating
Systems
Jabeen Quadir CEC Workshop on Green Building
Rating Systems Cocoyoc, Morelos, Mexico October
24, 2007
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EcoFriendly
Green
Market confusion, greenwashing
Materials and resources credits are especially
weak in rating systems . . .
. . . and very controversial
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The use of wood is a good example
No! Its about certification!
Its all about renewability!
Actually, youre both wrong . . .
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Materials and product selection is all about
trade-offs!
High CO2
Abundant resources
Locally available
Resistant to pests
CO2 neutral
Water pollution
Harvesting issues
Low energy
Biodegradable
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Weighing the options
By attribute?
Short-term/rapid Renewability
Cost
Durability
Recycled Content
or...
Low Maintenance
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By environmental performance ? LCA
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Life Cycle Assessment
A methodology for assessing the environmental
performance of a product over its full life cycle
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The ISO 14040 Series Framework
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LCA of Buildings
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Tracking Flows The Inventory Step
MATERIAL ACQUISITION
Raw Material Acquisition
Manufacturing
Products / Assemblies
BUILDING CONSTRUCTION (manufacturing)
DEMOLITION/DISPOSAL
Products / Materials
Recycle / Reuse
Waste Management
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Key Impact Indicators

• Solid waste emissions
• Pollutants to air
• Pollutants to water
• Weighted resource use
• Fossil Fuel Depletion
• Ozone Depletion

• Global warming potential
• Ground level ozone (smog)
• Acid rain
• Embodied primary energy
• Eutrophication
• Particulate releases

THE GOAL to measure ultimate impacts on human
and ecosystem health
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LCA Limitations

• LCA is not the answer to all problems
• Does not readily handle such issues as
• Indoor environmental quality
• Improved ability to deal with air quality
  possible in future
• Uncertainty and risk related to toxic releases
• Time sensitivity
• Change of use / adaptability

Focus on relative effects,not absolute numbers!
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Life Cycle Assessment is not the same asLife
Cycle Costing!

• Complementary methods
• Evaluate performance trade-offs against costs to
  implement them

LCA ? physical units LCC ?
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BEES (U.S.)
NIST
LCA-based product comparison tool for use at the
specification/procurement stage

• Focuses on environmental effects and life cycle
  costs
• Provides detailed results for a wide range of
  impact indicators
• Uses weighting factors to generate environmental
  and economic scores
• Based on Consensus Standards
• Life-Cycle Costing (ASTM E917)
• Building Element Classification (ASTM E1557)
• Environmental Life-Cycle Assessment (ISO 14040)
• Multiattribute Decision Analysis (ASTM E1765)

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NIST
BEES Impact Measures
Carbon Dioxide

Global Warming

Methane

Acidification



Eutrophication

Nitrous Oxide




Fossil Fuel Depletion



Indoor Air Quality

Environmental Performance Score


Habitat Alteration



Water Intake




Criteria Air Pollutants


Human Health

Overall Score

Smog

Ozone Depletion

Ecological Toxicity

Economic Performance Score
First Cost



Future Costs

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• LCA-based Whole building tool for use at the
  conceptual design stage

• Shows environmental effects of changes in shape,
  design or material make-up of a building
• User enters data, LCA runs in the background
• Allows designers to optimize operatingembodied
  energy effects over the complete building life
  cycle
• A range of indicators without weighting

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• LCA-based tool for evaluating and comparing the
  environmental effects of assemblies

• Simple to use spreadsheet tool
• Currently includes a library of about 400
  assemblies
• Uses 5 environmental impact indicators
• In rating system, credit better than average
  performance for each indicator within an assembly
  category
• Generic version, without credit links, is
  available as a free download
• Various regional versions under development

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LCA in Green Building Standards and Rating
Systems
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US Green Building Standards(all with an LCA
component)

• GBI/ANSI Standard 01-2007P Green Building
  Assessment Protocol for Commercial Buildings
• ASTM Standard Specification for the Minimum
  Attributes of a Building that Promotes
  Sustainability
• NAHB National Green Building StandardTM
• ASHRAE/USGBC/IESNA Std 189 High-Performance
  Green Buildings

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LCA in Green Globes

• Encourage selecting materials with the lowest
  life cycle environmental burden
• Incorporates assembly approach to LCA using
  Athenas LCA tool
• Work completed on the assembly ranking approach
• ATHENA Impact Estimator used for basic LCA of
  assemblies
• points based on performance relative to
  benchmarks for each of several measures (e.g.,
  global warming potential)
• Whole building LCA a possible alternative
  compliance path

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LCA in LEED

• Working Groups formed in 2004
• recommend how best to implement LCA-based credits
• goal and scope
• technical LCA issues
• weighting of impact measures
• Goal and scope WG recommended assembly ranking
  approach
• Initial focus on Materials Resources credits
• eventual merging with Energy and Atmosphere
  credits
• Accepted by USGBC board
• Research program underway to detail the approach
  

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In Conclusion LCA tools let you ...

• Take the environment into account throughout the
  project delivery process
• Focus on true environmental performance measures
• Look at the entire life cycle of a building
• Make functionally equivalent material comparisons
  
• Recognize and take account of environmental and
  economic trade-offs

A FINAL CAUTIONBE WARY OF SIMPLISTIC ANSWERSTO
COMPLEX QUESTIONS
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