Learning Objectives. The Role of LCA in Green Building Design and Assessment: Focusing on True Environmental Performance Measures

Transcription

1 The Role of LCA in Green Building Design and Assessment: Focusing on True Environmental Performance Measures Program Education Credit Information Wood Products Council and the Wood Solutions Fair is a Registered Provider with The American Institute of Architects Continuing Education Systems. Credit earned on completion of this program will be reported to CES Records for AIA members. Certificates of Completion for non-aia members are available on request. This program is registered with the AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation. Learning Objectives The why, what and how of Life Cycle Assessment (LCA) The LCA toolkit The integration of LCA in rating systems The near term approach of assembly assessment and ranking The freely available EcoCalculator for assemblies

2 Materials and resources credits are especially weak in rating systems and very controversial The use of wood is a good example It s all about renewability! No! It s about certification! Actually, you re both wrong...

3 Materials selection is all about trade-offs! Resistant to pests Abundant resources High CO2 Locally available Water pollution CO2 neutral Recycled content Low energy Harvesting issues Weighing material options By attribute? regional rapid renewability durability recycled content or... By environmental performance LCA Acid rain damage Air pollution Climate change Resource depletion Water pollution

4 transportation energy use water use resource use (depletion) Life Cycle Assessment resource extraction effects emissions to water emissions to air solid wastes A methodology for assessing the environmental performance of a product over its full life cycle The ISO Framework Life Cycle Assessment Framework Goal & Scope Definition Direct Applications Product Development & Improvement Strategic planning Inventory Analysis Interpretation Public policy making Marketing Other Impact Assessment LCA in Relation to Buildings

5 Tracking Flows: The Inventory Step MATERIAL ACQUISITION Material resources Energy Water Raw Material Acquisition Manufacturing Products / Assemblies BUILDING CONSTRUCTION (manufacturing) OCCUPANCY (use, reuse, maintenance) DEMOLITION/DISPOSAL Products / Materials Recycle / Reuse Waste Management Emissions to: Air Water Land Impact Assessment Phase Inventory Impact Indicators fossil fuel depletion global warming potential (characterization ozone depletion ground & level ozone (smog) acid Normalization) rain toxic releases air/water/land etc. Impact Assessment (Valuation) THE GOAL: to measure ultimate impacts on human and ecosystem health In the Case of Energy Even source energy doesn t get it all End use energy estimates just one part of the story The rest of the story is the energy to make and move energy called pre-combustion in LCA

6 LCA Limitations LCA is not the answer to all problems E.g., 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 Site specific resource extraction effects The Uncertainty Factor MATERIAL ACQUISITION Raw Material Acquisition Manufacturing Products / Assemblies OCCUPANCY (use, reuse, maintenance) Occurs over a relatively short time frame (e.g months) Focus BUILDING on CONSTRUCTION relative effects, (manufacturing) not absolute numbers! DEMOLITION/DISPOSAL Products / Materials Recycle / Reuse Waste Management Is likely to last many years ( or more) Life Cycle Assessment is not the same as Life Cycle Costing! LCA physical units LCC $ Complementary methods

7 The LCA toolkit Level 1 product focus 1A - for LCA practitioners SimaPro, GaBi, Umberto 1B - LCA in the background BEES Level 3 whole building focus ATHENA Impact Estimator LCA in the background Level 2 assembly focus ATHENA EcoCalculator funded by GBI for use in Green Globes rating system general use versions coming Assessment and rating system Green Globes LEED Minnesota Design Guidelines NAHB Green Home Guidelines BEES Model (U.S.) LCA-based Level 1 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 BEES 3 Impact Measures Carbon Dioxide Methane Nitrous Oxide Global Warming Acidification Eutrophication Fossil Fuel Depletion Indoor Air Quality Habitat Alteration Water Intake Criteria Air Pollutants Human Health Smog Ozone Depletion Ecological Toxicity First Cost Future Costs Environmental Performance Score Economic Performance Score Overall Score

8 Impact Estimator for Buildings LCA-based level 3 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 Allows designers to optimize operating+embodied energy effects over the complete building life cycle A range of indicators without weighting Design 1 Design 2 Regional Electricity Grids Transportation & Product Technologies Maintenance Schedules Bill of Materials Life Cycle Inventories Materials & Products Building Construction Operations Demolition/ Disposal Building Assemblies Energy precombustion effects INVENTORY Raw Materials Energy Use by type Water Use Emissions to Air Emission to Water Solid Wastes SUMMARY MEASURES Energy Use Global Warming Potential Air Pollution Water Pollution Resource Extraction Effects Solid wastes... informed environmental choices Picking the Right Tool

9 Functional equivalence... Want to compare functionally equivalent products Choice of one product other choices Differences in O & M implications Misleading comparisons more likely for structure and envelope products... be cautious about product comparisons The right data and tool for the task Generic at conceptual design Impact Estimator for Buildings Brand specific at procurement stage BEES LCA in Assessment, Rating Systems and Standards

10 Green Building Standards GBI/ANSI Standard P: Green Building Assessment Protocol for Commercial Buildings ASTM: Standard Specification for the Minimum Attributes of a Building that Promotes Sustainability NAHB: National Green Building Standard TM ASHRAE/USGBC/IESNA Std 189: High- Performance Green Buildings Options for LCA into rating systems Could progress over time, from short to long term ideal approach Option 1 pre-rate assemblies LCA in background limited demands on design teams more demands on the rating organization focus on materials simplistic Option 2 decisions based on LCA design teams may use whole building LCA tool(s) could combine embodied and operations effects difficult to verify high educational value Option 3 whole building LCA high demands on design teams need benchmarks (onus on rating system orgs.) combine embodied and operations effects supports optimization of envelope vs. operations LCA in Green Globes LCA education credits at present Work completed on the assembly ranking approach Points based on performance relative to benchmarks Will be included in ANS version of Green Globes after public comment and ANSI procedures complete Basic tool reviewed by the Building Research Establishment (UK), NIST and others Assembly definitions reviewed and refined by the ANSI resources sub-committee

11 LCA into LEED (US) September 2004 kick-off meeting Working Groups goal and scope technical LCA issues weighting of impact measures Goal and scope WG recommended assembly ranking approach Initial focus on MR credits Accepted by USGBC board Decision made to start with the EcoCalculator research program to detail the approach Whole House Residential Case Study Covers embodied effects from resource extraction through on-site construction % Results Overview 23% difference

12 Wood-Framed House Components by Mass Sheetrock 5% Insulation 5% Metal 3% Wood 17% Roofing 5% Siding 2% Although referred to as a wood-framed house, concrete is the dominant mass, with other materials playing lesser roles by mass. Concrete 63% If we go to the assembly level Exterior Wall Assemblies Relative GWP 170% difference

13 New Tool for use in Rating Systems Makes such information more accessible to design teams Impact Estimator for buildings EcoCalculator for buildings EcoCalculator for assemblies LCA-based tool for evaluating and comparing the environmental effects of assemblies Currently includes several hundred assemblies Uses 5 environmental impact indicators Regionalized, with more regions under development In rating system, credit better than average performance for each indicator within an assembly category Generic version, without credit links, is freely available

14 Simple to Use results in spreadsheet form Users only fill in yellow cells Instant answers EcoCalculator for assemblies 9 tons CO2e cradle to grave 60 year life Wood I-joist and OSB decking system, gypsum board, latex paint Key Assumptions Results on a per unit area basis (e.g., per ft 2 ) Estimates based on much larger areas, e.g., 1000 linear feet of wall Owner occupied buildings, 60-year lifespan Affects maintenance and repair/replacement schedules Other specific assumptions: Window to wall ratio Concrete strength and fly ash content Gypsum board type and thickness Live load for all intermediate floors, columns & beams, roofs Bay sizes and column heights External wall thicknesses depending on construction system Stud size/strength and spacing Sheathing and decking materials 3/31/08 42

15 3/31/08 43 EcoCalculator Versions Current Northern USA averages Southern USA averages 8 Canadian regions Vancouver, Calgary, Winnipeg, Toronto, Ottawa, Montreal, Québec, Halifax 4 US regions Atlanta, Minneapolis, Orlando, Pittsburgh Coming Los Angeles, New York, Seattle, Phoenix, Denver, + All with hi-rise and low-rise versions 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 CAUTION: BE WARY OF SIMPLISTIC ANSWERS TO COMPLEX QUESTIONS Questions/ Comments? This concludes the: American Institute of Architects Continuing Education Systems Program