|
Life Cycle Environmental Performance of Renewable
Building Materials in the Context of Residential Construction

PHASE I INTERIM RESEARCH REPORT ON THE RESEARCH
PLAN TO DEVELOP ENVIRONMENTAL-PERFORMANCE MEASURES FOR RENEWABLE
BUILDING MATERIALS WITH ALTERNATIVES FOR IMPROVED PERFORMANCE
JULY 15, 2002
Consortium for Research on Renewable Industrial Materials
(CORRIM, Inc.)
Consortium for Research on Renewable Industrial Materials (CORRIM,
Inc.)
Prepared with financial support from the USFS (JV11111169-156) and
contributions from a number of private companies based on a research
plan developed for the Department of Energy (DOE Agreement No. DE-FC07-96ID13437)
as a part of the American Forest and Paper Association's Agenda
2020 priorities. Any opinions, findings, conclusions, or recommendation
expressed in this publication are those of the authors and do not
necessarily reflect the view of the financially contributing entities

LIFE CYCLE ENVIRONMENTAL PERFORMANCE OF RENEWABLE
BUILDING MATERIALS IN THE CONTEXT OF RESIDENTIAL CONSTRUCTION
PREFACE
This report provides interim research results from a study to develop
a database and modeling capability to adequately describe the environmental
performance of building materials and their uses, addressing key
wood materials such as lumber, plywood, composite panels and other
wood derived products. The report documents progress on the original
research plan developed for the Department of Energy and the American
Forest and Paper Association under Agenda 2020 priorities for pre-competitive
research needs. The Consortium for Research on Renewable Industrial
Materials (CORRIM) with the financial support of its 21 institutional
and company members and the Department of Energy developed (1) a
research plan, (2) a Data, Standards and Procedures: Guideline for
LCI and Economic Analysis, and (3) an organizational approach to
conducting the research plan in 1998. A Phase I research plan was
designed to pilot-test the development of data and analysis procedures
for each stage of processing, while providing data for the primary
wood producing regions of the US. This Phase I report covers the
first 5 modules of the 22 module research plan focusing on forest
resources from the US Southeast and Pacific Northwest and residential
construction in a warm climate (Atlanta) and a cold climate (Minneapolis).
The USFS Forest Products Laboratory, 14 research institutions and
10 companies are providing financial support.
This report provides environmental and economic data on all life-cycle
stages from planting and growing the renewable raw material through
the manufacturing of product, design and construction of buildings
as well as activities associated with occupation, use and final
demolition. The collected data and subsequent analysis follows consistent
definitions and collection procedures that facilitate integration
of results across the full life cycle for all stages of processing
in order to address environmental performance questions. The findings
are interim, reflecting a mid-point progress report that intentionally
identifies data and procedural inadequacies that need to be corrected
before completion of the final report. One of the more substantive
impacts of this research effort has been the enhancement of institutional
capabilities to support the development of environmental performance
data and analysis.
The report is organized as follows: Major points are very briefly
summarized in an executive summary preceding the table of contents.
Section 1 provides the background, mission, organization of effort,
and objectives. Section 2 provides the Life Cycle Inventory and
Analysis (LCI/LCA) framework. The findings for each stage of processing
are reported on in 7 modules (Appendices A-G). The appendices are
essentially stand alone LCI reports for intermediate and final products.
The last module, Appendix G, covers the construction aspects, integrating
the information from the other modules for a residential structural
building shell. Information on final building use, maintenance and
ultimate disposal will be completed for the final report. The forest
resource module demonstrates the impact of management alternatives
on environmental performance. Additional scenarios and sensitivity
analysis examining the impacts of changes in management and processing
technologies will be included in the final report.

EXECUTIVE SUMMARY
The Consortium for Research on Renewable Industrial Materials (CORRIM)
was organized as a non-profit company supported by 15 research institutions
for the purpose of updating and expanding a 1976 landmark study by
the National Academy of Science on the energy implications of producing
and using renewable building materials. We use the same CORRIM acronym
as the 1976 study, which was managed by a committee of scientists.
An expanding list of environmental-performance issues has gained considerable
attention over the last two decades, yet there had been no update
of the 1976 CORRIM study, or extensions to include environmental issues
not addressed in the original study until this effort was undertaken.
Without a scientifically sound, life-cycle database on performance
measures, there can be no basis on which to formulate public policy
affecting the renewable materials industries, or for companies to
develop strategic investment plans that could improve environmental
performance.
This study's objectives are:
- To create a consistent database of environmental performance
measures associated with the production, use, maintenance, re-use,
and disposal of alternative wood and non-wood materials used in
light construction, i.e., from forest resource regeneration or
mineral extraction to end use and disposal, thereby covering the
full product life-cycle from "cradle to grave."
- To develop an analytical framework for evaluating life-cycle
environmental and economic impacts for alternative building materials
in competing or complementary applications so that decision-makers
can make consistent and systematic comparisons of options for
improving environmental performance.
- To make source data available for many users, including resource
managers and product manufacturers, architects and engineers,
environmental protection and energy conservation analysts, and
global environmental policy and trade specialists.
- To manage an organizational framework to obtain the best scientific
information available as well as provide for effective and constructive
peer review.
Data was collected through surveys of a range of mill types within
processing regions characterizing all inputs and outputs associated
with the production of lumber, plywood, and oriented strandboard.
For forest regeneration, growth and log production, growth and yield
models representative of conditions in the Pacific Northwest and Southeast
growing regions and recent studies of harvesting activities reported
in the literature were found to satisfy most data requirements with
minimal new data collection. The most difficult aspect of data collection
has been to maintain consistency across many products made from different
processes, and wood species. Product characteristics vary substantially,
as do the measurement practices used by different producers. Analysis
of the mass balance in and out of a processing stage provided a validity
check on the data quality. Different measurement conventions and imprecise
measurement of characteristics such as moisture content sometimes
corrupted data collection. In selected cases, as that for softwood
green lumber, additional data will be collected prior to the final
report to improve the sample size and resolve mass balance discrepancies.
Based on analysis of the designs of the representative residential
structures for a cold climate (Minneapolis) and a warm climate (Atlanta),
fifteen different wood and non-wood materials were found to be used.
Additional materials were used in the generation of energy used in
production processes.
In the United States, a little over half of the wood produced in the
forest is used directly in construction. The environmental burdens
from the production processes used to produce building materials were
allocated according to the mass of materials used in building construction.
Other burdens were allocated to co-products such as paper. Similarly,
the burdens accumulated from transportation, processing energy, and
construction energy were allocated to the building according to the
mass of materials used in building construction. The environmental
impacts from energy uses are derived from national/regional grids
of purchased electrical energy and fossil fuels. Thus the environmental
burdens derived from energy consumption are allocated according to
the specific type of energy consumed (7 types) and its place of origin
(raw material and manufacturing producing regions and construction
regions).
In this study, sixteen different kinds of air emissions are reported
for each stage of production (extraction, manufacturing, transportation,
and construction). Twenty-five different sources of water emissions
are identified with manufacturing. Six categories of solid waste are
tracked. Vital measures of the forestland environment are also tracked
to characterize impacts on water, habitat, carbon and biodiversity,
several of which require landscape-wide measures to be useful. This
complex array of environmental outputs for the construction of a residential
building are reduced to environmental performance indices to simplify
the analysis and communication of findings. However, the science behind
best weighting schemes to represent aggregate environmental risk indices
for water, air, solid waste, global warming potential, and forest
health are still evolving, and for the most part beyond the analysis
provided by CORRIM. The environmental impacts of forest management
are being analyzed at the landscape level and will be available for
the final report.
Indices for water and air emissions, solid waste, and global warming
potential were derived by the ATHENA Institute, a Canadian research
institute and cooperator on the project. The ATHENA model provides
Life Cycle Inventory (LCI) measures based on the bill of materials
developed for the US house designs and the LCI data that was developed
for each US product, thereby extending the ATHENA database to
cover US producing regions. These index measures currently do not
account for the impacts from use, maintenance and disposal of a building,
nor do they integrate the carbon stored in the forest as developed
in the Forest Resource module; these are impacts that develop over
a long period of time in contrast to the narrow time frame associated
with impacts from extraction to construction.
With one exception, all of these index measures indicate significantly
lower environmental risk for the wood design in Atlanta and Minneapolis
compared to non-wood construction (see table below). The one exception
is in Minneapolis where the steel design produces 9 % less solid waste
than the wood design. From experience with sensitivity analysis ATHENA
considers relative differences of less than 15% as not significantly
different.

Environmental
Performance Indices for Residential Construction
|
|
Minneapolis design
|
Wood
|
Steel
|
Difference
|
Other Design vs.
Wood (% Change)
|
| Embodied Energy ( Gj) |
186
|
308
|
122
|
66%
|
| (CO2 kg) |
39810
|
59290
|
59290
|
49%
|
| Air Emission Index (index scale) |
2778
|
4711
|
1933
|
70%
|
| Water Emission Index (index scale) |
185
|
1179
|
994
|
537%
|
| Solid Waste (total kg) |
12110
|
11020
|
-1090
|
-9%
|
| |
|
|
|
|
|
Atlanta design
|
Wood
|
Concrete
|
Difference
|
Other design vs.
wood (% change)
|
| Embodied Energy ( Gj) |
115
|
162
|
47
|
41%
|
| Global Warming Potential (CO2 kg) |
20020
|
33130
|
13110
|
65%
|
Air Emission Index (index scale)
|
1035
|
1862
|
827
|
80%
|
Water Emission Index (index scale)
|
86
|
99
|
13
|
15%
|
Solid Waste (total kg)
|
4270
|
7970
|
3700
|
87%
|
The primary difference between the Minneapolis wood and steel house
is the use of materials for floors and walls. Both designs share
the same basement and roof elements. For the Atlanta structure,
the only major difference between the wood and concrete design is
in the exterior wall structure as both designs use concrete floors
and wood roofs. Making cross design comparisons at the wall and
floor section shows much more dramatic percentage differences than
for the buildings as a whole (last two columns of the table below)
since some parts of the structure share common materials, and the
construction process itself is energy intensive and not that much
different across the designs. In effect a substantial environmental
performance difference for nearly substitutable products may not
seem so great for a completed structure with many common components.
An examination of a change in forest management suggests small but
significant changes in index measures. A small increase in PNW management
intensity resulting in an estimated 5% increase in forest productivity
increases the availability of wood such that the number of wood
homes built in Minneapolis increases and the number of those built
of steel decreases. It is assumed, for simplicity, that the increased
forest productivity forces product substitution within the region
rather than imports and exports from other regions or international
sources. Consequently there is a 6% reduction in embodied energy
and air emissions, a 25% reduction in water emissions and a 1% increase
in solid waste. The same forest productivity increase in the Southeast
results in a 17.5% increase in the construction of wood homes vs.
concrete in Atlanta and a reduction in all output measures ranging
from 3% for water emissions to 13% for solid wastes.
To support this environmental assessment for a residential structure
and be able to analyze the impact for each process, LCIs, were developed
for each wood product (logs, lumber, plywood, and oriented strandboard)
used in home construction.
The Forest Resource module (Appendix A) provides the environmental,
energy and resource impact data on the growth, management, and harvesting
of logs and reforestation of harvested timber for the Pacific Northwest
(PNW) and Southeast regions of the US for a representative acreage
within each region. The study calculates volume harvested for three
general combinations of management intensity and site productivity
for each region. The combinations were reduced to a single estimate
of yield using weighting factors for the acreage under each management
regime. The weighting scheme creates a base case for each region.
Alternative weights resulting from increasing the acres under a
different level of management intensity are used to produce alternative
cases, with a different calculated volume. For example, the increase
in merchantable volume under a prescribed alternative case was 21%
in the Southeast (including the volume from a partial second rotation
when rotation ages were reduced) and a nearly 16% increase in volume
in the PNW.
The portion of lumber and pulpwood produced in the Southeast changed
slightly under the alternative scenario; lumber share declined 2.1
percentage points as pulpwood share increased 2.1 percentage points.
The alternative scenario also leads to a 3.2 year reduction in the
average rotation age in the Southeast, which is responsible for
the percentage shifts in lumber and pulpwood produced. Lumber output
increased 15%, only 68% of the merchantable volume increase. Lumber
share remained at 100% in the base and alternative PNW scenarios.
System costs increased by around one percentage point above the
percent change in the amount of merchantable volume removed in the
Southeast, while increasing about the same percent as merchantable
volume removed in the PNW. A similar result is observed for fuel
and lubricant consumption during harvesting operations: an 11% increase
in the Southeast and 16% increase in the PNW roughly corresponding
to the changes in merchantable volumes harvested, although there
appears to be a slight increase in the consumption factors in the
Southeast due to the change in rotation age and products harvested.
The increase in harvested volume resulted from using 4 times more
nitrogen and phosphate in the Southeast and 2 times mores nitrogen
and phosphate in the PNW as fertilizer inputs in conjunction with
the other management changes.

Along with harvested volumes, the Forest Resource module also produces
harvesting cost data and air emission estimates related to stand growth
and harvesting, and regeneration. Resources used to produce the harvested
volume, such as fuel, fertilizer and herbicides, are quantified and
their impacts reported in the Environmental Impact Report (Appendix
G) during the extraction phase of the single family shell construction.
The Forest Resource Module also produces estimates of tree biomass
by component. These estimates are used to approximate the standing
and removed carbon pool over time. Other environmental performance
measures including indices of stand structure, diversity, and habitat
and fragmentation will be developed in subsequent phases of the project
using a landscape approach to forest management will be developed
in subsequent phases of the project.
Harvested volumes from the two forest resource regions are considered
in the context of lumber manufacturing in the Pacific Northwest and
Southeast regions. Here the research developed independent LCIs for
the two regions. The two regional lumber manufacturing modules were
developed to provide the environmental, energy and resource impact
data associated with the manufacturing of softwood lumber. In the
Northwest (Appendix B) a survey produced the data for sawing, drying
and planing processes. A unit process approach produced detailed descriptions
of activities and the resources used to produce specific outputs.
For example, the sawing process involves log movement within the mill,
sorting and storage, delivery to debarkers, and bucking to length.
The logs are then debarked and sawn into rough lumber producing rough
lumber, resulting in the CO-products pulp chips, bark and sawdust.
The rough lumber is transported within the mill to stacks for kiln
dryers or planer facilities. Maintenance work on equipment and vehicles
are also recorded, as were emissions to air, water and land. The results
of the survey work produced detailed information that was then analyzed
with the SimaPro life cycle program. The SimaPro analysis considered
four processes, including energy generation in addition to the three
processes mentioned above. The result of the analysis produces unit
factor estimates for one Mbf of planed dry lumber. These unit factor
estimates include raw material use, airborne, waterborne, and solid
emissions, and energy use. A similar module was used for Southeastern
lumber production (Appendix C).
Harvested volumes from the two forest resource regions were also considered
in the context of softwood plywood manufacturing in the Pacific Northwest
and Southeast regions (Appendix D). Surveys were implemented in a
manner similar to those used in conjunction with the the lumber manufacturing
modules. The plywood process was defined in terms of six processes:
bucking and debarking, block conditioning, peeling and clipping, drying,
lay-up and pressing, and trimming and sawing. The results of the survey
work produced detailed information that was then analyzed with the
SimaPro life cycle program to produce unit factor estimates for one
Msf of 3/8-in basis of plywood.
An LCI for Oriented Strand Board (OSB) production was produced in
a similar manner (Appendix E); however for this interim report, the
integrated residential construction analysis used plywood as the default
for all panels because the material balances were not completed at
the time that the integration analysis was performed. The survey also
collected information on log transport, production of phenol-formaldehyde
and MDI resins and wax.
Data is now available to provide a comparison of energy and resource
impacts relative to the 1976 CORRIM study. Data is also available
to provide a measure of resource use efficiency. With the LCI data
produced by the lumber, plywood and OSB modules, LCIs can be produced
for derived products such as glulams, trusses, and laminated veneer
lumber, all of which will be incorporated into the final report. Management
and process improvements can also be identified and analyzed with
key scenarios planned for the final report. An analysis of costs and
carbon accounting have been initiated in Phase I and can now be completed
in conjunction with a more thorough integration with resource harvesting,
production, and the ultimate use, maintenance, and disposal phases
of each product.
With these additions and corrections, the final report will provide:
- Measures of carbon emissions, and carbon storage on the forest
floor and in wood products for each stage of processing and region,
and comparable impacts for policy alternatives that result in
substitute products.
- Identification of alternative methods for reducing emissions
with quantified impacts across stages of processing and geographic
regions.
- Identification of performance measures and methods to improve
environmental performance in areas such as (1) energy and material-use
efficiency, (2) biodiversity and habitat protection indices for
uplands or riparian zones as well as other measures of the health
and sustainability of forest ecosystems, (3) solid waste reduction,
and (4) reduction in the production and emission targeted potentially
toxic chemicals.
- Assessments of the impact of policy proposals on the ability
of the forest sector to meet expected consumer demand for products.
- Cost effective approaches to meet changing environmental goals,
and develop investment strategies that are more responsive to
those needs.
- Opportunities to adopt strategies that improve environmental
performance where costs are not a limiting factor and support
for the development of policy alternatives that could offset cost
impacts when necessary.
LIFE CYCLE ENVIRONMENTAL PREFORMANCE OF RENEWABLE
MATERIALS IN THE CONTEXT OF RESIDENTIAL BUILDING CONSTRUCTION
Consortium for Research on Renewable Industrial Materials
(CORRIM)
Phase I Interim Research Report
January 27, 2002
Prepared by:
Jim Bowyer, University of Minnesota1
David Briggs, University of Washington
Bruce Lippke, University of Washington
John Perez-Garcia, University of Washington
Jim Wilson, Oregon State University
|
With supporting appendices by:
|
|
Forest Resources:
|
Softwood Lumber:
|
| Leonard Johnson, University of Idaho |
Michael Milota, Oregon State University |
| Bruce Lippke, University of Washington |
Ian Hartley, Mississippi State University |
| John Marshall, University of Idaho |
Cynthia West, Mississippi State University |
|
Plywood:
|
|
| Jim Wilson, Oregon State University |
Oriented Strandboard:
|
| Maureen Puettman, Oregon State University |
Earl Kline, Virginia Tech University |
| Eric Sakimoto, Oregon State University |
|
| Eric Dancer, Oregon State University |
Environmental Impacts of a Building:
|
|
Residential Buildings:
|
Jamie Meil, ATHENA |
| Bo Kasal, North Carolina University |
Bruce Lippke, University of Washington |
| Pat Huelman, University of Minnesota |
John Perez-Garcia, University of Washington |
1 Bowyer is director, Forest Products Management Development
Institute, Department of Wood and Paper Science, University of Minnesota;
Briggs is director, Stand Management Coop, Lippke is director, Rural
Technology Initiative and Perez-Garcia is associate professor, College
of Forest Resources, University of Washington; Wilson is professor,
Department of Forest Products, Oregon State University.
TABLE OF CONTENTS
| PREFACE |
| EXECUTIVE SUMMARY |
| 1.0 INTRODUCTION |
| 1.1
BACKGROUND |
| 1.2
OBJECTIVES, MODULAR DESIGN, AND
SCOPE OF CORRIM PHASE I |
| 1.3
ORGANIZATIONAL FRAMEWORK TO CONDUCT
PHASE I RESEARCH |
| 1.4
REPORT STRUCTURE |
| 2.0 LIFE
CYCLE ANALYSIS FRAMEWORK |
| 2.1
INTRODUCTION |
| 2.2
CORRIM FRAMEWORK AND GUIDELINES |
| 2.3
LIFE CYCLE ANALYSIS (LCA) |
2.4
CASTING THE CORRIM FRAMEWORK IN
THE LCA CONTEXT: LIFE-CYCLE
STAGES
|
| 2.4.1
LCA Components |
| 2.4.2
Initiation and Scope of
Phase I |
| 2.4.3
Inventory Analysis and Data
Collection |
| 2.4.3.1
Forest Growth and Harvesting |
| 2.4.3.2
Product Manufacturing & Unit
Processes |
| 2.4.3.3
Building Construction |
| 2.4.3.4
Building Use and Maintenance |
| 2.4.3.5
Building Demolition and Material Recycling or Disposal |
| 2.4.4
Impact Assessment |
| 2.5
IMPROVEMENT ANALYSIS AND SCENARIOS
|
| 2.6
TEMPORAL ISSUES IN THE LCA CONTEXT
|
| 2.7
SCENARIO ANALYSES: POLICY CHANGES AND ECONOMIC LINKAGES |
3.0 PHASE I ACCOMPLISHMENTS
|
| 4.0 REFERENCES |
LIST OF FIGURES
| Figure 1.1 |
Integrated Life-cycle of Biological Materials
(CORRIM 1998) |
| Figure 1.2 |
CORRIM Organization Chart (CORRIM 1998) |
| Figure 2.1 |
General Flows in a "Cradle-to Grave"
LCA System (Franklin Associates, 1990) |
| Figure 2.2 |
Main Components of an LCA Study (ATHENA 1997a) |
| Figure 2.3 |
A Depiction of CORRIM Phase I Research |
| Figure 2.4 |
The Time-Line of the CORRIM Life-Cycle |
| Figure 2.5 |
Simultaneous Cohorts in the CORRIM Life-Cycle
System |
| Figure 2.6 |
Temporal Progression of Cohorts in the CORRIM
Life-Cycle |
LIST OF TABLES
| Environmental Performance
Indices for Residential Construction |
| Table 1.1 |
The Research Organizations Comprising CORRIM II
|
| Table1.2 |
CORRIM Research Modules - (from CORRIM 1998) Phase
I Research consists of Highlighted Areas (CORRIM 1998) |
| Table 1.3 |
Lead Scientists Involved in CORRIM - Phase I Chair
of Technical Steering Committee, Dr. Jim Bowyer, University
of Minnesota |
| Table 2.1 |
Comparison of the Generic LCA Model and the CORRIM
Research Framework |
| Table 2.2 |
Wood Products for Which Unit Process Data has
been Collected by CORRIM |
| Table 2.3 |
Products Considered in CORRIM Using Data from
Studies |
1.0 INTRODUCTION
1.1 BACKGROUND
The motivation for creating CORRIM to conduct this research is increasingly
intense public interest and debate regarding environmental impacts
and sustainability of building products manufacture and use, and particularly
intense concerns with respect to forest management and the flows of
products that originate from forests. Unfortunately, the environmental
consequences of changes in forest management, product manufacturing,
consumption, and disposal are poorly understood and there is a lack
of current, scientifically sound life-cycle data in the United States
for wood and other bio-based products.
The last major research effort in the United States dealing with these
issues for wood and bio-based products was completed in 1976 by CORRIM
I, the Committee on Renewable Resources for Industrial Materials under
the auspices of the National Research Council (1976). Though an extensive
landmark study, information developed under CORRIM I is now both incomplete
and out-of-date in the context of current issues and concerns.
Recognizing the need for updated and more comprehensive information,
CORRIM II (the Consortium for Research on Renewable Industrial Materials)
was created to develop a scientific base of information relating to
the environmental performance of wood building products and to examine
factors that can affect the efficient use of energy and materials
in manufacturing and use of building materials. These factors include
forest management to increase carbon sequestration, improving the
efficiency of manufacturing processes, reducing waste and potentially
toxic materials, and sustain healthy forest ecosystems. The intent
in creating CORRIM II was to develop:
- A consistent database to evaluate the environmental performance
of wood and alternative materials from resource regeneration or
extraction to end use and disposal, i.e. from "cradle to
grave" (Figure 1.1)
- A framework for evaluating life-cycle environmental and economic
impacts
- Source data for many users, including resource managers, manufacturers,
architects, engineers, environmental protection and energy analysts,
and policy specialists.
- An organizational framework to obtain the best science and
peer review.

Figure 1.1. Integrated Life-cycle of Biological Materials (CORRIM
1998)
CORRIM is a nonprofit corporation of scientists from the 15 member
research organizations (Table 1.1).
Table 1.1: The
Research Organizations Comprising CORRIM II
|
|
APA The Engineered Wood Association
|
University of Idaho
|
|
Athena Sustainable Materials Institute
|
University of Minnesota
|
|
Forintek Canada Corp.
|
University of Tennessee
|
|
Louisiana State University
|
University of Washington
|
|
Mississippi State University
|
USDA-Forest Service, Forest Products Laboratory
|
|
North Carolina State University
|
Washington State University
|
|
Oregon State University
|
Virginia Tech University
|
|
Purdue University
|
|
Soon after the establishment of CORRIM II, a request for proposals
was issued by AF&PA in 1994 as part of its' Agenda 2020 program.
The Agenda 2020 program focuses on pre-competitive research needs
of the US forest products industry, and the '94 RFP targeted two
principal research objectives relative to environmental life cycle
inventory and analysis: (1) development of an updated analysis of
the environmental efficacy of renewable building materials, including
consideration of environmental impacts related to energy consumption
and (2) identification of alternatives for reducing environmental
releases associated with building materials through their life-cycles.
This led to funding of CORRIM II in 1996 by the U.S. Department
of Energy ($125,000) and the forest products industry ($54,000)
to develop a research plan. This plan, outlining research activity
within 22 modules over a 5-year span (Table 1.2) was released in
January 1998 (CORRIM 1998). In addition, protocols and standards
were described in the research plan to ensure that data collection
and analysis would be compatible with ISO life-cycle analysis guidelines
(ISO 1997, 1998, 2000a, 2000b) and LCI procedures developed for
the forest industry (AF&PA 1996).

Table1.2: CORRIM Research
Modules - (from CORRIM 1998) Phase I Research consists of Highlighted
Areas (CORRIM 1998)
All
estimated funding (monetary figures) are in $5 000's
|
FOCUS AREA
|
Year 1
|
Year 2
|
Year 3
|
Year 4
|
Year 6
|
Year 8
|
|
Forest Resource
|
1. Forest Resource
I
Regional - NW/SE $400 |
13. Forest Resources II
Regional - NE/NC/IW/Canada $400 |
|
|
Manufacturing Processes
|
2. Processes
I Structural Products $400 |
14. Processes II
Nonstructural Products $600 |
|
|
Structures
|
3.
Structures Ia
Component Systems $200 |
5. Structures Ib
Complete Structures $200 |
16. Structures II Alternatives
$200 |
|
Data Management
|
4. Data Management
(Funded as part of each module) |
|
Industrial Products
|
|
6. Industrial Products Treated/Untreaded
$150 |
|
20 Structures III Infrastructures
$150 |
|
Integrated Modeling
|
|
7. Integrated
Modeling $200 |
17 & 21. Integrated Modeling
II a&b $300 |
|
Nonstructural Products
|
|
8. Nonstructural Products I
Windows/doors/insulation etc. |
18. Nonstructural Products II
Millwork, flooring, etc. $200 |
|
Products Substitution
|
|
9. Substitution I Components
$200 |
15. Substitution IIa
Comprehensive Structure $200 |
19. Substitution IIb
Nonstructural $100 |
|
Biomass
|
10. Biomass Process
for Energy $200 |
|
|
Use, Disposal, Life Expectancy,
Durability
|
|
11. Life Expectance/Durability
$150 |
12. Use/Maintenance/
Disposal/Final Recycle $300 |
|
|
Use, Disposal, Life Expectancy,
Durability
|
|
22. Reporting/
Technology Transfer $250 |
|
Total Funding Need
|
$5000
|
Preceding the CORRIM II initiative was a project to develop current
environmental performance information for building materials used
in Canada. This project, titled "Building Materials in the
Context of Sustainable Development", was initiated in 1990
as the ATHENA project by FORINTEK Canada Corp, and is now
continuing at the ATHENA Sustainable Materials Institute.
In 1997, an alliance was established between CORRIM and ATHENA
to take advantage of previous ATHENA research and to broaden
the geographic and product representation of research.
1.2 OBJECTIVES, MODULAR DESIGN, AND SCOPE OF
CORRIM PHASE I
Subsequent to development of the long-term, 22-module CORRIM research
plan, funding was made available to conduct a first phase effort (modules
1-4, 7, and a portion of 12 as highlighted portions of Table 1.1),
with the following two objectives:
- to develop an adequate database and models of environmental
performance measures over the entire life-cycles of structural
building materials, beginning with extraction of resources, through
product manufacture and transportation, construction of a structure,
use and maintenance of the structure, and finally dismantling
of the structure and either disposal or recycling of the building
components.
- to examine a range of management, product, and process alternatives
to identify strategies that can improve environmental performance.
The Phase I research effort was concentrated on development of
life cycle inventory data for wood-based building materials produced
in the two regions of the US that account for the greatest production
of forest products - the Pacific Northwest and the Southeast. Further,
because of funding limitations, the scope of Phase I was limited
to consideration of the structural shells or envelopes of residential
buildings. Although focused on wood-based materials, Phase I research
did address environmental performance of wood-framed buildings in
comparison to residential buildings constructed of steel and of
concrete block. Data for these other materials was obtained from
the Athena Sustainable Materials Institute.

1.3 ORGANIZATIONAL FRAMEWORK TO CONDUCT PHASE
I RESEARCH
An organizational structure has been established for CORRIM II to
provide the best scientific talent available to complete the research
while obtaining competent and independent reviews. This structure
is organized around working panels of experts (Figure 1.2) including
a Data Standards and Procedures Panel, a Stages of Processing Panel
(with 4 technical sub-committees), and a Strategy Assessment Panel.
The Data Standards and Procedures Panel has responsibility for providing
data processing capability, assuring consistency and compatibility
in the design of data collection procedures across research modules,
and integrating the results of management and technology alternatives
throughout all stages of processing. Development of LCI data, on
the basis of individual unit operations, for a range of wood-based
building materials from harvesting and forest regeneration through
manufacturing, transport, construction of residential structures,
building maintenance, and reuse or disposal at the end of the useful
life of the building or building component is the responsibility
of the Stages of Processing Panel. The Strategy Assessment Panel
is charged with development and evaluation of a number of scenarios
that represent various strategies for improving environmental performance
of wood based building materials throughout their life cycles.

Figure 1.2. CORRIM Organization Chart (CORRIM 1998)
The specific assignment of scientists from CORRIM member institutions
to the Phase I modules is presented in Table 1.3.
Table 1.3: Lead Scientists
Involved in CORRIM - Phase I Chair of Technical Steering Committee,
Dr. Jim Bowyer, University of Minnesota
|
Module
|
Principal Investigator
|
Member Institution
|
|
Forest Resources I
|
Dr. Leonard Johnson
|
University of Idaho
|
|
Processes
|
|
|
|
Softwoods lumber-Pacific NW
Softwood lumber-south
Plywood
Oriented strand board
Laminated Veneer Lumber
Glued laminated Beams
I-joists & beams
Trusses
|
Dr. Mike Milota
Dr. Cynthia West
Dr. Jim Wilson
Dr. Earl Kline
Dr. Jim Wilson
Dr. Jim Wilson
Dr. Jim Wilson
Dr. Jim Wilson
|
Oregon State University
Mississippi State University
Oregon State University
Virginia Tech University
Oregon State University
Oregon State University
Oregon State University
Oregon State University
|
|
Structures
|
Dr. Bo Kasal |
North Carolina State University |
|
Use and Disposal
|
Dr. Paul Winistorfer |
Virginia Tech University |
|
Life Cycle Inventory through Construction
|
Dr. Jamie Meil |
Athena Sustainable Materials Institute |
|
Data Management & Integration
|
Dr. David Briggs
Bruce Lippke
Dr. Jim Bowyer
|
University of Washington
University of Washington
University of Minnesota
|

1.4 REPORT STRUCTURE
This interim report documents progress through the first half of
the Phase 1 research plan. The intent is to fully develop procedures
and collect data while identifying deficiencies that must be eliminated
before completion of the final Phase I Research Report. The final
report will also contain more detailed sensitivity and scenario
analysis on the impact of management and technology change.
Section 2 of this report provides the framework for developing Life
Cycle Inventory (LCI) data and Life Cycle Analysis (LCA) information.
Section 3 summarizes accomplishments to date.
The report is designed around the seven individual research modules
comprising Phase I of the project. These modules, presented in full
as appendices to this report, are in effect stand alone reports
covering each stage of processing through construction of a residential
building structure and provide LCI data for each wood product used
in the structure. The modules are:
- Module A: Forest Resources - identifies environmental
performance measures and presents life cycle inventory data for
specific unit operations in woodland management activities in
forests of the Pacific Northwest and Southeast regions.
The objectives of this module are to:
- Provide environmental, energy, and resource impact data on
the growth, management, harvesting and reforestation of timber
under five general scenarios of management intensity for the Northwest
and Southeast regions of the United States.
- Develop case studies to represent a typical range of forest
management objectives and stand and site conditions.
- Provide environmental performance measures including indices
of stand structure diversity, habitat, and fragmentation for each
of the case study scenarios.
- Provide inputs for the Processing Modules from the case study
scenarios.
- Module B: Pacific Northwest Softwood Lumber - presents
life cycle inventory data for specific unit operations associated
with the manufacture of softwood lumber manufactured in the Pacific
Northwest region of the United States.
The objectives of this module are to:
- Provide environmental, energy, and resource impact data on
the manufacture of softwood lumber in the US Pacific Northwest
region.
- Provide benchmarks for these products that will enable comparison
to process improvements or new processes.
- Provide input for the Structures Module.
- Compare fossil versus biomass fuel dependency.
- Provide a measure of resource use efficiency.
- Provide a comparison of energy and resource impacts relative
to the 1976 CORRIM study.
- Module C: Southeastern US Softwood Lumber - presents
life cycle inventory data for specific unit operations associated
the manufacture of softwood lumber manufactured in the Southeast
region of the United States.
The objectives of this module are to:
- Provide environmental, energy, and resource impact data on
the manufacture of softwood lumber in the US Southeast region.
- Provide benchmarks for these products that will enable comparison
to process improvements or new processes.
- Provide input for the Structures Module.
- Compare fossil versus biomass fuel dependency.
- Provide a measure of resource use efficiency.
- Provide a comparison of energy and resource impacts relative
to the 1976 CORRIM study.
- Module D: Softwood Plywood - US Pacific Northwest and
Southeast - presents life cycle inventory data for specific unit
operations associated the manufacture of softwood plywood manufactured
in the Pacific Northwest and Southeast regions of the United States.
The objectives of this module are to:
- Provide environmental, energy, and resource impact data on
the manufacture of softwood plywood in the US Pacific Northwest
and Southeast regions.
- Provide benchmarks for these products that will enable comparison
to process improvements or new processes.
- Provide input for the Structures Module.
- Compare fossil versus biomass fuel dependency.
- Provide a measure of resource use efficiency.
- Provide a comparison of energy and resource impacts relative
to the 1976 CORRIM study.
- Module E: Oriented Strandboard - presents life cycle
inventory data for specific unit operations associated the manufacture
of oriented strandboard manufactured in the Southeast region of
the United States.
The objectives of this module are to:
- Provide environmental, energy, and resource impact data on
the manufacture of oriented strandboard in the US Southeast region.
- Provide benchmarks for these products that will enable comparison
to process improvements or new processes.
- Provide input for the Structures Module.
- Compare fossil versus biomass fuel dependency.
- Provide a measure of resource use efficiency.
- Provide a comparison of energy and resource impacts relative
to the 1976 CORRIM study.
- Module F: Design of Residential Building Shells, Minneapolis
and Atlanta - outlines the design of typical light-frame residential
structures for two different climates: a hot and humid climate
represented by Atlanta, GA and a cold climate, represented by
Minneapolis, MN, for use in subsequent life cycle analyses of
representative structures.
The objectives of this module are to:
- Provide environmental, energy, and resource impact data on
the manufacture of floor, wall, and roof components for residential
and light commercial structures, both site constructed and factory
built.
- Provide environmental, energy, and resource impact data on
the manufacture of representative single residential structures,
both site-constructed and factory built, comprised of floor, wall,
and roof components (with considerations for windows, doors, roofing,
and siding based on ATHENA data).
- Provide input for the Use and Disposal Module and future Structures
Modules that will include internal components and fixtures.
- Provide data input for the Integration Module.
- Provide benchmark data for these processes that will enable
future comparison of process improvements or to new processes.
- Provide a comparison of energy and resource impacts to the
1976 CORRIM study for floor, wall, and roof components.
- Compare fossil versus biomass fuel dependency.
- Provide a measure of resource use efficiency.
- Module G: Building Construction, Use, Maintenance, and Disposal
- presents the results of a comprehensive analysis of environmental
impacts related to the use of wood and non-wood materials in residential
structures, and the durability of such structures relative to
longevity and eventual replacement, or final use and disposal.
Objectives of this module are to:
- Define the durability of wood materials used in the structural
shell of a building and to determine the longevity (useful life)
of wood materials used in the construction shell as impacted by
a given set of parameters. The parameters that impact the durability
of the materials will be defined in the module. Wood materials
to be considered in this module are softwood lumber, softwood
plywood, oriented strandboard (OSB), laminated veneer lumber (LVL),
parallel strand lumber (PSL), glulam beams, composite beams, and
trusses. Only exterior doors and windows will be considered in
addition to basic construction shell materials.
- Define those variables that influence durability of wood materials
used in the construction shell and develop a methodology for measuring
the impact of each material relative to its own durability and
subsequently to the durability and life of the structure as a
whole.
- Address durability from both a material performance and aesthetic
perspectives (i.e. exterior shell component remodel for aesthetic
reasons).
- Estimate the final disposition of components upon dismantling
of a building, along with associated impacts on life cycle inventories.
- Provide input data for other modules, especially energy use
and carbon storage comparisons.

2.0 LIFE CYCLE ANALYSIS FRAMEWORK
2.1 INTRODUCTION
Life-cycle analysis (LCA), which began in the 1960s, has evolved as
an internationally accepted way to address these complex impact questions
and resolve issues. "Life-cycle" refers to all activities
from forest resource regeneration or mineral extraction through manufacturing,
to end-use and eventual disposal or recycle, i.e. from "cradle
to grave" (Curran 1996). Guidelines for the conduct of LCAs are
set forth in the ISO 14000 series of standards (ISO 1997, 1998, 2000a,
2000b). Counterpart national standards have been adopted in many countries
and have been translated into guidelines for specific industries,
an example of which is the AF&PA user's guide for the US forest
industry (AF&PA 1996).
2.2 CORRIM FRAMEWORK AND GUIDELINES
Figure 1.1 illustrates the overall approach employed by CORRIM for
studying biologically-based materials and identifies the linkages
between the major steps in the life-cycle of a building structure.
Protocols and standards are described in the CORRIM research guidelines
(CORRIM 2001) to ensure that data and analysis are consistent with
methods for performing life-cycle inventories and life cycle analyses
as set forth in the ISO 14000 series of standards and AF&PA guidelines
for the forest industry.
2.3 LIFE CYCLE ANALYSIS (LCA)
Figure 2.1 presents the general flows in a typical "cradle-to-grave"
LCA and Figure 2.2 illustrates the major components of an LCA study.
An LCA begins with an initiation phase during which a problem is
defined along with the scope, system boundaries, data categories,
and review process. Initiation is followed by three interrelated
phases that may be conducted simultaneously or in a sequence that
best suits the problem being studied: a life cycle inventory phase
that identifies and quantifies the energy, resource use and environmental
effects of a particular product, service, or activity; an impact
assessment phase which investigates the potential environmental
consequences of energy and natural resource consumption and waste
releases associated with the system being studied, and an improvement
assessment phase where opportunities to reduce environmental impacts
and resource use are investigated. Figure 2.2 highlights some of
the factors likely to be considered within each phase and emphasizes
the iterative nature of the process.

Figure 2.1. General Flows in a "Cradle-to Grave" LCA
System (Franklin Associates, 1990)

Figure 2.2. Main Components of an LCA Study (ATHENA 1997a)

2.4 CASTING THE CORRIM FRAMEWORK IN THE LCA
CONTEXT: LIFE-CYCLE STAGES
The similarity between the CORRIM framework in Figure 1.1 and the
generic life-cycle approach presented in Figure 2.1 is evident.
There are, however, two rather unique features of the CORRIM framework.
First, while some LCAs involving agricultural products or bio-energy
have expanded the generic model by including a crop growing stage
prior to raw material acquisition (Andersson & Ohlsson 1999,
Mann & Spath 1997), forest growth is more complex. The relative
complexity of forest growth is due to 1) the much longer time frame
involved, 2) the use of intermediate harvests (thinning) to yield
products, 3) the broader array of joint products arising from a
single tree (saw, veneer, and pulp logs) and stand (due to mixed
species having different use preferences), and 4) the unique set
of forest CO-products (water, recreation, berries and mushrooms,
etc.) and environmental effects (such as water quality, species
diversity, wildlife habitat, and carbon sequestration).
Second, buildings, which account for the largest use of wood and
main focus of this study, are unique in their size, complexity,
and longevity. For example, a residential home is constructed, used
for a long period of time, and eventually demolished. The period
of use and occupancy involves cycles of maintenance and repair (re-roofing)
and may involve a series of owners each of which may remodel the
structure to accommodate changes in desired functionality and aesthetics.
As a result, the time frame between when tree seed germinates and
when a home is demolished could be on the order of one to several
centuries or more. Thus, the temporal distribution of events and
associated environmental effects during the seed to demolition life-cycle
must be considered; merely summing all of the events and effects
would produce the naïve and meaningless result that all of
the activities and associated impacts occur simultaneously.
Table 2.1 highlights the major differences between the generic LCA
model and the CORRIM framework. The major stages in the generic
LCA model evolved for investigating consumer products and packaging
materials with short lives where a simple temporal summation of
effects is reasonable. Table 2.1 also indicates a rough estimate
of time associated with each of the components of the CORRIM framework
with comments identifying some of the associated activities and
environmental effects. The procedure developed by CORRIM to deal
with these temporal issues in LCA is discussed more fully in Section
2.6. Identification of these temporal aspects of the forestry and
housing components leads to Figure 2.3, which shows the major stages
in the cradle-to-grave cycle of a building such as a residential
home and also illustrates the two long term stages (forest growing
and use of the building) that are important for carbon storage.
Table 2.1: Comparison of the Generic
LCA Model and the CORRIM Research Framework
|
Generic LCA Model
|
CORRIM
|
Comment
|
| |
Forest Growth
Time frame: 25-100+ years
|
Nursery, planting, thinning, fertilizing, during
the growth cycle. Effects on carbon sequestration/global warming,
diversity, habitat, streamside conditions, etc.
|
| Raw Material Acquisition |
Harvesting
Time frame: < 1 year
|
Logging during commercial thinning or final harvest.
Effects on soil compaction and productivity, diversity, habitat,
siltation, etc. |
| Manufacturing |
Manufacturing Processes
Time frame: < 1 year
|
Individual products (lumber, plywood, LVL, OSB,
etc)
Assemblies of products (trusses, glulam beams, I-joists, etc.)
Air & water emissions, solid waste.
|
Construction of Structures
Time frame: < 1 year
|
On-site or factory built components (floor, wall,
roof) and finished structure.
Solid waste.
|
| Use/Reuse/Maintenance |
Service Life & Use
Time frame: 40-100+ years
|
Maintenance cycles (painting, re-roofing, siding,
etc.) and remodeling. Energy use & associated emissions/waste,
energy & emissions associated with repair/remodel products.
|
| Recycle/Waste Management |
Recycling & Disposal
Time frame: < 1 year
|
Teardown, segregation of materials, recycle, combust
for energy, landfill. Energy use & substitution, air &
water emissions, solid waste/carbon sequestration. |

Figure 2.3. A Depiction of CORRIM Phase I Research

2.4.1 LCA Components
Table 2.1 and Figure 2.3 suggest that the LCA of a building system
is a composite of many separate, but interrelated, LCA'S. A building
system LCA is created through cumulatively embedding the LCAs of
many processes and their associated products, sub-assemblies and
assemblies, each containing a specific set of life cycle stages
from raw materials through recycling and waste management. For some
products, certain stages may become deferred and be dependent on
the aggregated LCA of the entire building of which they become a
part. Examples are wall studs and other main framing lumber products
that are covered by other materials and remain unchanged during
the building life; these items typically have no maintenance stage
of their own. Similarly, the recycling and disposal stage may only
apply to only some of the products when the building is finally
demolished (i.e. recycling and disposal of these individual products
is not separable from the building as a whole).
2.4.2 Initiation and Scope of Phase I
Construction of a complete residential home can be viewed as involving
three categories of component LCAs. The first of these includes
all of the products and assemblies required to produce the structural
skeleton of the building. The second category involves additional
products, such as siding, insulation, and roof topping, to complete
the building envelope. The third category involves products and
activities to complete the interior.
As noted earlier, the scope of Phase I CORRIM research is restricted
to a study of a subset of the overall system. This subset includes:
- Forest growth and harvesting and product manufacturing in the
US Pacific Northwest and Southeast. These two regions are the
predominant suppliers of domestically manufactured wood building
materials.
- Wood products and assemblies needed to create the closed-in
building envelopes that meet the requirements of prevailing building
codes in a warm climate (Atlanta, GA) and a cold climate (Minneapolis,
MN).
Methods developed for these selected regions and codes will be refined
and adapted to other regions in future work. Future research will
also entail extending the analysis to interior finishing and nonstructural
exterior work.
2.4.3 Inventory Analysis and Data Collection
Many types of data can be acquired to estimate production and environmental
performance measures for each process, all of which have been used
to some degree by other life-cycle researchers. However, it is important
to distinguish between primary and secondary data. Primary data are
those collected using recognized inventory data collection rules from
specific facilities or operations; such data is typically labeled
to indicate the date of collection and the estimated reliability of
the data. Secondary data are those obtained from secondary sources
such as simulation studies, or published articles containing industry
or region-wide, or company specific information. The various areas
of study within CORRIM are discussed in the following paragraphs,
with commentary regarding the type of data collected.
2.4.3.1 Forest Growth and Harvesting
Production of output from a forest ecosystem involves activities associated
with establishment and growth of trees and other vegetation, the removal
of wood biomass used as input into product manufacturing processes,
and associated impacts on non-wood forest CO-products including water,
habitat, diversity, and aesthetics. These impacts change through time
due to basic tree and plant physiology and competitive stand dynamics,
past and prospective technologies, evolving silvicultural practices,
and population demands for forest outputs. Time is a critical element
since the period from establishment to removal can vary from a few
years for short rotation, intensive culture fiber/energy plantations
to a century or more for selectively managed forests. Life-cycle inputs
and outputs include both quantitative measures of productivity, costs,
and environmental effects and qualitative measures that describe difficult
to measure aspects of the forest environment.
Consideration of impacts to a forest requires a landscape approach
since management levels of varying intensity, including no management,
are applied differentially to sites of different productive capability
and age classes that are often adjacent to one another. The blend
of management intensities and age classes within a landscape is important
in developing a balanced perspective on quantitative and qualitative
outputs and effects. The approach taken by CORRIM with respect to
forest growth and harvesting is to construct scenarios describing
conditions associated with the growth, removal and establishment of
forests for each region (Pacific Northwest, and Southeast) and to
use forest simulation models to estimate the effect of site productivity
and management intensity on the following two categories of measures.
Quantities of products (sawlog, veneer log, pulp log), costs, resources
consumed (energy, fertilizer, etc.), and associated emissions factors
that are passed to the Product Manufacturing stage.
- Measures of effects on diversity and habitat, stream quality,
etc. that are unique to the forest resource stage and provide
indications of the impact of the forest activity.
- All of the input and output data compiled by CORRIM Phase I
research on forest growing and harvesting activities are based
on regional forest growth and yield models and recent studies
of harvesting systems reported in the literature. No direct field
studies were commissioned by CORRIM.
2.4.3.2 Product Manufacturing &
Unit Processes
An objective of Phase I is to treat each major step of each manufacturing
process as a separate unit ("unit process") for data collection.
For example, a sawmill can be viewed as consisting of the following
processing centers (or unit processes): log yard, debarking and
bucking, primary breakdown of logs into trimmed, green lumber; kiln
drying, planer mill, and grading and packaging. This level of detail
allows for recognition of various product grades and joint products
from each center that may be sold to other industries without further
processing. It also recognizes alternative pathways of primary material
through the mill (green lumber to grading & packaging versus
green lumber to kiln drying). By performing data collection at the
unit process level, many potential issues with respect to co-product
allocation can be resolved and differences among various technological
configurations for a unit process can be examined. Data for individual
unit processes and facilities will vary by plant age and type, and
factors such as transportation distances will also vary by region.
Sampling individual facilities and unit processes provides a sense
of the variation in the industry and permits summarization that
provides the range, median, mode and upper/lower quartiles. This
permits analyses that can focus on the sensitivity of outcomes to
advances in adoption of technology such as indicated by the rhetorical
question: "What happens as the industry gradually improves
so the average moves up to the current upper quartile?"
CORRIM Phase I involved gathering of current data through questionnaires
sent to selected individual manufacturers. Table 2.2 lists wood
products and assemblies for which CORRIM data has been collected
from manufacturers during Phase I.

Table 2.2: Wood Products for Which Unit
Process Data has been Collected by CORRIM
| Softwood lumber, kiln dried (US Southeast, US Pacific Northwest) |
| Softwood lumber, green (US Southeast, US Pacific Northwest) |
| Softwood plywood (US Southeast, US Pacific Northwest) |
| Oriented strandboard (US Southeast) |
| Glue laminated beams |
| Laminated veneer lumber |
| Parallel strand lumber |
| Wood "I" joists & beams |
Construction of buildings also involves consumption of non-wood
materials such as concrete for foundations and steel for nails and
fasteners, etc. Life-cycle data for these materials and products
were taken from previous life-cycle studies compiled or conducted
by the Athena Sustainable Materials Institute. Table 2.3 lists products
for which CORRIM is using data from previously published LCAs during
Phase I.
Table 2.3: Products Considered
in CORRIM Using Data from Studies
Conducted by the Athena Sustainable Materials
Institute
|
Material
|
Product Considered
|
|
Concrete
|
- 10, 15, and 20 MPa ready mix
- Precast double T beams
- Precast hollow deck
- Standard concrete blocks
- Cement mortar
|
|
Steel
|
- Painted trusses (bar joists)
- Galvanized studs
- Galvanized decking
- Composite steel/wood joist components
- Reinforcement bar
- Painted hollow structural steel
- Painted tubing
- Painted heavy sections
- Painted light sections
- Hot & cold rolled sheet
- Welded wire mesh & ladder wire
- Nails and Fasteners
|
2.4.3.3 Building Construction
Construction of a building involves a fundamental shift from individual
products to the combination of these into building assemblies (wall,
floor, and roof systems) using spans, loads, and other variables
that comply with building codes. The activities associated with
construction include those involved in producing building materials,
as well as new life-cycle steps and impacts tied to construction
activity in which materials and energy are consumed, and solid wastes
and emissions are produced. Some effects are simply the aggregate
of the various materials used in the construction assemblies while
others are unique to the construction activities and are not attributable
to an individual component product. To integrate various combinations
of products into functionally equivalent assemblies and competed
structures, CORRIM used the Environmental Design Model of ATHENA
(1997) which contains more than 50 different assemblies incorporating
combinations of concrete, steel, and wood products. Working with
ATHENA researchers, CORRIM developed additional structural
designs based on residential building codes in Minneapolis, MN and
Atlanta, GA to represent cold and warm climate conditions, respectively.
2.4.3.4 Building Use and Maintenance
Unlike siding, roofing and other assemblies required to fully complete
the exterior of a building, the structural materials and assemblies
generally require little direct maintenance during the operational
life of a building. Consequently, maintenance requirements are not
considered in CORRIM Phase I. Maintenance will be analyzed in detail
in later research in the context of a fully completed and occupied
building.
Energy consumption during the operational life of the building will
be estimated based on the average home in each city hence providing
perspective on the relative importance of this stage on overall
life-cycle energy consumption and emissions. Further research on
energy consumption during the operational life of buildings will
be conducted in the future.
2.4.3.5 Building Demolition and Material
Recycling or Disposal
Recycling and waste management focus on the individual materials
for which recycling and waste management opportunities differ greatly.
Energy and emissions are involved in demolition/deconstruction,
separation and transport of the materials, and in recycling and
waste management processes. Since a building may not be demolished
for many years after construction, accurate depiction of this stage
would require forecasting technologies and markets for recycling
and waste management far into the future. Since these conditions
are unknown, CORRIM assumes that current practices are applicable.
Furthermore, research suggests that demolition, recycling, and disposal
differences between alternative designs are small (FORINTEK &
Wayne B. Trusty 1997). Therefore, comparisons between design alternatives
will be reasonably accurate in the absence of good data for this
stage. However, when absolute effects of individual designs are
required, better data for this stage will be necessary, a topic
for future research.

2.4.4 Impact Assessment
Impact assessment of LCA is presently at a rudimentary stage since
the environmental and human health consequences of emissions are difficult
to quantify in that they depend on temporal and geographical dispersion,
level and rate of exposure, and other factors. Furthermore, comparing
these consequences involve value judgments that are often contentious.
Some aspects of the CORRIM inventory analysis may be simultaneously
viewed as impact assessment. For example, quantities of concrete,
steel, and wood consumed relate to resource depletion. At this point
CORRIM research is not explicitly focused on impact assessment beyond
inferences associated with energy, water and materials consumption
and the use of widely accepted environmental equivalence measures
for some categories of emissions (e.g. expressing various greenhouse
gases in CO2 equivalents or global warming potential).
2.5 IMPROVEMENT ANALYSIS AND SCENARIOS
Improvement analysis refers to using LCA results to suggest opportunities
for environmental improvement or to evaluate proposed changes to
|