Chapter 11:
Environmental Impacts
Lecture 2: Life Cycle Analysis
of Bio-based Composites
Learning Objectives
• Introduce life cycle assessment
• Provide some life cycle data for bio-based
building materials
– Compare with steel & concrete
– Compare composites vs. solid
• Put building materials in whole-house context
What is LCA?
• Life Cycle Analysis
– AKA
•
•
•
•
Cradle-to-grave
Cradle-to-gate
Cradle-to-cradle
Well-to-wheel
– The investigation and valuation of the
environmental impacts of a given product over its
lifecycle
A Life Cycle Illustration
Life Cycle Analysis
Goal and Scope
Definition
Inventory Analysis
Impact Assessment
Interpretation
CORRIM
• Consortium for Research on Renewable
Industrial Materials
• Conduct LCA for building materials
• All data in this presentation are from CORRIM
– www.corrim.org
Membership in CORRIM
Research Institutions and Voting Board Members
University of Washington
Oregon State University
University of Minnesota
University of Idaho
FORINTEK, Canada
Virginia Tech
North Carolina State University
Purdue University
University of Maine
Penn State University
State University of New York
APA, The Engineered Wood Association
Western Wood Products Association
Composite Panel Association Research Foundation
Washington State University
Louisiana State University
Mississippi State University
Motivation
This website claims that steel is ‘green’
because it doesn’t require cutting trees. Is it
that simple?
http://www.ussi.ca/residential_steel.html
• The environmental
consequences forest
management, product
manufacturing, and
construction are
poorly understood
• Need life-cycle data
regarding wood and
bio-based products
Life Cycle Inventory Analysis
- for Wood Building Materials
Forest Management
(Regeneration)
(Transportation)
Raw Material Acquisition
(Harvest)
MATERIALS
(Transportation)
EMISSIONS
EFFLUENTS
SOLID WASTES
Product Manufacturing
ENERGY
(Transportation)
OTHER RELEASES
Building Construction
WATER
(Transportation)
Use/Maintenance
PRODUCTS
(Transportation)
Recycle/Waste Management
(Transportation)
COPRODUCTS
System Boundaries
“Cradle”
Forest Resources: NW and SE (25-100+ years)
Harvesting ( < 1 Year)
logs
NW and SE
“Gate
to
Gate”
Processing ( < 1 Year)
lumber
SE and NW (green and dry)
plywood NW and SE
OSB
SE
Glulam, LVL, I-Joists
Construction
( < 1 Year)
wood and steel Minneapolis (cold)
wood and concrete Atlanta (warm)
“Grave”
Use and Maintenance
Disposal
(< 1 Year)
(40 – 100+ years)
An Example of Life-Cycle Inventory Results
1.0 MSF 3/8-in. Basis Plywood Production
Bio-based Products are Green
3,500
kg of CO 2 per 768 sq. ft.
• Bio-based
materials use less
energy
• Much less fossilfuel energy than
steel or
concrete
731
%
3,000
2,500
454
%
2,000
1,500
Steel
1,000
Concrete
500
Lumber
2%
Lumber
0
Wood I-joists
Wood Dimension Joists
Concrete Slab
Steel Joists
Floor Type
Floors: GWP per component
Bio-based Products use Biomass
Energy
Product Manufacturing Carbon Emissions
CO2: Kg/cubic meter wood eq
800
700
600
carbon neutral biofuel
500
400
300
200
fossil
emissions
100
0
NW KD Lumber
1
NW Plywood
2
SE 3
OSB
4
Concrete
5
floor area eq.
Composites vs. Solid?
Total Energy for Life Cycle Stages (MJ/m3) SE/PNW ave.
12000
10000
Total Energy (MJ/m3)
• More
manufacturing
energy
• More efficient in
other ways
• More carbon
storage
Harvest
More
resin
Some resin
feedstock
8000
6000
Mfg.
Transport
4000
2000
0
OSB
Plywood
LVL
Glulam
Lumber KD
Lumber GR
Composites are Efficient
1.6
1.4
1.2
kg per sq. ft.
• Solid wood uses
105% more fiber
• Composite I-joists
(EWP) are
engineered
• More efficient
use of fiber
1
0.8
0.6
0.4
0.2
0
EWP
Dimension wood
Joist Type
Bio-based Products Store Carbon
Net Product Life Carbon Emissions
800
600
CO2: Kg/cubic meter wood eq.
• Many wood-based
materials store
more carbon than
is released during
their production
• Composites store
more carbon
• Denser and
contain resin
400
200
0
-200
OSB
KD
Lumber
no
product
carbon to
store
Plywood
Concrete
floor area eq.
-400
-600
-800
-1000
includes carbon
stored in product
New Scope - LCI of Whole Houses
• Compare houses
framed with wood
versus
concrete/steel
• Houses are
identical
otherwise
• Puts difference
among materials in
proper context
Minneapolis Example – Wood vs. Steel
Full Basement 2062 sq.ft. 2 Story
Characteristic
Wood Design
Steel Design
1st and 2nd Floors
Engineered wood “I” –joists @ 16”
(400mm) o/c & 19/32” (15mm)
plywood decking
Steel 18 ga. “C” joist @ 12”
(300mm) o/c & 19/32” (15mm)
plywood decking
Above grade exterior walls
2” x 6” wood studs @ 16”
(400mm) o/c, #15 organic
felt, OSB sheathing, R19
fiberglass batt insulation,
6mil polyethylene vapor
barrier, 12mm gypsum
board, vinyl siding
1.5” x 3.63” Steel 20 ga. “C” studs
@ 16” (400mm) o/c, #15
organic felt, OSB sheathing,
R13 fiberglass batt insulation,
1.5” EPS insulation, 6mil
polyethylene vapor barrier,
12mm gypsum board, vinyl
siding
Below grade exterior walls
2”x4” wood studs @ 24” (600mm)
o/c, R13 fiberglass batt
insulation, poly vapor barrier,
12mm gypsum board
1.5” x 3.63” Steel 25 ga. “C” studs @
24” (600mm) o/c, R13 fiberglass
batt insulation, poly vapor barrier,
12mm gypsum board
Partition walls
2”x4” wood studs @ 16” (400mm)
o/c, 12mm gypsum board two
sides
1.5” x 3.63” Steel 25 ga. “C” studs
@ 16” (400mm) o/c, 12mm
gypsum board two sides
Atlanta Example: Wood vs. Concrete
2153 sq.ft. 1 story On-Slab
Characteristic
Single-family dwelling type
Floor area
Wood Design
Concrete Design
1 story bungalow slab-on-grade
2153 sq. ft. (200 sq.m)
Structure & Envelope
Foundation (footing and slab)
3000psi (20 Mpa) concrete
Foundation walls
Main floor
Exterior walls
Window system
Partition walls
Roof
None
100mm reinforced Slab-on-grade on footings
2”x4” wood studs @ 16” (400mm) o/c,
#15 organic felt, OSB sheathing,
R13 fiberglass batt insulation, 6mil
poly vapor barrier, 12mm gypsum
board, vinyl siding
Concrete Block furred out with 2x4 wood
studs 24”(600mm) o/c, R13 fiberglass
batt insulation, 6mil poly vapor
barrier, 12mm gypsum board, two-coat
stucco finish
PVC frame, operable, double glazed Low “E” Argon filled
2”x4” wood studs @ 16” (400mm) o/c,12mm gypsum board two-sides
Light Frame Wood Trusses with OSB sheathing, R30 blown cellulose insulation, 6mil
poly vapor barrier, 16mm gypsum board with 25 yr durability asphalt shingles over
#15 organic felt building paper.
Summary - Minneapolis Building
Other Design
vs. Wood
Difference (% Change)
Minneapolis design
Wood
Steel
Embodied Energy (GJ)
651
764
113
17%
Global Warming Potential
(CO2 kg)
37,047
46,826
9,779
26%
Air Emission Index
(index scale)
8,566
9,729
1,163
14%
Water Emission Index
(index scale)
17
70
53
312%
Solid Waste
(total kg)
13,766
13,641
-125
-1%
Summary - Atlanta Building
Concrete Difference
Other Design
vs. Wood
(% Change)
Atlanta design
Wood
Embodied Energy ( GJ)
398
461
63
16%
Global Warming Potential
(CO2 kg)
21,367
28,004
6,637
31%
Air Emission Index
(index scale)
4,893
6,007
1,114
23%
Water Emission Index
(index scale)
7
7
0
0%
Solid Waste
(total kg)
7,442
11,269
3,827
51%
Other Studies – Same Results
• 1992 New Zealand study
– Wood office blg 55% of energy/70% carbon versus
concrete
– Steel wall 4x energy of wood wall
• 1992, 1993 Cdn studies
– Wood 1/3 energy and CO2 versus steel and
concrete
• Wood consistently lower emissions and less
energy
Interpretation:
ENVIRONMENTAL IMPROVEMENT
OPPORTUNITIES
• Redesign the house
– use less fossil-intensive products (bio-based is good!)
– reduce energy use (both active and passive)
– improve durability to increase useful life
• Improve the product
–
–
–
–
–
greater use of biofuel
engineered products for greater raw materials efficiency
increase process efficiencies, especially in drying
pollution control improvements
increase product durability
• Reduce, reuse, and recycle demolition wastes
Review Questions
• Diagram the life cycle of a bio-based
composite
• Name an environment-related advantage
and disadvantage of that product
• How could the environmental impact of that
product be reduced?
The details:
Corrim: WWW.CORRIM.ORG
Athena: WWW.athenaSMI.ca
LMS: http://LMS.cfr.washington.edu
USLCI database: www.nrel.gov/lci