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Carbon Implications of Construction Materials

Selection

Jim Bowyer Dovetail Partners, Inc.

Minneapolis, MN

“The Wood Products Council” is a Registered Provider with The American Institute of Architects Continuing Education Systems (AIA/CES). Credit(s) earned on completion of this program will be reported to AIA/CES for AIA members. Certificates of Completion for both AIA members and non-AIA members are available upon request. This program is registered with 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.

This presentation is protected by US and International Copyright

laws. Reproduction, distribution, display and use of the

presentation without written permission of the speaker is

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© The Wood Products Council 2012

Copyright Materials

Learning Objectives • To understand what research reveals about carbon

emissions linked to various design choices.

• To recognize the need for informed determination and interpretation of carbon emissions values .

• To gain an understanding of research underlying the WoodWorks Carbon Calculator, and application of this tool to evaluation of specific projects.

• To gain a basic understanding of the carbon dynamics of forests, and how forest management and periodic harvesting impact the carbon cycle.

Tracking Carbon

TRACKING CARBON - What to analyze (individual component, wall section, entire structure) - Bill of materials. - Track life cycle environmental impacts of every component. ● Raw material inputs ● Energy consumption ● Emissions ● Effluents ● Solid wastes ● By-products

In determining environmental impacts, consider: ● Raw material extraction ● Transportation ● All steps in manufacturing

If the “product” is a component assembled on-site or an entire structure, also assess:

● Transport of mat’ls to const. site ● Building construction ● Operation (heating/cooling) ● Maintenance ● End-of-building-life

OTHER RELEASES

PRODUCTS

COPRODUCTS

EMISSIONS

EFFLUENTS

SOLID WASTES

RECOVERED STEEL

OTHER MATERIALS

ENERGY

Mining

Crushing/Separation (Transportation)

Refining (Transportation)

Smelting

Forming (Transportation)

Steel Products Mfg

(Transportation)

WATER

(Transportation)

Building Construction

Use/Maintenance

(Transportation)

Recycling/Waste Mgmt

● Raw material extraction ● Transportation ● Processing to final product ● Transport to building site ● Building construction ● Operation (heating/ cooling) ● Maintenance ● End-of-life

● Raw material inputs ● Energy consumption ● Emissions ● Effluents ● Solid wastes ● By-products

Tracking Carbon

● Raw material inputs ● Energy consumption ● Emissions ● Effluents ● Solid wastes ● By-products

Tracking Carbon

● Carbon Dioxide (CO2) ● Methane (CH4) ● Nitrous Oxide (N2O) ● HFCs ● CFCs ● Sulfur hexafluoride

Greenhouse Gases

The Heat Trapping Efficiency of Various Greenhouse Gases is Not Equal

Compound

Heat Trapping Efficiency Compared

to Carbon Dioxide Carbon dioxide (CO2) 1

Methane (CH4) 23X

Nitrous oxide (N2O) 296X

HFCs 120-12,000X

CFCs 5,700-11,900X

Sulfur hexafluoride 22,200X

Calculating CO2 Equivalency (CO2e)

CO2e

Compute a weighted average, multiplying the relative heat trapping potential of each gas by the emissions of that gas.

The result is a carbon dioxide equivalent value (CO2e).

A Few Notes About Carbon Tracking: Cannot be done casually. Follow international scientific protocols. Include all critical elements. When comparing products, compare functionally equivalent products. Use same scope of activity for all products.

1. Carbon accounting through a products life cycle should be done in compliance with ISO 14040, and involve independent third party

oversight and review.

Follow International Scientific Protocols

2. When comparing products using LCA, the scope of the life cycle considered is important.

All critical elements included

Same scope for all products compared

3. When comparing products, the comparison must be between functionally equivalent products.

Comparisons of Construction Alternatives

Wälludden Project, Växjo, Sweden

Department of Ecotechnology, Mid-Sweden University,

Östersund, Sweden (2000)


Four-story apartment buildings, each containing 16 apartments. Total usable floor area in each

building of 12,809 ft2.


Designed and built in wood. Life cycle analysis

(LCA) of environmental

impacts

LCA of identical building “built” of

concrete.


Material Wood Concrete Lumber 58 23 Particleboard 18 9 Plywood 21 0 Concrete 223 2014 Plasterboard 89 22

Materials Use in the Buildings (mt)

Wälludden Project, Växjo, Sweden Wood Concrete Difference

Energy Consumption in Building Materials Production Total energy consumed in producing construction materials (GJ)

2330 2972 -22%

CO2 Emissions (mt CO2e) Fossil fuel use in mat’l production 51.3 67.7 -24% Emission from cement reactions 1/ 4.0 21.0 -81%

1/ It was assumed that 8% of CO2 emissions from calcination reactions would be reabsorbed by the concrete over a 100-year building life.

Wälludden Project, Växjo, Sweden Wood Concrete Difference

Energy Consumption in Building Materials Production Total energy consumed in producing construction materials (GJ)

2330 2972 -22%

CO2 Emissions (mt CO2e) Fossil fuel use in mat’l production 51.3 67.7 -24% Emission from cement reactions 1/ 4.0 21.0 -81%

Long-Term Carbon Storage in Building Materials (mt) Carbon stock in building materials 40.3 28.2 +43% Avoided Carbon Emissions Due to Displacement of Fossil Fuels Includes biofuel use in building materials production and biofuel recovery at end of life. 101.2 66.0 +53%

1/ It was assumed that 8% of CO2 emissions from calcination reactions would be reabsorbed by the concrete over a 100-year building life.

• The average greenhouse gas (GHG) mitigation over a 100-year perspective is 2 to 3 times better for the wood building than the concrete building. It is also better over 50-year and 300-year building life cycles.

• The use of wood building materials in place of concrete, coupled with the greater integration of wood by-products into energy production would be an effective means of reducing fossil fuel use and net CO2 emissions to the atmosphere.

Key Findings:

Växjo Wooden City

Part of an effort initiated in 1996 to become a fossil fuel free city and the “greenest city in Europe.” Results from the Wälludden Project were the basis for focus on wood

construction.

Energy Consumption and CO2 Emissions in Constructing a Large

Office Building

Athena Sustainable Materials Institute Ottawa, Canada

(1992)

Energy Consumption and CO2 Emissions in Constructing a Large Office Building

Wood Steel Concrete

Life cycle comparison of three designs.

Construction

Total Energy Use*

Above Grade Energy Use*

CO2 Emissions**

Wood 3.80 2.15 73

Steel 7.35 5.20 105 Concrete 5.50 3.70 132

* GJ x 103

** kg x 103

Analysis of a Large Office Building

CaCo3 CaO + CO2

• Wood building on concrete foundation had embodied energy only 67% of that of concrete and 53% of that of the steel building.

• Wood building had above grade embodied energy only 59% that of concrete and 42% that of steel building.

• Carbon emissions associated with wood structure only 60% and 70% of those of concrete and steel structure respectively.

Key Findings:

FP Innovations Laboratory, Vancouver, B.C.

Energy Consumption and CO2 Emissions in Constructing the Roof of Oslo International Airport Terminal

Agricultural University of Norway Oslo, Norway

(2002)

Energy Consumption and CO2 Emissions in Constructing the Roof of Oslo International Airport Terminal

Compared energy consumption and GHG emissions associated with two options for

construction of the roof structure: steel beams and glue-laminated spruce wood beams.

• Manufacturing steel beams uses 2 to 3 times more energy and 6 to 12 times more fossil fuels than manufacturing glulam beams.

• If virgin, rather than recycled, steel is used, the differences as indicated above become substantially greater.

• In the most likely scenario, steel beam manufacture results in 5 times greater GHG emissions than does the manufacture of glulam beams.

Key Findings:

Energy Consumption and CO2 Emissions in Constructing the Roof of Raleigh-

Durham Airport Terminal

Athena Sustainable Materials Institute (2011)

Energy Consumption and CO2 Emissions in Constructing the Roof of Raleigh-

Durham Airport Terminal

LCA showed that use of wood rather than traditional materials for this application resulted in:

energy savings of 5,600 MWh

GWP savings of 1,000 t CO2e

Energy Consumption in Construction of Warehouses Made

of Wood, Steel, and Concrete

Federal Research Centre for Forestry and Forest Products

Hamburg, Germany (2003)

Energy Consumption and GWP Associated with Construction of Alternative Warehouse Designs

Wood Steel Concrete

Energy (incl. operational energy) - GJ 5,330 6,580 8,000

GWP (mt CO2e) 1,030* 1,320 1,600

* If wood is recovered for energy generation at the end of building life, the GWP for the wood design drops to 829 mt.

• In a series of life cycle assessments of buildings and building components made of wood and non-wood materials, production of wood alternatives consistently used less energy and emitted less GHG than non-wood materials.

Key Finding:

LCA of Mid-Rise Office Building Construction Alternatives:

Laminated Timber vs. Reinforced Concrete

Canadian Wood Council/ University of British Columbia (2012)


Discovery Place – Building 12 Burnaby, B.C.

A 153,000 ft2 office building, constructed in 2009. Five story Three levels of underground parking Cast-in place reinforced concrete structural frame


Reinforced Concrete Glulam/CLT

LCA of structural system and enclosure of existing

building.

LCA of functionally equivalent structural system and building

envelope.


Glulam/CLT

LCA of functionally equivalent structural system and building envelope using a combination of glulam and cross laminated

timber (CLT) for the vertical and horizontal force resisting systems, in conjunction with reinforced concrete shear core.

Cross-Laminated Timber

Material Group

Unit of Measurement

Concrete Design

Timber Design

Foundation

Footings m3 of concrete 1,408 1,408

Slab-on-grade m3 of concrete 416 416

Foundation walls m3 of concrete 834 834

Below-grade columns m3 of concrete 151 151

P2, P-1, and ground floor slabs m3 of concrete 3,253 3,253

Superstructure

Primary shear walls and cores m3 of concrete 1,293 1,293

Vertical load-bearing walls m3 of concrete/CLT 181 128

Above-grade floors & roof m3 of concrete/CLT 3,628 2,950

Above-grade columns m3 of concrete/glulam 268 122

Beams & roof parapet m3 of concrete/glulam 166 947

Wood sealer m2 -- 1,586

Unit of Concrete

Design Details

Material Group

Unit of Measurement

Concrete Design

Timber Design

Building Enclosure

Curtain wall m2 2,415 2,415

Cedar siding m2 of 13 mm thickness -- 13,374

ccSPF insulation m3 2,134 --

R-13 insulation m3 258 115

Steel stud framing m2 @ 406 mm O/C 1,617 --

Wood stud framing m2 @ 406 mm O/C -- 1,617

Gypsum wall board m2 of 13 mm thickness 1,929 1,929

Design Details

Environmental Impact Comparisons

0 20 40 60 80 100 120

Fossil fuel depletion

Acidification

Smog

Ecological toxicity

Eutrophication

Water intake

Criteria air pollutants

Human health effects

Ozone depletion

Global warming potential

Laminated Timber/CLT Reinforced Concrete

Library Square, Kamloops, B.C.

FP Innovations (2012)

Library Square, Kamloops, BC

Library Square, Kamloops, BC Six story structure (Five stories of wood over podium slab). Combined residential/commercial. • 140 condo units • 14,000 ft2 street level commercial • 20,000 ft2 library • Underground parking

Volume of wood used 2,927 m3 Carbon sequestered and stored (CO2e)

2,124 metric tons

Avoided greenhouse gases (CO2e)

4,520 metric tons

Total potential carbon benefit (CO2e)

6,645 metric tons


Carbon savings from the choice of wood in this one project are equivalent to: 1,269 passenger vehicles off the road for a year Enough energy to operate a home for 565 years


An observation regarding consistency of findings:

Vs.

A Cautionary Note

Should you find a study that reports markedly different results, check the details.

- Were international protocols followed? - All critical elements included? - Same scope of operations evaluated? - Functionally equivalent products compared?

Forest Carbon Dynamics

Source: ).

The Global Carbon Cycle

Sequestered Carbon • Fossil Fuels

– Petroleum – Coal – Natural gas

• Limestone (CaCo3) • Forests

– Trees – Litter – Forest soils

• Other plants – Shrubs, grass, ag. crops – Algae

Sequestered millions of years ago

Sequestered, released, and

re-sequestered as part of

ongoing carbon cycle.

stereSeques

Fossil Carbon

s Biogenic Carbon

Growing trees capture carbon dioxide from the air and release

oxygen.

CO2 O2

Carbon

Species Ash C H O N

% % % % %

Douglas Fir 0.80 52.30 6.30 40.50 0.10

Hickory 0.73 47.67 6.49 43.11 0.00

Maple 1.35 50.64 6.02 41.74 0.25

Ponderosa Pine 0.29 49.25 5.99 44.36 0.06

Western Hemlock 2.20 50.40 5.80 41.10 0.10

Yellow Pine 1.31 52.60 7.00 40.10 0.00

White Fir 0.25 49.00 5.98 44.75 0.05

White Oak 1.52 49.48 5.38 43.13 0.35

BARK

Douglas Fir bark 1.20 56.20 5.90 36.70 0.00

Loblolly Pine bark 0.40 56.30 5.60 37.70 0.00

cies Ash C H O N

Proximate Analysis of Wood

Source: Biomass Energy Foundation (2009) (http://www.woodgas.com/proximat.htm)

Trends in U.S. Forestland Area 1630-2009

1045

759 732 760 756 762 755 744 739 737 747 751

0

200

400

600

800

1000

1200

1630 1907 1920 1938 1953 1963 1970 1977 1987 1992 1997 2009

Mill

ion

Acr

es

Source: USDA – Forest Service, 2009.

U.S. Timber Growth and Removals, 1920 - 2006

Billions of cubic feet/ year

0

5

10

15

20

25

30

1920 1933 1952 1976 1986 1996 2006

Net GrowthRemovals

Source: USDA - Forest Service, 2009.

Standing Timber Inventory – U.S. 1952-2007

0100200300400500600700800900

1000

1952 1962 1970 1976 1986 1991 1997 2002 2007

Hardwoods Softwoods

Bill

ion

Cub

ic F

eet

Source: USDA-Forest Service, 2009.

Carbon in Above-Ground Portion of Standing Trees, U.S. 1990-2009

11

11.5

12

12.5

13

13.5

14

14.5

15

1990 1995 2000 2005 2010

Aboveground Biomass

Bill

ion

Tons

Car

bon

Source: USEPA (2012). Inventory of US Greenhouse Gas Emissions and Sinks, 1990-2011, p. 7-15.

Forest Soil Carbon Inventory, U.S. 1990-2010

0

10

20

30

40

50

1990 1995 2000 2005 2010

Soil Organic C LitterDead Wood Belowground BiomassAboveground Biomass

Bill

ion

Tons

Car

bon


Forest Management

Slowing of Tree Growth with Increasing Age

Source: Brack, C. (1997) Australian National University).

100 – 150 yr

Carbon Storage in a Sustainably Managed Forest at Stand Level

Source: Adapted from Colnes (2011).

Carbon Storage in a Sustainably Managed Forest at Stand and Parcel Levels

Source: Adapted from Colnes (2011)

Carbon Storage in a Sustainably Managed Forest at the Landscape Level

Source: Adapted from Colnes (2011)

Carbon Storage in a Sustainably Managed Forest at Stand Level

Source: Adapted from Colnes (2011).

Clearcutting in lodgepole pine - Montana.

Similar area, two years following harvest.

Similar area ten years following harvest. All natural regeneration.

Harvesting Cycles of Lodgepole Pine in Nature

An example from Yellowstone National Park

Yellowstone 1988

Eleven years later..

Harvesting and Manufacturing

To the mill

Left on-site

Uses of Material Processed at Milling Sites

Source: Bowyer (2012). Data for United States, 2005.

52% processed into lumber. 36% converted to paper, particleboard, fiberboard, insulation board. 11-12% used to generate energy. ≤1% waste.

A substantial portion of this wood goes into long-term

use, such as building construction.

Carbon in Wood Products in Use, U.S. 1990-2010

1.1

1.15

1.2

1.25

1.3

1.35

1.4

1.45

1.5

1990 1995 2000 2005 2010

Bill

ion

Tons

Car

bon


Replacing Forest Carbon Transferred to

Wood Structures

Library Square, Kamloops, BC (2,927m3 of wood)

Time period needed for North American forests to replace the

volume of wood used in this structure at current net growth rates:

9 minutes

Summary • Carbon accounting is increasingly of interest to society.

• Accurate tracking of carbon requires rigorous assessment through the life-cycle of products.

• Systematic assessment consistently shows that production and use of wood products results in lower energy consumption and CO2 emissions than functionally equivalent non-wood products.

• Forests are renewable, and in U.S. and North American forests net annual growth far exceeds removals.

Summary • In the managed forests of North America, carbon stores are steadily increasing at the same time that carbon stores in wood structures are increasing as well.

In addition to carbon storage in wood structures, every time wood is used instead of more energy intensive alternatives, substantial carbon emissions are avoided.

This concludes The American Institute of Architects Continuing

Education Systems Course

Wood Products Council 866.966.3448 [email protected] Dovetail Partners 612.333.0430 www.dovetailinc.org

Questions?

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