Environmental Impacts of Structural Systems: What Life Cycle Assessment Reveals

Environmental Impacts of Structural Systems: What Life Cycle Assessment Reveals Jim Bowyer Professor Emeritus Dept. of Bioproducts and Biosystems Engineering, University of Minnesota

Environmental Impacts of Structural Systems: What Life Cycle Assessment Reveals Misperceptions about wood/alternative materials The nature of systematic evaluation using life cycle assessment and its increasing use in green building programs and model codes Elements needed for valid life cycle comparisons Limitations to relying on intuition to gauge relative environmental impacts Outcomes of multiple life cycle comparisons of various construction alternatives Carbon emissions Wood durability

Misperceptions About Wood/ Alternative Materials

Life Cycle Assessment

Determining the Environmental Impact of Products Brainstorming, intuition

Determining the Environmental Impact of Products

Determining the Environmental Impact of Products Brainstorming, intuition Systematic analysis environmental accounting Life Cycle Assessment

Determining the Environmental Impact of Products

Reducing the Environmental Impact of Products

Life Cycle Inventory (LCI) Examination of all measurable: Raw material inputs Products and by-products Emissions Effluents Wastes

Life Cycle Inventory (LCI) Typically involves all stages in production, use, and disposal, including: Extraction Transportation Primary processing Conversion to semi-finished products Incorporation into finished products Maintenance Disposal/reuse

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

- Analyze individual components, wall sections, entire structure. - Full bill of materials. - Track life cycle environmental impacts of every component. Raw material inputs Energy consumption Emissions Effluents Solid wastes By-products

Inventory Acetaldehyde Acetone Acrolein Benzene Carbon dioxide (fossil) Carbon dioxide (non-fossil) Carbon monoxide Methane SO 2, SO 3 NO x VOCs Organic substances Arsenic Cyanide Phenols Sulfides Ammonia Oil and grease Particulates Suspended solids Non-ferrous metals Dust (PM10) And hundreds to thousands of other compounds.

Life-Cycle Inventory results for 1.0 MSF 3/8-in. basis plywood production from the PNW region. Results include plywood production only; no emissions are included for the production and use of electricity, fuel, and phenol-formaldehyde resin. INPUTS OUTPUTS Materials Units Per MSF Materials Units Per MSF 3/8-in. basis 3/8-in. basis Wood/resin Bark Roundwood (log) ft. 3 6.56E+01 Bark waste lb. 1.31E+01 lb. 1.89E+03 Bark ash lb. 7.75E+00 Phenol-formaldehyde lb. 1.59E+01 Total lb. 2.09E+01 Extender and fillers a Products lb. 8.90E+00 Plywood lb. 9.91E+02 Catalyst a lb. 1.11E+00 Co-products lb. Wood chips lb. 4.25E+02 Soda ash a lb. 3.30E-01 Peeler core lb. 4.62E+01 Bark b lb. 1.98E+02 Green clippings lb. 3.10E+01 Veneer downfall lb. 3.44E+00 Dry veneer lb. 6.81E+00 Panel trim lb. 1.07E+02 Green veneer lb. 1.51E+01 Sawdust lb. 9.63E+00 Electrical energy Solid dry veneer lb. 6.68E+01 Total lb. 6.89E+02 Electricity kwh 1.39E+02 Air emissions Fuel for energy Acetaldehyde lb. 1.12E-02 Hog fuel (produced) b lb. 3.83E+02 Acetone lb. 4.80E-03 Acrolein lb. 4.95E-07 b Hog fuel (purchased) lb. 3.40E+01 Benzene lb. 4.77E-04 Wood waste lb. 5.00E-01 CO lb. 1.91E+00 CO Liquid propane gas gal. 3.59E-01 2 fossil lb. 2.78E+02 CO 2 non-fossil lb. 2.78E+02 Natural gas ft. 3 1.63E+02 Dust (PM10) lb. 2.08E-01 Diesel gal. 3.95E-01 Formaldehyde lb. 1.80E-02 Methanol lb. 1.28E-01 a These materials were excluded based on the 2% rule. NOx lb. 2.34E-01 b Bark and hogged fuel are wet weights whereas Organic substances lb. 2.20E-02 all other wood materials are ovendry weights; Particulates lb. 3.47E-01 bark weight is included in the hog fuel (produced) weight. Phenol lb. 8.27E-03 SO 2 lb. 7.74E-04 SOx lb. 1.01E-01 VOC lb. 6.26E-01

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

Inventory Impact Assessment

Impact Assessment Embodied energy (GJ) GWP (CO 2 kg) Air emission index Acidification potential Human toxicity Photochemical oxidation Ozone layer depletion Depletion of non-renewable resources Water consumption Eutrophication Solid waste (total kg)

If comparing two different products: They must be functionally equivalent. They must be evaluated: - in the same way and in accordance with international protocols. - using the same system boundaries. - including all significant aspects and emission factors.

Testing Your Intuitive Skills

Steel Design Columns hollow structural section steel, Beams wide flange steel; Intermediate floors open-web steel joists w/concrete topping; Exterior walls 2x4 steel studs 16 o.c., R-3.8 rigid insulation sheathing, stucco cladding, R-13 Batt insulation + PET membrane, gypsum board + latex paint; Roof open-web steel joists w/steel decking, R-20 rigid insulation + PET membrane, modified bitumen membrane, gypsum board + latex paint. Concrete Design Columns: concrete columns; Beams: concrete ; Intermediate floors pre-cast double-t truss with concrete topping; Exterior walls concrete block w continuous insulation and polyethylene membrane, stucco cladding; Roof pre-cast double-t concrete, R-20 continuous insulation + PET membrane, modified bitumen membrane, latex paint.

What LCA Reveals

IMPACTS BY BUILDING COMPONENT Fossil Fuel Cnsmpt (MJ) Weighted Resource Use (tonnes) GWP (tonnes CO 2 eq) Acidification (moles of H+ eq) HH Respiratory Effects (kg PM2.5 eq) Eutrophication (g N eq) Ozone Depletion (mg CFC- 11 eq) Smog (kg NOx eq)

CONCRETE VS. STEEL ENVIRONMENTAL IMPACT SUMMARY STEEL CONSTRUCTION Assembly Total area Fossil Fuel Consumpt. (MJ) Weighted Resource use (tonnes) GWP (tonnes CO 2 eq) Acidificatio n (moles of H+ eq) HH Respiratory Effects (kg PM2.5 eq) Eutrophica tion (g N eq) Ozone Depletion (mg CFC- 11 eq) Smog potential (g NOx eq) Foundations & Footings 20000 532,998 581 68 26,524 161 21,288 109 383 Columns and Beams 40000 1,400,670 123 56 24,486 114 99,964 0 144 Intermediate Floors 20000 1,428,947 590 101 35,813 266 51,300 71 336 Exterior Walls 12000 992,333 175 63 21,015 191 22,665 25 302 Windows 0 0 0 0 0 0 0 0 0 Interior Walls 0 0 0 0 0 0 0 0 0 Roof 20000 4,405,157 225 117 58,468 335 42,132 5 914 S 8,760,105 1,693 405 166,307 1,067 237,349 211 2,079 ENVIRONMENTAL IMPACT SUMMARY CONCRETE CONSTRUCTION Assembly Total area Fossil Fuel Consumpt. (MJ) Weighted Resource use (tonnes) GWP (tonnes CO 2 eq) Acidificatio n (moles of H+ eq) HH Respiratory Effects (kg PM2.5 eq) Eutrophica tion (g N eq) Ozone Depletion (mg CFC- 11 eq) Smog potential (g NOx eq) Foundations & Footings 20000 532,998 581 68 26,524 161 21,288 109 383 Columns and Beams 40000 2,273,849 1,053 167 67,127 388 162,579 198 735 Intermediate Floors 20000 1,081,422 851 117 47,221 347 37,693 183 701 Exterior Walls 12000 3,758,182 662 280 76,860 436 113,229 223 1,051 Windows 0 0 0 0 0 0 0 0 0 Interior Walls 0 0 0 0 0 0 0 0 0 Roof 20000 4,099,144 599 129 66,871 404 32,761 117 1,166 S 11,745,595 3,746 761 284,604 1,737 367,551 832 4,037

CONCRETE VS. STEEL ENVIRONMENTAL IMPACT SUMMARY STEEL CONSTRUCTION Assembly Total area Fossil Fuel Consumpt. (MJ) Weighted Resource use (tonnes) GWP (tonnes CO 2 eq) Acidificatio n (moles of H+ eq) HH Respiratory Effects (kg PM2.5 eq) Eutrophica tion (g N eq) Ozone Depletion (mg CFC- 11 eq) Smog potential (g NOx eq) Foundations & Footings 20000 532,998 581 68 26,524 161 21,288 109 383 Columns and Beams 40000 1,400,670 123 56 24,486 114 99,964 0 144 Intermediate Floors 20000 1,428,947 590 101 35,813 266 51,300 71 336 Exterior Walls 12000 992,333 175 63 21,015 191 22,665 25 302 Windows 0 0 0 0 0 0 0 0 0 Interior Walls 0 0 0 0 0 0 0 0 0 Roof 20000 4,405,157 225 117 58,468 335 42,132 5 914 S 8,760,105 1,693 405 166,307 1,067 237,349 211 2,079 ENVIRONMENTAL IMPACT SUMMARY CONCRETE CONSTRUCTION Assembly Total area Fossil Fuel Consumpt. (MJ) Weighted Resource use (tonnes) GWP (tonnes CO 2 eq) Acidificatio n (moles of H+ eq) HH Respiratory Effects (kg PM2.5 eq) Eutrophica tion (g N eq) Ozone Depletion (mg CFC- 11 eq) Smog potential (g NOx eq) Foundations & Footings 20000 532,998 581 68 26,524 161 21,288 109 383 Columns and Beams 40000 2,273,849 1,053 167 67,127 388 162,579 198 735 Intermediate Floors 20000 1,081,422 851 117 47,221 347 37,693 183 701 Exterior Walls 12000 3,758,182 662 280 76,860 436 113,229 223 1,051 Windows 0 0 0 0 0 0 0 0 0 1.3X 2.2X 1.9X 1.7X 1.6X 1.5X 3.9X 1.9X Interior Walls 0 0 0 0 0 0 0 0 0 Roof 20000 4,099,144 599 129 66,871 404 32,761 117 1,166 S 11,745,595 3,746 761 284,604 1,737 367,551 832 4,037

Steel Design Columns hollow structural section steel, Beams wide flange steel; Intermediate floors open-web steel joists w/concrete topping; Exterior walls 2x4 steel studs 16 o.c., R-3.8 rigid insulation sheathing, stucco cladding, R-13 Batt insulation + PET membrane, gypsum board + latex paint; Roof open-web steel joists w/steel decking, R-20 rigid insulation + PET membrane, modified bitumen membrane, gypsum board + latex paint. Wood Design Columns LVL; Beams LVL; Intermediate floors wood I-joists with plywood decking; Exterior walls 2x6 wood studs 16 o.c., R-19 cavity insulation + PET membrane, wood structural panel sheathing, stucco cladding, gypsum board + latex paint; Roof glulam joists w/ plank decking, R-20 continuous insulation + PET membrane, modified bitumen membrane, gypsum board + latex paint.

WOOD VS. STEEL ENVIRONMENTAL IMPACT SUMMARY STEEL CONSTRUCTION Assembly Total area Fossil Fuel Consumpt. (MJ) Weighted Resource use (tonnes) GWP (tonnes CO 2 eq) Acidificatio n (moles of H+ eq) HH Respiratory Effects (kg PM2.5 eq) Eutrophica tion (g N eq) Ozone Depletion (mg CFC- 11 eq) Smog potential (g NOx eq) Foundations & Footings 20000 532,998 581 68 26,524 161 21,288 109 383 Columns and Beams 40000 1,400,670 123 56 24,486 114 99,964 0 144 Intermediate Floors 20000 1,428,947 590 101 35,813 266 51,300 71 336 Exterior Walls 12000 992,333 175 63 21,015 191 22,665 25 302 Windows 0 0 0 0 0 0 0 0 0 Interior Walls 0 0 0 0 0 0 0 0 0 Roof 20000 4,405,157 225 117 58,468 335 42,132 5 914 S 8,760,105 1,693 405 166,307 1,067 237,349 211 2,079 ENVIRONMENTAL IMPACT SUMMARY WOOD CONSTRUCTION Assembly Total area Fossil Fuel Consumpt. (MJ) Weighted Resource use (tonnes) GWP (tonnes CO 2 eq) Acidificatio n (moles of H+ eq) HH Respiratory Effects (kg PM2.5 eq) Eutrophica tion (g N eq) Ozone Depletion (mg CFC- 11 eq) Smog potential (g NOx eq) Foundations & Footings 20000 532,998 581 68 26,524 161 21,288 109 383 Columns and Beams 40000 563,758 248 28 10,535 55 11,569 0 51 Intermediate Floors 20000 470,627 264 24 10,864 120 11,721 4 148 Exterior Walls 12000 718,674 225 44 17,331 198 12,630 26 193 Windows 0 0 0 0 0 0 0 0 0 Interior Walls 0 0 0 0 0 0 0 0 0 Roof 20000 3,954,455 333 89 52,331 308 20,874 5 925 S 6,240,512 1,651 251 117,585 842 78,082 144 1,701

WOOD VS. STEEL ENVIRONMENTAL IMPACT SUMMARY STEEL CONSTRUCTION Assembly Total area Fossil Fuel Consumpt. (MJ) Weighted Resource use (tonnes) GWP (tonnes CO 2 eq) Acidificatio n (moles of H+ eq) HH Respiratory Effects (kg PM2.5 eq) Eutrophica tion (g N eq) Ozone Depletion (mg CFC- 11 eq) Smog potential (g NOx eq) Foundations & Footings 20000 532,998 581 68 26,524 161 21,288 109 383 Columns and Beams 40000 1,400,670 123 56 24,486 114 99,964 0 144 Intermediate Floors 20000 1,428,947 590 101 35,813 266 51,300 71 336 Exterior Walls 12000 992,333 175 63 21,015 191 22,665 25 302 Windows 0 0 0 0 0 0 0 0 0 Interior Walls 0 0 0 0 0 0 0 0 0 Roof 20000 4,405,157 225 117 58,468 335 42,132 5 914 S 8,760,105 1,693 405 166,307 1,067 237,349 211 2,079 ENVIRONMENTAL IMPACT SUMMARY WOOD CONSTRUCTION 1.4X 1.02X 1.6X 1.4X 1.27X 3.0X 1.5 X 1.2X Assembly Total area Fossil Fuel Consumpt. (MJ) Weighted Resource use (tonnes) GWP (tonnes CO 2 eq) Acidificatio n (moles of H+ eq) HH Respiratory Effects (kg PM2.5 eq) Eutrophica tion (g N eq) Ozone Depletion (mg CFC- 11 eq) Smog potential (g NOx eq) Foundations & Footings 20000 532,998 581 68 26,524 161 21,288 109 383 Columns and Beams 40000 563,758 248 28 10,535 55 11,569 0 51 Intermediate Floors 20000 470,627 264 24 10,864 120 11,721 4 148 Exterior Walls 12000 718,674 225 44 17,331 198 12,630 26 193 Windows 0 0 0 0 0 0 0 0 0 Interior Walls 0 0 0 0 0 0 0 0 0 Roof 20000 3,954,455 333 89 52,331 308 20,874 5 925 S 6,240,512 1,651 251 117,585 842 78,082 144 1,701

WOOD VS. CONCRETE ENVIRONMENTAL IMPACT SUMMARY CONCRETE CONSTRUCTION Assembly Total area Fossil Fuel Consumpt. (MJ) Weighted Resource use (tonnes) GWP (tonnes CO 2 eq) Acidificatio n (moles of H+ eq) HH Respiratory Effects (kg PM2.5 eq) Eutrophica tion (g N eq) Ozone Depletion (mg CFC- 11 eq) Smog potential (g NOx eq) Foundations & Footings 20000 532,998 581 68 26,524 161 21,288 109 383 Columns and Beams 40000 2,273,849 1,053 167 67,127 388 162,579 198 735 Intermediate Floors 20000 1,081,422 851 117 47,221 347 37,693 183 701 Exterior Walls 12000 3,758,182 662 280 76,860 436 113,229 223 1,051 Windows 0 0 0 0 0 0 0 0 0 Interior Walls 0 0 0 0 0 0 0 0 0 Roof 20000 4,099,144 599 129 66,871 404 42,132 117 1,166 S 11,745,595 3,746 761 284,604 1,737 367,551 832 4,037 ENVIRONMENTAL IMPACT SUMMARY WOOD CONSTRUCTION Assembly Total area Fossil Fuel Consumpt. (MJ) Weighted Resource use (tonnes) GWP (tonnes CO 2 eq) Acidificatio n (moles of H+ eq) HH Respiratory Effects (kg PM2.5 eq) Eutrophica tion (g N eq) Ozone Depletion (mg CFC- 11 eq) Smog potential (g NOx eq) Foundations & Footings 20000 532,998 581 68 26,524 161 21,288 109 383 Columns and Beams 40000 563,758 248 28 10,535 55 11,569 0 51 Intermediate Floors 20000 470,627 264 24 10,864 120 11,721 4 148 Exterior Walls 12000 718,674 225 44 17,331 198 12,630 26 193 Windows 0 0 0 0 0 0 0 0 0 Interior Walls 0 0 0 0 0 0 0 0 0 Roof 20000 3,954,455 333 89 52,331 308 20,874 5 925 S 6,240,512 1,651 251 117,585 842 78,082 144 1,701

WOOD VS. CONCRETE ENVIRONMENTAL IMPACT SUMMARY CONCRETE CONSTRUCTION Assembly Total area Fossil Fuel Consumpt. (MJ) Weighted Resource use (tonnes) GWP (tonnes CO 2 eq) Acidificatio n (moles of H+ eq) HH Respiratory Effects (kg PM2.5 eq) Eutrophica tion (g N eq) Ozone Depletion (mg CFC- 11 eq) Smog potential (g NOx eq) Foundations & Footings 20000 532,998 581 68 26,524 161 21,288 109 383 Columns and Beams 40000 2,273,849 1,053 167 67,127 388 162,579 198 735 Intermediate Floors 20000 1,081,422 851 117 47,221 347 37,693 183 701 Exterior Walls 12000 3,758,182 662 280 76,860 436 113,229 223 1,051 Windows 0 0 0 0 0 0 0 0 0 Interior Walls 0 0 0 0 0 0 0 0 0 Roof 20000 4,099,144 599 129 66,871 404 42,132 117 1,166 S 11,745,595 3,746 761 284,604 1,737 367,551 832 4,037 ENVIRONMENTAL IMPACT SUMMARY WOOD CONSTRUCTION Assembly Total area 1.9X 2.3X 3.0X 2.4X 2.1X 4.7X 1.1X 2.4X Fossil Fuel Consumpt. (MJ) Weighted Resource use (tonnes) GWP (tonnes CO 2 eq) Acidificatio n (moles of H+ eq) HH Respiratory Effects (kg PM2.5 eq) Eutrophica tion (g N eq) Ozone Depletion (mg CFC- 11 eq) Smog potential (g NOx eq) Foundations & Footings 20000 532,998 581 68 26,524 161 21,288 109 383 Columns and Beams 40000 563,758 248 28 10,535 55 11,569 0 51 Intermediate Floors 20000 470,627 264 24 10,864 120 11,721 4 148 Exterior Walls 12000 718,674 225 44 17,331 198 12,630 26 193 Windows 0 0 0 0 0 0 0 0 0 Interior Walls 0 0 0 0 0 0 0 0 0 Roof 20000 3,954,455 333 89 52,331 308 20,874 5 925 S 6,240,512 1,651 251 117,585 842 78,082 144 1,701

Environmental Impacts of Structural Systems: What Life Cycle Assessment Reveals

Wälludden Project, Växjo, Sweden Department of Ecotechnology, Mid-Sweden University, Östersund, Sweden (2000)

Wälludden Project, Växjo, Sweden Four-story apartment buildings, each containing 16 apartments. Total usable floor area in each building of 12,809 ft 2.

Wälludden Project, Växjo, Sweden Designed and built in wood. Life cycle analysis (LCA) of environmental impacts LCA of identical building built of concrete.

Wälludden Project, Växjo, Sweden Materials Use in the Buildings (mt) Material Wood Concrete Lumber 58 23 Particleboard 18 9 Plywood 21 0 Concrete 223 2014 Plasterboard 89 22

Wälludden Project, Växjo, Sweden Wood Concrete Difference Energy Consumption in Building Materials Production Total energy consumed in producing construction materials (GJ) 2330 2972-22% CO 2 Emissions (mt CO 2 e) 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 CO 2 emissions from calcination reactions would be reabsorbed by the concrete over a 100-year building life.

Key Findings: 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 CO 2 emissions to the atmosphere.

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 CO 2 Emissions in Constructing a Large Office Building Athena Sustainable Materials Institute Ottawa, Canada (1992)

Energy Consumption and CO 2 Emissions in Constructing a Large Office Building Wood Steel Concrete Life cycle comparison of three designs.

Analysis of a Large Office Building Construction Total Energy Use* Above Grade Energy Use* CO 2 Emissions** Wood 3.80 2.15 73 Steel 7.35 5.20 105 Concrete 5.50 3.70 132 * GJ x 10 3 ** kg x 10 3 CaCo 3 CaO + CO 2

Key Findings: 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.

Energy Consumption and CO 2 Emissions in Constructing the Roof of Oslo International Airport Terminal Agricultural University of Norway Oslo, Norway (2002)

Energy Consumption and CO 2 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.

Key Findings: 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.

Copperfield Hills Apartments Robbinsdale, Minnesota

Copperfield Hill Apartments 165,000 ft. 2 5 stories over pre-cast concrete parking garage 4 wings around central atrium 157 apartments + kitchen, dining room, library, game room craft shop, arts center

Copperfield Hill Apartments Wood frame construction 44,500 ft. 3 of lumber and wood panels (1,260 m 3 )

Key Findings: An evaluation of the structure which examined carbon emissions from raw material extraction, conversion to building products, transport to the job site, and construction and comparison with functionally equivalent structure of steel/ concrete showed avoided emissions of 2,280 metric tons of CO 2 equivalent. In addition to avoided emissions, the wood from which the building is constructed contains 1,070 metric tons of CO 2 equivalent.

The Carbon Issue

Net land use change, including deforestation 1.1 PgC/yr Net land carbon flux, excluding land use changes but including growth of existing forests 4.3 PgC/yr 7.8 PgC/yr 1.6 PgC/yr 0.8 PgC/yr Basics The Carbon Cycle Emissions of CO 2 from fossil fuel combustion, with contributions from cement manufacture, are responsible for more than 75% of the increase in atmospheric CO 2 concentration since pre-industrial times. (IPCC Fourth Assessment Report) Atmosphere Vegetation 420-620 PgC Soils 1500-2400 PgC Fossil fuel combustion and Cement production Source: IPCC Fifth Assessment Report (2013) Line Widths proportional to amount of flow Ocean Surface Ocean 920 PgC Intermediate and Deep Ocean: 37000 Pg C Freshwater outgassing, Volcanism, and Rock weathering

Net land use change, including deforestation 1.1 PgC/yr Net land carbon flux, excluding land use changes but including growth of existing forests 4.3 PgC/yr 7.8 PgC/yr 1.6 PgC/yr 0.8 PgC/yr Basics The Carbon Cycle Emissions of CO 2 from fossil fuel combustion, with contributions from cement manufacture, are responsible for more than 75% of the increase in atmospheric CO 2 concentration since pre-industrial times. (IPCC Fourth Assessment Report) Atmosphere: 829 PgC, increasing by 4 PgC/yr. Vegetation 420-620 PgC Soils 1500-2400 PgC Fossil fuel combustion and Cement production Source: IPCC Fifth Assessment Report (2013) Line Widths proportional to amount of flow Ocean Surface Ocean 920 PgC Intermediate and Deep Ocean: 37000 Pg C Freshwater outgassing, Volcanism, and Rock weathering

Carbon and the Built Environment

Projected U.S. Building Sector Operations 2005-2030 2005 2010 2015 2020 2025 2030 Source: Architecture 2030. (2014). Roadmap to Zero Emissions.

Projected U.S. Building Sector Operations 2005-2030 -16.8 QBtu Equivalent to 620 500MW power plants 2005 2010 2015 2020 2025 2030 Source: Architecture 2030. (2014). Roadmap to Zero Emissions.

Projected U.S. Building Sector Operations 2005-2030 Applying Best Available Technology -16.8 QBtu Equivalent to 620 500MW power plants -6.9 Qbtu EIA AEO 2013 Best Available Technology 2005 2010 2015 2020 2025 2030 Equivalent to 256 500MW power plants Source: Architecture 2030. (2014). Roadmap to Zero Emissions.

Embodied Energy/Carbon The raw resource extraction, manufacturing, transportation, construction, usage, and end-oflife stages of building products consume significant amounts of energy, each generating associated GHG emissions. As buildings improve from an operational perspective, the embodied energy and emissions associated with building materials and construction will become more important. Source: Architecture 2030: 2030 Challenge for Products.

Embodied Energy and Carbon Emissions in the Life Cycle of a Building Extract Raw Materials End of Life Transport Operate Manuf. Building Materials Build Transp. to Site

Embodied Energy (Typical Residence) 2010 2015 2020 2025 2030 2035 2040 2045 2050 2055 2060 Source: Architecture 2030: 2030 Challenge for Products.

Durability of Wood Structures Butler Building, Minneapolis 500,000 ft 2, 8 stories, built 1906

Source: O Connor, J. (2004). Average Expected Service Life for Non- Residential Buildings A Survey of 683 Architects, Structural Engineers, Builders, and Developers in the U.S. and Canada Masonry Wood Concrete Steel 0 20 40 60 80 100 Expected Service Life (Years)

Percent of Buildings 0 10 20 30 40 50 Demolition of 227 Buildings in Minneapolis/St. Paul 2000-2003 Steel Concrete Wood 0-25 26-50 51-75 76-100 100+ Unknown Age Group in Years Source: O Connor, J. (2004).

Reasons for Demolition Fire Physical condition No longer fits needs Area redevelopment No longer fits needs Area redevelopment Phys. condition Fire damage Imp. to code too exp. Maint. too exp. Changing land value Soc. undesirable use Other Source: O Connor, J. (2004).

Percent of Each Building Type Demolished Because of Fire Damage 12 10 8 6 4 2 0 Concrete Steel Wood Concrete Steel Wood Source: O Connor, J. (2004).

Proportion of 105 Non-Residential Buildings by Primary Structural Material Concrete Steel Wood Aluminum Concrete/Wood Wood/Steel Concrete/Steel Source: O Connor, J. (2004).

Distribution of 105 Non-Residential Buildings by Age at Demolition 50 45 40 35 30 25 20 15 10 5 0 0-25 26-50 51-75 76-100 100+ Source: O Connor, J. (2004).

Distribution of 94 Non-Residential Buildings by Structural Material and Age at Demolition 70 60 50 40 30 20 Concrete Steel Wood 10 0 0-25 26-50 51-75 76-100 100+ Source: O Connor, J. (2004).

Key Findings: Despite a pervasive perception that the useful life of wood structures is lower than other buildings, no meaningful relationship exists between the type of structural material and average service life. Most buildings are demolished for reasons that have nothing to do with the physical state of the structural systems. Age at demolition is generally less than 50 years. (A study of office buildings in Japan found a typical life span of 23-41 years).

Summary Environmental impacts of materials and products cannot be accurately determined through intuition. Life cycle analysis (LCA) performed in accordance with international protocols does allow accurate determination of environmental impacts and product comparisons. Systematic assessment of various building types and components consistently shows that production and use of wood products results in lower environmental impacts than functionally equivalent non-wood products.

Summary There is no meaningful relationship between the type of structural material and building life.

Questions? This concludes The American Institute of Architects Continuing Education Systems Course Wood Products Council 866.966.3448 info@woodworks.org Dovetail Partners 612.333.0430 www.dovetailinc.org