Wood A Natural Choice - How the Building Material Contributes to Sustainable Design
•Download as PPTX, PDF•
10 likes•8,594 views
This presentation contributes to the discourse on sustainability that is driving ongoing improvement in the way buildings are designed and constructed. Specifically, it focuses on the growing trends of wood use as a low environmental-impact building material and the effect green building rating systems have on design choices.
Recommended
More Related Content
What's hot
What's hot (20)
Viewers also liked
Viewers also liked (20)
Similar to Wood A Natural Choice - How the Building Material Contributes to Sustainable Design
Similar to Wood A Natural Choice - How the Building Material Contributes to Sustainable Design (20)
More from Think Wood
More from Think Wood (6)
Recently uploaded
Recently uploaded (20)
Wood A Natural Choice - How the Building Material Contributes to Sustainable Design
- 1. A Natural Choice How Wood Contributes to Sustainability’s Triple Bottom Line (Part 3 of a 3-part series) Photo: naturallywood.com
- 2. Overview Materials Matter (Part 1) Materials in Action (Part 2) A Natural Choice (Part 3)
- 3. Copyright Materials This presentation is protected by U.S. and international copyright laws. Reproduction, distribution, display and use of the presentation without written permission of reThink Wood is prohibited. © 2013, reThink Wood, www.rethinkwood.com
- 4. Learning Objectives Describe accepted definitions of sustainability. Discuss ways in which wood contributes to sustainable design. Explain the trends behind the increased use of wood as an environmentally sound building material. Evaluate the impact of building rating systems and codes on environmentally sound design.
- 5. Table of Contents Section 1 True Sustainability Section 2 Wood and the Environment Section 3 Wood and Social Goals Section 4 Wood and Economic Considerations Section 5 Codes & Green Rating Systems
- 6. SECTION 1 TRUE SUSTAINABILITY
- 7. Sustainable Development “Development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” -- Brundtland Commission, 1987 United Nations
- 8. Sustainable Building Up 50% from 2008-2010, from $42 billion to $71 billion Accounted for 25% of new construction in 2010 Estimated to reach $135 billion by 2015 Green Outlook 2011: Green Trends Driving Growth McGraw-Hill Construction Blackfeet Community College Montana Architect: Gordon Whirry LEED Platinum Photo courtesy of Gordon Whirry
- 9. Elements of Sustainable Design Sitting and structural design Energy efficiency Materials efficiency Indoor air quality Operations and maintenance Waste reduction Photo: Jeremy Bitterman, courtesy EHDD David & Lucile Packard Foundation California Architect: EHDD LEED Gold and Net Zero Energy
- 10. SECTION 2 WOOD AND THE ENVIRONMENT
- 11. Wood and the Environment University of Washington West Campus Student Housing – Phase 1 Washington Architect: Mahlum Photo: naturallywood.com; Photo: Benjamin Benschneider
- 12. Life Cycle Assessment Allows comparison of alternate building designs based on their estimated environmental impacts Promotes informed decision-making
- 13. LCA Studies Wood is better for the environment in terms of air pollution, embodied energy, greenhouse gases and water pollution. Source: Data compiled by the Canadian Wood Council using the ATHENA EcoCalculator with a data set for Toronto, Canada
- 14. Comparing Wall Assemblies Source: CORRIM Minneapolis House Wood Frame Steel Frame Difference Steel vs. Wood (% change) Embodied energy (GJ) 250 296 46 18% Global warming potential (CO2 kg) 13,009 17,262 4,253 33% Air emission index (index scale) 3,820 4.222 402 11% Water emission index (index scale) 3 29 26 867% Solid waste (total kg) 3,496 3,181 -315 -9% Atlanta House Wood Frame Steel Frame Difference Steel vs. Wood (% change) Embodied energy (GJ) 168 231 63 38% Global warming potential (CO2 kg) 8,345 14,982 6,637 80% Air emission index (index scale) 2,313 3,372 1,060 46% Water emission index (index scale) 2 2 0 0% Solid waste (total kg) 2,325 6,152 3,827 164%
- 15. The U.S. Forest Service is now: Preferentially selecting wood in new building construction Actively looking for ways to demonstrate innovative uses of wood using green building rating systems Herrington Recovery Center Wisconsin Architect: TWP Architecture LEED Gold Shaping Government Policy Photo: Curtis Waltz
- 16. Sustainable Forestry Carbon Cycle
- 17. Making Informed Material Choices Replacing steel floor joists with engineered wood joists reduces the carbon footprint of the joists by nearly 10 tons of carbon dioxide for every ton of wood used Photo: APA
- 18. Calculated using the WoodWorks Carbon Calculator, available at woodworks.org Calculating Carbon Benefits Avalon Anaheim Stadium California Architect: Withee Malcolm Architects Photo: © Arden Photography
- 19. North American Forests 50 years of forest growth that exceeds harvest More certified forests than anywhere else in the world As of August 2013 Sources: www.pefc.org, www.fscus.org, www.fsccanada.org, www.fsc.org, www.certificationcanada.org, www.mtc.com.my
- 20. Sustainable Forest Certification Verifies that a forest meets the requirements of the certification standard Two international umbrella organizations – FSC and PEFC More than 50 certification standards worldwide
- 21. End of Life Issues What happens to a material at the end of its useful service life? Photos: Dreamstime stock photos
- 22. Reduce, Recycle, Reuse Once considered waste, sawdust from lumber manufacturing is now used to make composite products or as a renewable energy source. Photo: naturallywood.com
- 23. Design for Deconstruction Increasingly, wood from buildings is being reclaimed and reused. Photos: Dreamstime stock photos
- 24. SECTION 3 WOOD AND SOCIAL GOALS
- 25. Carby Chapel Center Texas Architect: Roesler Associates, Inc./Architects Michael Ortega Architectural Photography Wood and Social Goals
- 26. Michael Smith Laboratory, University of British Columbia British Columbia Architect: IBI Group/Henriquez Partners Architects Photo: naturallywood.com
- 27. Study: Wood and Health Herrington Recovery Center Wisconsin Architect: TWP Architecture Photo: Curtis Waltz
- 28. Wood in Schools Rosa Parks Elementary School Washington Architect: Mahlum Architects Photo: Benjamin Benschneider
- 29. SECTION 4 WOOD AND ECONOMIC CONSIDERATIONS
- 30. Wood Costs Less Photo: APA Lower material costs Faster construction Reduced foundation Availability of skilled tradespeople Photo: VanDorpe Chou Associates
- 31. El Dorado High School Arkansas Architect: CADM Architecture High School Saved $2.7 Million Photos: W.I. Bell (under construction); Dennis Ivy
- 32. Direct and Indirect Jobs U.S. – 900,000 American Wood Council Canada – 600,000 Forest Products Association of Canada Worldwide – 1.6 billion World Bank Photos: naturallywood.com
- 33. SECTION 5 CODES AND GREEN RATING SYSTEMS
- 34. Codes and Green Rating Systems California Green Building Standards Code (CALGreen) First U.S. code to incorporate life cycle assessment ASHRAE 189.1 Sets minimum green building requirements First code-intended standard for high-performance buildings in the U.S. International Green Construction Code Released in 2012, being adopted on a voluntary basis
- 35. Recognizing Wood’s Value Carbon benefits of El Dorado High School Estimated using the Carbon Calculator, available at woodworks.org Grows naturally, renewable Low embodied energy Less air/water pollution Light carbon footprint Adaptable / reusable / recyclable
- 36. LEED Green Globes Built Green NAHB Model Green Home Building Guidelines Photo: Anne Garrison Robert Paine Scripps Forum for Science, Society and the Environment California Architect: Safdie Rabines Architects LEED Silver Green Rating Systems in North America
- 37. Green Rating Systems in North America Living Building Challenge SB Tool Bullitt Center Washington Architect: The Miller Hull Partnership Living Building Challenge 2.0 Photo: John Stamets
- 38. International Green Rating Systems Lancaster Institute of Contemporary Arts United Kingdom Architect: Sheppard Robson BREEAM Outstanding Photo: Sheppard Robson
- 39. Rating Systems and Wood Wood’s most significant ecological benefits—that it is the only carbon-neutral construction material and that it can significantly reduce a building’s life cycle impacts—are largely unrecognized by the most commonly used rating systems. -- Light House Sustainable Building Centre “ “
- 40. Passive House Standard Austria House British Columbia Architect: Treberspurg & Partner Architekten Photo: Ira Nicolai Focuses solely on reducing energy consumption
- 42. THANK YOU! For more information on building with wood, visit rethinkwood.com
Editor's Notes
- The design community has for many years sought to create buildings that are energy efficient, better for the environment and healthier for occupants. This has been the driving force behind the modern green building movement, but actually goes back to the energy crisis of the 1970s—when (Part 1 of a 3 sharply rising oil prices provided all the part incentive people needed to reduce fossil fuel consumption. Materials Matter series) Construction Materials and Environmental Costs Today, concern about the effects of carbon dioxide and other greenhouse gases has given the movement a reinvigorated sense of urgency … and expanded the focus to include, not only energy use, but the resulting carbon impacts of buildings.
- “Materials Matter” CEU Series Overview Materials Matter (Part 1) Materials in Action (Part 2) This presentation is part one in a three-part series, based on a CEU, Materials Matter, first published in Architectural Record in 2011. Some of the statistics have been updated based on new information. • “Materials Matter” (Part 1 of 3) documents the environmental footprint of wood, concrete, and steel. • “Materials in Action” (Part 2 of 3) covers their performance during construction, operation and end-of-life, reaffirming that in the quest for carbon-neutral buildings, materials do matter. • “A Natural Choice” (Part 3 of 3) covers how these materials factor into green design and high-performance buildings as well as how green design projects are currently defined. This presentation will address the overt differences between three common materials—wood, steel and concrete—and their life cycle environmental impacts. These materials will also be discussed in terms of responsible procurement, sustainability and community issues. A Natural Choice (Part 3)
- reThink Wood sponsors this program provided by McGraw-Hill Publishers. As an AIA- and GBCI-approved program, the information presented is not intended to be an approval or endorsement by the AIA or GBCI of any product, material, or method of construction. Credit earned upon completion of this program will be reported to AIA for AIA members. Certificates of completion are available for self-reporting and record-keeping needs. Questions related to the information presented should be directed to reThinkWood via email – info@rethinkwood.com - upon completion of this program.
- This program is protected by U.S. and international copyright laws. Reuse of any portion of this program without written consent from reThink Wood is prohibited.
- More specifically, this presentation will show how life cycle assessment is making it easier for designers to incorporate environmental considerations into their decision making. It will demonstrate that, when viewed over its life cycle, wood is better for the environment than steel or concrete in terms of embodied energy, air and water pollution and greenhouse gas emissions. And it will highlight other benefits of wood such as recyclability and renewability, a light carbon footprint, third-party certification and chain of custody.
- There are 6 sections to this presentation:Section 1: Materials MatterSection 2: Life Cycle Assessment - A Scientific Way to Calculate Environmental ImpactsSection 3: ManufacturingSection 4: TransportationSection 5: Renewable Versus RecyclableSection 6: Responsible Procurement
- Every design and building professional knows the building sector has a significant impact on the environment, but it may surprise you to know the extent.For example, the building industry uses more than 3 billion tons of materials a year worldwide, and accounts for 40 percent of the world’s raw materials. Buildings also consume 30-40 percent of the world’s energy. Clearly there is a need—and an opportunity—to construct buildings in a way that reduces their environmental impact.Sources:Bullets 1 and 2 – D.M. Roodman and N. Lenssen, A Building Revolution: How Ecology and Health Concerns are Transforming Construction, p. 5., Worldwatch Paper 124, Worldwatch Institute, Washington, D.C., March 1995 http://www.worldwatch.org/node/866Bullet 3 – Buildings and climate change: Status, challenges and opportunities, p.4-7, United Nations Environment Programme, 2007. http://www.unep.org/sbci/pdfs/BuildingsandClimateChange.pdf
- Faced with these realities, the architecture and construction industries have been making significant efforts to lighten the environmental footprint of tomorrow's structures. This goal is particularly pressing in light of the fact that 1.6 billion square feet are added each year in the commercial building sector alone. That's nearly 110,000 buildings annually at the mean size of 14,700 square feet or roughly half a million buildings every five years.Source: Energy Efficiency Trends in Residential and Commercial Buildings, US Department of Energy, 2008Photo: Magnus L3D Wikipedia
- Until now, the main focus of building green has been operational energy efficiency— and considerable strides have been made both in terms of improving the building envelope and otherwise reducing energy consumption. So much so that designers are now looking beyond operational energy to the embodied and end-of-life impacts of their building materials. Building green includes embodied, operational and end-of-life impacts. Most material choices ignore impacts of manufacture, maintenance and disposal. Environmental costs of production are not fully acknowledged.
- The information we’re looking for has layers and layers of complexity. In the past, the green building movement has taken a prescriptive approach to choosing building materials. This approach assumes that certain “prescribed” practices are better for the environment regardless of their manufacturing process or disposal issues. One example is recycled content: most green building rating systems reward steel with recycled content over wood products that, not only require far less energy to produce, but result in considerably less greenhouse gas emissions, air pollution and water pollution. Locally produced materials are another example. In most green building rating systems, materials produced within 500 miles of the job site are rewarded regardless of their manufacturing process or end-of-life disposal.The prescriptive approach is overly simplistic and can lead designers to incorrect assumptions … which is why, increasingly, it is being replaced by the scientific evaluation of estimatedimpacts through life cycle assessment, or LCA.
- LCA is an internationallyrecognized method for evaluating the environmental impacts of products, materials, assemblies or even whole buildings over their entire lives.Defined by the International Organization for Standardization (ISO), it is an objective way of quantifying and interpreting the energy and material flows to and from the environment. The analysis includes emissions to air, water and land, as well as the consumption of energy and material resources.
- In a building context, LCA considers a full range of impacts from the extraction or harvest of raw materials through manufacturing, transportation, installation, use, maintenance and disposal or recycling.Internationally, the United Nations Environment Programme has been promoting LCA for more than a decade. It is more common in Europe than North America, but its use is increasing in both markets because of its holistic approach and power as an evaluative tool.
- Because calculating life cycle impacts is complex and time consuming, tools exist to help architects judge the environmental merits of various materials and building assemblies. In North America, the Athena Impact Estimator is the only software tool designed to evaluate whole buildings and assemblies based on internationally recognized LCA methodology. Developed by the Athena Sustainable Materials Institute, it allows building designers and others to easily assess and compare the environmental implications of industrial, institutional, commercial and residential designs—both for new buildings and major renovations. The impact estimator is available as a free download.BEESis a free, U.S.-based tool for product-to-product comparisons. It was developed by the National Institute of Standards and Technology, and results are based on proprietary, unpublished data.Envestis a UK-based, LCA-based building design tool. It addresses only the whole building and provides results in highly summarized “ecopoints.”The Forest Industry Carbon Assessment Tool (FICAT) calculates carbon footprints of the effects of forest-based manufacturing activities on carbon and greenhouse gases along the value chain. It’s a joint venture of the National Council for Air and Stream Improvement and the International Finance Corporation and is available as a free download.Just as there are different LCA tools for building professionals, there are different tools intended for use by LCA practitioners. GaBi is a tool from Germany, comprised of primarily European data.SimaPro is a tool from the Netherlands. It includes a comprehensive suite of databases for building materials applicable to the United States, Japan and various European countries.United States, Japan and various European countries.
- LCA studies consistently demonstrate wood’s environmental advantages over steel and concrete when it comes to embodied energy, air and water pollution, global warming potential and other environmental impact indicators.1In this graph, three hypothetical homes (wood, steel and concrete) of identical size and configuration are compared. Assessment results are summarized into six key measures during the first 20 years of operating these homes. The wood home outperformed the others in terms of air pollution, embodied energy, global warming potential (or greenhouse gases) and water pollution. It performed comparably to steel and better than concrete in terms of solid waste and resource use.Source: Data compiled by the Canadian Wood Council using the ATHENA EcoCalculator with a data set for Toronto, Canada, 2004; Green Building with Wood Toolkit, LCA, http://www.naturallywood.com/architectstoolkit/#/inspire/pdf/201Werner, F. and Richter, K. 2007. Wooden building products in comparative LCA: A literature review. International Journal of Life Cycle Assessment, 12(7): 470-479.
- A landmark study conducted by the Consortium for Research on Renewable Industrial Materials (CORRIM) also compared wood-frame and concrete homes in the hot climate of Atlanta and wood and steel-frame homes in the cold climate of Minneapolis—the framing types most common to each city.Among other things, the global warming potential of the steel and concrete homes were 26 and 31 percent higher, respectively, than the wood-frame homes.This chart focuses on the wall assemblies only and shows that the steel and concrete assemblies had 80 percent and 38 percent higher global warming potential than the wood assembly.Source:Life Cycle Environmental Performance of Renewable Building Materials in the Context of Residential Construction – Phase I, 2005 - http://www.corrim.org/pubs/reports/2005/swst/3.pdf
- The building sector consumes more energy than any other sector. Most of this energy is produced from burning fossil fuels, making this sector the largest emitter of greenhouse gases on the planet. Many people believe we are heading toward irreversible climate change and, as a result, are placing an increasing emphasis on reducing the carbon footprint of buildings.Architect Michael Green believes that, to reduce carbon footprint, we need to consider the impacts associated with different building materials and choose wisely.The building pictured here is the Prince George Airport, an expansion of which was designed by Mr. Green’s architectural firm, Michael Green Architecture. Glulam and glass were used to create a design that’s architecturally stunning while integrating new and existing parts of the building.
- The manufacturing of materials requires the greatest amount of energy in the entire construction process. When it comes to material selection and carbon, embodied energy is a key part of the equation. How much energy does it take to extract, process, manufacture, transport, construct and maintain a material or product—and what is the impact of that energy in terms of greenhouse gas emissions? When the construction process is viewed as a whole, the manufacturing of materials is the most energy intensive. Photos (in order): dreamstime (stock), dreamstime, naturallywood.com
- From an energy perspective, an advantage of wood is that it’s produced naturally. Compared to steel and concrete, wood products don’t need much processing, so the manufacturing phase requires far less energy and results in far less carbon dioxide emissions. This has been demonstrated time and time again in LCA studies.Another advantage is that more than half the energy that is required to produce wood products comes in the form of renewable biomass. It’s common for companies to have cogeneration facilities, also known as combined heat and power, which convert sawdust, bark and other residual fiber to electrical and thermal energy. The electricity is used to power equipment.Photos: naturallywood.comSources:Bullet 2 – Synthesis of Research on Wood Products and Greenhouse Gas Impacts, Sarthre, R. and J. O’Connor, 2010, FPInnovations; Wooden building products in comparative LCA: A literature review, Werner, F. and Richter, K., 2007, International Journal of Life Cycle Assessment, 12(7): 470-479Bullet 3 –AF&PAEnvironmental, Health & Safety Verification Program – Biennial Report and Improve Energy Efficiency fact sheet, 2012;The State of Canada's Forests Report – 2012
- A mill for producing lumber is relatively straightforward. Once the bark is removed, logs are sawn and trimmed to precise lengths, dried, and then planed, grade-stamped and packaged.
- In addition to LCA, another environmental aspect to consider is the fact that trees and forest products can help to minimize our carbon footprint over the long term.In terms of wood’s positive impact on a building’s carbon footprint, there are several elements to consider:1) As trees grow, they clean the air we breathe by absorbing carbon dioxide from the atmosphere, storing the carbon in their wood, roots, leaves or needles, and surrounding soil, and releasing the oxygen back into the atmosphere. Young, vigorously growing trees absorb the most carbon dioxide, with the rate slowing as they reach maturity. 2) When trees start to decay, or when forests succumb to wildfire, insects or disease, the stored carbon is released back into the atmosphere. However, when trees are harvested and manufactured into forest products, the products continue to store much of the carbon. In the case of wood buildings, this carbon is kept out of the atmosphere for the lifetime of the structure—or longer if the wood is reclaimed and manufactured into other products. 3) In any of these cases, the carbon cycle begins again as the forest is regenerated, either naturally or by planting, and young seedlings once again begin absorbing carbon. 4) Manufacturing wood into products requires far less energy than other materials—and very little fossil fuel energy. Most of the energy that is used comes from converting residual bark and sawdust to electrical and thermal energy, adding to wood’s light carbon footprint. Photos: naturallywood.com (top), W.G. Clark Construction/Mahlum (bottom)Source for Bullet 2: FPInnovations
- Increasing emphasis on carbon footprint is one of the reasons wood buildings are getting taller—along with wood’s safety and performance record and innovative new products such as cross laminated timber, or CLT, which offer exceptional strength and dimensional stability.The Forté in Melbourne, Australia includes 10 stories of CLT and, at the time of construction, was the world’s tallest modern wood building. Designing the structure in wood allowed the developer to create “as close to a net zero carbon building as possible.” Between the carbon sequestered in the wood itself and the greenhouse gas emissions avoided by not using steel or concrete, Lend Lease estimates that Forté kept approximately 1,450 metric tons of carbon dioxide (equivalent) out of the atmosphere.In the UK, eight-story Bridport House is the first high-rise in the UK built entirely in CLT, including the ground floor. According to calculations by Stora Enso, each of the 41 apartment units contain 30-40 cubic metres of timber (approximately1,000-1,400 cubic feet), which is equivalent to more than 30 metric tonnes (33 tons) of carbon dioxide. (Source: Stora Enso)Likewise, a company in Austria has developed a hybrid, wood-based building system for what it calls Life-Cycle Towers, which can be up to 30 storieshigh and reduce the building’s carbon footprint by 90 percent compared to typical structures. (More information: http://www.creebyrhomberg.com/files/CREE_Standard_english.pdf )In British Columbia reducing carbon footprint was one of the reasons the building code was changed to increase the number of permitted stories in residential wood buildings from four to six.
- The process to manufacture steel on the other hand is fossil fuel-intensive. Iron smelted from ore contains more carbon than is desirable. To become steel, the iron must be melted at extremely high temperatures and reprocessed to reduce the carbon and to remove silica, phosphorous and sulfur, which weaken steel Energy intensive Iron ore is extracted through open pit mining and heated to extremely high temperatures using fossil fuel energy, usually charcoal or coke. Manufacturing involves reducing carbon in the iron, which also results in CO2 emissions. Sources:Photo: Trinec Iron and Steel Works (Trineckézelezárny)
- Most modern steel plants use a basic oxygen furnace in which high-purity oxygen blows through the molten pig iron, lowering carbon levels and those of other impurities. Alloys are added at this time to create the desired properties of the steel product. Liquid steel is then cooled as bars or rods and later rolled and flattened into sheets.Source: World Coal Association, www.worldcoal.org
- Typically, a concrete mix is about 10 to 15 percent cement,1 though the amountchanges based on required strength and flexibility. While most of concrete’s ingredients are manufactured products themselves or mined materials, it’s the cement that has the highest embodied energy. Source: 1Portland Cement AssociationPhoto: dreamstime (stock) – no commercial use permitted
- The major ingredient needed for cement is limestone. In most cases, limestone is blasted from surface mines and removed in large blocks to a crusher where it’s mixed with other raw materials. From there, it’s transferred to a rotating furnace and heated to about 2,700 degrees Fahrenheit, powered by coal or natural gas, in order for the materials to coalesce. The mixture is cooled and ground to fine gray powder (cement), which is then transported to its destination by truck, rail or ship. To reduce the carbon footprint of the end product, fly ash, volcanic ash or magnesium oxide are sometimes substituted for a portion of the cement. However, cement manufacturing is still a carbon-intensive endeavour. In Canada, for example, producing one metric tonne of cement (1.1 tons) results in the emission of approximately one metric tonne (1.1 tons) of carbon dioxide and cement manufacturing accounts for 5 percent of anthropogenicglobal carbon dioxide emissions.Sourcesof data: EcoSmart Concrete: www.ecosmart.ca; SOS: An Optimization System for the Sustainable Use of Supplementary Cementing Materials in Concrete, 2006, http://www.ecosmart.ca/Docs/SOS-CSCEPaper.pdf; International Energy Agency, Technology Roadmap – Cement, http://www.iea.org/publications/freepublications/publication/name,3861,en.html
- As the movement to carbon-neutral buildings takes hold, makers of building materials are well aware of the need to improve the environmental footprint of their products. For its part, the steel industry has exceeded Kyoto accords for energy-efficiency improvement by more than 240 percent and made sizeable reductions in GHG emissions. According to the American Iron and Steel Institute, the industry has reduced its energy consumption by 33 percent since 1990.1 Coal figures heavily in energy consumption, but as steel scrap is increasingly used to make new steel, natural resources are being conserved and energy consumption reduced, with manufacturers reducing annual energy consumption by an amount that would power 18 million households for one year. While significant amounts of energy are required to convert iron ore and scrap to steel, the US EPA reports that the sector's energy use per ton of steel shipped improved over the last decade, with corresponding reductions in actual energy used. At the same time, the EPA states, "Release of CO2 is inherent to the chemical reactions through which iron ore is chemically reduced to make iron, and from the carbon content of iron when reduced to make steel. These emissions cannot be reduced except by changing the process by which iron and steel are made or by capturing and storing the CO2 after it is created. Research into new methods of steelmaking, is also targeting low-carbon processes."The steel industry has also established the carbon dioxide Breakthrough Program to fund the development of new steelmaking technologies. Source: 1http://consumerenergyalliance.org/american-iron-and-steel-institute-wins-energy-efficiency-award/-wins-energy-efficiency-award/ Photo: dreamstime (stock)
- Mining, particularly open pit mining, is harsh on the environment. According to the Portland Cement Association, the cement industry is minimizing the disruption with "new technologies and a concerted effort to work closely with the communities in which quarries reside." Careful practices during operations minimize the impact, as does restoration of the sites to beneficial use. Sand, gravel, and crushed stone are typically mined in close proximity to their use, which gives quarry operators a strong incentive to be environmentally responsible and to maintain good relationships with the host community. Often, quarries are reclaimed for development, agriculture, or recreational uses. The Association says that, since 1972, the cement industry has reduced the energy it takes to make a ton of cement by over 37 percent, along with associated combustion emissions. In 1990, U.S. cement manufacturers set performance improvement goals—among them, a means for continuous improvement through Environmental Management Systems that track, report and improve environmental performance. Specific goals per unit of production were set for 2020 and include reducing carbon dioxide by 10 percent, energy use by 20 percent, and cement kiln dust by 60 percent. Recognising the need to reduce the CO2 intensity of cement production, the International Energy Agencyhas worked with the World Business Council for Sustainable Development (WBCSD) Cement Sustainability Initiative (CSI) to develop a technology roadmap for cement. This document outlines a possible transition path for the industry to make continued contributions towards a halving of global CO2 emissions by 2050. The roadmap estimates that the cement industry could reduce emissions b 18% from current levels by 2050.Sources: Portland Cement Association, http://www.cement.org/smreport09/sec_page2_3.htm; Concrete Joint Sustainability Initiative, http://www.sustainableconcrete.org/?q=node/42;International Energy Agency, Technology Roadmap – Cement, http://www.iea.org/publications/freepublications/publication/name,3861,en.html
- Maximizing resource use: the term “waste” is largely obsolete in the context of forest product manufacturing. The term 'waste' is largely obsolete in the context of today’s North American forest products industry. Logs brought to U.S. and Canadian sawmills and other wood product manufacturing centers are converted almost totally to useful products, leaving little to no waste. This is attributable to state-of-the-art sawmilling that maximizes the quality and quantity of boards that can be cut from a tree, combined with further processing fiber that is unsuitable for lumber production into composite products such as OSB or fiber boards and paper. It is also common for companies to have cogeneration facilities, also known as combined heat and power, which convert sawdust, bark and other residual fiber to electrical and thermal energy. In a carbon-focused world, this integration is especially important.Source: Utilization of Harvested Wood by the North American Forest Products Industry, Dovetail Partners Inc. Photos: naturallywood.com
- Compared to manufacturing, which requires the greatest amount of energy in the construction process, transportation of building materials represents only a fraction of total fossil fuel consumption. For a typical wood-frame house in Minnesota, construction transportation constitutes only 3.6 percent of total fossil fuel consumption. That said, the impacts will be greater or less depending on the distance, mode of transportation, and material being transported.Source: This data was calculated by FPInnovations using the Athena Impact Estimator for Buildings, 2011
- While distance may seem like the most significant element for determining transportation effects, a product travelling a long distance in a highly efficient mode will actually have a smaller environmental footprint than a product with fewer miles to travel in an inefficient manner. Road transport is by far the most carbon-intensive option, and is about six times more energy-intensive than rail transport and 15 times more energy-intensive than sea transport.Source: Brentwood Consulting, based on Leadership in Energy and Environmental Design values for energy use
- Wood is light compared to other materials and is transported first by road to the mill and then further by rail and ship. Concrete has the advantage of being produced locally, but is heavy and transported by truck. Due to its weight, steel is high in embodied energy, which equates to CO2 emissions.For wood, the capacity of trees to absorb and store carbon can be factored against the carbon dioxide emissions incurred during drying, processing and transporting wood products. The result may be a carbon-neutral building material. Source: Photo: dreamstime (stock)
- When viewed overall, the embodied energy in wood products is significantly lower than the embodied energy in concrete or steel—either virgin or recycled. But there are other considerations when evaluating the choice of building materials ...Source: Data compiled by the Canadian Wood Council using the ATHENA EcoCalculator with a data set for Vancouver, British Columbia
- Is it Renewable? Concrete – NO Steel – NO Wood – YES ... such as renewability. A natural resource is renewable if it can be naturally replaced at the rate at which it is consumed. When the sand and gravel in concrete are mined from an area, they will not be replenished naturally in a reasonable time. Likewise, iron ore, the primary ingredient in steel, will not be replaced in a timely manner. Of the three building materials, wood is the only renewable resource.
- Recyclability, which also factors into environmental decision making, is another consideration. All three materials are recyclable.In the U.S., more than 80 million tons of steel are recycled each year and the overall recycling rate for 2011 was 92 percent. When one ton of steel is recycled, 2,500 pounds of iron ore, 1,400 pounds of coal and 120 pounds of limestone are conserved. However, there are still two considerations. First, the worldwide demand for steel outstrips the supply from demolished or scrap steel. Second, even though recycled steel requires about half the energy to produce as virgin steel, it is still considerably more than wood. Steel can also be reused. The industry says that steel frames with bolted connections can be easily dismantled. Entire structures are demountable and can be reconstructed in a different location in a matter of days. Concrete, too, can be recycled … and this is becoming an accepted way of disposing concrete structures that were once routinely shipped to landfills. Typically, concrete is collected and put through a crushing machine, often along with asphalt, bricks, and rocks. In reinforced concrete, the rebar is removed with magnets, and the remaining concrete chunks are sorted by size. Smaller pieces of concrete can be used for gravel for new construction projects, in shoreline protection, or as a road base. Recycled or reclaimed wood has the added cachet of architectural quality and character. Older beams and timbers are dense with a high ring count, and are praised by builders for their low moisture content. This makes them extremely stable, particularly in exterior situations. Antique wood has a striking patina that comes from oxidation that occurs on its surface. The color of old wood used in interior applications is generally mellower than the original, and history may also shine through, with the scuffs and scrapes of warehouse flooring still visible after sanding. Seasoned old growth lumber from demolition of historic structures has found new life as beams, exposed trusses, millwork, flooring, and furniture. Still, recycling timber is time-consuming and labor intensive—demolition must be careful to preserve as much of the timber as possible, wall studs must be trimmed off, nails pulled out and the lumber refinished. Recycled wood may not always fit in a new project, either from a size or a building code perspective, and there is not a well-established supply in many areas.
- While all three materials can be recycled, wood is the only materialthat has third-party certification programs in place to confirmthat products have come from a sustainably managed resource. While life cycle assessment evaluates the environmental aspects of products or materials, forest certification verifies the sustainability of forest management. More than 50 independent forest certification programs exist worldwide, reflecting the diversity of forest types, ecosystems, and ownership.The two largest umbrella certification programs are the Forest Stewardship Council (FSC) and the Programme for the Endorsement of Forest Certification schemes (PEFC). PEFC endorses the Sustainable Forestry Initiative (SFI), the Canadian Standards Association (CSA), and the American Tree Farm System (ATFS). All of these standards are used in North America and recognized internationally.
- North Americais internationally recognized for its supply of quality wood products from well-managed forests. As of August 2012, more than 500 million acres of forest in Canada and the U.S. were certified under one of the four internationally recognized programs used in North America: the Sustainable Forestry Initiative (SFI), Canadian Standards Association’s Sustainable Forest Management Standard (CSA), Forest Stewardship Council (FSC), and American Tree Farm System.Sources: www.pefc.org, www.fscus.org,www.fsccanada.org, www.fsc.org, www.certificationcanada.org, www.mtc.com.my
- Leadership in Forest Certification This represents more than half of the world’s certified forests. Sources: www.pefc.org, www.fscus.org, www.fsccanada.org, www.fsc.org, www.certificationcanada.org, www.mtc.com.my
- Certified wood is the only product that can carry the added value of chain-of-custody certification—which confirms that it came from sustainably managed, third-party certified forests. Similar to tracking packages, chain-of-custody tracks forest products through all phases of ownership, processing and transportation, from the forest of origin to the end consumer. The chain-of-custody system is verified through an independent third-party audit. The result is that buyers know their building materials are coming from forests managed in accordance with strict sustainable forest management certification standards—and not from controversial sources such as illegal logging. The concrete and steel industries have no third-party sustainability certification or chain-of-custody certification. However, progress is being made in responsible procurement. In particular, some steel companies are reportedly encouraging suppliers to adopt responsible practices and/or management systems certified to ISO standards. In certain cases, companies dedicate online resources to screening potential suppliers and to promoting and monitoring the performance of existing vendors. Steel is often imported from developing countries and the absence of a third-party certification program makes it impossible to accurately assess the environmental and social impacts of steel products. Photos: naturallywood.comSources: Photos: naturallywood.com Manufacturing Timber importer Chain of Custody certificate Chain of Custody certificate Chain of Custody certificate
- Environmental product declarations (EPDs) are the next wave in the world of environmental labeling. An EPD is designed to provide accurate, accessible and comparable information about the environmental impacts associated with goods or services. Much like nutritional food labels on products, EPDs are about making sure the data is transparent and leaving judgment up to the audience. Based on LCA data, EPDs are standardized (ISO 14025) and applicable worldwide for all interested companies and organizations. EPDs are voluntarily developed and include information about the environmental impacts of a product or service, such as raw material acquisition, energy use and efficiency, emissions to air, soil and water, and waste. They also include product and company information. The wood industry is taking a leadership role by adopting EPDs in advance of regulatory requirements. This will help to advance the sustainability cause in the building construction sector and demonstrate its strong environmental values.Examples of EPDs can be found at:American Wood Council, www.awc.org/greenbuilding/epd.phpCanadian Wood Council, www.cwc.ca/index.php/en/design-with-wood/sustainability/life-cycleFPInnovations,www.fpinnovations.canaturallywood.com
- In reducing the environmental footprint of tomorrow’s structures, wood is a sustainable building choice. LCA studies repeatedly show that it outperforms steel and concrete in terms of embodied energy, air and water pollution and global warming potential. It stores carbon. Certified wood that has a chain-of-custody provides documentation of responsible procurement. And the forest industry creates jobs and well being for millions of people worldwide. Photo: W.G. Clark Construction, AnkromMoisan Architects
- Ready to take the Online Continuing Education Unit (CEU) test? You can earn 1.00 HSW credit and 1 GBCI CE hour(s) for LEED Credential Maintenance. Click on the button above, or go to: http://continuingeducation.construction.com/article.php?L=221&C=754
- Thank you for your time. Visit www.rethinkwood.com for more information, or email info@rethinkwood.com with any questions.