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the_international_code_council_shall_adopt_stringent_performance-based_building_codes [2019/05/30 23:51]
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 But when a government enacts a building code, there will be real inspections and enforcement mechanisms, and so there is an increasing demand for tighter environmental standards to be legislatively adopted and legally enforced. ​ But when a government enacts a building code, there will be real inspections and enforcement mechanisms, and so there is an increasing demand for tighter environmental standards to be legislatively adopted and legally enforced. ​
  
-But, for two reasons, this has not helped matters much so far. First, building codes only are relevant to new houses ​or to old houses ​being renovated. Only about one percent of all buildings are replaced each year, so few houses and commercial buildings will be required to improve. This is no way to make quick progress worldwide. ​+But, for two reasons, this has not helped matters much so far. First, building codes only are relevant to new buildings ​or to old buildings ​being renovated. Only about one percent of all buildings are replaced each year, so few houses and commercial buildings will be required to improve. This is no way to make quick progress worldwide. ​
  
 Second, enacting legislation for tough new regulations is a political issue, and it will almost always encounter opposition. This is inevitable, since there will usually be start-up costs involved in the change, even if everyone can expect to benefit financially in the end from it. Carbon taxation is a case in point. ​ Second, enacting legislation for tough new regulations is a political issue, and it will almost always encounter opposition. This is inevitable, since there will usually be start-up costs involved in the change, even if everyone can expect to benefit financially in the end from it. Carbon taxation is a case in point. ​
  
-The best way to reduce the consumption of energy is not to change the building codes but simply to tax heavily the carbon in fuel. Unfortunately,​ the consumer can see the higher price every time she refills her heating oil tank or pays her electric ​bill. Even when governments promise to refund all the carbon tax money to households or spend it on greater services for the working class, such legislation will be opposed and maybe defeated. Voters seem more amenable to toughening up the building code and adding the extra costs onto the selling price of the building. But again, that only applies to new buildings and to old ones being refurbished. ​+The best way to reduce the consumption of energy is not to change the building codes but simply to tax heavily the carbon in fuel. Unfortunately,​ the consumer can see the higher price every time she refills her heating oil tank or pays her gas bill. Even when governments promise to refund all the carbon tax money to households or spend it on greater services for the working class, such legislation will be opposed and maybe defeated. Voters seem more amenable to toughening up the building code and adding the extra costs onto the selling price of the building. But again, that only applies to new buildings and to old ones being refurbished. ​
  
 And there is another explanation for the slow progress toward greening the world’s buildings: Banks normally only pay to upgrade one thing at a time, such as installing insulation. But it would be better to retrofit a whole house at once, including by adding digital thermostats to lower the use of energy.((//​The Economist//,​ op.cit.)) ​ And there is another explanation for the slow progress toward greening the world’s buildings: Banks normally only pay to upgrade one thing at a time, such as installing insulation. But it would be better to retrofit a whole house at once, including by adding digital thermostats to lower the use of energy.((//​The Economist//,​ op.cit.)) ​
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 The same factors partly explain why cities vary so much in their impact on the climate. For example, Denver residents emit twice as much CO<​sub>​2</​sub>​ as New Yorkers, mainly because of New York’s greater density and lesser need to commute by car.((A. Ramaswami, T Hillman, B, Janson, M. Reiner and G. Thomas,“A Demand-centred,​ Hybrid Lifecycle Methodology for City-scale Greenhouse Gas Inventories,​” //​Environmental Science and Technology//,​ vol. 42, No.17, pp. 6455-6461.)) Cities that include large industrial areas or airports account for more carbon emissions than cities where a large proportion of the inhabitants work in “knowledge” jobs.  The same factors partly explain why cities vary so much in their impact on the climate. For example, Denver residents emit twice as much CO<​sub>​2</​sub>​ as New Yorkers, mainly because of New York’s greater density and lesser need to commute by car.((A. Ramaswami, T Hillman, B, Janson, M. Reiner and G. Thomas,“A Demand-centred,​ Hybrid Lifecycle Methodology for City-scale Greenhouse Gas Inventories,​” //​Environmental Science and Technology//,​ vol. 42, No.17, pp. 6455-6461.)) Cities that include large industrial areas or airports account for more carbon emissions than cities where a large proportion of the inhabitants work in “knowledge” jobs. 
  
-Still, neither density nor affluence explains all of the variation between cities’ emission levels. A more adequate explanation takes account of the differences between emissions caused by //​production // and those caused by //​consumption//​ . Many of the activities that produce and emit carbon can be located far outside of towns, whereas it is cities that consume their products. Take electricity,​ for example. Hydroelectric dams, coal mines, and nuclear power plants are located in rural areas, but most consumption of electric power occurs in urban areas. Likewise, farms produce much of the carbon and nitrous oxide in the air, but they do so to produce food for city-dwellers to eat.((Daniel Hoornweg, Lorraine Sugar, and Claudia Lorena Trejos Gomez, “Cities and Greenhouse Gas Emissions: Moving Forward.” Sage Publications,​ //​Environment and Urbanization//​ 2011, Vol. 23 (1): 207-227.)) And some cities are primarily consumers of CO<​sub>​2</​sub>​-generating products, whereas industrial cities are mainly the producers. ​+Still, neither density nor affluence explains all of the variation between cities’ emission levels. A more adequate explanation takes account of the differences between emissions caused by //​production // and those caused by //​consumption//​ . Many of the activities that produce and emit carbon can be located far outside of towns, whereas it is cities that consume their products. Take electricity,​ for example. Hydroelectric dams, coal-fired plants, and nuclear power plants are located in rural areas, but most consumption of electric power occurs in urban areas. Likewise, farms produce much of the carbon and nitrous oxide in the air, but they do so to produce food for city-dwellers to eat.((Daniel Hoornweg, Lorraine Sugar, and Claudia Lorena Trejos Gomez, “Cities and Greenhouse Gas Emissions: Moving Forward.” Sage Publications,​ //​Environment and Urbanization//​ 2011, Vol. 23 (1): 207-227.)) And some cities are primarily consumers of CO<​sub>​2</​sub>​-generating products, whereas industrial cities are mainly the producers. ​
  
 There is a wise old saying that people should be responsible for cleaning up their own messes instead of putting the burden onto others as “externalities.” However, if we want to assign responsibility (or blame) for greenhouse gas emissions, who should have to clean up the mess — the (often rural) producers or the (often urban) consumers? Actually, like it or not, we all do. It’s our mess now. There is a wise old saying that people should be responsible for cleaning up their own messes instead of putting the burden onto others as “externalities.” However, if we want to assign responsibility (or blame) for greenhouse gas emissions, who should have to clean up the mess — the (often rural) producers or the (often urban) consumers? Actually, like it or not, we all do. It’s our mess now.
  
-Fortunately,​ there are some general principles that, if observed, can make cities greener. These are not necessarily covered by building codes but can be part of a city’s overall plan. One simple principle is just to build spaces no larger than necessary. If we want density, we cannot have “urban sprawl,” or even gigantic houses that use immense ​amount ​of energy. Zoning regulations can help to limit the size of housing units. Besides, mansions are passé. Buy a condo downtown instead and have more fun. +Fortunately,​ there are some general principles that, if observed, can make cities greener. These are not necessarily covered by building codes but can be part of a city’s overall plan. One simple principle is just to build spaces no larger than necessary. If we want density, we cannot have “urban sprawl,” or even gigantic houses that use immense ​amounts ​of energy. Zoning regulations can help to limit the size of housing units. Besides, mansions are passé. Buy a condo downtown instead and have more fun. 
  
-Second, we can strategize ways of cooling urban “heat islands” — the areas in a city where hot buildings and pavements have replaced cool, permeable soil and vegetation. A one city of million people can be 1–3°C warmer than its surroundings((T. R. Oke, “Urban Climates and Global Environmental Change,” in R.D Thompson, and A. Perry (eds.) //Applied Climatology:​ Principles & Practices//,​ New York: Routledge, 1997, pp. 273-287.)) and on a clear, calm night, the temperature difference can be as much as 12°C.((T.R. Oke, //Boundary Layer Climates//, New York, Routledge, 1987.)) We need to plant far more trees, shrubs, and rooftop gardens to counteract such heat islands.+Second, we can strategize ways of cooling urban “heat islands” — the areas in a city where hot buildings and pavements have replaced cool, permeable soil and vegetation. A city of one million people can be 1–3°C warmer than its surroundings((T. R. Oke, “Urban Climates and Global Environmental Change,” in R.D Thompson, and A. Perry (eds.) //Applied Climatology:​ Principles & Practices//,​ New York: Routledge, 1997, pp. 273-287.)) and on a clear, calm night, the temperature difference can be as much as 12°C.((T.R. Oke, //Boundary Layer Climates//, New York, Routledge, 1987.)) We need to plant far more trees, shrubs, and rooftop gardens to counteract such heat islands.
  
-Much of the heat island differential can be attributed to the “albedo effect” — the reflection of light back into space from white or pale-colored surfaces, and the absorption of light (and therefore heat) by dark surfaces. This fact gives us a solution: paint roofs white, or pave with pale beige concrete instead of black asphalt. There are some disadvantages to this, however: Concrete sidewalks and roads can be more slippery with ice in the winter than asphalt, and the pale pavement can reflect heat onto nearby buildings, whose inhabitants may have to use more air conditioning,​ which defeats your purpose. ​+Much of the heat island differential can be attributed to the “albedo effect” — the reflection of light (and therefore heat) back into space from white or pale-colored surfaces, and the absorption of light (and therefore heat) by dark surfaces. This fact gives us a solution: paint roofs white, or pave with pale beige concrete instead of black asphalt. There are some disadvantages to this, however: Concrete sidewalks and roads can be more slippery with ice in the winter than asphalt, and the pale pavement can reflect heat onto nearby buildings, whose inhabitants may have to use more air conditioning,​ which defeats your purpose. ​
  
-Ordinary pavements also have another disadvantage when it comes to water-retention. Concrete and asphalt are hard, impermeable surfaces. When it rains, the water must run off into sewers and conduits, where it is wasted or sometimes ​overflow ​and becomes a flood. ​+Ordinary pavements also have another disadvantage when it comes to water-retention. Concrete and asphalt are hard, impermeable surfaces. When it rains, the water must run off into sewers and conduits, where it is wasted or sometimes ​overflows ​and becomes a flood. ​
  
 Lately good solutions have been developed for this problem: permeable blocks of cement that can allow stormwater to seep through into the soil below, or at least can be set far enough apart to allow water to flow through the cracks and return to the groundwater.((“Atlanta is Home to Largest Permeable Pavers Project in US”, news.wabe.org,​ 2015)) This is not an adequate solution for roads that must support heavy traffic, for their structure must be strong, but it works well for many sidewalks and patios, cooling the environment somewhat and reducing the risk of floods. Lately good solutions have been developed for this problem: permeable blocks of cement that can allow stormwater to seep through into the soil below, or at least can be set far enough apart to allow water to flow through the cracks and return to the groundwater.((“Atlanta is Home to Largest Permeable Pavers Project in US”, news.wabe.org,​ 2015)) This is not an adequate solution for roads that must support heavy traffic, for their structure must be strong, but it works well for many sidewalks and patios, cooling the environment somewhat and reducing the risk of floods.
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 As noted above, the construction industry has not progressed far in reducing carbon pollution in their new buildings. This shortcoming has to be attributed largely to the fact that three of the main building materials — steel, concrete, and glass — are still large sources of carbon emissions. Though manufacturers are seeking solutions to these problems, none are very satisfactory yet.  As noted above, the construction industry has not progressed far in reducing carbon pollution in their new buildings. This shortcoming has to be attributed largely to the fact that three of the main building materials — steel, concrete, and glass — are still large sources of carbon emissions. Though manufacturers are seeking solutions to these problems, none are very satisfactory yet. 
  
-To be sure, there are some novel ideas for materials to be used in buildings: These include straw bales; bamboo; recycled plastic or sawdust mixed into concrete; rammed earth; and ferrock, a mixture of recycled materials such as steel dust, which absorbs carbon dioxide when it dries, thus being actually a carbon-neutral substance instead of emitting CO<​sub>​2</​sub>​. But major improvements in materials are disappointingly slow to arrive. Iron and steel account for 24 percent of the building industry’s emissions and cement ​accounts for 18 percent. ​+To be sure, there are some novel ideas for materials to be used in buildings: These include straw bales; bamboo; recycled plastic or sawdust mixed into concrete; rammed earth; and ferrock, a mixture of recycled materials such as steel dust, which absorbs carbon dioxide when it dries, thus being actually a carbon-neutral substance instead of emitting CO<​sub>​2</​sub>​. But major improvements in materials are disappointingly slow to arrive. Iron and steel account for 24 percent of the building industry’s emissions and concrete ​accounts for 18 percent. ​
  
 ===Steel=== ===Steel===
  
-For at least 150 years the method of making steel has not changed much. Iron is put into large blast furnace with coke, a fuel made from coal, and this turns the iron ore into liquid metal, which is then refined into steel. Inevitably, carbon dioxide is in the output, though it is possible to reduce the quantity of it by using scrap metal and electric arc furnaces instead of raw materials ​and omitting the coke. Unfortunately,​ there is not enough scrap metal for this to help much.((Michael Pooler in IJMuiden, [[https://​www.ft.com/​content/​3bcbcb60-037f-11e9-99df-6183d3002ee1|“Cleaning up Steel is Key to Tackling Climate Change”]],​ //Financial Times// series on climate control, Jan 1, 2019.)) The Indian manufacturer Tata Steel Europe is working on a method of reducing both CO<​sub>​2</​sub>​ emissions and energy consumption by one-fifth, but that modest improvement is not likely to be used commercially until at least the 2030s. The delay is caused by the technical difficulties. The most promising possibility is to eliminate carbon emissions from the ironmaking stage by using hydrogen, though then there will be a problem obtaining the hydrogen. It can be produced by electrolysis,​ but in the end, such steel will cost more.((ibid.))+For at least 150 years the method of making steel has not changed much. Iron is put into large blast furnace with coke, a fuel made from coal, and this turns the iron ore into liquid metal, which is then refined into steel. Inevitably, carbon dioxide is in the output, though it is possible to reduce the quantity of it by using scrap metal and electric arc furnaces instead of raw iron ore and by omitting the coke. Unfortunately,​ there is not enough scrap metal for this to help much.((Michael Pooler in IJMuiden, [[https://​www.ft.com/​content/​3bcbcb60-037f-11e9-99df-6183d3002ee1|“Cleaning up Steel is Key to Tackling Climate Change”]],​ //Financial Times// series on climate control, Jan 1, 2019.)) The Indian manufacturer Tata Steel Europe is working on a method of reducing both CO<​sub>​2</​sub>​ emissions and energy consumption by one-fifth, but that modest improvement is not likely to be used commercially until at least the 2030s. The delay is caused by the technical difficulties. The most promising possibility is to eliminate carbon emissions from the ironmaking stage by using hydrogen, though then there will be a problem obtaining the hydrogen. It can be produced by electrolysis,​ but in the end, such steel will cost more.((ibid.))
  
 At present, steel is widely considered essential for the structural frames of tall buildings, but it does present certain challenges for the engineers and architectural planners. Steel conducts heat very well, which is sometimes an advantage but often not. When high-rise apartment buildings are being retrofitted to reduce energy use, the balconies present a special problem. The steel beams that support the whole building generally protrude outward, supporting each balcony, and in doing so they transfer heat out and waste it. If these balconies are to become “green,​” their support must somehow be detached from the steel beams, so they do not waste heat.((Paul Dowsett in his video conversation with Metta Spencer, [[https://​youtu.be/​UfYOM9IW0tA|“Sustainable Buildings”]],​ April 15, 2019.)) At present, steel is widely considered essential for the structural frames of tall buildings, but it does present certain challenges for the engineers and architectural planners. Steel conducts heat very well, which is sometimes an advantage but often not. When high-rise apartment buildings are being retrofitted to reduce energy use, the balconies present a special problem. The steel beams that support the whole building generally protrude outward, supporting each balcony, and in doing so they transfer heat out and waste it. If these balconies are to become “green,​” their support must somehow be detached from the steel beams, so they do not waste heat.((Paul Dowsett in his video conversation with Metta Spencer, [[https://​youtu.be/​UfYOM9IW0tA|“Sustainable Buildings”]],​ April 15, 2019.))
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 ===Concrete=== ===Concrete===
  
-Cement ​has a long and wonderful history. It was apparently used more than 8,000 years ago in Jordan, to create floors, buildings, and underground cisterns. The Pantheon in Rome remains to this day the largest unsupported concrete dome in the world. ​>Roman concrete was based on a hydraulic-setting cement. It is stronger and more durable than our modern product because it contained volcanic ash, which prevents cracks from spreading.((David Moore, US Dep. of the Interior, Bureau of Reclamation,​ Upper Colorado Region [[http://​www.romanconcrete.com|"​The Riddle of Ancient Roman Concrete"​]],​ Feb. 1993.))+Concrete ​has a long and wonderful history. It was apparently used more than 8,000 years ago in Jordan, to create floors, buildings, and underground cisterns. The Pantheon in Rome remains to this day the largest unsupported concrete dome in the world. Roman concrete was based on a hydraulic-setting cement. It is stronger and more durable than our modern product because it contained volcanic ash, which prevents cracks from spreading.((David Moore, US Dep. of the Interior, Bureau of Reclamation,​ Upper Colorado Region [[http://​www.romanconcrete.com|"​The Riddle of Ancient Roman Concrete"​]],​ Feb. 1993.))
  
-Concrete is still used everywhere. According to a BBC report, “production has [[https://​www.earth-syst-sci-data.net/​10/​195/​2018/​essd-10-195-2018.pdf|increased more than thirtyfold since 1950 and almost fourfold since 1990]]. China used more cement ​between 2011 and 2013 than the US did in the entire 20th Century,” and cement ​production is expected to increase by a quarter by 2030.((Lucy Rodgers, [[https://​www.bbc.com/​news/​science-environment-46455844|“Climate Change: The Massive CO2 emitter You May not Know About.”]] BBC Science and Environment,​ Dec. 17, 2018))+Concrete is still used everywhere. According to a BBC report, “production has [[https://​www.earth-syst-sci-data.net/​10/​195/​2018/​essd-10-195-2018.pdf|increased more than thirtyfold since 1950 and almost fourfold since 1990]]. China used more concrete ​between 2011 and 2013 than the US did in the entire 20th Century,” and concrete ​production is expected to increase by a quarter by 2030.((Lucy Rodgers, [[https://​www.bbc.com/​news/​science-environment-46455844|“Climate Change: The Massive CO2 emitter You May not Know About.”]] BBC Science and Environment,​ Dec. 17, 2018))
  
-Unfortunately,​ concrete also contributes more CO<​sub>​2</​sub>​ to the climate crisis than aviation fuel. One ton of cement ​production produces a [[http://​www.global-greenhouse-warming.com/​cement-CO2-emissions.html|ton of CO<​sub>​2</​sub> ​emissions]],​ and with 5 to 7 percent of the world’s carbon emissions emanating from its production,​((Doug Pelton, [[https://​earthmaven.io/​planetwatch/​humanity-in-the-anthropocene/​cement-and-co2-emissions-yCWoJt-ly02Bsw3-9Vu6rQ/​|“One Ton of Portland Cement Produces a Ton of CO2 Emissions; Can Alternatives Reduce That by 97 Percent?​”]] //Earth Maven//, Aug. 20, 2014.)) it presents us with a problem in urgent need of a solution. ​+Unfortunately,​ concrete also contributes more CO<​sub>​2</​sub>​ to the climate crisis than aviation fuel. One ton of concrete ​production produces a [[http://​www.global-greenhouse-warming.com/​cement-CO2-emissions.html|ton of CO2  ​emissions]],​ and with 5 to 7 percent of the world’s carbon emissions emanating from its production,​((Doug Pelton, [[https://​earthmaven.io/​planetwatch/​humanity-in-the-anthropocene/​cement-and-co2-emissions-yCWoJt-ly02Bsw3-9Vu6rQ/​|“One Ton of Portland Cement Produces a Ton of CO2 Emissions; Can Alternatives Reduce That by 97 Percent?​”]] //Earth Maven//, Aug. 20, 2014.)) it presents us with a problem in urgent need of a solution. ​
  
-Concrete is made of Portland cement, water, and aggregate (rock, sand, or gravel). The Portland cement itself is made from crushed limestone and aluminosilicate clay, which are heated together in a huge kiln at about 2,640 degrees Fahrenheit. The heat splits the limestone’s calcium carbonate in two – creating calcium oxide, the lime content, and carbon dioxide, the waste that is causing so much trouble to the world today. The product at the end of the cooking is called “clinker,​” which is cooled, mixed with gypsum, and ground into powder—the cement. This process is called “decarbonizing limestone,​” and it is the source of about 60 percent of the emissions. The remaining 40 percent comes from other processes using energy to manufacture the cement+Concrete is made of Portland cement, water, and aggregate (rock, sand, or gravel). The Portland cement itself is made from crushed limestone and aluminosilicate clay, which are heated together in a huge kiln at about 2,640 degrees Fahrenheit. The heat splits the limestone’s calcium carbonate in two – creating calcium oxide, the lime content, and carbon dioxide, the waste that is causing so much trouble to the world today. The product at the end of the cooking is called “clinker,​” which is cooled, mixed with gypsum, and ground into powder—the cement. This process is called “decarbonizing limestone,​” and it is the source of about 60 percent of the emissions. The remaining 40 percent comes from other processes using energy to manufacture the concrete
  
 To make concrete, the Portland cement is mixed with water to form a paste, which is then combined with aggregate. This mushy substance is placed into forms, where it dries and hardens into a rock.  To make concrete, the Portland cement is mixed with water to form a paste, which is then combined with aggregate. This mushy substance is placed into forms, where it dries and hardens into a rock. 
  
-Most concrete nowadays also contains fly ash, a fine powder that is a by-product of burning pulverized coal in [[https://​www.thebalancesmb.com/​world-greatest-power-generator-systems-4061821|electric generation power plants]]. When combined with lime, fly ash can be used as a substitute for some of the Portland cement, and in fact improves the quality of the final concrete It is generally stronger than the type made only with cement and, like the Romans’ volcanic ash, it reduces crack problems. Its main advantage is that, by replacing some of the Portland cement, the fly ash reduces CO<​sub>​2</​sub>​ emissions.((Juan Rodriguez, [[https://​www.thebalancesmb.com/​fly-ash-applications-844761|“Uses,​ Benefits, and Drawbacks of Fly Ash in Construction”]],​ //The Balance Small Business//, Feb. 17, 2019.)) ​+Most concrete nowadays also contains fly ash, a fine powder that is a by-product of burning pulverized coal in [[https://​www.thebalancesmb.com/​world-greatest-power-generator-systems-4061821|electric generation power plants]]. When combined with lime, fly ash can be used as a substitute for some of the Portland cement, and in fact improves the quality of the final concreteIt is generally stronger than the type made only with Portland ​cement and, like the Romans’ volcanic ash, it reduces crack problems. Its main advantage is that, by replacing some of the Portland cement, the fly ash reduces CO<​sub>​2</​sub>​ emissions.((Juan Rodriguez, [[https://​www.thebalancesmb.com/​fly-ash-applications-844761|“Uses,​ Benefits, and Drawbacks of Fly Ash in Construction”]],​ //The Balance Small Business//, Feb. 17, 2019.)) ​
  
-Unfortunately,​ this is not a huge improvement,​ since the fly ash itself is a by-product of coal-fired power plants—which are themselves probably the worst sources of CO<​sub>​2</​sub>,​ and top priority for environmentalists to close down. Moreover, because it is produced by burning coal, about 15 tons of carbon dioxide is emitted for each ton of fly ash produced. That means that the use of fly ash in cement ​can offset only five percent of those emissions.((Paul Hawken, ed. //Drawdown: The Most Comprehensive Plan Ever Proposed to Reverse Global Warming//, New York: Penguin, 2017, pp 162-63. See also http://​a.co/​dZCBPIM)) That is better than nothing, so long as coal is being used anyway, but the goal must be to replace quickly both coal use and Portland cement with the better materials.+Unfortunately,​ this is not a huge improvement,​ since the fly ash itself is a by-product of coal-fired power plants—which are themselves probably the worst sources of CO<​sub>​2</​sub>,​ and top priority for environmentalists to close down. Moreover, because it is produced by burning coal, about 15 tons of carbon dioxide is emitted for each ton of fly ash produced. That means that the use of fly ash in concrete ​can offset only five percent of those emissions.((Paul Hawken, ed. //Drawdown: The Most Comprehensive Plan Ever Proposed to Reverse Global Warming//, New York: Penguin, 2017, pp 162-63. See also http://​a.co/​dZCBPIM)) That is better than nothing, so long as coal is being used anyway, but the goal must be to replace quickly both coal use and Portland cement with the better materials.
  
 And there has been progress toward that goal recently. The most promising substitute for the current method of producing cement is a type of “slag cement,” developed by Drexel University engineers. It is activated by alkali — an industrial by-product called slag—plus limestone, and its production does not require heating. The ingredients are abundant and cheap, so the new Drexel cement costs about 40 percent less than Portland cement and reduces energy consumption and carbon dioxide production by 97 percent. It is apparently as strong as Portland cement.((Britt Faulstick, Drexel University, [[https://​drexel.edu/​now/​archive/​2012/​February/​Engineers-Develop-Cement-With-97-Percent-Smaller-Carbon-Dioxide-and-Energy-Footprint|Engineers Develop Cement With 97 Percent Smaller Carbon Dioxide and Energy Footprint]])) ​ And there has been progress toward that goal recently. The most promising substitute for the current method of producing cement is a type of “slag cement,” developed by Drexel University engineers. It is activated by alkali — an industrial by-product called slag—plus limestone, and its production does not require heating. The ingredients are abundant and cheap, so the new Drexel cement costs about 40 percent less than Portland cement and reduces energy consumption and carbon dioxide production by 97 percent. It is apparently as strong as Portland cement.((Britt Faulstick, Drexel University, [[https://​drexel.edu/​now/​archive/​2012/​February/​Engineers-Develop-Cement-With-97-Percent-Smaller-Carbon-Dioxide-and-Energy-Footprint|Engineers Develop Cement With 97 Percent Smaller Carbon Dioxide and Energy Footprint]])) ​
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 The manufacture of glass is a simple process. It involves heating ordinary sand (which is mostly silicon dioxide) at about 1700 degrees C until it melts and turns into a liquid. A certain amount of carbon dioxide is released in the process, and more CO<​sub>​2</​sub>​ is also generated by creating the electricity used for heating the silicon. We need to reduce those sources of carbon emission, which can be achieved to some degree by increasing the proportion of recycled glass used in place of raw materials. However, this improvement is limited by the availability of recyclable glass of acceptable quality.((Pilkington Architects, UK and Ireland. [[https://​www.pilkington.com/​en-gb/​uk/​architects/​glass-information/​glassandtheenvironment/​environment|“Glass and the Environment”]].)) ​ The manufacture of glass is a simple process. It involves heating ordinary sand (which is mostly silicon dioxide) at about 1700 degrees C until it melts and turns into a liquid. A certain amount of carbon dioxide is released in the process, and more CO<​sub>​2</​sub>​ is also generated by creating the electricity used for heating the silicon. We need to reduce those sources of carbon emission, which can be achieved to some degree by increasing the proportion of recycled glass used in place of raw materials. However, this improvement is limited by the availability of recyclable glass of acceptable quality.((Pilkington Architects, UK and Ireland. [[https://​www.pilkington.com/​en-gb/​uk/​architects/​glass-information/​glassandtheenvironment/​environment|“Glass and the Environment”]].)) ​
  
-Still, the problem that building designers face with glass it not so much the production of waste CO<​sub>​2</​sub>​ during production as its poor performance as insulation against the transfer of heat. A major source of heat loss from a house is through its windows. The best available solution is double glazing of the windows — or even triple glazing. Two or three panels of glass are put into a frame, separated by a vacuum or gas-filled space to reduce the transfer of heat. Still, although floor-to-ceiling windows are attractive to buyers of new modern homes, architects who aim for sustainability are far less enthusiastic about them, since windows pose, at best, a major challenge for the conservation of energy. ​+Still, the problem that building designers face with glass it not so much the production of waste CO<​sub>​2</​sub>​ during production as its poor performance as insulation against the transfer of heat. A major source of heat loss from a building ​is through its windows. The best available solution is double glazing of the windows — or even triple glazing. Two or three panels of glass are put into a frame, separated by a vacuum or gas-filled space to reduce the transfer of heat. Still, although floor-to-ceiling windows are attractive to buyers of new modern homes and condos, architects who aim for sustainability are far less enthusiastic about them, since windows pose, at best, a major challenge for the conservation of energy. ​
  
-Most new office towers are covered with glass and they too present problems for the architect. However, those buildings have an advantage over private homes: The glass sheath covering the exterior of the building is usually a “curtain wall,” which is non-structural. It is separate from the interior part of the building, being hung outside ​on a concrete slab, using anchors. Curtain walls are self-supporting and give a building’s exterior the look of top-to-bottom glass, admitting light. Because they consist of a single unit, curtain walls are superior to the windows ​of most residences in their resistance to moisture, wind, earthquakes,​ and the transfer of heat.(([[https://​www.lenmak.com/​curtain-window-wall/​|“Curtain Wall Versus Window Wall: What’s the Difference?​”]] Lenmak Architecture Design Advice. See also the video discussion with Paul Dowsett and Michael Yorke, “Sustainable Buildings,​” op. cit.))+Most new office towers are covered with glass and they too present problems for the architect. However, those buildings have an advantage over private homes and condos: The glass sheath covering the exterior of the building is usually a “curtain wall,” which is non-structural. It is separate from the interior part of the building, being hung outside ​of the concrete slab, using anchors. Curtain walls are self-supporting and give a building’s exterior the look of top-to-bottom glass, admitting light. Condos are built with a “window wall” that is sandwiched between the concrete floor slabs, allowing the uninsulated floor slabs to thermally-bridge to the exterior. Because they consist of a single unit, curtain walls are superior to the window walls of most condo residences in their resistance to moisture, wind, earthquakes,​ and the transfer of heat.(([[https://​www.lenmak.com/​curtain-window-wall/​|“Curtain Wall Versus Window Wall: What’s the Difference?​”]] Lenmak Architecture Design Advice. See also the video discussion with Paul Dowsett and Michael Yorke, “Sustainable Buildings,​” op. cit.))
  
 ===Wood=== ===Wood===
  
-At last we come to a building material that everyone can love: wood. Many current green building projects —both new construction and renovations — are using wood. Trees grow naturally, using energy from the sun, and wood is sustainable,​ renewable, and recyclable. ​It is an effective insulator that requires far less energy to produce than concrete or steel. So long as wood is in use for dwellings and furniture, it is keeping the CO<​sub>​2</​sub>​ locked up that it originally captured from the air. If the wood is burned ​or allowed to rot in the forest, ​that carbon ​will return to the atmosphere. ​So, use wood!+At last we come to a building material that everyone can love: wood. Many current green building projects —both new construction and renovations — are using wood. Trees grow naturally, using energy from the sun, and wood is sustainable,​ renewable, and recyclable. ​While wood is growing ​in the wood factory, ​or forest, ​trees draw down carbon ​from the atmosphere ​through photosynthesis,​ and emit oxygen — not a bad form of ‘pollution’
  
-Smaller pieces of wood can be laminated together to make thick prefabricated posts called “mass timber,​” ​to replace much of the steel or concrete in the structures of high-rise ​buildings. For examplethere is an 1 8-storey mass timber hybrid student residence building at the University of British Columbia.((Naturally:​Wood,​ https://​www.naturallywood.com/​emerging-trends/​mass-timber)) Many more towers are being planned, though ​the public still has to be convinced ​that they are safe+Wood is an effective insulator that requires far less energy ​to produce than concrete ​or steel. So long as wood is in use for buildings ​and furnitureit is keeping ​the CO<​sub>​2<​/sub> locked up that it originally captured from the airIf the wood is burned or allowed ​to rot in the forest, ​that carbon will return to the atmosphereSo, use wood for buildings!
  
-In a video conversation Paul Dowsett and Michael Yorke argued in favor of using wood as structural members for large buildings.((Paul Dowsett ​and Michael Yorke, ​Sustainable Buildings,” op cit.)) They addressed first the question ​of firewhich is the objection that initially occurs to most people. Wood isof course, famously flammableHowever, when a thick slab of wood is in a fire, the exterior half inch will char, but the interior part will retain its structural integrity. It compares favorably with steel in allowing the inhabitants of a tall building enough time to escape.+Smaller pieces ​of wood can be laminated together to make thick prefabricated slabs--that can be cut into columns, beams, ​and panels--called ​mass timber,” to replace much of the steel or concrete in the structures ​of high-rise buildings. For examplethere is an 1 8-storey mass timber hybrid student residence building at the University of British Columbia.((Naturally:​Wood, https://www.naturallywood.com/​emerging-trends/​mass-timber)) Many more towers are being plannedthough ​the public still has to be convinced that they are safe
  
-Finally, there is a concern about cutting down trees at the very time when forests are most needed as carbon sinks. We need lots of trees absorbing carbon from the atmosphere and storing it in their trunks, roots, and leaves. Indeed, the most feasible means of reducing global warming probably is to plant about a trillion fast-growing trees in suitable locations and nurture them to maturity. Cutting timber would seem to be a gross threat to the best method of preserving our planet.+In a video conversation Paul Dowsett and Michael Yorke argued in favor of using wood as structural members for large buildings.((Paul Dowsett and Michael Yorke, “Sustainable Buildings,​” op cit.)) They addressed first the question of fire, which is the objection that initially occurs to most people. Wood is, of course, famously flammable. However, when a thick slab of wood is in a fire, the exterior half inch will char, but the interior part will retain its structural integrity, protected by the created layer of char. It compares favorably with steel in allowing the inhabitants of a tall building enough time to escape. 
 + 
 +Finally, there is a concern about cutting down trees at the very time when forests are most needed as carbon sinks. We need lots of trees absorbing carbon from the atmosphere and storing it in their trunks, roots, and leaves. Indeed, the most feasible means of reducing global warming probably is to plant about a trillion fast-growing trees in suitable locations and to nurture them to maturity. Cutting timber would seem to be a gross threat to the best method of preserving our planet.
  
 Yes, but that notion should be qualified. Trees are at their most active phase of sequestering carbon while they are young and growing fast. Many trees slow down their carbon intake when they reach maturity, though they do still serve as reservoirs, containing it until they finally fall over and rot, releasing the carbon back into the atmosphere. Yes, but that notion should be qualified. Trees are at their most active phase of sequestering carbon while they are young and growing fast. Many trees slow down their carbon intake when they reach maturity, though they do still serve as reservoirs, containing it until they finally fall over and rot, releasing the carbon back into the atmosphere.
the_international_code_council_shall_adopt_stringent_performance-based_building_codes.txt · Last modified: 2019/06/21 02:13 by 99.238.240.127