Potential harmful environmental impacts as a consequence of material and system specifications, installation, and operations in current U.S. green building practices
Potential harmful environmental impacts as a consequence of material and system specifications, installation, and operations in current U.S. green building practices
2.1 Introduction
Current green building practice suffers from disconnects between the owner/occupier desires and perceptions; the actual means and methods used to construct a building; and the environmental impacts during use. While U.S. market transformation toward green building has occurred utilizing a dollar-value-installed equation, life-cycle effects relating to raw material production (cradle-to-use phase), construction means, and end-use energy savings have largely been ignored. This chapter focuses on the discussion on life-cycle emissions and green buildings from three perspectives that include the primary material production, construction means and methods, and occupied phases of a building’s life-cycle. The three perspectives are: (1) emissions/environmental harm from material manufacturing for the construction phase, (2) emissions/environmental harm from equipment/processes during the construction phase, (3) emission/environmental harm from the completed building (post construction).
Issues in these areas include the characteristics of some of the primary raw materials used to produce basic construction materials and the misconceptions regarding their environmental impacts; concerns about the harmful properties of certain manufactured materials/systems; and concerns about emissions by installed systems over their warranted life-cycle and use with particular regard to fundamental energy production. Governance in these areas is often incomplete and/or inconsistent with the intent of green building. The governing bodies that are in charge of industry standards have membership drawn largely from vested industry participants. These bodies tend to utilize consensus-based voting procedures that leave the standards’ development subject to conflicts of interest. Furthermore, discussions regarding energy efficiencies and the focus on greenhouse gas emissions forgo more serious implications of point-source emissions of toxic material.
This chapter is organized in sections and is written with the intent of providing an overview and brief discussion about select materials specifications, system specifications, construction processes, and building operations. The chapter exposes some of the potentially harmful environmental impacts and hopes to initiate more dialogue resulting in speedy resolutions that are devoid of harmful environmental impacts. Ultimately these resolutions will inform and direct future environmental legislation.
2.2 Background
Environmental activism in the United States began early in the nineteenth century and has grown as there has been a convergence of interest in the conservation of natural resources and an interest in public health and quality of life. Increased interest in environmentalism began as a response to the negative environmental impacts of the industrial revolution along with the modern chemical revolution. During the industrial revolution nature was objectified and viewed as an agricultural and economic commodity in which land itself was devoid of its association with nature; it was thought of as separate from nature – only as property (Keeler and Burke, 2009). The technology developed during the industrial revolution provided landowners with multiple means to optimize the land use for profit. Unfortunately this was more often than not done at any cost to the environment with extremely harmful consequences.
Following the industrial revolution was the modern chemical revolution. In 1962 the book Silent Spring, by a young biologist named Rachel Carson, exposed the impact of the modern chemical revolution on the biosphere, food chain, water cycle, and ultimately humans (Keeler and Burke, 2009). Carson’s book exposed common practices for storage, disposal, and transport in the chemical industry. “Her book prompted discussion and controversy, which eventually gave rise to the establishment of governmental oversight agencies, such as the U.S. Environmental Protection Agency (EPA), in spite of the chemical industry’s efforts to discredit and vilify Carson.” (Keeler and Burke, 2009)
The EPA was established in July 1970 in response to the growing public demand for cleaner water, air, and land. The federal government realized that it was not structured to make a coordinated attack on the pollutants that harm human health and degrade the environment. As a result the EPA was assigned the daunting task of repairing the damage already done to the natural environment and establishing new criteria to guide Americans in making a cleaner environment a reality.1
Environmental legislation passed by legislators and politicians since the 1970s has increased significantly in response to public outrage about the harmful impacts on the environment from the industrial revolution and modern chemical revolution. Examples of such legislation include the Clean Air Act of 1970 (including revisions in 1977, 1981, and 1990); Clean Water Act (Federal Water Pollution Control Amendments of 1972); fuel-efficiency standards for automobiles; Resource Conservation and Recovery Act (1976, and subsequent Federal Hazardous and Solid Waste Amendments of 1984); Safe Drinking Water Act of 1974 (and subsequent amendments in 1986 and 1996); Pollution Prevention Act of 1990; Energy Policy Acts of 1992 and 2005; and regulations on pollution emission controls. This list does not fully encompass the plethora of acts and regulations enacted during the last forty years. Legislation is typically passed for a particular component or problem in the system, rather than addressing the entire system. This lack of a systems approach extends to the built environment and is evident in standards, codes, and regulations set forth by governing agencies that oversee the building design and construction industry.
In 1994 Task Group 16 of Conseil International du Bâtiment (CIB) at the First International Conference on Sustainable Construction in Tampa, Florida, formally defined the concept and articulated the principles of sustainable construction (Kibert, 2005). According to the CIB, the Seven Principles of Sustainable Construction are:
1 Reduce resource consumption
2 Reuse resources
3 Use recyclable resources
4 Protect nature
5 Eliminate toxics
6 Apply life-cycle costing
7 Focus on quality
It is the goal of this chapter to present current practices in the U.S. green building industry and initiate dialogue as a stimulus for actions to resolve inconsistencies evident between the intent of green building and U.S. standards, codes, regulations, and environmental legislation.
2.3 Manufacturing processes of materials used in green building
Green building materials are currently evaluated on a life-cycle basis. Certain materials are touted for their recycled content or least impact or simply accepted for their systemic integration into the products used within the building industry. The discussion on the four materials cited below will focus on those aspects of their life cycles that have significant impact either through human health factors or environmental consequences.
2.3.1 Aluminum
The green building industry and the recycling movement in general in the United States hails aluminum as the recycled content poster child. While recycling is a major consideration in continued aluminum use, less than half of all the aluminum currently produced to meet demand originates from recycled raw materials (USGS, 2009). Aluminum can be recycled over and over again without loss of properties, but current and projected usage will still require the mining of bauxite and the conversion to aluminum through the Bayer process.
Aluminum is the third most abundant element in nature, comprising 8 percent of the earth’s crust. The ore from which aluminum is produced is bauxite. More than 130 million tons of bauxite are mined each year, the major deposits being in the tropics and sub-tropics. Bauxite is currently being extracted in Australia, Central and South America (Jamaica, Brazil, Surinam, Venezuela, and Guyana), Africa (Guinea), Asia (India, China), the Commonwealth of Independent States, and parts of Europe (Greece and Hungary). In many of these regions bauxite is the only valuable natural resource.
Alumina, the raw material for primary aluminum production, is extracted from bauxite. Bauxite is processed into pure aluminum oxide (alumina) before it is converted to aluminum by electrolysis. In this process, called the Bayer chemical process, the aluminum oxide is released from the other substances in bauxite in a caustic soda solution, which is filtered to remove insoluble particles. The aluminum hydroxide is then precipitated from the soda solution, washed, and dried, while the soda solution is recycled. After calcination, the end-product, aluminum oxide (Al2O3), is a fine-grained white powder. Four tons of bauxite are required to produce two tons of alumina, which in turn produces one ton of aluminum at the primary smelter. In 2003, 59 million tons of alumina were produced world-wide.2
Jamaica is the third largest producer of bauxite ore in the world and fourth in the production of alumina. Jamaican bauxite and alumina accounted for about 75 percent of total exports with the United States being the major market.3 Nearly all bauxite consumed in the United States in 2009 was imported, with 31 percent coming from Jamaica, 22 percent from Guinea, 19 percent from Brazil, 12 percent from Guyana, and 16 percent from various other sources (USGS, 2009a).
The major environmental problem caused by the industry is the disposal of the tailings, which form an alkaline red mud that in the past was stored in dammed valleys and spent ore mines. In Jamaica, these “red mud lakes” resulted in the percolation of caustic residues (sodium) into the underground aquifers in local areas. These sites have never been remediated. Current methods are to build clay sealed ponds that are designed to hold 5–7 years of mud storage; however, these ponds never “dry out” and are basically abandoned. Recent readings obtained from domestic water wells in the vicinity of Jamaican alumina refineries have indicated elevated sodium and Ph readings.
2.3.2 PVC
Primary concerns relating to PVC are introduced during the production and disposal phases. The continued use of PVC despite social equity issues and environmental contamination is typically weighed against life-cycle costs and the almost universal use of PVC within the construction industry. Products typically associated with PVC include conduit, valves, connectors, electrical shielding, window frames, resilient flooring, drain/waste/vent piping, and siding.
In 2003, the U.S. Green Building Council assembled a technical advisory group to discuss the life-cycle impacts of PVC and to promote the discussion as to a possible incentive point in the LEED (Leadership in Energy and Environmental Design) system that would promote the avoidance of PVC in the built environment. The task group investigated “whether for those applications the available evidence indicates that PVC-based materials were consistently among the worst of the materials studied in terms of environmental and health impacts” (Altschuler et al., 2007). This task force assembled over 2,500 studies relating to the life cycle and toxic effects of PVC.4
The study went on to compare the life-cycle impacts of PVC with other materials used similarly in the built environment, for example aluminum window frames with vinyl window frames, wood siding with vinyl siding, etc. With regard to human health impacts, specifically cradle-through-use, the report states: “aluminum frames are worst among alternatives studied. [With the] addition of end-of-life including burning: aluminum frames remain worst for combined human health impacts, but PVC is worst for cancer-related impacts among alternatives studied.” This study included aluminum frames with and without thermal breaks, and considered the energy usage (and methods of energy generation, discussed below) to be as harmful as direct exposure.
Furthermore, the study identified that PVC was worst for cancer-related impacts in piping, siding, and resilient flooring. However, when the life-cycle performance of PVC relative to the other materials was determined, the study questioned whether the focus should be on human health impacts or environmental impacts and where the limits of life-cycle scope are placed. Relative to human health impacts, and a narrow life-cycle cradle-throughuse, PVC performed better than some alternatives for windows, siding, and piping, but worst for flooring. However, with end-of-life, and occupational exposures (although the study pointed out that the literature was less complete for occupational exposure data) the study stated “PVC remains among the worst materials studied for human health.” In the end, the task groups’ recommendations were ambivalent and fractured, relating clear statistics only to stages in the life-cycle and refraining from weighting human health risks with environmental impact since “they found no scientific evidence” to do so.
Primary post-consumer issues with PVC relate to disposal issues. Combustion of PVC produces hydrogen chloride (HCl) due to its chlorine content. The chlorine content is not derived from HCl in the flue gases, but dioxins arise in the condensed solid phase by the reaction of inorganic chlorides with particulate structures in the ash particles. Since most incinerated wastes are washed, dried, and disposed of in landfills, this correlates with the findings relating to increased dioxin levels in monitoring sites adjacent to landfills.