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 To PVC or Not to PVC If polyvinylchloride products pose environmental hazards, what are the alternatives for landscape applications? By Meg Calkins Reprinted Courtesy of Landscape Architecture Magazine, March 2006.
This sentence may well be the most common spec in a landscape architect's standard irrigation specification set. Most landscape architects don't give PVC pipe a second thought. After all, it's underground, so it's not an aesthetic concern. It's the industry standard. It's inexpensive and will last a long time. So no problem--right? Wrong. Currently environmental groups, green building organizations, and vinyl industry trade associations are hotly debating the hazards of polyvinylchloride, also known as PVC or vinyl. Research increasingly shows that, in many phases of its life cycle, PVC can be harmful to both human and environmental health. Many practitioners don't know about PVC's hazards. More than half of the landscape architects and engineers contacted for this article were unaware of the magnitude of the problems and admit that PVC is their material of choice for piping and even deck rails and fencing. Steve Benz of Judith Nitsch Engineering and a LEED accredited professional, is aware of some problems with PVC but says, "We don't hear much in the trenches about the pitfalls of PVC use. The average civil engineer probably doesn't even know it's an issue." Nor does the average landscape architect. Those who are aware of the problems and try to specify alternatives are often thwarted by higher costs, resistance from contractors, and local building codes. And while some designers and builders are working to specify alternatives to PVC, it is the industry standard for many applications, and substitutes are not widely used, available, or cost competitive. Some reasons for this: PVC is a good product for water lines that are pressurized. It has good tensile strength. It is rigid, but when flexibility is needed, plasticizers can be added to create flexible pipe. And it is lightweight in comparison with cast iron and other metals. The glue fitting joinery is simple, and PVC elbows and other fittings are readily available. It is also inexpensive, and again, it is the industry standard for many pipe applications. If PVC constitutes a hazard, the danger is widespread: This versatile resin appears in many forms and products (see "Landscape Products That Can Contain PVC,"). The American Plastics Council estimated in 2002 that more than 14 billion pounds of PVC are produced yearly in North America, with 75 percent of this amount used in the construction industry in piping, siding, flooring, windows, electrical wire, and cable. In addition to these uses, PVC in fencing, decking, and signage is growing at a rate of 8.1 percent per year.
The Hazards of PVC Production impacts. Problems with PVC, Thornton explains, start in the first phase of manufacturing. PVC, unlike most other plastics, is 57 percent chlorine by weight--and chlorine gas, acutely hazardous if inhaled, is on the EPA's list of extremely hazardous substances. PVC production also creates hazardous byproducts."At numerous points in the vinyl life cycle," Thornton writes, "very large quantities of hazardous organochlorine by-products are formed accidentally and released into the environment." Steingraber adds that when the chlorine is combined with ethylene it forms an oily liquid, ethelyne dichloride (EDC), which is reasonably anticipated to be a carcinogen and can leak into groundwater. Steingraber also points to studies that link the vinyl chloride monomer to liver, blood, and brain cancers in PVC manufacturing workers. And transporting vinyl chloride has been declared "ultra-hazardous" by the National Toxicology Program, resulting in emergency legislation early in 2005 banning truck or train transport of vinyl chloride through the District of Columbia--yet liquid vinyl chloride is used by construction workers in gluing PVC pipe joints. The most harmful byproducts of PVC manufacture and disposal, however, are dioxins, which, Thornton writes, are "the most potent synthetic carcinogen ever tested in laboratory animals and appear to be equally carcinogenic in people." Some PVC products require toxic additives--such as phthalates, lead, cadmium, and tin--to make them stable and usable. As PVC is inherently rigid and brittle, phthalate plasticizers are added (in amounts of up to 60 percent of the product's weight) to make flexible vinyl products such as drip irrigation tubing, garden hoses, and lawn edging. Studies show that phthalates are released into the environment during PVC manufacture and disposal in landfills or incinerators. The EPA's National Toxicology Program classifies diethylhexyl phthalate (DEHP), the most common plasticizer, as a human carcinogen. Research has also recently linked DEHP to abnormal reproductive tract development in male babies. Metal stabilizers such as lead, cadmium, and tin are also added to PVC to extend the life of some products, yet these metals are neurotoxins for humans. Significant quantities of lead have been found in water flowing from PVC pipes. End-of-life impacts. Many studies indicate that PVC disposal has environmental and health impacts, and disposal is a major issue since an estimated seven billion pounds of PVC are discarded every year. Studies show that plasticizers in landfills can leach into air and groundwater, and burning PVC releases dioxin, chlorine compounds, and heavy metals. While incineration of waste is strictly regulated, the ash containing these chemicals is disposed of in landfills and can seep into groundwater. Additionally, unregulated burning of PVC products releases large amounts of dioxin into the air and soil. (Steingraber recalls that the burning vinyl from the 9/11 attack on the World Trade Center created a dioxin cloud that hung over lower Manhattan.) Recycling prospects for PVC are extremely limited. Post-consumer recycling results in "downcycled" products that don't have equivalent qualities to the original PVC products. And because PVC is a contaminant, according to the American Plastic Recyclers Association, one PVC product mixed in with other plastics being recycled can contaminate the entire batch.
The Debate in the Building Industry and Beyond While the environmental and health impacts of PVC have been proven by many research studies, vinyl industry groups point to other studies (some of which they sponsored) that show far fewer harmful effects of PVC. And while many hazards are proven, in some cases the degree of exposure that causes harm is not well understood. As a result, environmental groups, green building organizations, and national and foreign public agencies are discussing whether to encourage less use of PVC or to advocate a total phase-out. As groups debate the issue, they point to flaws in research methods and question motivations behind the various studies. John Motloch, director of Ball State's Land Design Institute, cautions that one should know the organization that commissioned the study and what its motivations are when examining results. "Any organization that seeks to contribute positively to the dialogue," says Motloch, "should base its statements and communications upon research generated outside the PVC industry and should cast a wary eye toward research funded directly or indirectly by the PVC industry." The PVC debate is in full force at the U.S. Green Building Council, sponsors of the LEED system. In response to a proposed credit awarding PVC-free projects, the USGBC formed a task force that has been studying the PVC issue since 2002. The task force's extensive process has involved solicitation of research and technical studies from stakeholders, life-cycle and risk analysis for PVC products and their alternatives, and an online forum for members and the public to submit comments. Thousands of stakeholders, from industry organizations to designers, are awaiting the outcome of the study, which is sure to have an enormous effect on the PVC and construction industries. Policy makers in European countries and some U.S. states and municipalities are discussing reducing the use of PVC. The United Nations Stockholm Convention aims to reduce releases of persistant organic pollutants, and the European Union is debating the REACH proposal, a policy requiring the registration of all toxic chemicals, including PVC. In 2002, the Seattle City Council passed Resolution 30487, which directs city departments to reduce the use of materials that contain or emit persistent bioaccumulative toxins (PBTs), including PVC. Seattle's Office of Sustainability and Environment developed an implementation plan focusing on reducing PVC in building materials in city projects. And the state of New York and cities of San Francisco and Boston are also encouraging less use of products that contain PBTs. Even some major corporations such as Microsoft, Sony, Wal-Mart, General Motors and Honda are looking for PVC-free alternatives. Alternatives to PVC do exist, but changing the industry standard will involve many costs that must be borne by individual projects and government agencies.
PVC-Free Alternatives
A PVC alternatives study performed for the city of Seattle also found HDPE and PEX to be good alternatives for some pipe and conduit applications. These findings have resulted in changes to HDPE pipe for drain lines in Seattle Parks Planning and Development Division standard specifications. These changes are being piloted with six miles of four-inch HDPE drain lines for the city's Magnuson Sports Meadow project. An examination of costs on this project found a savings of $2,170 for 31,000 feet of pipe. (The PVC cost was $.76 per foot, and the HDPE cost $.69 per foot.) In general, however, the cost of HDPE pipe is higher because of different construction and joining methods. Brett Jefferys, Director of Irrigation Services with EDAW's Fort Collins, Colorado, office, has found the material cost of HDPE pipe to be only 16 percent higher in irrigation water supply applications, but the installation cost is sometimes twice as high because contractors lack familiarity with the fuse-welding installation methods and need special equipment to accomplish it. Jefferys says that fuse-welding actually produces a better water line as the weld is less likely to leak than the typical PVC glue fitting, and HDPE's flexibility results in fewer ruptures from freezing and construction around the pipes. Jefferys sees HDPE increasingly used for mainline irrigation pipes on large projects such as golf courses and large parks; he adds that the price should come down substantially as contractors get more requests for HDPE, become more familiar with the material, and purchase the necessary welding equipment. HDPE is more commonly used in stormwater applications. Michelle Adams, principal engineer with Cahill Associates in Philadelphia, explains that Cahill routinely specs HDPE for stormwater pipes for underground stormwater retention structures. But Cahill often specs PVC for inlets, catch basins, and cleanouts because few options are as structurally sound. In wastewater applications, PVC is often required by codes. Because of its corrosion resistance, durability, and economics. "The real issue, however, is acceptance of alternatives by regulating agencies," Benz says. "Regulating agencies are reluctant to vary from a tried and true product." In irrigation applications, HDPE and polyethelene (PE) are comparable alternatives to PVC for all irrigation components. Jeffreys explains that EDAW's standard spec for lateral lines is still PVC for economic reasons, but EDAW is increasingly using PE pipe that has a clamp insert fitting connection in both nonpressurized and pressurized applications. Drip irrigation components and soaker hoses can also be found in HDPE.
Fencing, Railing, and Decking Polyethelene-coated composite lumber and hollow HDPE fencing and decking products, very similar to PVC, are manufactured by only a few companies but seem to be gaining a share of the market. Manufacturers claim that these products will last longer than PVC, which is susceptible to failure in extreme cold temperatures and is said to lose strength as it ages. These products, with recycled contents ranging from 10 to100 percent, can also be cut and joined in a similar manner to wood, whereas PVC has special connections that accommodate its high thermal expansion and contraction. The hollow HDPE products claim to have thicker walls, making the product stronger and more durable without the metal or wood reinforcing that PVC fencing requires. Some companies offer both vinyl and HDPE fence, gate, and decking products, so careful examination of the product literature is critical. HDPE or composite plastic lumber can also be used to make custom-built fences. Vinyl-coated chain-link fencing comes in a range of colors and weather protection. An alternative to vinyl coating is a polyester powdercoating that is electrostatically applied to the chain-link. While the polyester powdercoating is not without environmental effects, it appears to be less harmful than vinyl. Some manufacturers offer both options and will guarantee the vinyl coating for 12 years and the polyester coating for 15 years. Mark Brumbaugh of Brumbaugh & Associates, landscape architects, emphasizes the importance of "assuring that any viable replacement for PVC is not equally onerous in some aspect of the product life cycle." For instance, PE pipe is less dense than PVC, so to make a similar product, manufacturers may need to use more PE than they would PVC. An Environment Canada report states that when three times as much PE is used, the toxic numbers start to be just as high as those of PVC. As the debate continues over just how harmful PVC really is, many green building industry leaders, including Lucia Athens, chair of the city of Seattle's Green Building Team, argue for approaching the PVC issue within the framework of the Precautionary Principle adopted by the U.N. Conference on the Environment and Development in 1992. This principle reads: Where an activity raises threat of harm to the environment or human health, precautionary measures should be taken even if some cause and effect relationships are not fully established. "The Precautionary Principle," Athens says, "permits a lower level proof of harm to be used in policy making whenever the consequences of waiting for higher levels of proof may be costly or irreversible." Athens goes on to emphasize that many other materials and products containing PBTs should be examined by policy makers as well. A positive result of the PVC debate is the increasing research on the harmful aspects of PVC, so hazards that were relatively unproven 10 years ago are better understood today. And as the dialogue moves into the construction industry through efforts of organizations like Healthy Building News and the U.S. Green Building Council, designers and policy makers will start to investigate alternative products and materials. Meg Calkins is an assistant professor in the Department of Landscape Architecture at Ball State University.
Resources Healthy Building News offers a PVC-alternatives database at http://www.healthybuilding.net/pvc/PVCFreeAlts.html. The database, organized by CSI divisions, lists product types and links to suppliers. Healthy Building News claims it is a work in progress, but it is a good resource. Greenpeace offers a PVC-alternatives database at http://archive.greenpeace.org/toxics/pvcdatabase. This is an international database oriented primarily to architectural and pipe applications and currently does not list fencing and decking alternatives. GreenSpec, http://www.buildinggreen.com/menus, is a subscription product information service that provides detailed listings for 1,800 environmentally preferable products. While this is not a PVC-free database, it does list many alternatives to PVC products screened carefully by Building Green's staff. It contains links to manufacturers and additional resources.
Reprinted Courtesy of Landscape Architecture Magazine, March 2006.
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