March 20, 2007
For several years, product manufacturers, designers, and other building industry professionals have been anxiously awaiting the final report by a U.S. Green Building Council committee studying the environmental and health impacts of polyvinyl chloride (PVC), a widespread compound used in many building materials. Although the waiting came to end last month, the determination was far from straightforward.
Since late 2002, the council’s Technical and Scientific Advisory Committee (TSAC) has been evaluating a proposed change to the LEED rating system that would add a credit for avoiding the use of PVC, commonly known as vinyl. Like an earlier draft released two years ago, the final report does not endorse a vinyl-avoidance credit. But as TSAC chair Malcolm Lewis observes, it does provide a “nuanced answer” to the question “does the available evidence indicate that PVC-based materials are consistently among the worst in terms of environmental and health impacts?” Many stakeholders would have liked a clear-cut answer, he adds, but “it is much more complicated than that.”
TSAC combined lifecycle assessment and risk assessment to study four common applications for vinyl: siding, piping, resilient flooring, and window frames. The committee found the material’s performance varied depending on how broadly its lifespan was defined, and on whether the investigative focus was PVC’s impact on human health or the environment. Its report concludes that vinyl performs better than many alternative materials if the life of the material is defined narrowly as “cradle through use.” But it notes that when occupational exposure and end-of-life issues, such as burning the material in a backyard or landfill, are taken into account, “PVC is among the worst materials studied for human health risk.” Burning PVC releases dioxins, toxins that can cause cancer.
Tim Burns, president of the Vinyl Institute, called the committee’s recommendation that LEED not include a credit for PVC avoidance “the right decision.” But he expressed concern about the robustness and applicability of the TSAC data. “Landfill fires are extremely rare in the United States, and burning of waste at construction sites is outlawed in most jurisdictions, so this is largely a non-issue,” Burns says.
Lewis acknowledges that the data regarding backyard burning and landfill fires are incomplete, but he counters that “the data that does exist [indicates] that there is a serious end-of-life problem.”
In addition to its conclusions about the environmental and health impacts of vinyl, TSAC also released a set of recommendations regarding how materials should be assessed in LEED. These include a call for more integrated methods for product evaluation that depend on a “comprehensive, whole-building approach,” and the creation of credits that provide incentives for the development and use of improved products.
The Healthy Building Network, a national group of building professionals and environmental advocates, praised the committee’s findings and recommendations. “This approach makes sense to us,” says Tom Lent, the organization’s policy director. “It will help avoid the replacement of one material with another that could also have a negative impact.”
Although TSAC did not recommend the creation of a PVC-related credit, rating system modifications could follow. The next step is for the LEED steering committee to evaluate the report’s policy implications. A timeline for this task has yet to be set.