Vinyl Windows and Vinyl Siding
Can a house with plastic components be considered green?
Should vinylCommon term for polyvinyl chloride (PVC). In chemistry, vinyl refers to a carbon-and-hydrogen group (H2C=CH–) that attaches to another functional group, such as chlorine (vinyl chloride) or acetate (vinyl acetate). building materials be banned from green homes? Some environmentalists think so. There seem to be three categories of building materials that particularly irk the anti-PVC crowd: vinyl siding, vinyl windows, and vinyl flooring. Since there are alternatives to all of these materials, these environmentalists argue, green homes shouldn’t include any of them. (Although the anti-vinyl group sometimes mentions PVC pipe used for drains and vents, it seems that neither plastic pipe nor the vinyl insulation on Romex wiring raises as many hackles as vinyl siding, windows, and flooring.)
Vinyl-framed windows now outsell windows with wooden frames, aluminum frames, or fiberglass frames. Moreover, in many areas of the country, vinyl siding outsells all other types of residential claddingMaterials used on the roof and walls to enclose a house, providing protection against weather. , and PVC is by far the most common material used to manufacture residential drain pipes. While these facts probably distress anti-vinyl crusaders, they provide evidence that these vinyl building products outperform competing products in some ways. Vinyl building products fill a niche. Vinyl is durable, weather-resistant, low-maintenance, and affordable.
The anti-vinyl position rests on several arguments:
- The raw materials used to manufacture vinyl — chlorine and fossil fuels — are associated with environmental problems.
- Some of the chemicals present in vinyl as a contaminant — especially dioxin — raise environmental concerns.
- Workers in plants that manufacture PVC resin face health risks.
- Some vinyl products include plasticizers that may be released into indoor air, potentially damaging occupants’ health.
- When vinyl building products wear out, they aren’t always disposed of in an environmentally appropriate way.
- When buildings catch fire, vinyl building products release toxic smoke, endangering firefighters.
- A life-cycle assessment of vinyl’s environmental impacts may indicate that vinyl is less desirable than some alternatives.
All of the above arguments have been used by anti-vinyl groups. Some of the points are indisputable, while others are debatable. On some points, evidence points to an opposite conclusion than the one reached by anti-vinyl crusaders. On other points, the evidence is inconclusive, and more research is needed before we can reach firm conclusions.
For a good background on the issues surrounding the PVC debate, I recommend an Environmental Building News article written in 1994 by Nadav Malin and Alex Wilson, Should We Phase Out PVC?
Environmental life-cycle assessments attempt to weigh all of the pluses and minuses of building materials so that one product can be compared to another. It’s important to remember than any life-cycle assessment is only partially scientific, and involves more judgment than calculation.
The U.S. Green Building Council (USGBC) has issued at least two reports on PVC building materials — a 2004 draft report, followed by a 2007 final version called “Assessment of Technical Basis for a PVC-Related Materials Credit for LEED.”
In the 2004 draft report, the authors wrote, “Using current data for LCALife-cycle assessment. Examination of environmental and health impacts of a product or material over its life cycle; provides a mechanism for comparing different products and materials for green building. [Life-Cycle Assessment] and risk assessment, our analysis of the chosen building material alternatives shows that PVC does not emerge as a clear winner or loser. In other words, the available evidence does not support a conclusion that PVC is consistently worse than alternative materials on a life cycle environmental and health basis. … Therefore, the current body of knowledge as analyzed in this report … does not support a credit in the LEED rating system for eliminating PVC or any other material.”
According to the best available evidence, many vinyl building materials are preferable to available alternatives. The authors of the 2007 USGBC report concluded, “The evidence indicates that a credit that rewards avoidance of PVC could steer decision makers toward using materials that are worse on most environmental impacts, except for the case of resilient flooring, in which sheet vinyl and VCT are worse than the alternative materials studied for most environmental impacts.”
The environmental effects of disposing of worn-out vinyl materials are hard to pin down. The authors of the 2007 USGBC report wrote, “Data on end-of-life emissions are highly uncertain and therefore there is a wide range of exposure possibilities; if end-of-life emissions are close to the upper end of our range, then PVC is among the worst materials studied for health risk, but if end-of-life emissions are close to the lower end of our range of possible values, then PVC is among the mid or better materials studied for health risk in the product categories of window frames, pipe, and siding.”
According to the 1994 Environmental Building News (EBN) article on vinyl, “Except for the space taken up, landfilling PVC is not usually a problem. Attesting to the stability of PVC in landfills is the fact that most landfill liners are made from PVC.”
Although there are valid reasons for concerns over the health of workers in plants that manufacture PVC resin, it’s important to note that workers’ exposure to dangerous emissions in these plants have dropped in recent decades.
According to the 1994 EBN article, “In 1971 a rare cancer of the liver, angiosarcoma, was traced to vinyl chloride exposure among PVC workers, and strict workplace exposure limits were established by the Occupational Safety and Health Administration (OSHA). These restrictions necessitated radical changes in the manufacturing environment — all polymerization vats had to be sealed and controlled. … To the credit of the chlorine and PVC industries and government regulatory bodies, … vast improvements have been made in manufacturing processes over the past twenty years, and many of the worst environmental offenders (DDT, dieldrin, and CFCs, for example) are already gone or on their way out. The residual vinyl chloride gas in PVC products has been reduced to (perhaps) insignificant levels, compared with two decades ago. The environmental and health risks associated with PVC are greatest at the two ends of its lifetime: during manufacturing and disposal (if by incineration). Most PVC products are safe to use and some offer significant durability, cost, and maintenance advantages compared with competing products.”
A group representing the vinyl industry (an admittedly biased source) claims, “In reality, in today’s closely controlled and closed-loop manufacturing process, occupational exposure to VCM is so low that cancer (angiosarcoma or ASL) incidence is virtually zero. The Vinyl Institute says it is not aware of any U.S. worker being diagnosed with ASL who began employment after the OSHA standard was adopted in 1974.”
Workers face dangers when harvesting wood
Builders who prefer wood windows to vinyl windows need to acknowledge an important truth: you can’t have wood windows without logging, and logging is a dangerous profession — more dangerous than working in a chemical plant. I have friends and neighbors who work as loggers; one lost an eye in a logging accident, while another still limps from a serious leg injury.
According to one report on work injuries, “The highest rates of fatal injuries — the most per worker employed — occurred among loggers, pilots, and fishermen. Loggers recorded 85 fatalities in 2004, a rate of 92.4 deaths for every 100,000 workers, more than 22 times the rate among all workers. Loggers deal with tremendous weights when they fell trees and it’s not always possible to know exactly where a tree will fall or when. Too, they often work on steep hillsides, in poor weather, and in a hurry.”
Needless to say, I’m not advocating that green builders specify vinyl windows to reduce injuries to loggers. (The loggers I know enjoy their work, and don’t want to see their industry shrink.) I’m just pointing out the fact that workers in many industries face risks.
Moreover, the installation of siding and windows also carries risks — whatever material the products are made of. According to a government report, “Construction accounted for the second most fatal work injuries of any industry sector in 2011.”
A list of the ten deadliest jobs in the U.S. — a list based on government data — puts logging at #2 and roofing at #5.
Intuition doesn’t help
When builders and home buyers try to weigh the environmental pluses and minuses of different building materials, they often reach conclusions based on intuition rather than logic. But intuition can lead us astray. For example, how many builders know that fiber-cement siding requires more energy and water to manufacture than vinyl siding?
Intuition might lead you to think that cast-iron drain pipe is environmentally preferably to PVC pipe. But an article in Environmental Building News reports, “Because of the high embodied energyEnergy that goes into making a product; includes energy required for growth, extraction, and transportation of the raw material as well as manufacture, packaging, and transportation of the finished product. Embodied energy is often used to measure ecological cost. and the pollution emissions from coking plants used to produce cast iron, we have removed from GreenSpec cast-iron drain pipe, which had previously been listed as a greener alternative to the nearly ubiquitous PVC drain pipe installed in homes. And concerns about the energy intensity of fiber cement are forcing us to reexamine our endorsement of fiber-cement siding and shingles.”
Many elements of the anti-vinyl argument are emotional and inconsistent. Those who aim to build a plastic-free home rarely argue in favor of plastic-free computers or plastic-free cell phones. Similarly, very few people who are injured or sick insist on treatment in a plastic-free hospital — and considering the dependence of modern surgery and patient care on plastic materials, that's a very good thing.
Anyone who gets excited by the thought of owning a Prius needs to acknowledge that plastic materials are often extremely useful. According to one source, more than 50% of a typical vehicle’s volume is composed of plastics.
Only a small percentage of homeowners really want a plastic-free house. Most who do will end up compromising, since it’s hard to wire a house without vinyl-insulated electrical cable. If a few Luddites manage to build a plastic-free house, it’s likely to resemble homes built 150 years ago. It’s an achievable but impractical goal.
Writing in EBN in 1994, Malin and Wilson concluded, “For builders and architects, our recommendation is not to avoid vinyl altogether, but to seek out better, safer, and more environmentally responsible alternatives. Also, keep an eye on the PVC debate. A process has been put into motion that will take many years or even decades to unfold. Newer, safer, materials will almost certainly be developed by industries that are increasingly aware of environmental concerns.”
What really matters
So, does it really matter if your window frame is made of vinyl or something else? Perhaps. If you hate the idea of having any vinyl in your house, it obviously matters. If you can afford alternative materials, you should specify exactly what you want. When it comes to an environmental analysis, however, the bottom line on vinyl is uncertain.
To sum up:
- All materials, including wood and even recycled materials, carry an environmental cost.
- Workers in most industries associated with the manufacture of building materials and construction face a risk of job-related injuries or death. This problem is not restricted to workers in plants that manufacture PVC resin.
- It may make more sense to use fossil fuels to manufacture plastics than it does to burn fossil fuels in our car engines.
- Vinyl products are ubiquitous. While it makes sense to manufacture plastics in ways that minimize environmental impacts and to lower exposure to dangerous chemicals in the workplace, it’s important to emphasize that plastics are now essential for the manufacture of cars, airplanes, electronic devices, and medical equipment. Most Americans buy all kinds of vinyl-containing products — including pens, potato peelers, and beach toys — without a second thought.
- The biggest environmental impact associated with a home is the energy required to operate the building, not the impacts associated with material choices.
- If you want to minimize the environmental impact of a construction project, the best thing you can do is not to build a new building. If you insist on building a new building, make sure that it is as small as possible, and that it is built with energy efficiency in mind.
- Almost any type of flooring is a better choice than vinyl flooring.
Many of us fret about the environmental effects of our daily decisions, but we tend to focus on issues that don’t matter very much. Meanwhile, we manage to get the big things wrong. We may fret over whether we have properly separated recyclables from our trash, or fret over whether to choose a plastic bag or a paper bag when we go shopping. We may admonish family members who leave the water running while brushing their teeth. And when we build a new home, we wonder whether wood windows make more sense than vinyl windows.
But the biggest environmental impacts made by American families concern our profligate use of energy and our voracious appetite for raw and manufactured materials. The best thing we can do to lower our environmental impact is to stop shopping.
Instead of wondering whether you should buy vinyl siding or fiber-cement siding, you might consider whether there is any way to live in an old apartment building rather than to build a new house.
Martin Holladay’s previous blog: “Rainscreen Gaps and Igloos.”
- Intus Windows
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