The other day I came across a plastic house. Not the futuristic World’s Fair variety--this was just an ordinary old house that had been “improved” with a brace of glaring-white vinyl windows, lots of wavy vinyl siding, and some flimsy looking vinyl gutters and downspouts. As icing on the petrochemical cake, it was ringed by a white vinyl picket fence. If there were any termites left in the place, they must have been pretty hungry.
Vinyl is, of course, the plastics industry’s more euphonious name for polyvinyl chloride, or PVC . It’s the world’s second-largest commodity plastic, second only to polyethylene. About 35 million tons of the stuff are cranked out in a typical year, but with the housing market in rebound, production is now predicted to reach 49 million tons by 2017.
You may be surprised to learn that the building industry is the world’s biggest consumer of PVC. According to an industry website, <pvc.org>, about 23% of PVC production is used for pipes and fittings alone. Another 27 % goes to extruded profiles such as those used in vinyl window frames, gutters, and the like, and 10% or so to other building applications such as coatings and vinyl flooring (the latter, not to be confused with more eco-friendly linoleum, shows up in two out of three American kitchens).
Like many other environmentally troubling manmade materials, PVC starts out innocuously enough: its raw ingredients are salt and petroleum. Salt water is electrolyzed to produce chlorine, which is then combined with ethylene obtained from oil to produce ethylene dichloride. This compound is processed at high temperature to create a vinyl chloride monomer--still with me?--which is finally polymerized to form a polyvinyl chloride resin. Various additives make the resin suitable for different uses and protect it from its archenemy, ultraviolet light.
The final result is a material that’s cheap and easily processed, which is one reason millions of tons of PVC are gobbled up each year in the form of vinyl windows, siding, gutters, flooring, and other economy-grade building products. Alas, when these not-very-substantial products end up in the landfill--which they usually do much sooner than the traditional materials they aim to displace--there’s trouble. A number of environmental authorities consider PVC to be the most toxic plastic in the environment. Bury it in a landfill, and it just sits there. Burn it, and it produces dioxin, a toxic chemical compound that’s a known teratogen, mutagen, and carcinogen.
PVC has proven its usefulness in many applications. On the other hand, it’s also wended its way into markets for which it simply isn’t suited. PVC gutters, for example, are neither durable nor attractive--in fact, other than their cheap first cost, they have no advantage whatever over more traditional gutter materials such as sheet metal, wood, aluminum or copper. The same goes for PVC fencing and the host of other nominally architectural PVC products on the market. Even in the vastly successful arena of vinyl windows, long term durability remains an unknown, manufacturer’s claims notwithstanding.
Every miracle material conjured up by man has downsides, and PVC is no exception. Since for practically every newfangled architectural use of PVC there are more eco-friendly traditional materials at hand, it’s worth thinking twice before choosing “vinyl” for your home. By any other name, it’s still 35 million tons of PVC.