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Who’s the Greenest?
LCA organizations are well aware that they may be sought out for market advantage, not simply eco-altruism. For example, EPD notes that one of its primary goals is “to provide the basis for a fair comparison between goods and services having the same principal function based on their inherent environmental performance.”


But often direct comparison of LCA results from different systems such as BEES, Athena or EPD is tough. For example, which data should carry more weight—a product’s CO2 emissions and impact on global warming, or its contribution to water pollution? Or its level of known carcinogens?


“LCAs and Social Impact Analyses (SIAs) are highly technical,” says sustainability design expert Nathan Shedroff f (www.nathan.com). “This makes engineers and builders comfortable. However, they suffer greatly from ‘garbage in, garbage out,’ and, as such, can be a little malleable to make whatever point someone wants to make.”


A good example is the new LCA (actually an LCIA, or life-cycle impact assessment) of insulating vinyl siding done by CertainTeed, using the BEES modeling system. It’s the kind of information that should make comparing siding products for their environmental impacts easy. But it’s not that simple. For example, the data compares certain brands of vinyl with cedar siding, and on some criteria, the wood siding is slightly more toxic to the environment, presumably because of chemicals used in long-term maintenance. BEES does “weight” different impact categories, but choosing the “greenest” product can still be tough when you’re looking at two rated products side by side, especially for consumers without any technical knowledge.


Another problem is that not every product in a category will have LCA data available. So how can companies that have taken the high road hold their products up side by side with competitors? Some of the LCA databases do contain information on general materials, but not necessarily branded products. Cosentino, for example, has plenty of EPD data on its Eco by Cosentino line, but how do they compare with solid surfacing countertops that have not completed LCA analyses?


 


VINYL’S CHANCE TO SHINE
GB gives the PVC industry a chance to make its case for reduced environmental impacts.
By Matthew Power, Editor-In-Chief


I’ve often expressed skepticism at the vinyl industry’s contention that their products should be considered “green.” My reasons? Past research I’ve read on toxins released in the material’s manufacture, weak research on durability (siding and windows especially), and lack of recycling of post-consumer PVC.


We know a lot of you have similar concerns. In fact, when we ran some advertising for the vinyl people a couple years ago, we took a lot of heat from our readers, who frankly thought we were sellouts. So about a year ago, I told representatives from the vinyl industry that if they would answer some tough questions with third-party science, we would give them a fair shake. To their credit, they came through. Here’s our interchange with Sustainable Solutions, the firm they assigned to reply to our technical queries. We had to shorten some responses, but you can read the whole exchange on our website here: http://greenbuildermag.com/GBM/media/videos/PDF/Vinyl-Questions-Answered.pdf


GB: Although many claims are made about PVC’s long life and durability, it’s impossible to find any data on vinyl siding lifespan—or vinyl window lifespan. I hear anecdotally from builders that it doesn’t hold up—at least the old stuff prior to better UV inhibitors.


SS: There is, unfortunately, very little research available on the viable lifetime of vinyl siding and many other, newer building products. This is due to the fact that there simply hasn’t been sufficient time for vinyl siding, particularly the newer, more durable formulations, to demonstrate the ability to endure for decades. There are examples of homes that have had vinyl siding for 30-40 years without the need for replacement, and examples of homes that have needed to replace their vinyl siding more frequently; however, the numerous claims about vinyl siding’s durability and long life are based on several key factors. These factors include the 50-year and lifetime warranties offered by manufacturers as well as the improved UV resistance and impact resistance of current vinyl siding products.


In the decades since vinyl siding was first developed, significant improvements have been made to the manufacturing process. The move from plastic pellets to a blended, engineered powder in the 1970s resulted in a more consistent and durable product … The outer layer, the topcoat, includes UV-inhibitors, which protect it and the inner layer, the substrate, from UV damage. Co-extrusion also makes it easier to incorporate recycled content into the product, because it can be mixed into the substrate.


GB: I’m sure you’re familiar with the Greenpeace pyramid of plastics. Vinyl does very poorly (http://archive.greenpeace.org/toxics/pvcdatabase/bad.html). I’ve heard similar things from material scientists. Why not use HDPE or some other more easily recyclable plastic to do the same job?


SS: The Greenpeace Pyramid of Plastics provides a qualitative ranking that does not include complete life-cycle data for the comparison of the environmental impacts of various plastic resins. The Pyramid only examines “the production, additives, product emissions during use, disposal and recycling.” Also, it is not clear if the Greenpeace Pyramid includes any risk-exposure analysis. All materials cause negative impacts to the environment, and it is important to use the best data at hand to choose materials that are low-impact and appropriate to their use. It is better to use complete LCA data when comparing plastic resins.

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