Polyurethane credentials
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| Posted in Green Products and Materials on
In looking at polyurethane and its many variances, can the product considered in any way to be acceptable as a green product?
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You could argue that polyurethane products contribute to the performance of a "green" building, but always with regrets that the material itself is petroleum derived, toxic in various ways, not biodegradable, combustible and hazardous when burned. It is a banned substance within the Living Building Challenge (on the "materials red list"). Still it can be hard to entirely avoid in the process of building a well insulated and airtight structure.
The product has been promoted to me as being inert once manufactured. the supplier is acknowledgeing that it is petroleum based and during manufacture includes some toxic substances. Apparently it is slao able to be treated like a "cake mix" in that it can be beldned to exhibit various qualities. His assertion in regard to flamability is that his product can therefore be mixed to char rather than burn. essentially being self extinguishing. Yout thoughts?
What product are you talking about here? Presumably this is a component in a wall or roof assembly. There are many ways to build a wall or a roof, and with varying degrees of toxicity, risk, durability, thermal performance, cost, etc. It would be helpful if you start by describing what you are hoping to accomplish.
Product is to form part of the ceiling insulation layer in my building.
Tony,
You're going to hear a lot of opinions on this issue, many from builders who proclaim that the greenest building should be made out of straw, sticks, and mud. (In fact it's quite possible to build a home out of such materials.)
But most U.S. homes with green labels include copper wiring insulated with PVC, as well as many other plastic components, especially in the plumbing system and for air-sealing and insulation purposes. It's hard to completely avoid plastic, although some builders come close. Remember, once the homeowners move in, they're going to install a plastic computer, a plastic TV, a plastic radio, and a boxful of plastic toys for their kids. They will also park a car in the garage -- a car that is half plastic.
Wiring made of sticks and mud rather copper and plastic? That has some limitations. But insulation is one example of what could be either a significant quantity of not-so-green material or a much greener alternative. I think the evidence is clear that PU foam insulation is less green than other options, and of course the usual top recommendation is cellulose. In many circumstances, and especially with new construction, there's really no compromise or limitation in choosing a greener insulation.
I agree with Thomas. There may not be many alternatives to standard plumbing or electrical components but there are certainly some insulations that are far "greener" than others.
Ask yourself if you want someone mixing a "cake mix" out of toxic chemicals then spraying it inside your home.
Read the debate for yourself:
https://www.greenbuildingadvisor.com/blogs/dept/green-building-blog/does-spray-foam-insulation-out-gas-poisonous-fumes
https://www.greenbuildingadvisor.com/community/forum/green-products-and-materials/14537/out-gassing-bad-stuff-spray-foam-insulation
https://www.greenbuildingadvisor.com/blogs/dept/green-building-blog/tripolymer-spray-foam-insulation-healthy-choice
I think the question of building materials (or of the materials of commerce and commodities in general) is the most vital question of our upcoming age. Martin's initial blog states energy efficiency is the most important green building consideration. I agree but this points to the limitations of green building to make a positive impact on the environment. (And funny how our contemporary debates about the state of economy and its future projection don't consider the material basis of commerce.)
I've worked on projects that have used lots and lots of petroleum products. Do these projects have a positive impact on the environment? These projects have 'less an impact' as projects that follow the status quo. We need to be careful to avoid using 'green' as a justification.
You know the saying "all politics are local". All impacts are local. How many times have we seen reports of the consequences of material extraction, manufacturing, disposal on communities of people and other sentient beings? These are difficult issues with no easy clearcut answers and I hope people approach them with the intention of acting more compassionately to others having heard the stakes. What did I support when I bought the rigid EPS panel from Home Depot? I don't know exactly and that concerns me.
Another thing to think about is what these structures will look like at the point of demolition, some ways into the future. What will people say about this thing you've built, when it's exposed for autopsy? You can find pictures of old buildings pulled down, sometimes scooped entirely into a dumpster and other times carefully dismantled for scrap. Maybe it's tempting to think that day will never come for your building but unless it's made of solid brick, this is inevitable. Embedding framing in sticky foams does appear to seal up the envelope nicely, but eventually it will be a mess for someone to deal with.
To put this another way, consider the ethics of resource use from a long-term perspective. It takes a lot of trees to build a timber frame, but that's not quite the same as *consuming* those trees. The timbers could continue to be useful for centuries, either in the original structure or salvaged for a new one. Now compare that to something built from smaller pieces all stuck together with glues and sticky foams. It's less likely to have a long usable lifespan, nearly impossible to reuse and difficult to dispose of.
To Thomas' point, I've been throwing out much pine, cedar and redwood that's been in good shape recently because I have no good means of removing lead paint or storing the wood with the lead paint.
Although I'm a bit of a critic of Bill McDonough, the concept of a "monstrous hybrid" from the book "Cradle to Cradle" is an important one.
I think this is an excellent point. In a future where material and energy resources are dwindled or non-existant, a cornerstone of any future economy (if any) will have to be the recycling and scavenging of materials which we can no longer afford (in any terms you care to define) to harvest. A long view of these problems must be adopted or we will pre-emptively hamstring ourselves with "monstrous hybrids".
The concept of the monstrous hybrid brings to mind the Tetra Pak milk carton--so many layers of paper, plastic and metal all fused together. Plastic milk jugs easily turn into composite decking, but it's not so easy to turn old Tetra Paks into anything useful. It's an example where technology is counterproductive, because glass jugs can be rinsed and reused, plastic jugs get recycled or at least downcycled, and layered cartons end up in landfills.