How Green is Polystyrene Insulation? EBN's Position, and How It Affects GreenSpec-Listed Products

Chart from the feature (requires login): Human Health and Environmental Concerns with Polystyrene Constituents (click image to enlarge)

The August EBN feature article, "Polystyrene Insulation: Does it Belong in a Green Building?" (requires BuildingGreen Suite membership) and an accompanying editorial "Rethinking Polystyrene Insulation" (free content) has led our company to reexamine some of the products we list in the GreenSpec Directory.

As those articles (and the related blog post, "Avoid Polystyrene Insulation") point out, there are some troubling health and environmental concerns with both extruded and expanded polystyrene insulation (XPS and EPS). These concerns relate both to the underlying chemistry of polystyrene (especially the benzene used in its manufacture) and a flame retardant, HBCD, that is used in all building-related XPS and EPS products.

Given these concerns, our editorial staff reached the conclusion that polystyrene insulation made with HBCD is "less green" than most other insulation materials. This doesn't mean that there aren't green products made with EPS or that alternative products are necessarily benign. But when there are alternative insulation products that we consider to be more attractive from a health or environmental standpoint and when they offer comparable energy performance, then we consider those alternative materials to be preferable.

So, what does this mean relative to our GreenSpec listings?

Due to environmental concerns with ozone-depleting HCFC blowing agents (which are to be phased out by the end of this year), we do not, and have never, included XPS products in GreenSpec, so there is no change there.

We did remove several EPS boardstock insulation products, and we are working hard to replace them with what we believe to be greener products, such as additional rigid mineral wool insulation products.

However, there are a lot of EPS-based products that are remaining in GreenSpec because we believe that their energy-saving benefits outweigh the health and environmental concerns. These are mostly structural insulated panels (SIPs) and insulated concrete forms (ICFs) — of which we list dozens of each — as well as some specialized products, such as exterior insulation systems used for insulating existing buildings. These products are being used in many of the lowest-energy buildings being built today. Note that our inclusion of these products may be reconsidered in the future if good, non-EPS alternatives emerge in the marketplace and EPS manufacturers fail to find an alternative to HBCD. While we very much hope to see the HBCD flame retardant removed from these products — and we are confident that manufacturers are working to identify safer replacement chemicals — we recognize that energy performance of buildings is a top environmental priority, and EPS continues to play a vital role with many such products.

We look forward to participating in a dialog about life-cycle concerns with polystyrene insulation and hope that our position begins that discussion.

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