Recently in Healthy Building News, Jim Vallette described positive changes in the composition of residential fiberglass insulation where formaldehyde has been completely phased out in the US and Canada.(1) We have also learned, in the course of research for the BlueGreen Alliance Foundation, that significant material changes are imminent in polystyrene insulation as well, where commonly used blowing agents and hazardous flame retardants are slated for phase out in the coming years.
Rigid polystyrene foam insulation – often referred to by Dow’s trade name for its polystyrene product, Styrofoam™ – comes in two forms, expanded and extruded polystyrene (EPS and XPS). These products primarily differ in their manufacturing process and blowing agents, leading to differing performance and cost. Both can be used in a variety of insulation applications including under slab, foundation wall, and exterior wall sheathing, and both currently include substances of concern for human and environmental health.
Flame retardants are used in polystyrene foam insulation in order to meet building code and fire safety requirements.(2) HBCD (hexabromocyclododecane), the standard flame retardant treatment for both XPS and EPS insulation products (3), is a highly toxic, persistent, and bioaccumulative chemical.(4) It has been widely found in humans and the environment, is highly toxic to aquatic life, and a known human health hazard.(5)
In 2010, the US EPA initiated an alternatives assessment to determine less hazardous alternatives to HBCD flame retardant in polystyrene building insulation. Their final report, released in June 2014, outlines the hazards of HBCD and identifies the alternative butadiene styrene brominated copolymer (trade name PolyFR) as having low hazards for human and aquatic toxicity.(6) While the health and environmental impacts of this alternative are believed to be lower than HBCD, there are still data gaps for this particular substance, which should be further explored.
In the meantime, other countries have already adopted the use of this alternative. Japan banned the use of HBCD as of May 2014 with the EU close behind in August 2015. According to Exiba, the trade association for XPS manufacturers in the EU, all member organizations met the August 2015 deadline for discontinuing use of HBCD.(7)
Not all polystyrene insulation manufacturers were onboard with this transition timeline, however. In February of 2014, several EPS manufacturers petitioned the European Chemicals Agency for an extension on the use of HBCD. BASF opposed this extension, stating that, “A safer and better alternative to HBCD is available and already successfully introduced,” and that, “extensive tests with EPS and extruded polystyrene (XPS) containing PolyFR have shown that the foam properties are equal to those of material containing HBCD.”(8)
Environment Canada also proposed a ban on HBCD in polystyrene foam insulation in April of 2015. The period for public comment has passed, but the outcome is unclear at this time.(9) The proposal stated that, “EPS and XPS foams that contain HBCD and are used for building or construction applications would be prohibited after December 31, 2016.”(10)
Despite these changes in other parts of the world, consumers in the US will have to wait a while longer. Both industry associations for North American manufacturers – the Extruded Polystyrene Foam Association (XPSA) and the EPS Industry Alliance – indicate that the changeover is currently underway, but product literature still indicates the use of HBCD or does not disclose the specific flame retardant used. The EPS Industry Alliance noted in a June 2013 bulletin that, “The polystyrene foam insulation industry has begun the steps to make production changes and conduct performance testing required to satisfy the necessary approval processes such as building code evaluation reports. These are important steps in the transition process, but it will take time to be fully implemented.”(11) In a document published sometime after June 2014, the XPSA stated that, "A transition from HBCD to the alternative flame retardants assessed under the DfE program is expected to occur over the next four to five years, as global production capacity of the new flame retardants ramps up."(12) Just months later in November 2014, BASF reported that, “Another PolyFR manufacturer has recently announced that it has started up a new production line. This means that the global demand for PolyFR can be satisfied.”(13) It is unclear how this increased production capacity may impact the adoption timeline.
Polystyrene insulation manufacturers in the US and Canada are also playing catch-up on blowing agents. Polystyrene insulation requires the use of blowing agents during manufacturing to expand the plastic (polystyrene) into a closed cell foam structure, which increases the insulation properties. The blowing agent is off-gassed during the course of manufacture, use, and disposal of the insulation. In the case of EPS, the blowing agents are typically mixtures of pentane isomers, which are air pollution concerns but not significant factors for global warming. The blowing agents used in XPS, however, are powerful global warming agents and are present in the final product at approximately 9% by weight. The most commonly used blowing agent in XPS insulation, HFC-134a, has a global warming potential (GWP) of 1,430. This means it is a 1,430 times more powerful global warming agent than carbon dioxide. (14)
In the past, regulations have pushed the industry away from environmentally damaging blowing agents (such as the ban on ozone depleting chlorofluorocarbons under the Montreal Protocol), and an EPA rule is set to do so again. The rule, enacted in July 2015, will require XPS manufacturers to stop using high GWP HFCs by the year 2021.(15) Alternative blowing agents are already available and in use in XPS made in Europe.(16) Exiba, the EU XPS trade association, reports that the large majority of their members do not use fluorinated greenhouse gases as blowing agents.(17) But the EPA cites North American industry concerns – manufacturers say they need time to change over equipment and complete new product certifications – in allowing the industry six more years to use HFCs in polystyrene insulation.(18)
The primary replacement for current HFC blowing agents, HFO-1234ze, has a far lower GWP of six, compared to HFC-134a’s GWP of 1,430. So this transition, when it happens, will dramatically decrease the global warming impact of XPS insulation.(19)
Positive environmental and human health changes are coming to polystyrene foam insulation, but with no specific timeline in place for the phase out of HBCD and years left till the EPA regulations on HFCs take effect, it is unclear how quickly these improved products will be available to consumers in the US and Canada.
(1) Jim Vallette, “Residential Fiberglass Insulation Transformed: Formaldehyde is No More,” Healthy Building News, October 30, 2015, http://www.healthybuilding.net/news/2015/10/30/residential-fiberglass-insulation-transformed-formaldehyde-is-no-more
(2) US EPA, Flame Retardant Alternatives for Hexabromocyclododecane (HBCD), June 2014, http://www2.epa.gov/sites/production/files/2014-06/documents/hbcd_report.pdf (EPA HBCD)
(3) Extruded Polystyrene Foam Association, XPSA - Q&A on flame retardants and XPS foam insulation, http://www.xpsa.com/pdf/XPSA_QA_on_HBCD_and_DfE_Report_Final.pdf (XPSA); EPS Industry Alliance, Flame Retardants: Fire Resistance In Building and Construction Applications, 2012, http://www.epsindustry.org/sites/default/files /Polystyrene%20Industry%20Flame%20Retardants%20Bulletin%20-%20EPSIA.pdf, (EPS)
(4) Pharos Project, [3194-55-6] HEXABROMOCYCLODODECANE, last updated January 10, 2013, https://www.pharosproject.net/material/show/2004475
(5) EPA HBCD
(6) EPA HBCD
(7) Exiba, After sunset – according to REACH, HBCD is banned after 21st of August 2015, last updated 25 September 2015, http://www.exiba.org/hbcd-banned (Exiba)
(8) Dede Williams, “BASF Opposes Extension of HBCD Flame Retardants,” CHEManager International, June 20, 2014, http://www.chemanager-online.com/en/news-opinions/headlines/basf-opposes-extension-hbcd-flame-retardants
(9) Environment Canada, Hexabromocyclododecane, last updated April 23, 2014, http://www.ec.gc.ca/toxiques-toxics/Default.asp?lang=En&n=58F1CC80-1
(10) Environment Canada, Regulations Amending the Prohibition of Certain Toxic Substances Regulations, 2012, April 4, 2015, http://www.gazette.gc.ca/rp-pr/p1/2015/2015-04-04/html/reg2-eng.php
(13) BASF, Fire protection with an improved environmental profile, November 25, 2014, http://www.standort-ludwigshafen.basf.de/group/corporate/site-ludwigshafen/en/news-and-media-relations/news-releases/P-14-407
(14) US EPA, “Global Warming Potentials and Ozone Depletion Potentials of Some Ozone-Depleting Substances and Alternatives Listed by the SNAP Program,” last updated November 6, 2014, http://www3.epa.gov/ozone/snap/subsgwps.html (EPA GWP)
(15) 40 CFR Part 82: Protection of Stratospheric Ozone: Change of Listing Status for Certain Substitutes Under the Significant New Alternatives Policy Program; Final Rule, July 20, 2015, http://www.gpo.gov/fdsys/pkg/FR-2015-07-20/pdf/2015-17066.pdf (Final Rule)
(16) Scott Gibson, “Friendlier Foam Insulation On the Way, Eventually,” Green Building Advisor, June 2, 2015, http://www.greenbuildingadvisor.com/blogs/dept/green-building-blog/friendlier-foam-insulation-way-eventually; also, Exiba
(18) Final Rule
(19) EPA GWP