Passive House Institute U.S. has decided to err on the side of environmental caution regarding the global-warming potential of spray foam insulation and the embodied energy of petroleum-based insulation materials in general, according to a recent post by Environmental Building News.
Specifically, PHIUS executive director Katrin Klingenberg told EBN last week that spray polyurethane foam (SPF) insulation using hydrofluorocarbon blowing agents with a high global warming potential would be disallowed on projects seeking certification through the institute’s PHIUS+ program, which was introduced in November and whose full details are due to be finalized by January 1. The no-SPF rule does not apply to most types of open-cell spray foam, and the new rule is optional for projects that had lined up PHIUS pre-certification before November.
PHIUS’s perspective on polyurethane spray foam also will carry over to its examination of and guidance on all insulation materials whose embodied energy is linked to greenhouse gas emissions.
“It does not make any sense at all to use them if one of the major overarching goals of energy conservation in buildings is to counteract and decrease global warming and climate change,” Klingenberg told EBN. “There really is no point to go through all the trouble of detailed Passive House design calculations if you use high-GWP [global-warming potential] spray foam.”
In place of spray foam insulation, PHIUS+ will recommend insulation materials with low embodied energy, unless the application is such that no other insulation material will yield the required performance. And while high-density expanded polystyrene is acceptable for below-grade uses, Klingenberg says she prefers the use of cellular glass, such as Foamglas.
SPF has long been seen by some in the building industry as a thorough and effective insulator when applied properly, and by others as a material whose use carries serious risks that extend well beyond the potential for greenhouse gas emissions. Overexposure to the polyisocyanates used in SPF, and in other building materials such as sealants and finishing products, can cause lung damage, trigger an asthmatic attack, or even cause fatal injury.
The potential for health problems among people exposed to uncured polyisocyanates – particularly methelene diphenyl diisocyanate, which is found in a number of consumer and commercial products, and toluene diisocyanate (TDI) – has prompted the Environmental Protection Agency to solicit data on the use of products containing the compounds, which could lead to additional regulations to ensure they’re used safely.
Get building science and energy efficiency advice, plus special offers, in your inbox.