Ecological Building Network - The Art and Science of Building Well

Excerpt by Bruce King from "Tradition and Sustainability" © 2010 The Prince's Foundation / Compendium Publishing

When I am working on a problem, I never think about beauty . . .

but when I have finished, if the solution is not beautiful, I know it is wrong.

Arlene Blum, Green Science Policy Institute

Polystyrene, polyisocyanurate, and polyurethane are highly energy efficient insulation materials whose use in green buildings is increasing.  However, due to their flammability, fire retardant chemicals (FRs) must be added to meet building codes.  Many of the FRs currently in use are halogenated organic chemicals, meaning that they contain chlorine or bromine bonded to carbon. Most of these FRs have not been adequately evaluated for their impact on human health and the environment. When tested, many are found to be persistent, bioaccumulative, and/or toxic. Being persistent means that they do not break down into safer chemicals in the environment over months or years. Being bioaccumulative means that they accumulate in plants and animals, becoming more concentrated as they move up the food chain.  Additionally, some of these FRs are carcinogens, mutagens, and/or reproductive, neurological, thyroid, and/or developmental toxicants.

The impacts of exposure to fire retardant chemicals upon workers, human and animal health, building occupants, wildlife and the global environment should be considered when selecting insulation materials.

• All polystyrene foam insulation used in building insulation (both XPS, such as Styrofoam, and EPS) is treated with hexabromocyclododecane, (HBCD), a persistent, bioaccumulating, and toxic fire retardant.  This chemical was recently nominated for the first EU list of sixteen "Substances of Very High Concern" and will likely be banned in Europe.  It has been widely detected in household dust, sewage sludge, breast milk and body fluids as well as wildlife and the global environment.   HBCD is also used with fabrics and plastic; however 85% is used with polystyrene insulation, which is likely the primary source of the global contamination.

• Polyisocyanurate (polyurethane) board often contains TCPP (tris (1-chloro-2-propyl) phosphate).  While its toxicity in mammals appears to be limited, the effects of long-term exposure are unknown, and it is toxic in aquatic environments.  Triethyl phosphate (TEP), a non-halogenated FR used in the EU, is a safer alternative.

• Polyurethane boards can contain up to five percent "blowing agents", which are usually volatile hydrocarbons or halogenated hydrocarbons.  Polyurethane spray foam formulations can contain both blowing agents and proprietary FRs with unknown composition and health effects.

• For example, Dow THERMAX(TM) Insulation board contains a maximum of ten percent of TCPP and five percent 1-Bromopropane. The MSDS states that this blowing agent can cause central nervous system effects in humans and harm to male and female reproductive organs and the liver as well as interference with reproduction and fertility and toxicity to the fetus in animal studies. The sheet also states that "normal handling and cutting are unlikely to result in exposure levels of 1-bromopropane sufficient to cause the listed effects."
  
  The impact of long term and cumulative exposures to mixtures of such chemicals upon the health of workers, inhabitants of homes, and the environment is not known.

Halogenated fire retardants are becoming widespread in the environment

Larry Strain, Siegel & Strain Architects

While it may be obvious that smaller buildings use fewer resources and energy than larger buildings - they're smaller after all - it's not so obvious that smaller buildings use less than larger buildings per square foot.

Why is this? When buildings reach a certain size; the way they are built changes; the materials they are built with changes; and the way they operate changes.

And when those things change, environmental impacts change, and they tend to go up.