North Americans spend 90% of their time indoors so it can be safely argued that the indoor environmental quality (IEQ) of a building has a significant impact on the health and productivity of its occupants. Occupant comfort, both thermal and acoustical, is essential components of IEQ. EPS insulation helps maintain a consistent air temperature, providing thermal comfort, and can prevent noise transmission through both interior and exterior walls.
EPS is manufactured with pentane, a hydrocarbon blowing agent that is not harmful to the stratospheric ozone layer and which diffuses during or shortly after the molding process is complete. Since the blowing agent is rapidly replaced by air, the installed insulation does not experience off-gassing that may affect indoor air quality (IAQ). Expanded polystyrene does not contain harmful formaldehydes. The American Lung Association’s (ALA) Health House guidelines, among the toughest in the nation for indoor air quality, acknowledges EPS sheathing as a safe material to insulate foundation walls and floors. Other ALA registered homes have incorporated insulating concrete forms (ICFs) in order to meet their stringent requirements. Although ALA representatives do not promote specific materials or products, they cite that expanded polystyrene walls release no lung damaging fibers.
Mold & Moisture
Another important IEQ factor is the prevention of airborne bacteria, mold, and other fungi through a building envelope design that prevents moisture intrusion. The EPS Molders Association sponsored a test program focusing on EPS and mold resistance in January 2004. EPSMA contracted SGS U.S. Testing Company for test services on EPS applying ASTM C1338, “Standard Method for Determining Fungi Resistance of Insulation Materials and Facings.” Test samples of Type I ASTM C578/Type 1 CAN/ULC S701, representing a typical product for most building and construction applications, were evaluated. The test subjected the EPS to the following five specific fungi to check for growth:
• Aspergillus niger
• Aspergillus versicolor
• Penicillium funiculosum
• Chaetomium globosum
• Aspergillus flavus
EPS Insulation Mold Resistance (PDF)
The results show that in a lab under ideal growth conditions, the fungi did not grow. Although EPS is not impermeable it does have a high degree of resistance to moisture absorption. This controls humidity and air infiltration, which can help prevent the development of mold.
One of the major performance benefits of insulating concrete forms is their superior sound reduction. With recent awareness of the adverse effect of excess noise on personal health, comfort, work efficiency and privacy, ICF applications are especially beneficial in diminishing noise transmission in structures such as hotels, condos or multi-family buildings, theatres and structures near airports and busy roads.
The sound audibility of speech ranges from 25–50 decibels (DB). At 35 decibels the human ear can hear speech that is loud but unintelligible. A typical 3” ICF wall with 1/4” Gypsum board on both sides can reduce sound transmission in a room to 36 DB. ICFs come in different thicknesses. When component materials such as concrete and Gypsum board are factored in, sound abatement properties can increase up to 52 DB depending on the thickness of the application.
Copyright © EPS Molders Association 2008