Emission of Volatile Organic Compounds from Multi-layer Structural Insulated Panels

Indoor air quality is recognized as one of the most important environmental concerns, since people spend almost 90% of their lifetime indoors. Indoor sources of volatile organic compounds (VOCs) are a determinant of air quality in houses. Many materials used to construct and finish the interiors of new houses emit VOCs. These emissions are a probable cause of acute health effects and discomfort among occupants. Ventilation is another determinant of indoor air quality in houses, because it serves as the primary mechanism for removal of gaseous contaminants generated indoors. Thus, higher contaminant concentrations are expected at lower ventilation rates given constant emission rates. The trend in new construction is to make house envelopes tighter for higher energy efficiency. The use of Structural Insulated Panels (SIPs) in new construction and major renovation to create very tight building envelopes is one popular approach to realizing this goal. The basic SIPs configuration uses oriented strand board (OSB) and polystyrene foam (PSF) in a multi-layered sandwich-like structure. Specific benefits of SIPs include lower energy consumption, stronger more durable structures and better resource efficiency. These advantages make panelized systems very attractive from both environmental impact and energy use perspectives. However, there is a potential for houses constructed with SIPs to have degraded air quality relative to conventionally constructed houses that utilize fewer engineered wood products. OSB emits pentanal and hexanal, two odorous aldehydes. These contaminants originate in the wood drying process through the breakdown of wood tissue and are, thus, inherent to most engineered wood products. The PSF in SIPs is a major source of styrene. The large surface area of installed SIPs systems (typically the entire exterior shell), combined with the resulting decrease in ventilation rate due to very low infiltration, exacerbates the