Everyone loves that 'new car smell'. Most people do not realize however, that the smell comes from the off-gassing of the materials used to build the car. These gases are often a wide assortment of volatile organic compounds (VOCs) released by the plastic, rubber, adhesives, and fibers used in the interior of the automobile. Exposure to these should be minimized.
For the same reason the new car smell should be minimized or avoided, we should also avoid new building smells. The best way to improve the indoor environmental air quality of a new build is to use building materials that produce less off-gassing to begin with. An ounce of prevention is priceless.
Carpeting, plywood, paneling, insulation, and many other building products often contain hazardous materials, such as formaldehyde. When these materials are used in a new building or renovation project the off-gassing may produce acute symptoms in the tenants, such as burning eyes, coughing, headaches, dizziness, etc. (OSHA, 1999). When sourcing new low-emitting building materials a manufacturer’s environmental and health claims should be validated thorough qualified organizations such as Scientific Certification Systems (www.scs1.com), Forest Stewardship Council (www.fscus.org), Green Seal (www.greanseal.org), Green Guard (www.greenguard.org), Carpet & Rug Institute (www.carpet-rug.org), Building Green Inc. (www.buildinggreen.com), and Energy Star Roof program (www.energystar.gov).
Because it is rarely possible to avoid all sources of toxic off-gassing in building materials, it is important to give the materials time to breathe (or off-gas) before allowing tenants to move into the structure. This can be achieved by storing the materials in ventilated containers prior to their use and applying the materials according to the manufacturer’s directions. It is also beneficial to keep the structure well-ventilated during installation of the materials, as well as after, as this should speed up the off-gassing process and help remove the emissions from the structure. This is also referred to as a “flush-out”.
USGBC requires, as part of their certification process, that the building be flushed with 14,000 cubic feet of conditioned outdoor air per square foot of occupied space after construction is complete. Depending upon how soon after construction occupancy needs to occur, two paths that can be taken to implement the flush-out. The first path is a 100% flush-out conducted before occupancy. The second path involves completing a minimum of one-third of the flush-out before occupancy and two-thirds while the building is occupied. When considering the flush-out option you must evaluate the construction schedule and the air handling system capacity to determine the amount of time that will be required to complete the flush-out. In some buildings, particularly during the summer and winter months, the capacity of the air-handling system to deliver outdoor air and maintain indoor temperature and humidity requirements is especially limited, resulting in flush-out time periods that are not feasible. For most buildings, either flush-out option will require a minimum of one to two weeks (or substantially longer) to completed after construction, but prior to occupancy, and that timeline is often prohibitive.
Other priorities for improving indoor environmental air quality include choosing building materials that do not promote microbial growth and preventing exposure of building materials to moisture damage, including high humidity. Non-porous surfaces are best when building in areas that are likely to experience moisture issues, such as bathrooms and showers. Carpeting should never be used in these areas. In addition, ensuring that HVAC systems are properly-installed, including HEPA filtration, and running it continuously during the highest off-gassing period, will provide a better breathing environment. This will also help remove the finer particulates produced during the construction process (EPA, 2012).
Emilcott has been assisting clients make sound indoor environmental quality issues for over two decades.
by Dale Wilson, CIH, LEED AP