NAHB ‘Tech Set’ Shows Builders How to Improve Indoor Air Quality

John P. Lapotaire, CIEC

With the release of its Tech Set No. 9, the Partnership for Advancing Technology in Housing (PATH) presents simple steps that contractors and home owners can take to improve indoor air quality.

In addition to cooking odors, a home’s air may also contain excess humidity, dust, mold spores, chemical fumes, radon, combustion products from mowers running outside or furnaces running inside and other potential irritants, according to PATH.

Although most people aren’t significantly affected by indoor air, “as anyone with asthma or other respiratory problems knows, poor air quality can become a serious matter,” said Darlene Williams, assistant secretary of the Department of Housing and Urban Development. “HUD’s PATH program is committed to providing builders, remodelers and home owners with the information they need to assure a healthy home.”

Tech Set No. 9 outlines the basic steps that ensure a comfortable and allergen-free indoor environment:

Use products with low VOCs (volatile organic compounds). On the list of materials that can contain high levels of VOCs that can diminish air quality: conventional paints, finishes and glues; stains and sealers; carpeting; plywood and OSB sheathing; and plastic-based products.

“Today, low- and no-VOC paints and finishes are available almost anywhere, as are low-VOC building products,” says PATH. “They release no or minimal VOC pollutants, and are virtually odor-free. This improves the indoor air quality of the home, making it particularly safer for people with chemical sensitivity.” Also, by using water as their solvent and carrier, latex paints allow both easier cleanup and are generally less toxic.

Custom-design heating, ventilation and air conditioning systems for the home. The solution for optimizing air quality in a given home may be as simple as good, well-placed spot ventilation fans providing several areas with local ventilation that augments the space heating system, or as complex as whole-house ventilators and humidity control integrated with an HVAC system that brings a measured amount of outdoor air to the inside unit for conditioning at regular intervals, according to PATH.

“All HVAC systems contain some method for filtering the room air that is returned to the unit for reconditioning,” PATH says. “Filters vary by the size of particulates that can be trapped, ability to filter out moisture and ability to sterilize micro-organisms (usually with ultra-violet light). Some filtration methods can be implemented by switching to a different filter medium, whereas others require an additional unit. Stand-along room units can accomplish some filtration, as well.”

PATH advises that all outdoor air intakes should be at least 10 feet away from exhaust outlets or areas where vehicles idle.

Check for radon, which can cause lung cancer at high levels of exposure. Radon kits can be purchased for as little as $9.95. “Where radon is detected or is likely to be present, there are reliable, simple construction techniques that will mitigate the gas within the home,” PATH says.

Use durable building envelope details to repel moisture and air, such as covered entries, redundant weather barriers and grading that moves water away from the structure.

“In homes with attached garages, it is particularly important to completely seal the boundary between the home and garage,” PATH says. “One study found that 75% of the benzene in the home environment is introduced from the garage. Connecting doors between the garage and living space should be gasketed and made substantially airtight with weather stripping, and attached garages should have a 100 cubic-foot-per-minute exhaust fan venting outdoors.”

Ensure that combustion appliances are sealed. “Heating equipment that burns natural gas, oil, wood or any other fuel that relies on an open flame within the home should be vented to the outside by a sealed vent so that burning byproducts cannot vent back into the home (backdraft). Backdrafting, which can be caused by wind currents or unbalanced ventilation, deposits chemical toxins like carbon monoxide as well as dust, dirt, soot, smoke and unburned fuel.”

The occupants need to be vigilant. “The occupants of the home ultimately control the quality of indoor air long after good material specification and construction practices were employed in its construction. Without due care, occupants may introduce chemical contaminants with their selection of cleaning products, furnishings and finishes. Particulate control starts with keeping outdoor contaminants out — practices like closing the windows while mowing the lawn, regular (out-of-home) washing and brushing of pets, insect and pest control, and wiping or removing shoes worn outdoors upon entering a home. Regular particulate removal via dusting, damp mopping and vacuuming is required to maintain a healthy indoor environment.

PATH advises that the HVAC system should be maintained and its filter replaced at regular intervals. Smoking, using aerosol sprays and room fresheners, and burning candles are discouraged indoors.

http:// www.nbnnews.com/NBN/issues/2007-08-13/Research/2.html

•John P. Lapotaire, CIEC•Certified Indoor Environmental Consultant•Microshield Environmental Services, LLC• www.Microshield-ES.com