Checklist for Minimizing IAQ Problems With Carpets
Specifying Carpet
• Consider alternatives: Many people prefer hard flooring with natural-fiber area rugs instead of wall-to-wall carpeting. Area rugs can be easily removed for cleaning when necessary, or to dry out if they get wet. This strategy avoids both new carpet emissions and old carpet problems like accumulated toxins and mildew. • Demand a warranty of safety: If your job is big enough to get manufacturers’ attention, you should require test results far more detailed than the industry’s label requirements. IAQ consultant Hal Levin suggests looking for total VOC emissions below 100 micrograms per square meter per hour, measured after 24 hours. Have the manufacturer specify the adhesive as well, and request a warranty of total VOC emissions for the installation. • Look to the CRI label as a minimum standard, but not as a guarantee of safe carpet. Companies not participating in the CRI program should be held to standards at least as strict. Be sure to consider carpet pads, adhesives, and seam sealants when evaluating emissions of a carpet system. • Keep carpet away from entrances where toxins tracked in from outside can collect, and away from water sources that might wet the carpet. Only use carpet if proper maintenance can be assured. • Avoid adhesives if possible. In homes and small commercial buildings specify only tackless strips at room perimeters. In commercial applications where heavy use or large spaces make perimeter connection insufficient, look for non-adhesive fastening systems such as Tac-Fast™, products that can be installed with double-stick tape, or peel-and- stick carpet tiles. • Specify low-VOC seam sealant.
During Installation
• Clean old carpet before removal. There is a tendency to neglect carpet maintenance in the period leading up to replacement, according to consultant Brian Greenberg of Toronto, Canada. That can be a big mistake because the carpet, which has been filtering and collecting dust and dirt of all types, will likely release much of it back into the space when it is torn up. Those particles circulating in the air and HVAC system can themselves cause an IAQ disaster. • Clean area thoroughly. Once the old carpet is removed, clean the entire space as thoroughly as possible to remove dirt and contaminants that may have been trapped under the carpet or newly released into the air from it. Removal of the old carpet is an important opportunity to get rid of everything trapped in and under it, and the opportunity is missed if the whole space isn’t cleaned before the new carpet is installed. • Pre-ventilate carpet elsewhere. All the chemicals known to offgas from new carpet drop off significantly after several hours to several days. By unrolling and airing out new carpet for several hours or days in an uninhabited, well-ventilated space, most of the chemical emissions from the carpet itself can be avoided. In practice this treatment is not feasible for most installations, but it’s a good idea when possible. • Avoid using conventional adhesives. If adhesive is needed, use only solvent-free, low-VOC products. These products can be more sensitive to ambient conditions such as temperature and humidity, so follow manufacturers’ directions carefully. • Maximize ventilation during installation. Pass as much air as possible through the space during installation and for several days or weeks afterwards. If possible, ventilate the area directly to the outside, bypassing any ductwork where VOCs could accumulate. Some consultants have suggested that heating the space with a new carpet to above-normal temperatures while increasing ventilation might cause more chemicals to offgas from the carpet, making it safer for occupants. So far there is no evidence that this method is more effective at reducing ambient pollutant levels than simple ventilation. • Isolate area from rest of building. If part of the building is being carpeted while the rest is occupied, it’s important to isolate the area being worked on and ventilate it directly to the outside. Definitely avoid circulating air from the newly carpeted area into other parts of the building. • Clean the new carpet. Have the installer thoroughly vacuum the new carpet with a high-efficiency particulate air (HEPA) filtration vacuum to remove any loose fibers or particles resulting from the installation process. • Vacate for as long as possible. Schedule any carpet installation to allow as much time as possible before the space is inhabited. In offices, just before long weekends is best if workers cannot be temporarily displaced on workdays. In homes, plan to be away for several days if possible after the installation, and keep bathroom or other exhaust ventilation fans running.
General Maintenance
• Clean often and thoroughly. Regular vacuuming is critical to controlling contaminant levels in carpets, but typical paper vacuum bags often recirculate more dust than they hold. HEPA-style filters are recommended for trapping particles as small as 0.3 microns. In homes, use the most efficient vacuum system available. For deep cleaning, consultant Brian Greenberg recommends hot water extraction performed by well-trained technicians. • Dispose of wet carpet. Carpet that has been saturated for over a day is likely to have mold and mildew contamination that is very difficult to control. Rather than risk breeding these allergens or exposing people to toxic treatments, most experts recommend simply replacing the wet carpet. • Ensure adequate, continuous ventilation. Minimum ventilation levels should be maintained to prevent any build-up of toxic emissions in the space. To be effective, ventilation must be well distributed throughout the space.
