Carpet and Health
Good News About Carpet and Air Quality
Carpet Favours Respiratory Health
Carpet and Indoor Air Quality
Some designers and specifiers are still hesitant to recommend carpet as a design tool and to specify its use in new buildings and homes because of unfounded concerns regarding poor indoor air quality (IAQ) resulting from the installation of carpet.
Canadian carpet manufacturers have since 1993 been complying voluntarily with a rigorous industry standard that sets limits on the levels of volatile organic chemicals (VOC) emissions from specific products. The program monitors VOC levels, collects scientific data, screens out objectionable products and provides a strong basis for consumer confidence. Carpet specimens are taken directly from the manufacturing line in air-tight packaging to an independent laboratory where they pass or fail. Carpets that have passed this testing program are identified with the GREEN LABEL affixed to the back of carpet samples.
Research conducted by Host/Racine (a US manufacturer and supplier of carpet cleaning equipment and materials) showed that “carpet is an asset to the health of indoor environments”. After collecting data from schools and private homes, the firm determined that dust, pet hair, pollen and mould spore allergens either fall onto carpet from indoor air or are deposited by walkers. Part of their study, conducted between 1995 and 1997 in 17 carpeted classrooms located in Nebraska, Wisconsin, Florida and North Carolina, analysed mould spore levels and found that the air held far fewer spores than the carpet, less than 1% of the carpet levels in some cases. Carpet plays the role of a filter and a trap that holds biologicals out of the breathing zone until they are removed easily by efficient vacuuming.
Further evidence that carpet does not contribute to poor IAQ has come from the results of a number of projects conducted in Norway and Sweden. Leading Norwegian indoor environmental consultant Gaute Flatheim concluded that “soft floorings have unfairly received bad press for contributing to poor indoor (air) quality without any real evidence to support this”.
A Norwegian test institute, Rogaland Research, carried out a comparative test between soft and hard flooring in four classrooms in Lilliehammer, to discover which type of flooring would provide better IAQ. Two of the classrooms were carpeted, and two were fitted with hard flooring. IAQ measurements were taken before, during and after school hours. Says scientist Ernst Olsen: “It looks as if the carpeted rooms are slightly better compared to the hard floors. The fine dust seems to be bound into the carpets.” These results, added to the other benefits of carpet (noise reduction and a perceived improvement in the standard of the rooms, to name but two), show that carpet can be beneficial in improving the surroundings of both work and school buildings.
Although there is a perception that carpet in a health care facility is not as sanitary as a hard surface, a study by the US Center for Disease Control found no increase in bacterial or fungal (grouped as microbial) growth in carpet in a hospital as compared with a hard surface, when the carpet is properly maintained.
VOCs, Carpet and Indoor Air Quality
All living matter, as well as many of the materials used to make household products and building materials, is made of organic chemicals. Volatile organic compounds (VOCs) are those which are light enough to evaporate at room temperature and so escape into the air. Most VOCs are harmless in the concentrations encountered in normal life. For example, methane is emitted from animals but it is not considered hazardous in the concentrations found in dairy barns. Ethyl alcohol is emitted from cocktails but it is not hazardous in the concentrations found in bars.
In new homes and offices, there is a “new house” scent caused by VOCs emitted by items such as paint, particle board, furniture and carpet. “New house” scent diminishes rapidly, usually lasting only a few weeks because of ventilation and declining emissions. Most people enjoy the smell of a new house and, in our experience at the Canadian Carpet Institute, consumers have never complained about it.
As new house occupants begin to use household products (e.g. furniture polish, hair spray) which emit VOCs, the VOCs in the indoor air increase to a level which is then maintained more or less constantly. Meanwhile, the VOC content of the building materials and furnishings continues to decline until there is essentially nothing left. A crossover then occurs within the first few months of occupancy, when emissions from consumer products increasingly outweigh any residual emissions from building materials and home furnishings.
There are, however, people who have anxieties about the composition of indoor air, and researchers are searching for any relationship which might possibly exist between the VOCs in indoor air and the concerns of individuals who may be hypersensitive to certain VOCs.
Since 1993, carpet manufacturers in Canada have been complying voluntarily with a rigorous industry standard which sets limits on the levels of VOC emissions from specific products. The program monitors VOC levels, collects scientific data, screens out objectionable products, and provides a strong basis for consumer confidence. Carpet specimens are taken directly from the manufacturing line in air-tight packaging to an independent laboratory where they pass or fail.
Consumers can identify carpets which have passed this testing program by the GREEN LABEL affixed to the back of carpet samples. The label indicates that the carpet meets the standards of the Indoor Air Quality Program of the Canadian Carpet Institute.
A new carpet, fresh from the carpet mill where it was produced, rolled up and packaged, will have a “new carpet” smell. This is most noticeable when the roll is opened and it may continue to be noticeable for a few days afterward. Consumers or building managers aiming to minimize the VOC content of indoor air should pay particular attention to the ventilation of newly-carpeted spaces in those first few days. In rare instances where an individual’s hypersensitivity is an issue, arrangements may be made for rolls to be opened and laid flat off-site for a short while before delivery and installation.
The majority of VOCs in a roll of new carpet is gone within a few days. At that point, the consumer has a floor covering essentially free of VOCs which can be expected to provide colour, comfort, noise suppression and cost-effective service for many years.
Carpets and Airborne Particulates
The Canadian carpet industry has been saying it all along: carpet fibres trap dust, pollen and other allergens until the carpet is cleaned properly with a performance vacuum.
A high percentage of the particles held by a carpet’s fibres never reaches the breathing zone (which, by the way, is closer to the floor in schools), as evidenced by these two graphs.
The first compares the amount of particles in the air after walking on a carpet and on a hard surface; the second after vacuuming those same dusty surfaces. These tests were supervised by the Professional Testing Laboratory in Dalton, Georgia, USA.
Click here for another study on airborne particulates.