Microbiological Problems Associated With Carpeting

Carpeting, as rugs, wall to wall, or carpet squares, must serve multiple purposes in our commercial buildings, residences, and a wide variety of vehicles such as cars, boats, and airplanes. The technical requirements for carpets are as diverse as the end uses and must account for the use, abuse, and ultimate disposal. The technical limits of carpet are more stretched then when challenged by microbiological problems. Microorganisms are part of our everyday lives and environments. When in balance they are positive, but when out of balance they cause untold damage in terms of odors, staining, deterioration, and human health. Control of microorganisms can be accomplished by prudent choices of materials of construction, chemical treatments of fibers or constructed carpets, or by chemical additions to already installed carpeting. This paper will cover the problems caused by microorganisms in carpeting and the chemical strategies employed in their control. Introduction Consumers frequently demand the right to control and select their environment with respect to colors, texture, temperature, humidity, odors, light, and sound. Carpeting constitutes a major environmental surface for both residential and commercial establishments. Consequently, the dyeing and finishing industries are constantly challenged to produce carpeting with desired and needed functional and aesthetic features. A desirable feature, as shown in market studies, concerns freedom from foul odors. Carpeting by its construction and use provides a habitat for a large variety of microorganisms, some of which not only produce putrid and mildew odors, but also contribute to unsightly defacement and deterioration of carpet components. These microbes may also produce infectious and/or allergenic conditions in humans. The Need for Antimicrobial Treatment The increased use of carpets in hospitals, schools, and other institutions demonstrates the need for an additional property in carpeting: the prevention of bacterial and fungal growth. The need is obvious in hospitals, where the greatest concern about carpeting is the possibility of infectious hazards. However, the need for a safe antimicrobial treatment is not limited to hospitals. Inhibiting bacteria and fungi is equally important in carpeted areas of playrooms, convalescent bedrooms, sanitariums, and hotel/motel rooms. All of these areas may serve as a reservoir for potentially harmful bacteria and fungi. In addition, there is the problem of odor and deterioration Microbiological Problems Associated with Carpeting 2 Form #4E4 caused by the presence of microorganisms and their breakdown products. Extension of this need to the home is obvious as we consider the use of carpeting in bathrooms, kitchens, below-grade areas, recreation and family rooms, as well as other areas where pets and babies roam. The need for hygienic freshness is a reality in the consumer's mind. Microbes Microorganisms are a part of our everyday lives and include many diverse organisms. They include bacteria, fungi, yeasts, and algae that are found wherever moisture, temperature, food sources, and receptive substrates allow. They include thousands of different species, and are found everywhere in the environment as well as on our bodies. Some of these organisms are beneficial and a natural part of the environment. Others can and do cause serious problems including deterioration, defacement, rotting, surface degradation, staining of useful goods/substrates, and health problems ranging from simple discomfort to physical irritation, allergic sensitization, toxic responses, and infection. Consumer and commercial operators are challenged by the presence of these microorganisms and the negative effects they cause. Antimicrobial treatments for bacterial, fungal, and mite control, are proving to be popular among consumers, manufacturers, and building operators. These treatments not only provide protection from microorganisms they also add aesthetic and emotive values to a full range of products. Deterioration, defacement, odors, and “harboring” medically significant microorganisms, are all dramatic effects we see in buildings and products where microbial contamination is present. The ability to make surfaces and carpeting resistant to microbial contamination has advantages and values in many applications and market segments served by the carpet industry. Additionally, carpets require the need to control microscopic arthropods such as mites. Mites are associated with dirt and dust and their presence in bedding and other home furnishing products has been linked to allergenic responses in humans. Control strategies for these organisms are complex, taking into consideration the life habits of these organisms as well as their metabolic and reproductive habits. The Impact of Microorganisms on Substrates Microorganisms have an unending ability to adjust to their environments. Microbiological contamination of textiles (wovens and nonwovens), foams, other finished substrates such as carpet, raw materials, wet processes in the mills, roll or bulk goods in storage, and finished goods in storage or transport, can result in dire economical consequences. In addition this can be an annoyance and aesthetic problem to an athlete or consumer. These critical consequences can range from a product recall costing millions of dollars to product spoilage that requires untold resources. This can also cause the shut down of production facilities to redesign processes and products. If human health problems are incurred, the human toll in sick days, illness, and death, can be even more devastating, and the legal consequences can be staggering. For years, the military has fought the problems associated with microbiologically contaminated material and equipment, especially in the field where exposure to continual moisture and use accelerates the formation of odors, staining, and degradation of military gear and equipment. In addition, the substrates themselves can harbor medically significant (pathogenic) microorganisms, thereby posing additional problems for the personnel, especially under crowded conditions. The medical and research communities require antimicrobial protection for textiles, foams, and other substrates used in medical and research facilities, nursing facilities, veterinary clinics and hospitals, as well as the fabrics used for personnel attire and housekeeping supplies. This protection reduces odors due to microbial decomposition and the risk of infection resulting from Microbiological Problems Associated with Carpeting 3 Form #4E4 substrates that are contaminated with pathogenic organisms. It is especially predominate in hospitals and other institutions where crowded conditions prevail and there may not be an opportunity for frequent cleaning. In the 1950’s, Stuart (1957) reported that surgical drapes treated with a residual bacteriostat prior to heat sterilization kept down the bacterial count during long operations, and that treatment of diapers and bed pads assisted in preventing the formation of ammonia from urea by bacteria in the urine of infants and incontinent patients. Hurst, et al. (1958) demonstrated that the air in hospital laundry chutes contained pathogenic bacteria, presumably from contaminated laundry. An extensive research study in 1982 (White and Olderman) on a nonwoven surgical drape treated with a silanequat antimicrobial (AEM 5700 Antimicrobial) indicated that this antimicrobial could reduce the levels of bacterial contamination on the drape itself, control and/or kill the bacteria commonly associated with surgical wound infections, take an active role in maintaining an aseptic field at the wound site, and allow the drape fabric to retain all the positive handling and appearance characteristics desired by the operating room (OR) and surgical staff. In 1979, this antimicrobial was listed by the FDA under the 510 (k) provisions of the Medical Devises Act for use on surgical drapes. It is registered with the Environmental Protection Agency (EPA) for use in other textiles. Consumers are keenly aware of the problems caused by microorganisms and their awareness is reinforced daily by “press events” highlighting the risks associated with such contamination. They are concerned over the problem of odor, staining, deterioration, and human health conditions such as allergies, infectious diseases, and “sick building syndrome (SBS).” These concerns have led to their demand for goods and products for home, sports, and personal use, to be protected from the effects of microbial contamination. According to some manufacturers, concern about microorganisms in the environment is another recent trend affecting a number of market opportunities, especially in the industrial wipes and garments industry. Medical clean-rooms, pharmaceuticals, and food industries, have been forced to recognize that inanimate surfaces (garments, other finished goods, building materials, and furnishings) can and do harbor microorganisms that affect the quality of the goods being produced and/or the health, welfare, and comfort to the occupants. Carpeting, soft goods, and furnishings have hit the top of the list regarding concerns for microbial contamination and amplification. Control strategies for the contaminants, (i.e., the target microorganisms that have a negative impact on substrates) must include careful consideration for destroying them without affecting the non-target organisms and without allowing or encouraging the target organisms to adapt to the control chemical. What Causes Microbial Growth? The microorganisms represented in an environment are complex. Every element of this indoor environment, from its carpeting, furnishings, and occupants, offers a home for microorganisms. Microorganisms need moisture and nutrients, and more than 95% of them need to be associated with a surface. Moisture results from catastrophic as well as normal events a leaking roof, a sweating pipe, a leaking radiator, condensation on windows, condensation on more subtle surfaces where dew points are reached, humidified air from the HVAC system, or from hundreds of other sources. A hotel or resort facility compounds the problem with the moisture from pools, spas, individual air conditioners, and literally hundreds of bathrooms. This, along with wall-to-wall carpeting, draperies, wall coverings, furniture, bedding, and ceiling tiles, creates ideal habitats for microorganisms. Nutrients utilized by microorganisms can be organic material, inorganic material and /or living tissue. For example, bacteria play an important role as part of the body’s microflora, and along Microbiological Problems Associated with Carpeting 4 Form #4E4 Fig. 2 The building indoor environmental quality. Fig. 3 Building airflow illustration Fig. 1. Relevant pollutants with skin, are shed continuously. Given acceptable growth conditions, some types can multiply from one organism to more than one billion in just 18 hours. A building may be infested during construction and catastrophic events (particularly with fungi), but more commonly its occupants or air infiltration routes bring the organisms into the building. Fungi (typically outdoor organisms known as mold, mildew, yeast and dust mites) enter the building on clothing, are wafted in through open doors, or are pulled in as “make up” air by the HVAC system. Bacteria follow these same routes but are primarily associated with human carriers and very wet areas such a drain pans and places with constant or standing water. Airborne Pollution Although most organisms grow on receptive building surfaces, they and their spores become airborne through normal occupant traffic and activities such as vacuuming. Once airborne, the HVAC systems, chases, and elevator shafts efficiently transport the microorganisms throughout the building. They settle on other receptive surfaces and quickly begin to reproduce. One good growth source for a particular organism can quickly result in outbreaks throughout the building. Additionally, with the universal use of air conditioning, recycling air to improve energy efficiencies takes place. But that recycling tends to concentrate indoor air pollutants – including microorganisms and their annoying, irritating, sensitizing, and toxic by-products.