Basic info is found in Chapters 9, 10 and 11.
Carpet as a floor covering has the primary function of providing a more comfortable surface to walk on. It is soft, has little thermal conductivity, and a good noise absorption capacity. Carpeting can be woven, knitted, tufted or needle-punched in many different natural fibres: cotton, wool, bristles, sisal, coconut fibres (coir), jute (hessian) and hemp, as well as in synthetic fibres such as nylon, acryl, polypropylene, polyacrylnitrile, polyester and rayon.
In the East, carpeting has been used for centuries. In Europe, hides have traditionally been used as carpets. Here the first true carpets originated about 200 years ago. Until then, people managed with natural materials strewn on the floor: juniper or bracken, sawdust or sand, which absorbed dust and damp. This kept the floor clean, as it was regularly changed. In the 1960s, wall-to-wall carpeting was introduced, transforming the carpet from a loose floor covering to an independent floor covering, often laid directly onto a base of concrete. The spread of this type of covering was very rapid, in housing and in buildings such as schools, offices, public buildings, etc. In the beginning, natural fibres were used, but synthetic fibres soon took over, making up half of the market by 1967 and the majority of the market today.
The procedure used for the production of carpets varies according to the technique and material used. Weaving and knitting requires spun thread. Needle-punched carpets are made of unspun wool. For needle-punched and tufted carpets, a carpet backing in one or two layers is used to keep the fibres in place and add strength, stability and elasticity. The backing usually consists of a woven underlay of fibreglass, jute or propylene coated with styrene-butadiene rubber (SBR), foamed polyurethane, polyvinyl chloride or natural latex, and is most often glued to the textile layer with polyvinyl-acetate (PVAC), ethylene-vinyl-acetate (EVA), acrylate adhesives or bitumen. Products with polyvinyl chloride usually have phthalates added as softeners. A modified backing can also be used for some woven and knitted products.
All carpets, both natural and synthetic, can contain flame retardants including chlorinated and brominated hydrocarbons, anti-static agents, and substances to protect them against moths and fungus, often ammonium compounds. Woollen products are often impregnated with pyrethrin. Jute may have been sprayed with chemicals during its cultivation or at the time of transport, in some cases with DDT.
Loose carpets are laid directly onto an existing floor. Fitted carpets are usually laid on an underlay of polyvinyl chloride, polyurethane or foamed synthetic rubber; latex, cork, woollen felt and hessian are alternatives. The carpets are fixed to the floor with skirting boards or glue. Different sorts of glues, such as PVAC and acrylate adhesives, can be used. Joints are sewn or glued.
European renewable raw materials for the production of carpeting are wool, flax, eelgrass, hemp and nettles. Timber is the raw material for rayon. Sisal comes from Mexico, whilst coconut is found in the tropics, where it is often a major resource. Synthetic fibres such as polyamide, polypropylene and polyacryl are all based on fossil oils. These days, some products can contain a certain proportion of recycled plastics. The energy needed for the production of plastic-based products is high, and a wide range of pollutants can be emitted, including large amounts of carbon dioxide.
All carpets contribute to the gathering and distribution of dust into the indoor air. Alarming emissions from glues, plastic components, fungicides, etc. have also been recorded (Ehmsperger et al.,
2006). Synthetic carpets can lead to electrostatic charging of the inhabitants, which in turn can lead to irritation of the mucous membranes.
The durability of carpets is relatively low. If they are glued, removing them can be difficult. However, the market now includes leasing systems whereby the carpeting is delivered in fairly small tiles that can easily be replaced as needed.
Wall-to-wall carpeting has little chance of being re-used, and probably hardly any chance of being recycled because of the many different materials it contains. Most carpets can be burned for energy recovery in incinerators with special filters. The emission of carbon dioxide when burning plastic materials is similar to the burning of oil. Ash and waste from plastic products and natural products with plastic-based glues, toxins against mould, etc. have to be deposited at special tips. Carpets of pure natural fibres can be composted.
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