Why Wool Carpet Works
By Elise Demboski
In carpet fibers and other applications, wool's texture and resilience enable it to recover well from crushing, resist soiling and clean readily. Its unique fiber construction provides natural flame-resistance and high durability, resulting in a product that retains its appearance for years.
Wool is a complex fiber that has evolved over thousands of years with the sheep who produce it, to protect them over a wide range of climatic conditions.
Wool cells come in two different types: the paracortex and the orthcortex, which lie on opposite sides of the fiber and grow at slightly different rates. This causes a three-dimensional corkscrew pattern of coiled springs much like shock absorbers, giving wool high elasticity and a "memory" that allows the fibers to recover and resume normal dimensions. Wool fibers can be stretched up to 30 percent without rupturing and still bounce back.
Wool is also soil-resistant - releasing soil up to 25 percent more readily than synthetic fibers. The cuticle, or outer layer of the wool fiber, has a finely waxed surface with overlapping scales to keep soil in the upper area of the t, where it is easily removed.
The protective membrane on the cuticle also prevents water from readily penetrating the individual wool fibers. This same waterproof membrane allows the fiber to absorb moisture in vapor form.
Water vapors coming through the cuticle pores bond with amino acids in the cortex - the main bulk of the fiber. This lets wool absorb up to one-third of its weight in moisture without feeling damp, making it resistant to static electricity. This moisture-absorption property also helps wool recover from pressure marks.
Wool's high moisture content and protein constituents provide natural flame resistance.
Proper cleaning is important to maintain a wool carpet's original appearance. A planned maintenance program should take into account the likely level of soiling and cleaning costs. Facts to be considered include: traffic patterns; type of soiling, such as street grime near entrances or food and drink in refreshment areas; cleaning schedules; and personnel, equipment and resources available.
For deep cleaning, evaluate the nature and extent of soiling before deciding on the cleaning method. The accompanying chart describes types of soiling and appropriate cleaning methods.
Elise Demboski is communications manager for Wools of New Zealand in Atlanta, GA.