The Fear Factor of Wool
He had heard all of the stories about shrinkage, browning and the bad odor that wool gives off when it gets wet, and he was afraid of what could happen to the carpet if he were to clean it.
Now don’t get me wrong; I believe in using caution when and where it is called for. But that student’s reaction reminded me of something Franklin D. Roosevelt once said: “The only thing we have to fear is fear itself.” If you follow recommendations when selecting cleaning agents and use sound cleaning procedures, including drying aids as needed, all you will experience from cleaning wool is the pleasant feeling of increased profits.
There are a lot of wool broadloom goods currently being sold in the United States, and always to “upscale” environments. The popularity of wool is easy to understand when you consider its properties: wool has a soft, warm, luxurious “hand,” while synthetics can be somewhat hard. Wool’s unique chemical structure allows it to take all types of dyes, and each wool fiber accepts the dye internally, creating a color bond that will last for the life of the carpet in spite of traffic and multiple washings.
There are a number of reasons for wool’s popularity. Wool performs well as an insulator, keeping floors warm in winter and cool in summer. Burns in the carpet are not a problem with wool. The fiber doesn’t melt like synthetic; instead it merely chars when burned, leaving no hard plastic blob.
But first on its list of attributes is its superb resilience. The IICRC defines resilience as “the fiber’s ability to return to an upright position after being crushed or walked upon.” The “molecular memory” of wool fibers allows them to spring back to shape and normal pile height better and faster than a synthetic fiber.
The fears that accompany wet-cleaning wool are, for the most part, unfounded. Wool is hair, just like the hair on your head and, like your hair, wool likes to be washed regularly. But there are limits to the types of cleaners that can be used. The correct pH for cleaning wool is between 4.5 and 8.5. Using a higher pH may destroy the fiber. Any full-line chemical supplier will have at least one product with the proper pH for wool cleaning.
The next thing to remember is no bleaches on wool. In a 5.5 percent solution of chlorine bleach, wool fibers will dissolve to a liquid in 15 minutes, and it goes without saying that all color in the fiber will be lost. Also, no optical/fluorescent brighteners should be used on wool. When used improperly these products can cause permanent damage to the colors of a wool rug.
The last criteria is that the cleaning leaves a dry, powdery residue. This is good practice on all fibers, not just wool. Residues that are sticky or tacky will bind soils and result in a rapid re-soiling situation developing.
The problems of shrinkage and browning are related to the backing or foundation yarns rather than the wool face fiber. If you remember your IICRC carpet cleaning technician course, recall that shrinkage occurs in the backing of the carpet, not in the face yarns. Much of the wool broadloom you will encounter is woven with natural warp and/or weft yarns. These natural yarns will absorb moisture that will effectively cause shrinkage of the carpet or rug. In carpets that are properly installed and seamed, this shrinkage should not be enough to open seams or pull edges. In some cases you may find tufted wool products with a “monk’s cloth” backing. This is a canvas-like material that is usually woven from cotton and may shrink if overwet. Some investigation of the makeup of the backing/foundation should tell you when to worry and when not to worry.
Synthetic backing/foundations will not shrink, just as the wool yarn itself will not shrink. After all, you don’t see sheep wearing ponchos when it rains.
The problem of cellulosic browning also does not stem from the wool fibers but from the foundation/ backing materials. Cellulosic browning is the result of wicking of material called lignin cellulose from the cellular structure of a cellulosic material. Wool is a protein fiber, and therefore it cannot contribute to cellulosic browning. However, slow drying of a wool product with cellulosic (jute or cotton) backing/foundation yarns may contribute to the occurrence of cellulosic browning.
When cleaning wool carpets or rugs with jute or cotton backing/foundation yarns, take all the necessary steps, such as blowers and dehumidifiers, to ensure rapid drying to help prevent browning from occurring. If browning does occur, it is usually very easy to correct using a formulated browning corrector available from any full-line supplier. If you have wool with synthetic backing/foundation yarns, cellulosic browning is not possible.
The smell, while not pleasant, is something that must be tolerated when wet-cleaning wool. Open up, air out, and the odor will be gone when the carpet is dry, usually in two or three hours.
All things considered, wet-cleaning wool is not so scary. Follow chemical recommendations, utilize drying systems as required and, most important, inspect thoroughly before accepting the job. Since most of the ills that may arise will be related to excess moisture left in the carpet, why not just make an extra drying pass to help speed the drying? Make sure seams are properly constructed and that edges are well secured. As with any other fiber or carpet, qualify the job before you begin.
I hope that these thoughts will help you when you get the chance to clean your next wool carpet. Don’t give in to fear; just follow directions. Until next month, seeya!