In maintaining commercial facilities, much of the emphasis should be placed on daily maintenance. Daily carpet care is far less expensive than restorative carpet cleaning and carpet appearance levels can be maintained at much higher levels. The average life of carpet will last for years longer, if proper daily care is performed. However, in todayâ€™s economy with tight budgets and limited personnel, it seems that facility maintenance is always the first area to undergo budget cuts.
However, even with limited budgets, it is important that carpet cleaning be performed properly. Improper technique or improper use of cleaning chemicals can actually increase cleaning costs or increase the frequency of carpet cleaning.
Carpet cleaning, performed correctly, is a highly technical profession. Carpet cleaning can be described as a science due to the amount of chemistry involved in the cleaning process. On the surface, many people who are not associated with the carpet cleaning profession can not comprehend the intricacies involved. For those people who are about to become associated with the field, the complexity of the information may seem overwhelming initially. It may be necessary to define various cleaning terminology and describe the basic principles of the cleaning process to get a good basic understanding of the field.
Carpet cleaning can be divided into four categories: dry soil removal or dry vacuuming, soil suspension, extraction or removal, and drying.
Dry soil removal or vacuuming has been discussed in detail in the preventative maintenance section but the importance of vacuuming cannot be over emphasized. The carpet should be thoroughly vacuumed prior to any type of cleaning. Vacuuming the carpet pile is essential for effective soil removal. Vacuuming helps to separate the pile fibers, which aids in the release of soil during the suspension and cleaning phases.
Once the carpet has been pre-cleaned (vacuumed), it is time to pre-condition the carpet to prepare for the actual cleaning. The purpose of the pre-conditioning phase is to remove or suspend the soil from the fiber. Soil suspension can be illustrated by pouring water into a flour mixture. Particles of flour attach to the molecules of water. The mixture (dough) can then be removed. Soil suspension works in a similar fashion. A cleaning solution is added which attaches to the particles of soil. This solution completely surrounds the soil which removes it from the fiber.
The way in which suspension works is really very simple. To simplify the theory of suspension, four terms should be explained: hydro=water- lipo=oil- phobic= fear- philic=love. A detergent molecule (as shown below) has two ends. In the illustration below, one part of the molecule is described as hydrophylic (water loving), which means it attaches to a water molecule. The other part is described as lipophylic (oil loving), which attaches to oily soils found in carpet. Agitation or mechanical action is used to break the soil molecules from the carpet surface. At this point, detergent molecules completely surround the soil molecule which suspends the soil. This process is known as deflocculation or suspension.
There are four basic components to the soil suspension process:
1. Temperature 2. Agitation 3. Chemical action 4. Time
Temperature is necessary to speed the cleaning process. Every increase of 18 degrees F over 118 degrees F will double the speed of the process. Hotter is generally better but care should be exercised to insure that the fibers, dyes, or stain treatments are not adversely affected.
Agitation is the process in which the fiber is cleaned or the vehicle for application of the cleaning solution. Agitation is necessary to break the bond between soils and the fiber. Agitation may include the brushes used in dry absorbent compounds, rotary shampoos, or dry foam cleaning methods. It may include the absorbent pad used in the bonnet method and the water pressure delivered in the hot water extraction method. Agitation allows the particles to be loosened and rinsed away.
Chemical action is the most difficult area of cleaning to comprehend. The purpose for the use of chemicals is to aid in loosening, bringing to the surface, or dissolving the soil contained in the carpet. Chemical action will be discussed in detail later in this section. Time refers to the recommended amount of time for the cleaning to take place. Some cleaning methods may be more effective the longer the time allowed, but other methods, such as dry absorbent compounds, must be removed within a specific time frame for maximum efficiency.
Each of these basic components are equally important for effective soil suspension. If one of the components is reduced or eliminated, the three remaining components must be increased. For example, if no chemicals are to be used in the hot water extraction process, agitation, time and temperature will need to be increased dramatically for effective soil removal. If heat will not be used in any of the methods, agitation, time, and chemicals will need to be increased for effective soil removal.
Extraction or soil removal is the next step in the cleaning process. Cleaning can be defined as the removal of foreign substances. According to this definition, extraction can be defined as the actual cleaning process. Extraction is the removal of soil from the fiber. Extraction may come in a variety of forms. In hot water extraction, rotary shampoo extraction and the dry foam method- extraction is a natural part of the cleaning method. The bonnet method uses and absorbent pad that aids in extracting soil. A vacuum cleaner is used to remove the dry powder in the dry absorbent compound method.
Drying is an essential part of each of the cleaning methods. The various cleaning methods have been divided into two categories. Minimum or low moisture methods which are composed of the dry foam method, dry absorbent compound, and the bonnet method. Rotary shampoo and hot water extraction are classified as wet methods.
Depending on environmental conditions and operator skill, all methods should be completely dry within 8 hours. Even the wet methods are usually dry within 8 hours. It is imperative that the carpet be completely dry within 8 hours due to biological concerns. For wet methods, air movers can be used to speed drying time.
The effectiveness of cleaning depends a great deal on the effectiveness of the chemicals used to make the job easier. It is important that the proper chemicals be used in the proper amounts. Some technicians make the mistake of mixing chemicals to accomplish two or more tasks at the same time. In some instances this may work but in other instances it may develop into a sticky gob that is difficult to remove. Another common problem for maintenance technicians is the idea that more is better. If the directions for a chemical read: mix 8 oz. of chemical to a quart of water, some technicians think that if 16 oz. are added the job will be twice as easy and clean twice as well, but this is not the case. Mixing a higher concentration may leave residues in the carpet pile that may cause the carpet to resoil rapidly. Too much chemical can also create a number of other problems such as browning, yellowing, dye transference or fading.
Most facility maintenance managers have heard the expression- "wait as long as you can before you clean your carpet because it gets dirty, faster, after it is cleaned". This statement may have been true at one time but not with today's cleaning chemicals. At one time "true soaps" were used for carpet cleaning. These soaps were made using animal and vegetable fats and an alkali (see pH). The first soaps used in carpet cleaning were made from coconut oil. These soaps formed a weak bond with the water used in cleaning. Because of this weak bond, soap particles broke apart from the water molecules and were deposited in the carpet. True soaps are composed of a hydrophylic tail which attaches to water molecules and a hydrophobic tail that attaches to substances that are not composed of water. In the past, these formulas were very difficult to remove from the carpet due to the weak bond to the water molecules. As a result, the residue that remained in the carpet continued to perform its function of attaching to soil particles. This residue caused rapid resoiling.
Most of today's synthetic detergents perform the same function as the true soaps of the past but they are more efficient in soil removal and more easily removed. Detergents provide a number of benefits that make cleaning easier and they provide a number of functions. The first function is to remove surface tension. The detergent acts as a "wetting" agent. Its purpose is to break apart the bond between the water molecules and allow penetration by the soap molecules. This chemical is added to many cleaning compounds and is called a surfactant.
The second function a surfactant provides, suspension or defloculation, has already been mentioned but soil separation is important enough to discuss in greater detail. As mentioned, soap molecules have a hydrophobic end and a hydrophilic end. The hydrophilic end (water loving) has a negative charge and is called anionic. The negative charge attaches to the water molecule and the positive (cationic) tail attaches to any other substance such as soil or the fiber. Like charges tend to repel one another (positive- positive) just as like ends of a magnet. As the negative ends line up around soil particles and the fiber, the resistance forces the soil from the fiber. As the soil is removed other detergent particles surround the soil eliminating the attraction. This is called suspension if the soil is insoluble. If the soil is oil-based this process is called emulsification.
Once the soil particles are surrounded by the surfactant, the carpet should then be rinsed or extracted thoroughly. The soil will remain suspended as long as water is present. If the carpet dries prior to extraction, the soil is redeposited on to the fibers. As you can see, the purpose of the surfactant is to wet, emulsify or suspend soils contained in the carpet. It may be necessary to add other chemicals to attain the desired cleanability. Many professional cleaning chemicals already have these chemicals in their formulation. Be aware of the chemicals that have been added to the mixture. The chemical supplier can be very helpful in providing information regarding which chemicals should not be mixed and which chemicals have already been added.
Alkaline builders raise the alkalinity of the mixture. Alkaline builders provide a number of useful functions. The first benefit of an alkaline builder is to soften water. In some areas of the country, the water may contain trace elements of various minerals. The level of these minerals is rated in "grains of hardness per gallon". Your local water supplier should be able to supply you with this information. If the level is above 15 grains per gallon, an alkaline builder should be added, otherwise the detergent particles will react with these minerals (suspension) and become useless for further cleaning.
Another useful feature of alkaline builders is to increase alkalinity. Generally speaking, the higher the pH (see pH) the more effective the detergent. While alkaline builders are not efficient cleaners by themselves since they cannot perform a wetting function, they do increase the cleaning capability of a formulation.
Alkaline builders require dwell time to enable them to work properly. Dwell time can be defined as the time needed for a chemical to perform its function. Most preconditioners contain alkaline builders. These preconditioners are sprayed topically to the carpet prior to cleaning. Most preconditioners require 10-20 minutes to adequately suspend soils.
Dry solvents can be a cleaners best friend in the cleaning and spot removal process. Dry solvents are used mainly in preconditioners. They are critical in the emulsification (suspension) of oils.
Defoamers are used in situations where a large amount of detergent residue is allowed to build up in the carpet. Hot water activates these detergents which can cause foaming. Foaming can clog hot water extraction lines limiting cleaning efforts. There are two basic types of defoamers. The first is diluted and added directly to the recovery tank. This reduces the amount of foam in the tank. The problem lies in the vacuum recovery hose. This hose can become clogged, which reduces the amount of soil extracted from the carpet surface. The second type of defoamer is applied directly to the carpet and is directed at this problem. Since both of these types of defoamers are silicone-based, directions for dilution requirements should be followed closely. Many silicone-based additives may cause resoiling.
Acid additives such as a 10% citric acid solution or a 10% acetic acid solution can be very beneficial for spotting and cleaning. They are normally used in situations involving browning, yellowing, to stabilize certain dyes, and to neutralize alkalinity. White vinegar is a 5% acetic acid solution and can be used safely by most technicians.
Optical brighteners may be listed as an ingredient for some cleaning chemicals, but these should never be used on carpet. These brighteners are actually fluorescent dyes. Optical brighteners do an excellent job of making the carpet look clean but in most cases the carpet may take on a purple cast in sunlight. If a spotting solution is selected which contains optical brighteners this purple cast may be more noticeable due to the limited use area
Deodorants can be used to neutralize general odors. These may come in the form of general deodorants which are used principally for odor. Disinfectants are used to kill a variety of bacteria and fungi (especially mildew). Sanitizers are another deodorant which is less concentrated than a disinfectant but it is ideal for schools.
Many disinfectants and sanitizers are cationic (negatively charged). Many of today's stain resistant carpets will not accept cationic compounds. These compounds eliminate the stain resistant chemicals which are applied to these carpets.
The electrical charge of various cleaning chemicals are not the same. Cleaning chemicals may carry a positive, negative, neutral or both positive and negative electrical charge. The charge of the chemical will determine which substances it will react with. Some chemicals may react with one another providing a beneficial result, while others may produce a negative cleaning result. It is for this reason that we should be aware of the specific polarity we are dealing with.
In the case of cationic surfactants (positive charge), they are marginal cleaners because of their electrical charge but they are very effective for use as bacteriocides, deodorants, and anti-stats. As mentioned, they may damage acid dye- resist stain treatments and they may react with anionic cleaning compounds. Use of a cationic solution on a fifth generation (stain resistant) carpet will instantly void all stain warranties on the particular carpet.
Most anionic surfactants (negative charge) are excellent cleaners. They are very effective in the emulsion (suspension) of oil and they are very effective for use with hard water. Anionic surfactants rinse quite easily from the carpet. It does have a tendency to foam if it is not completely rinsed, however. Anionic compounds are recommended for acid dye-resist stain treatments. The use of a cationic compound and an anionic compound will cause a reaction between the two. As a result of the combination of these two compounds, a jelly-like residue may develop which is difficult to remove. If there is any doubt whether two chemicals are compatible, it is best to mix a small quantity of the two chemicals and observe for a reaction. If a gummy mixture develops, the two compounds are probably not compatible.
A nonionic surfactant has a neutral charge and normally works well with both anionic and cationic compounds. Nonionic compounds are excellent wetting agents and are used quite frequently with anionic cleaning chemicals.
Amphoteric surfactants may carry a positive or negative charge. Amphoterics are surfactants that are generally used in the dye process of carpet.
The selection of proper cleaning chemicals depends a great deal on the method of cleaning selected. The carpet industry recognizes five (5) methods of cleaning. In addition, each carpet manufacturer may have a specific preference for the type of cleaning system that should be used on their carpet. Use of a method not recommended by a particular manufacturer may void all warranties on a particular carpet. To better understand each cleaning method and where it fits into the cleaning process, cleaning has been divided into three classifications: Preventative (see Preventative Maintenance), Interim cleaning, and Restorative cleaning.
Preventative maintenance has been discussed earlier. This section should be reviewed carefully.
Interim cleaning can include any of the five methods recommended by the Carpet and Rug Institute. For most schools, interim cleaning of carpets should take place a minimum of once per year. Some schools may require more frequent cleanings depending on soil type and indoor environmental conditions. The selection of a cleaning method may depend on these conditions. Many people are misinformed in assuming that carpet should be cleaned less frequently to extend its life. Maintaining a clean carpet can extend the life of the carpet and improve environmental quality, just as cleaning other surfaces will also improve the quality of the indoor environment.
In preparation for cleaning, with any cleaning method selected, the first chemical that should be selected is a top quality preconditioner. The preconditioner is sprayed onto the carpet and allowed about 10-20 minutes of dwell time. A quality preconditioner should contain surfactants for wetting, suspension, and emulsification and an alkaline builder to soften water for more effective soil neutralization. A preconditioner is generally used in traffic lanes to ease efforts of actual soil removal. The selection of a preconditioner should be based on the type of carpet that is to be cleaned. A highly alkaline (see pH 11+) formula usually works well on most commercial-type carpets and on non-stain resist treated carpets. A low pH formula (pH 10-) should be used on most acid dye stain resist carpets.
The first periodic maintenance method that should be discussed is the dry extraction method. This method is the lowest moisture method that can be used on carpet. Absorbent compounds have been around for several years. It is among the easiest methods of carpet cleaning. Many consumers, who know very little about carpet cleaning, may use this method quite effectively.
Dry Extraction compounds can be very useful to schools because they are relatively safe for all types of carpet, there is no chance of over wetting the carpet since it is a low moisture method and problems such as browning and yellowing are minimized using this method. Many schools use these dry extraction compounds to clean traffic areas on a regular basis.
Dry extraction compounds use a dry sponge-like powder that is usually moistened with water , a detergent, and a dry solvent. The compound is sprinkled onto the carpet and worked into the pile using a mechanical brushing action. The amount of compound should be applied according to the manufacturers recommendations. Once the compound is worked into the carpet a vacuum is utilized to remove the powder and the soil that has attached to the compound. Some manufacturers may suggest that the powder be allowed 20-30 minutes of dwell time. The compound is engineered to absorb soil particles.
Bonnet cleaning is another minimum moisture method. Bonnet cleaning essentially consists of a cotton, rayon and/or polypropylene pad and a rotary shampooer. It is among the easiest methods to learn and is used in a large number of schools. Primarily there are three procedures for using the bonnet method.
As in all cleaning methods, the carpet should be sprayed with a quality preconditioner. The first procedure involves spraying a chemical solution onto the carpet pile. The solution should be applied in sufficient quantities to saturate the fibers. Drying time may be extended by using more chemical but extra chemical may be necessary to attain the desired results. If too little chemical is used, the resistance may cause pile distortion. Chemicals are relatively inexpensive. It is recommended that an appropriate amount be used.
The second procedure used in the bonnet method involves the use of a rotary shampoo machine and a moistened rayon/cotton/polypropylene pad. This pad is attached to the rotary machine and the rotating pad is used to agitate and aid in suspension of soils. The bonnet pad absorbs these soils and therefore should be cleaned or replaced regularly. Once the pad becomes saturated with soil, the soil is then transferred back to the carpet pad.
Since the rayon pad is not totally effective in the extraction of soils, todays detergents are engineered to hold onto soils after they have dried. As a result, a third procedure may be necessary to extract part of the remaining soil. By thoroughly vacuuming the area after the area is dry, much of the remaining soil can be removed.
The Bonnet method is among the easiest methods to learn and the method is effective in cleaning for in reasons. Many schools have used the Bonnet method on the same carpet installation for 8-10 years and the carpets hold up very well. The following steps should be followed when using the Bonnet method:
The dry foam extraction method is an effective low moisture, rapid drying method that has been used for decades. The dry foam method is similar to the rotary shampoo method in that brushes are used to agitate the carpet pile. In the dry foam method an aerator is used to whip the solution into a foam. The foam is dispensed into the horizontally rotating brushes. As with all methods, the more chemical that is applied, the longer the drying time. Some machines have their own extraction capability. These machines have the capability to remove shampoo and attached soil particles. Other machines do not have extraction capability. A wet/dry vacuum must be used to remove the shampoo and soil.
The chemicals used for this method should contain a quality surfactant, an alkaline builder to soften water, and a dry solvent to assist in emulsification of oils. A defoamer is normally used to eliminate foaming in the vacuum recovery tank.
The following steps should be followed for use of the dry foam cleaning method:
The hot water extraction method or steam cleaning, as it is more popularly called, is among the most popular methods of carpet cleaning used today. It is a relatively easy method to learn and it provides a number of very useful benefits.
Many school systems have began to institute the use of hot water extraction as a part of their regular cleaning regimen. This method does an excellent job in extracting soil from deep in the carpet pile and can be very effective in removing other contaminants. Studies have shown that hot water extraction can remove as much as 99% of the contaminants found in some neglected carpets.
The hot water extraction process uses a combination of water pressure for agitation, hot water to increase reaction time, and a wide array of chemicals to make the task easier, as well as, a vacuum unit to extract these soils and chemicals once the carpet has been cleaned. The hot water extraction process has undergone constant design changes over the past several years and equipment is now state-of-the-art. A wide variety of equipment is available. From truck-mounted units that can provide high water temperatures and water pressure of up to 1000 pounds per square inch (p.s.i.), to portable units, which are ideal for schools, that provide 100-300 p.s.i.
The hot water extraction method has numerous steps involved in the process. Between mixing chemicals, wand stroking techniques and learning the proper method of holding the wand for maximum soil extraction, the hot water extraction method made appear to be the most difficult method to master but the procedures are really quite simple.
The first item that should be addressed is "the grip". Holding the wand correctly can effect the results of the cleaning as well as effect the stamina of the technician. In cleaning large areas, such as schools, technician stamina can be vital to the results of the cleaning. The technician should stand erect with the left (or right) hand on the guide (stirrup) handle. Failure to stand erect can create pressure on the lower back, leading to back pain. The other hand should be placed at the top of bend where the hose is attached. The hand at the top of the bend should be raised/lowered to seal the vacuum at the base of the wand. This hand is used to push the wand back and forth. The hand that is placed on the stirrup handle is used to guide the wand and to apply additional pressure for stubborn stains.
Hot water extraction utilizes a push-pull stroke for effective cleaning. The hot water sprayer is located on the rear of the extraction wand. When the rearward thrust is made hot water is injected into the carpet pile where it is extracted a split second later by the extraction cup. The forward stroke is used to remove excess moisture and any remaining soil. For heavily soiled areas continuous back and forth motions can be used to increase the temperature of the area to assist in soil removal. A smooth, effortless back and forth motion should be used for increased stamina and effective cleaning. There are many wand stroking techniques that may be used but for simplicity the basic wand operation should be discussed.
To begin the stroke, push forward on the wand and depress the hot water injection lever. Push the wand forward and depress the injection lever. Pull the wand backward over the area to remove water and soil. For faster drying and more effective cleaning results, these procedures can be repeated without depressing the water injection lever. This will removed excessive moisture and additional soils.
The following procedures should be used for hot water extraction:
The rotary shampoo method is the oldest method currently used for carpet cleaning. It is still among the best cleaning methods in use today. The shampoo method received a great deal of negative publicity during the early years of carpet cleaning due to the ineffectiveness of chemicals. As described earlier, many of the early cleaning chemicals were true soaps that left a residue on the fibers. These residues caused a rapid resoiling problem. In addition, the early rotary shampoo machines did not have the benefit of extraction as many of these units have today. Todayâ€™s machines offer the advantages of improved chemicals, brushes that offer excellent agitation and extraction to remove imbedded and suspended soils.
The rotary shampoo method takes time to master the various techniques. Operation of the rotary brush machine is very similar to the rotary bonnet machine. Lowering or raising the handle will allow the machine to move left or right. Twisting the handle will move the machine forward and back.
The following steps should be followed in using the Rotary Shampoo method:
Restorative cleaning takes place when regular maintenance has failed. The purpose of the maintenance program is to maintain a high appearance level as well as to maintain a healthy environment. Restorative cleaning consists of three methods which have already been discussed: Hot water extraction, rotary extraction (rotary shampoo with extraction capabilities) and a dual process method which utilizes both hot water extraction and rotary shampoo.
For restorative cleaning purposes, the dual process method is probably the best method available. The rotary shampoo method is used first to agitate and suspend the soils contained in the carpet pile. The hot water extraction method is then used to extract these suspended soils, detergents and other contaminants which may be contained in the carpet. The combination of these two methods does an excellent job of cleaning. For many schools it may be an excellent suggestion that this dual process method be used on a yearly basis with interim cleanings performed 1-2 times during the school year.
Schools face a difficult challenge. Reduced funding means tighter budgets. These tighter budgets require reduced their maintenance budgets to move funds to areas that appear to be more directly related to education.
Many of these schools have developed indoor air quality problems as a result of these maintenance budget cuts. These IAQ problems have reduced the learning capacity of many students as a result of illness and higher absentee rates. Some parents have placed a greater burden on these schools by insisting that their children have suffered permanent health effects and request at-home education programs or monetary damages. In many cases, the solutions to these problems may lie in a more effectively planned maintenance program. A well developed, correctly administered maintenance program can reduce overall maintenance costs as well as provide a more healthy classroom environment.
About the Author
Michael Hilton was the original creator of Carpet Buyers Handbook. Having owned and operated a carpet wholesale company, Hilton has a vast knowledge about all-things carpet related as well as other types of flooring.