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Commercial Carpet Maintenance

By Michael Hilton

Start with good performance. Carpet performance can be the result of:

  1. Specifications... was the correct carpet specified in relation to intended use of the carpet at its location?
  2. Color Selection... Was the proper carpet color selected to meet local soiling conditions, traffic conditions, intensity of sunlight?
  3. Installation... Was the quality of the carpet installation satisfactory?
  4. Maintenance... Was a regular carpet maintenance plan designed to serve the needs of the location?

Good performance begins with clear specifications which meet the needs of the functions to be performed and is completed with a maintenance plan to be put into effect immediately upon installation. The omission of any of these four items can seriously affect the perceived or actual performance of the carpet. Satisfactory performance of any carpet selected depends on the specification of proper construction, color and carpet fiber content. Maintenance will have a greater effect on the appearance of the carpet than any other single factor.

Carpet Specifications

Making an informed floor covering choice for commercial facilities, schools, and offices can be a difficult task. Budget concerns such as maintenance costs must be considered in addition to facility needs and the needs of the occupants.

One of the first decisions which should be made is the type of carpet fiber system preferred. All fiber systems have specific advantages. The two primary fiber systems used in commercial applications are olefin (polypropylene) and nylon.

Olefin has become one of the fastest growing fiber systems used in the manufacture of carpet. Olefin is one of the most inexpensive fiber systems available because of the capability that carpet producers have in extruding their own yarn. One of the limitations of olefin is the restrictive number of color choices. Limitations in color are a result of the dye method that must be used.

Most yarn systems such as nylon, polyester, wool, or cotton are dyed using a topical treatment of liquid dyes. These yarn systems contain tiny holes (dye sites) which allow the dyes to penetrate the yarn. Dye can be applied in a dye bath (beck) or sprayed-on topically. Olefin does not contain dye sites which allow dye to penetrate the fiber. Olefin is dyed using a solution-dye method. Solution dyeing occurs when the yarn is transformed from polymer chips to fiber. Polymer chips are added to a chamber and heated. Color chips are added during the heating process.

At the bottom of the chamber is a device called a spinneret which contains hundreds of tiny holes. As the solution melts and pours through these holes filaments of fiber are formed. It may take 1500 or more of these filaments to make up one-plyed yarn. As the color chips and polymer chips melt, the yarn is dyed through and through with color. Olefin's limitations in dyeing capabilities also can be considered an advantage.

Most carpet stains occur due to penetration of the dye sites. Olefin does not contain dye sites, making it almost impossible to stain. Another advantage of solution dyeing is the ability to withstand bleaches and oxidizing agents. Since the color is throughout the yarn, fading and bleaching cannot occur. Nylon can also be dyed using the solution-dye method but most nylon is dyed using the less expensive topical or beck dyeing method.

Nylon has been the fiber of choice for many years. Approximately 80% of the carpet manufactured in the United States is produced using nylon. It has very good resiliency, offers excellent color choices, and recent innovations in stain technology have improved nylons' ability to withstand stains. Solution-dyed nylon is even more stain resistant due to the dye method.

Carpet Construction

The construction of a prospective style of carpet has a major impact on the life expectancy and performance a carpet will provide. Carpet density is the major factor of construction that should be considered. Density is a combination of several factors. Gauge rate is the distance between tufts (loops) or needles in the widthwise direction.

# of needles per:

Gauge per Inch # across 12 ft width
5/32 6.4 922
1/8 8 1152
1/10 10 1440
5/64 12.8 1843

Stitch rate is the distance between tufts (loops) or the number of times the needle bar strikes in the lengthwise direction. Various styles may be measured differently. Stitches per inch is the most common unit of measurement but stitches per 6 inches may be found frequently.

Pile height is the length of the tuft (loop) from the base of the tuft (primary backing) to the tip of the tuft. Pile height is normally measured as a fraction of an inch or as a decimal equivalent.

3/16" = .188
1/4" = .250
5/16" = .313
3/8" = .375

Twist level has recently been identified as a major performance factor in many commercial cut-pile and residential cut-pile constructions. Twist level is measured in twists per inch. A close look at the tufts on a cut-pile product will reveal two bundles of yarn that have been plyed (twisted) together and heatset to "lock-in" the twist. Generally speaking, the more twists per inch, the better the performance.

Density can be defined as the amount of face yarn per unit area. There are several methods used for determining density. The primary method uses a simple empirical formula to quantify density.

Average Pile Density = 36 X Pile Yarn Weight / Pile Height (or pile thickness) in inches

Variations may occur due to differing methods of quantifying pile height. There are essentially 3 methods for determining pile height. Each method will deliver differing results.

In the first instance (pile height), a small ruler is inserted down to the backing to read the overall height of the tuft. This is not a precise method due to variations in results by various technicians. There may also be variations due to measurement timing (preshearing or post shearing).

The second method for determining pile height (pile thickness) is a much more precise method due to consistency of results. This is a much more complex method but it is the preferred method for determining pile height. This method involves the use of a compressometer, which measures thickness of materials under a slight load, between a platen and a circular foot. In using this method, the total thickness of the pile and backing material are quantified. The pile is then sheared and the backing thickness is calculated. These values are deducted and pile thickness is determined.

The third method, (tuft height) is also a laboratory technique which is reproducible. Ten tufts are sliced from the primary backing and inserted into a metal block. These "V" shaped tufts are then covered with a clear plate and measured using a precision scale. Problems can develop when product specifications are written using varying methods. A 30%-40% variance is possible on similarly manufactured goods when less precise methods are used.

Problems can develop when product specifications are written using varying methods. A 30%-40% variance is possible on similarly manufactured goods when less precise methods are used.

Carpet Color Selection

Few people realize the importance that carpet color selection has on carpet performance. Most people believe color should be selected based on aesthetic needs rather performance requirements. Carpet color can significantly reduce the cost of maintenance by reducing the appearance of soiling. Very light tones and very dark tones tend to reveal more soiling while middle-tones, multi-tones, patterned, tweed, and heathered tones can hide the effects of soiling. The geographic soil conditions should also be considered when carpet color is selected.

Traffic conditions may play a very large role in color selection. Carpet has the ability to trap tracked-in soils and restrict them to entryways. This can enable a specifier to alter carpet color with soil type and traffic load at each entryway.

Carpet Installation

Proper installation can directly affect carpet performance and increase the life expectancy of carpet. A large number of carpet installations are replaced due to installation failure rather than carpet failure. In many of these instances carpet replacement could have been prevented if proper installation guidelines had been followed. These guidelines are listed in Publication CRI-104 for commercial installations and CRI 105 for residential applications. A copy of these guidelines should be obtained and reviewed prior to carpet installation. They can be obtained through The Carpet and Rug Institute (706)-278-0232.

Prior to installation several points should be reviewed with the flooring contractor or architect/specifier.

  1. A rough sketch or diagram should be provided, detailing room measurements, openings, and unusual angles. Windows and doors should be noted along with direction of natural lighting sources.
  2. Be sure there is an understanding between the contractor and the building owner as to the location of all carpet seams that may be required prior to the beginning of the installation. If possible seams should be run perpendicular to the primary light source. In some installations the seams will peak when the carpet is stretched. This peaking may cast a shadow on the opposite side of the light source if the seams are run parallel to the light source. Keep in mind that no seam is completely invisible. Visibility will vary with type of carpet purchased. A bead of seam adhesive must be applied to all seam edges as well as all exposed edges. This will help in reducing seam separation and unraveling of the yarn.
    • If possible, seams should be kept to a minimum.
    • Seams should run the length of the area.
    • Main traffic should run along the seam rather than across the seam.
    • Seams should be away from areas subject to pivoting traffic.
    • Seams should not be perpendicular to doorway openings.
  3. The amount of carpet purchased should be reviewed prior to carpet purchase. Be aware that the amount of carpet purchased will likely be greater than the actual room dimensions due to standardized carpet widths. More seams may be added to reduce the amount of yardage but carpet must be run in the same direction throughout the installation due to color changes caused by reversing the pile direction. Less seams can be used in some installations by increasing the yardage which will increase waste. Seams must be used in rooms that are wider than standard carpet width. Most carpet styles are produced in either 12 ft, 13'6", or 15 ft widths.
  4. Carpet is usually glued directly to the floor in commercial applications and stretched over carpet padding in residential applications. Appropriate cushion should be used for the carpet specified. Should you have any questions concerning the type of cushion required contact the carpet manufacturer for their recommendation. Any carpet installed over pad must be stretched using a power stretcher. A knee kicker will not provide the necessary stretch needed for a good quality installation. The type of adhesive used to attach the carpet to the floor should be carefully considered. It is recommended that a low emitting adhesive be specified.
  5. Prior to removal of old carpet vacuum thoroughly to remove as much soil as possible. During removal this soil can become airborne which may temporarily cause a reduction in air quality. The subfloor should be vacuumed or cleaned thoroughly prior to installation of the new carpet. It should be understood, prior to removal of the old carpet, who is to be responsible for removal and disposal of the old carpet. There may be an additional charge for this service. In many areas of the country it is more cost effective to pay the installer to remove and discard the old carpet since landfill fees may equal or exceed the cost of the labor alone.
  6. When using any renovation materials it is recommended that the area should be ventilated for the first 48-72 hours. Certain renovation materials may require additional time for ventilation. If you or anyone in the area to be recarpeted is considered overly sensitive to chemicals, it is advisable that they leave the area during this initial 48-72 hour period. New carpet smell may be offensive to hypersensitive individuals. These odors should decay within the first 48-72 hours. The area to be carpeted should be free of obstructions. There may be an additional charge to move furniture or items considered fragile. Advance preparations should be made should any utilities need to be connected/ disconnected to insure a proper installation
  7. An installation date should be set and agreed upon. It is recommended that someone from the facility inspect the carpet prior to installation to insure proper style and color have been received.
  8. There may be leftovers or scrap materials left over from the installation. Notify the installers of your policy regarding these scraps. It is an excellent idea to save all the scraps from the installation. These scraps can be used as door mats to help reduce the amount of tracked in soil or they can be held in reserve should any area become stained or damaged. Sections of the carpet can be removed and portions of these scraps can be reinserted and seamed into these areas.
  9. Preparations should be made to insure that site environmental conditions should be between 65 degrees and 95 degrees and the relative humidity should be between 10% and 65%.
  10. All installation guidelines contained in CRI 104-CRI 105 should be followed for each installation.

Categorizing Maintenance

The maintenance plan should be divided into four categories: preventative maintenance, daily maintenance, periodic cleaning, and intensive cleaning.

An effective maintenance plan should be divided into four categories:

  1. Preventative maintenance
  2. Daily maintenance
  3. Periodic cleaning
  4. Intensive cleaning

Among the goals of a regular maintenance plan is to prolong the life of the carpet. It is crucial that the maintenance staff anticipate dealing with soil from the very first day the carpet is installed, prior to being placed into service. Otherwise abrasive dirt may build up faster than it can be handled. One of the most effective approaches in handling soil is to eliminate soil before it reaches the carpet. This is called preventative maintenance.

Preventative Maintenance

Preventative maintenance may include any steps taken to reduce the amount of soiling prior to exposure to the carpet. Preventative maintenance is among the least expensive methods of maintenance. Properly administered, it can dramatically reduce interior maintenance costs, as well as prolong the life of the installation. The most obvious method of preventative maintenance would be outside maintenance.

Carpet maintenance should begin outside the building. Just as any homeowner would sweep the garage or porch to prevent soil from being tracked into the home, parking lots, sidewalks, and other exterior areas should be swept to keep them free of soil. Snow and ice should be removed rather than chemically treated or covered with sand. Fallen leaves should be removed quickly.

Soiling barriers such as walk-off mats should be installed at all entry points. Walk-off mats, if properly used, can be the most cost effective method of maintenance available. With walk-off mats, most of the soil is trapped or "localized" before it can reach the carpet. These walk-off mats should be large enough to trap as much dirt as possible. The proper length for a walk-off mat should be 12-15 feet. One third of the soils are captured during the first 3 feet while approximately 85% is trapped within 15 feet.

Another area where walk-off mats should be utilized is on stairway landings. These areas usually receive less maintenance than other areas of the building. In addition, movement up and down the stairway tends to release additional soil from the shoes.

Generous use of walk-off mats in cafeteria lines, in front of vending machines, copiers and funnel areas that receive high traffic will extend the life of the carpet and reduce maintenance. It is imperative that all walk-off mats are cleaned thoroughly on a regular basis. Once these mats become filled with soil, the mat then becomes a source for additional soiling. A soiled walk-off mat can allow soil to transfer to the soles of the shoes and allow soil to spread throughout the building. It is a good idea to obtain two mats for every doorway. A replacement mat can be installed while the initial mat is being cleaned. The purchase of extra mats is necessary to establish a suitable rotation schedule. It would not be necessary to purchase 2 mats for every doorway if an acceptable, verifiable rotation schedule can be established. Many janitorial supply businesses will rent these mats and replace them every 2-3 weeks, which may be less costly in the short run.

Another preventative maintenance measure which will prove extremely effective is monthly replacement of HVAC filters. It is amazing how inexpensive these filters are, yet many school systems insist on trying to extend the replacement cycle of the filter beyond its usable life. These filters are very effective in trapping airborne soils which are the most difficult to remove from carpet. They are also very effective in trapping other infectious airborne contaminants as well. Additional (unnecessary) maintenance costs are incurred as a result of this practice. More money could be saved by replacing these filters and reducing the maintenance required.

Eliminate smoking indoors. Residue from tobacco smoke is extremely difficult to remove from all surfaces within a building, without mentioning the health risks associated with second hand smoke.

Designate eating and drinking areas. Do not allow foods or beverages to be consumed outside of these areas. If it is impractical to restrict these areas, reduce the container size of the beverages to be consumed. Smaller spills are easier to contain.

Do not allow chewing gum to be used anywhere on the premises. Gum can be tracked in on the soles of shoes as well as dropped on the carpet. Supply plenty of waste baskets throughout the building. This usually encourages students and teachers to use them.

Have the HVAC system inspected and serviced twice yearly to make certain it is operating at maximum efficiency. Biological contamination could have occurred during periods of non-use. Turning on the system will allow the contaminants to spread throughout the building. When turning on the heating or air conditioning it is a good idea to turn it on over a weekend to allow time for particulates which have built up in the ductwork to settle. This should be coordinated with the maintenance staff to insure extra cleaning will take place after the system has been turned on.

In areas with high humidity, dehumidifiers may be used to reduce humidity levels in the classroom. High indoor humidity levels can be a nightmare for school maintenance personnel, as well as risk management personnel. High humidity readings can initiate the growth of fungi such as mold and mildew or bacteria on walls, windows, ceiling tiles and corkboard. To rid the classroom of these organisms the diligent use of biocides must be used by the maintenance staff. Some biocides may exhibit harmful health effects in some children. It is for this reason that preventative maintenance measures such as dehumidifiers and improving ventilation can help in reducing the maintenance budget.

Chair pads should be used beneath all furniture or chairs that have castors. Desk chairs can damage the carpet as well as the underlayment. Chair pads protect the carpet as well as allow the chairs to move more freely.

An excellent preventative maintenance method that is very effective but rarely used is to require students to pick-up litter around their work area, prior to leaving. This encourages students and teachers to keep the classroom clean and it effectively reduces the amount of maintenance time necessary. This can be carried one step further by having students move desks and chairs to the side or place light-weight chairs on tabletops for easy access by the maintenance staff. This will dramatically reduce the amount of time required to perform daily maintenance activities. Spills should be reported immediately to the maintenance staff for removal, no matter how slight.

Daily Maintenance

Daily maintenance includes all those activities that take place during the course of daily operations, for the purpose of extending the usable life of the carpet. The two most important procedures of daily maintenance are vacuuming and spot cleaning.

Vacuuming is the single-most important soil management procedure. The purposes of vacuuming are to reduce the soil load in order to broaden the time between cleanings and to prolong the life of the carpet. Over 80% of the soil that enters a building can be removed with thorough vacuuming, yet it is surprising that so little attention is given to this important area of maintenance. Most maintenance staffs spend 25% of their time vacuuming the carpet where 80% of the soil is trapped while 75% of their time is spent cleaning 20% of the soil from other surfaces.

As mentioned earlier, carpet does an excellent job of absorbing all types of soils and trapping them until they can be properly extracted through vacuuming or cleaning. Hard surface floor coverings release these soils and allow them to settle on other surfaces which must then be cleaned.

Carpet is a fairly "new" floor covering to many schools and commercial facilities. Most school systems feel that they should dedicate as much maintenance effort to other interior surfaces as they did when a hard surface floor covering was the flooring of choice. With fewer particulates and dust in the air with carpet, less time needs to be allocated to cleaning other surfaces.

The first decision that should be made in establishing a vacuuming procedure is the type of equipment that should be used. Most consumers and school maintenance supervisors know very little about the various types of vacuum cleaners. Their purchase decision is based solely on the skill of the salesperson. Many vacuum cleaners offer features that are actually gimmicks that do nothing to improve the performance of the unit. These gimmicks are often marketing tools or an attempt to distinguish the product from the competition. There are essentially 7 features that should be evaluated in the purchase of any vacuum cleaner. 1) Dual motors vs a single motor, 2) Powerful airflow, 3) Effective filtration, 4) Internally-housed vacuum bag vs a cloth bag, 5) Brush height adjustment, 6) Agitation, 7) Top fill bag.

Dual Motors vs Single Motor

With a dual motor system the airflow and brushes are powered by two separate motors. In other words, one motor is devoted to loosening the soil and the other motor is devoted to removing the soil. With a single motor vacuum, if the brushes require more power due to a deep pile, the power is generated by reducing suction. With a dual motor unit each motor continues to work at optimum efficiency.

Powerful Airflow

Airflow is essentially the amount of suction a unit can provide. A vacuum must be able to remove contaminants and soil from the carpet. The greater the airflow, the less maintenance time must be spent on extracting soils. Airflow is measured in cubic feet per minute (CFM"s). CFM's were mentioned earlier under ventilation. In vacuum cleaners, the higher the CFM's, the higher the airflow and the better the soil recovery.


Filtration is one of the most important aspects of vacuum selection. The most powerful vacuum manufactured is useless if it allows particulates to travel through the vacuum bag (filter) and reintroduces the tiny particulates into the air. An illustration of this activity would be the housekeeper that dusts the furniture and then vacuums the room. The residential vacuum cleaner allows the tiniest particulates to pass through the filter and releases them into the air. These particulates then settle on the furniture which requires dusting 30 minutes after vacuuming.

Many commercial vacuums offer secondary filtration as well as exhaust filtration which are much more efficient and reduce related maintenance activities. High Efficiency Particulate Air (H.E.P.A.) filters have recently become available which lower the amount of particulates which are allowed to pass through the vacuum. H.E.P.A filters are actually vacuum bags that filter out particles as small as .3 microns with 99.9% efficiency. (See contaminant size chart below)

Internally Housed Vacuum Bag

Internally housed vacuum bags are an extension of the filtration feature of your vacuum. Once the soils have been removed from the carpet, it is important that these particulates remain captured. The smallest particles may remain airborne indefinitely and these particulates can be inhaled leading to further medical problems. An internally housed vacuum has a vacuum bag that is housed within the body of the vacuum cleaner.

A dusty, cloth external bag without an enclosed bag is not recommended for use unless the cloth bag can be cleaned frequently. A recent study involving cloth bags indicated between 10,000 and 1,000,000 colony forming units (CFU's) of bacteria, yeasts, and molds per square inch of fabric on a number of cloth bags. If a cloth bag is to be used, it is recommended that a filter be used that contains a biocide designed to prevent the growth of these organisms.

Brush Height Adjustment

Brush height adjustment is important for a number of reasons. The most obvious is wear and tear on the brushes. Operating the vacuum at too low of a setting will cause the brushes to wear prematurely. The brushes are an important element in effective soil removal. Once they become worn, the amount of soil removed is significantly reduced.

Operating the brushes at too low of a setting restricts airflow which reduces the capability to reduce soil. Air must flow through and around the brushes in order to allow adequate soil removal.


A vacuum with beater bar and brushes are recommended for most residential applications. Most residential carpets are installed over cushion. The beater bar bounces the carpet up and down which aids in the removal of soil. In commercial applications, where the carpet is glued directly to the floor, there is some confusion as to whether the vacuum cleaner should include the beater bar. Some people feel the beater bar drives soil deeper into the pile making it more difficult for the brushes to remove. Regardless of which theory is accurate, brushes should be used and these brushes should be inspected frequently for wear.

Top Fill Bag

Another useful feature is a top fill bag. A large number of bags introduce soil into the bottom of the bag. Part of the power generated by the motor must be dedicated to lifting the soil already in the bag to deposit more soil into the bag. As the bag becomes more than half full the soil removal efficiency is greatly reduced. When the bag begins to fill, back pressure is generated by the reduction in surface area and the weight of the soil inside the bag. When the bag becomes 25% full, the vacuum has lost 80% of its pick-up capabilities. A top fill bag eliminates this reduction in efficiency by reducing this back pressure. A top fill bag will also eliminate the recirculation of soil into the impeller blade thus reducing efficiency even further.

Other Considerations

Another feature that may be considered in selecting a vacuum cleaner is the length of the power cord. It is recommended that a 30 ft cord be utilized to reduce the amount of time required to perform the maintenance. Shorter cords require more frequent location changes of electrical outlets which will increase the time needed to complete the maintenance.

The width of the power head may increase/decrease the amount of time necessary to complete the maintenance. Various vacuum manufactures may produce their vacuums in 12", 15", or 18" widths. Wider widths may reduce the efficiency of the airflow which reduces the amount of soil that can be removed.

The type of brush design should be considered when selecting a particular vacuum unit. There are two types of brush design that should be mentioned, chevron and spiral. A chevron brush is designed to move the soil to the center of the power head. The spiral brush is designed to move the soil from one side of the power head to the other. (See illustration) The air intake should be located in the area where the soil is channeled for maximum efficiency. Many vacuum manufacturers may produce their unit with a chevron brush roll with an air intake on the left or right or they may select a spiral brush roll with the air intake located in the center. This is an improper use of brush design. It is essential that the vacuum motor and the brush roll work together to insure maximum efficiency.

Some commercial vacuums are equipped with sensors that indicate when the bag is filled, when the air intake has become clogged, when the brushes have become worn and many other routine checkpoints. Other machines are designed so that the machine will not run when these mishaps occur. These units can be quite useful or they can be quite bothersome since many are difficult to figure out.

Since most commercial vacuums are not motor propelled as some residential units, it may be beneficial to select a unit that is easy to maneuver and light enough to enable your staff to perform the necessary maintenance without tiring easily.

Developing a Vacuum Cleaning Schedule

The time that the carpet is being specified is the time a vacuum schedule should be developed. The plan should identify the soil localizing areas (wipe-off regions, congested channels, and principal passage routes) on a floor plan. There are numerous businesses that offer computer software or offer services in which a diagram of a specific building can be reproduced and maintenance intervals are specified. These plans identify the various areas that should receive extra attention. (see illustration). These areas are where the bulk of your maintenance efforts should be concentrated. The vacuum schedule and vacuuming techniques will be different in high traffic areas such as entryways than in less traveled areas such as conference rooms. Therefore vacuuming should be divided into three parts; high traffic areas, moderate traffic areas, and low traffic areas. Once these areas have been identified, a schedule should be established to determine the frequency of vacuuming required. Identifying these areas can lower overall maintenance costs by redirecting unnecessary maintenance efforts to areas where increased maintenance can increase carpet life.

The first areas that should be identified are high traffic areas. These areas include all exterior doorways and wipe- off regions, funnel areas such as interior doorways, congested traffic areas such as around vending machines. Principal passage routes such as hallways or stairways receive the most abuse and should be considered critical areas in establishing a maintenance plan. Another area that is often overlooked is any area of carpet that adjoins any hard surface floor covering. Hard surfaces are very poor "attractors" of soil and allow soil to be spread throughout the building. Carpet will absorb most of this track-off within the first 12-15 feet.

The amount of vacuuming necessary for high traffic areas will vary depending upon the traffic load. It is difficult to prescribe a generic maintenance plan for every facility but for most schools, carpeted entryways should be vacuumed a minimum of twice daily. Areas such as lunch room entrances and congested areas around vending machines should also be vacuumed twice daily. Hallways and break areas should be vacuumed thoroughly once per day. Other high traffic areas should be evaluated on the number of foot traffics received and the amount of soiling that takes place. All high traffic areas should receive a thorough vacuuming a minimum of once per day.

Moderate traffic areas may include classrooms, libraries, or offices. These areas will need to be evaluated by the individual maintenance staff member. As some maintenance staff members will testify, some classrooms are more prone to getting soiled than others. Every classroom should be vacuumed every school day but rather than quickly vacuuming each classroom every day it may be wise to thoroughly vacuum each classroom on Monday, Wednesday, and Friday and quickly remove surface soils on Tuesday and Thursday. Some classrooms may require a thorough vacuuming each school day due to heavy soiling conditions. Some classrooms may have an exterior doorway and should be classified as high traffic areas.

Light traffic areas may include conference rooms, unused offices or classrooms, and closets. These areas should be vacuumed a minimum of once per week. Keep in mind that some of the hardest types of soil to remove are airborne soils. If an area receives no foot traffic whatsoever, it can still be soiled by airborne soil. These oily, sticky-type soils will attract other dry soils or they can be tracked-off to other areas where severe soiling can take place.

Frequent and thorough vacuuming will delay the time when it becomes necessary to clean the carpet to restore the color or texture of the carpet. It is much easier and much less costly to remove soil from the carpet surface rather than allowing soil to become imbedded in the pile. Proper vacuuming procedure can be as important as frequency in removing soil from the pile.

Vacuum Procedures

Vacuuming is the single most important activity for extracting soil from a building's interior, but most maintenance staff members do not understand the proper technique that should be followed. Most maintenance staff members use the "sunburst method" to vacuum. (See illustration) The sunburst method consists of standing in one place and using a back and forth "sawing" motion. This sawing motion removes less imbedded soil and causes the staff member to tire more easily than correct vacuuming methods.

The most effective vacuum method removes more imbedded soil and is much less tiring to the maintenance staff member. To understand this method it is necessary to briefly describe carpet construction. A thorough understanding of carpet construction can make soil removal much easier. As you can see in the illustration below, the face fiber leans in the lengthwise direction. In level loop carpets the lengthwise direction can be determined by locating a side seam. Most carpet is manufactured in 12 foot widths so there should be a seam every 12 feet. Once the length is determined the vacuum should be pushed in the direction that the tufts are leaning. Walk in a straight line, in a long, slow, smooth gait, from one end of the room to another. The vacuum brushes are now rotating with the carpet pile direction, removing the surface soils. When you have reached the other side of the room, back up, pulling the vacuum with you and continue walking backward, vacuuming the area you have just vacuumed. You will notice more resistance on the vacuum when you are pulling the vacuum against the pile direction than when you were pushing the vacuum. This resistance is standing the carpet pile erect and removing more embedded soils. The vacuum is removing more soil when you are walking backward, pulling the vacuum than when it is being pushed so take your time and pull the vacuum slowly. When the wall is reached again, move over about 3/4 the length of the vacuum width and repeat the process.

In most cases, if the vacuum is pulled slowly enough, it is not necessary to vacuum the area 2-3 times as some people suggest. However, in high traffic areas, track-off areas, or other heavily soiled areas it may be necessary to repeat this process. In entry areas it may be necessary to turn your vacuum at a 90 degree angle and repeat the process. A little extra effort in the entry areas and track-off areas can save you a great deal of effort in other areas. In entry areas the soil is still localized and less effort is required to remove the soil in these restricted areas.

Spills, Stains, and Spot Removal

The removal of spots, spills and stains should be included as a normal daily maintenance procedure. Carpet is subject to a variety of spills which can produce spots or permanent stains. Spills should be categorized as a form of soiling. Stains normally occur as a result of improper removal of spots and spills. Stains should be classified as any substance that adds color to the fiber. Stains can give a carpet the perception of being dirty. A dirty carpet without stains appears more clean than a clean carpet with stains. Spots can be classified as anything that adds substance to the fiber (gum, oil, tar, etc.). Spots are usually soluble.

Staining normally occurs when a substance penetrates the dye site of the fiber. The substance actually dyes the fiber in the same way that acid dyes are used to permanently dye the fiber. Most of today's fibers have been treated with acid dye resistors which allow most spills to be removed more easily, however, no carpet can be classified as stain proof. When a spill is allowed to remain on the fiber for an extended period of time, even on stain resist carpets, the dye sites begin to swell and the substance is allowed to penetrate the fiber.

The removal of spots and spills can be highly technical. If a spill can be identified it is easy enough to identify a method for removal but removal of an unknown spill may require an elemental understanding of chemistry. It is recommended that every school have a specified maintenance staff member to deal with spills. This maintenance member should work during the normal school day and his first priority should be the removal of spills before they become stains. S/he should work closely with teachers and administrators. Teachers should notify the spotting technician as soon as any spill occurs, prior to attempting to clean-up the spill themselves. Certain clean-up procedures may intensify the effects of some spills.

In dealing with spills, the objective is to remove the spilled substance without damaging the fiber. To accomplish this, it may be necessary to transform the substance into a form in which it can be removed. Spills can be grouped into 4 categories; water soluble, non-water soluble, combination, and chemical.

Most spills can be classified as water soluble. These spills can be removed using water based cleaning solutions. Water soluble spills are the easiest to remove.

Non water-soluble spills consist of oil-based products. Since oil and water do not mix, it may be necessary to covert these spills to a water soluble form, prior to attempting removal.

Some spills may be a combination of water-based and oil based ingredients. These types of spills may require the use of both water based and non-water based cleaners.

Chemical spills must be chemically treated prior to using any water based or non-water based cleaning solution. Failure to do so may create a permanent stain. These spills may include certain medicines, rust, wine, etc.

Forms of Stains

Spots, spills and stains may come in a variety of forms. Surface spills, absorbed spills, compound spills, and destructive stains, can all alter the color of the fiber if they are not dealt with properly. It is important to identify the form of spill that has occurred prior to removal.

Surface Spills

The spilled substance is on the fibers. These spills should be removed using a spoon or bone scraper. As much of the substance as possible should be removed prior to using stain removal solutions.

Absorbed Spills

The spill has been absorbed into the fiber. These spills can be very difficult to remove. Examples might include blood, coffee, ink, urine.

Compound Spills

The spill is on and in the fiber. Oil based paint, lipstick, or shoe polish would be good examples of compound spills. These spills may have an oil base with a pigment capable of staining the carpet.

Destructive Stains

These stains actually alter the structure of the fiber. They are often the most difficult stains to remedy. They may include burns caused by acids which alter the nature of the fiber or they may be bleaches which attack the color. Chemical stains or destructive stains are the most difficult stains to accept by the building owner. In most cases, these stains are not discovered until the damage has been done. Medicines such as acne medications or plant foods may remain on the carpet pile for weeks or even months before they are activated. Many of these chemicals remain dormant until they are activated. In the case of acne medications, the activator is moisture drawn from the air. As moisture is drawn from the air the area will slowly change color until all the dye has been destroyed. In many cases the stain will be white at the center with a pink or orange "halo" around the perimeter of the area. In some situations involving acne medications, actual hand prints can be identified after the chemical has completed its transformation.

Spot Removal Techniques

Often the removal of spots and spills is simply a matter of identifying the substance, locating the substance on a stain chart, and following the procedures recommended. At some point, however, you are bound to come across a stain that cannot be identified.

Removal of unknown spills may be a bit more complicated. A basic understanding of chemistry may be helpful in removing unknown spills before they become permanent stains. For example, spills can be identified by whether the substance is alkaline, neutral, or acid. The basic idea is, if a spill is alkaline, it can be removed by using an acid solution. A pH scale has been established to easily identify the appropriate chemical to be used to remove the spill.

The pH scale is easy to understand and simple to read. All substances can be classified according to their pH. The pH scale is divided into three major divisions. 7, at the center of the scale is neutral. Distilled water would be considered to have a pH of 7. 0-6 would be considered an acid or acidic. Orange juice contains citric acid and would have a pH of 3-4. 8-14 is considered alkaline. Any substance with a pH higher than 12.5 and lower than 2.5 is considered caustic or corrosive to human flesh and metals.

The use of the pH scale is also useful in evaluating the cleaning solution we use to remove spots and spills. A cleaning solution with a very high alkalinity may damage some stain resist treatments.

Litmus paper or a pH meter is used to identify the pH of any substance. When confronted with a liquid spill. The indicator paper is pressed against the spill and the paper will change color according to the pH. A scale will accompany the litmus paper which identifies which color change corresponds to the appropriate pH range. A word of caution should be noted when using litmus paper. Certain dyes used in the paper may cause staining of the fiber if the paper is allowed to remain on the area too long. A pH meter is much easier to use. The meter is inserted into the substance and the dial or digital readout displays the pH of the spill.

The majority of carpet soils are on the acid side of the pH scale, therefore most cleaning agents used, fall on the alkaline side of this scale. Acid soils are neutralized by these alkaline detergents which aids in the removal of these soils.

The Stain Removal Kit

A number of items should be included in every spotting kit for those unexpected emergencies. There are a number of commercial spotting kits that are available. Many of these include a number of effective chemicals for removing these spills. It would be wise to request Material Safety Data Sheets (MSDS sheets) for each chemical used in this spotting kit.

These MSDS sheets provide useful information ranging from: pH, flammability, health effects, toxic ingredients, products it may react with, special precautions, handling procedures and the address of the company should you have any special concerns or situations.

Several companies now offer portable (mini) extraction units as a part of their stain kits. These mobile units contain many items necessary for effective stain removal with the advantage of a hot water extraction unit for small water spills or more effective stain removal.

A complete stain kit should include:

A tray or container is helpful for organization. Often the call will come to remove a spill unexpectedly. It is essential that the spill is attended to quickly. An organized, fully stocked carrying tray will speed response time and exhibit professionalism.

A dry cotton towel or cloth is a necessity for every well- stocked stain kit. These towels should be white, which does not allow cloth color to bleed on to carpet. The white color is also helpful for observing transferrence of the stain from the carpet to the towel. They should be absorbent for removing liquids and foreign matter.

A spotting or tamping brush should be included in every staining kit. The tamping brush is used for agitation for easier stain removal. Care should be used in using this brush. Too much agitation may cause distortion of the carpet pile. It is a good idea to purchase two brushes for the kit. The first brush should have white, nylon bristles for use in water based spotting. The value of using white bristles is for the detection of prior contamination from previous spots. The technician would not want to compound a stain by introducing additional foreign matter to a spill. The second brush should have black bristles for use with dry cleaning solutions. This will allow the technician to distinguish between brushes and the solutions used for removal.

A bone spatula or scraper is used for removal of solids, semi-solids and for use with most stain removal solutions. These can be purchased where most cleaning chemicals are distributed. This spatula is used to break-up solids so they can be vacuumed. Semi-solids can be removed with the spatula by spooning the foreign matter from the surface. The spatula is also used to prevent the spotting agent from allowing the spill to spread. It can also be used for gentle agitation of the pile fibers to ease the removal of the spill. Most spatulas are made of bone or stainless steel. These must be composed of some material that will not react with the chemicals used in spotting.

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.

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