Cleaning Methods

The organization who write those standards is called IICRC, or the Institute Of Inspection Cleaning & Restoration Certification. Their standard is called IICRC S100 Standards Reference Guide for Professional On-location Cleaning of Installed Textile Floor Covering Materials.

Five Recognized Methods:

  1. Steam Cleaning or Hot Water Extraction (HWE)
  2. Rotary Shampoo
  3. Dry Foam Shampoo
  4. Dry Powder Absorption
  5. Dry Pad Absorption

A chart showing strengths and weaknesses can be found here!

Most of the problems that occur from cleaning are due to mistakes made by the technician and/or his failure to comply with the cleaning standards. Problems with defective carpet, faulty equipment, and defective chemicals happen less often.

Five Basic Steps for All Methods of Carpet Cleaning:

  1. Pre-vacuuming. -- 74-79% of the soil in carpet can be removed by vacuuming. Not vacuuming before cleaning can lead to excessive usage of the cleaning method which can lead to other problems depending upon the method. The most common problem it leads to is over-wetting and browning. If you have an all-synthetic carpet with no cellulose materials, then this brown discoloring situation can be easily overcome with re-cleaning.
  2. Pre-conditioning -- The strongest detergent in a cleaning method should be applied several minutes before the cleaning method is employed. The release of oily soil should take place in this step of cleaning. The only exceptions to not doing this procedure would be on certain cellulose fibers like Sisal, Coir, Sea Grass, Abaca, and Cardage.
  3. Agitation -- Once the preconditioner is on the carpet, it should be agitated with a brush or grooming rake. The use of an electric brush or even a rotary shampooer is permissable. The Shampoo and Dry Foam methods may skip this part because agitation is inherent in the method.
  4. Soil Removal -- In the cases of Steam Cleaning and Dry Absorption Pad Cleaning, the method itself is what removes the  soil. With Dry Absorption Power, Shampoo, and Dry Foam cleaning, the chemicals that capture the soil have to be removed by vacuuming afterwards. There are variations on Shampoo and Dry Foam methods where a wet vacuum is built into the system. For Shampoo this variation is call the Chemstractor by CHEMSPEC and for Dry Foam the variation is called Von Shrader.
  5. Grooming -- This is achieved with a brush or tool that looks like a rake and the idea is to stand the pile of the carpet up and align all of the pile in the same direction. This helps the carpet to dry and wear better in the future.
  6. Drying -- It is highly recommended that drying take place in 6-8 hours but never more than 24 hours. Given modern advancement in equipment, drying can take place in less than 15 minutes with all methods.

The question often arises on which method is the best and the answer to could be likened to 'what is the best automobile.' A better question might be who is the best cleaning technician. A cleaning technician with IICRC CCT, Certification from opinion is a good choice. However, there are some likely inherent difference between methods.

  • DRYING -- Dry Powder Absorption methods like HOST and CAPTURE will allow the carpet to back into service immediately after cleaning. Dry Absorption Pad like the ChemDry Method and Dry Foam Cleaning will likely dry faster than Steam Cleaning. Steam cleaning drying times vary depending upon the size of the power of the vacuum. All carpet should dry within 24 hours regardless of all other conditions. Soil conditions and the type of fiber will also make a difference on how fast the carpet will dry. A list of the fastest-drying fibers to the slowest-drying fibers are:
  1. Olefin
  2. Acrylic
  3. Polyester/Corterra
  4. Nylon
  5. Wool/Silk
  6. Cotton and other cellulose fibers, (some cellulose fiber like Sisal, Coir, Sea Grass, Abaca, & Cardage should not be wet cleaned with on location wet clean methods, reference ). There are some companies willing to except the risk and with certain precaution can be successful.
  • ABRASION -- Dry Powder Absorption methods like HOST and CAPTURE will likely cause the most abrasion while Steam Cleaning will likely cause the least. However, there can be strong exceptions on both sides. Some carpet manufacturers do not recommend the Dry Absorption Pad Method. A possible reason for this could be that it causes yarns to slip or pull. If this happens to a tufted carpet, then an investigation onto quality of the backing may be in order.
  • RESOILING & RESIDUE -- is in part, a function of villainous components of detergents. Anionic surfactants from the sulfonate family are likely to dry to non-adhering powders. Nonionic surfactant are more likely to be sticky. Phenolic nonionics like the octyl phenol ethoxylates and nonylphenols ethoxylates are the some of the worse villains. In addition, organic acids like citric and gluconic can also leave sticky residue. The concentration of these villainous component needs to exceed 0.5% of the mass of the faceyarn to be a problem. The GENERAL SERVICES ADMINISTRATION sets a maximum amount of extractable matter at two percent, reference link
    bullet Antisoiling Agents -- Residue from detergents based upon the encapsulation or embrittling agents will retard the soiling process. Instead of being based upon surfactants, this type of detergent dries to a crystal. For a reference see An example of a new method of cleaning based upon this technology is the 'Mist & Scrub' method of cleaning. S100 recognizes this method under the Shampoo Method. See
  • SANITATION & AIR QUALITY -- In general, the quality of the air inside a dwelling is not as good as the air outdoors and the Federal EPA has done studies involving testing for microbial activity after the carpet has been cleaned as it relates to InDoor-Air-Quality, 'IAQ'. Of the methods tested, steam cleaning using a truckmounted cleaning machine made improvements in IAQ when the face yarn reached temperatures of 120 degrees Fahrenheit or more.

To see what could go wrong after the carpet is cleaned, click here.