When Should Carpet Be Cleaned? (Part 1)

When Should Carpets be Cleaned? (Part 1)

Carpet is a Major Investment and Integral to a Facility's Appearance.

Note: This is the first article in a two-part series answering the ever-asked question: When should commerical carpet be cleaned? Read Part 2 here.

Because carpet is a major investment and so integral to a facility's appearance, dirt and stains can have significant negative impacts, whether facilitating a bad image of the building or health and safety concerns. With 10.8 billion square feet of carpet shipped in 2012, in addition to that which was previously installed, there is much cleaning to be done to maintain that fresh, new appearance. But there is still no consensus on when to clean.

Think about your current process of determining when to clean the carpet. Are you noticing unsightly stains or dull colors? Or is it based on an arbitrary schedule like once a year, quarterly, or during vacation holiday times of the year?

While a carpet’s cleanliness is often determined simply by looking at it, soil that is invisible to the human eye is accumulating from the moment the carpet is installed. Waiting to clean until the soil is visible means that the dirt has reached an unacceptable level, putting the carpet at risk for early, and therefore costly, replacement.

The carpet is at risk because allowing soil to build up until it is unsightly severely hinders a cleaner’s ability to recover its appearance. Heavily soiled carpet requires “restorative” deep cleaning to attempt to recover the carpet’s original appearance. This method could lead to erratic or uneven appearance levels that degrade significantly over time. This type of ‘deep restorative cleaning’ is expensive, disruptive, and more often than not requires the use of more hazardous chemicals.

Objectively Measuring Appearance

In a laboratory test conducted by Cleaning Research International, a spectrophotometer was used to determine the effectiveness ofcleaning by measuring the change in lightness of a white carpet. A spectrophotometer is a color measuring instrument that uses numerical color data to accurately communicate colors and color differences.

Using the value “L” to describe the lightness of the carpet, numerical values are associated with the carpet’s appearance by its ability to reflect light. In figure 1, there are 20 soiling cycles that were recorded. Each of these “soiling cycles” represents approximately 10,000 footsteps on the carpet. The numerical value for each soiling cycle reflects the carpet’s appearance at that time, with higher numbers exhibiting that the carpet’s appearance is darker, or has more soil present. The closer to zero the number is, the cleaner the carpet.

The carpet’s appearance began at 17.7 after the first soiling cycle, and that number increases over time. At the end of each cycle, the carpet was vacuumed. By the 20th cycle, or after 200,000 footsteps, the carpet’s appearance degraded to a value of 35.5.

Now, consider the previous statement that “This method (of ‘restorative’ deep cleaning) could lead to erratic or uneven appearance levels that degrade significantly over time.” It is obvious that if this test carpet was installed in a facility, the new “clean” after a wet extraction would be 27.3, not the original value of 17.7. After more soiling occurs over time, the next deep cleaning would attempt to recover the carpet’s appearance to a value as close to 27.3 as possible. The process would repeat over and over again until the carpet simply looked so poor that it had to be replaced. The following graph illustrates this degradation resulting from these lower “restore” points.

Much research has been done leading to the development of the Carpet Appearance Management System, a patented program owned by R.E. Whittaker Company. This system can determine soiling levels with precision and objectiveness rather than estimating with the eye. Using a Tristimulus Colorimeter measurement device by Konica Minolta, it is possible to measure the change in color of any facility’s carpet.

Not only does this system allow for research in determining generalities relating to carpet maintenance, but it can also be used on site to assist in the creation of a proper maintenance plan specific to any facility.

One of the differences between this system and the previous test by Cleaning Research International is that the entire color spectrum is measured to ensure accuracy on multi-colored carpet. This addition of “chromaticity” into the measurements introduces the values “a” and “b,” resulting in color space values: L*a*b*

When measuring the appearance of a facility’s carpet, the chosen areas are compared against a target set of L*a*b* values. This target may be either attic stock or the cleanest, least trafficked area of the building. The result of these measurements comparing target to sample is described as ΔE, or the change in color space.

Objective soil measurements reveal that carpets need cleaning before ΔE equals 3.

In other words, after the measurements of a desired appearance are obtained, measure another area of interest. If, for example, the result of these measurements is 2.3ΔE, the carpet should be cleaned soon, if not immediately.

This practice is especially helpful when followup measurements are taken. If, in three weeks after cleaning, the carpet has reached a ΔE of between 1.5 and 3.0 again, it becomes apparent that that area of carpet needs to be cleaned every three weeks.

All of this scientific research lays the groundwork for the general carpet maintenance concepts to follow. Applying what we have learned about degrading carpet appearance, an “interim” method of maintenance was put to the test to compare appearance results. This test utilized the Whittaker SmartCare® Carpet System, so results may vary based on product selection and effectiveness.

Figure 4 introduces a third column to the soil measurement test in which interim maintenance using SmartCare® is performed every fifth soiling cycle.

There is a notable difference in the amount of soil present after interim cleaning is performed. In the case of the sample which was vacuumed only, this change continues to worsen until a plateau is reached which is an equilibrium between the color of the soil and the color of the carpet. However, in the case of the carpet subjected to interim cleaning, each subsequent clean restores the carpet to a value around that obtained after a single soiling.

Furthermore, after ‘restoration cleaning’ using hot water extraction equipment, the recovery of the carpet regularly maintained with the SmartCare® system is significantly better than that which does not have the benefit of interim maintenance.

In comparing these two methods of cleaning carpet, it is easy to see which one will maximize a carpet investment.









Note: This is the first article in a two-part series answering the ever-asked question: When should commerical carpet be cleaned? Read Part 2 here.