By Randy Pierce
Cleaning carpet — any type of carpet, any type of soil, any spot or stain — requires four fundamental elements:
· Chemical Action
These are all interdependent: raise the temperature of your cleaning solution (within limits) and carpet can be cleaned in less time (and more effectively). Give a weaker solution more time and it will clean better.
This has its limits, though. As cleaning solutions cool, they lose the ability to clean. And removing some soils, such as cooking grease or anything else with a high melting point, may be nearly impossible if cleaning solution is too cool. If chemicals are ineffective, all the time in the world won’t make them clean any better.
To understand the science of carpet cleaning, the first step is to fully understand these four components.
Many carpet cleaners believe that hotter cleaning solution is always better. Those that took a little science in school will note that many chemical reactions double every 18 degrees above a certain point. More chemical reaction must mean more cleaning power, right?
The reality is that cleaning solution must be hot enough to be above the melting point of the soil in the carpet. (For example, try washing butter off a knife with cold water, then with hot water.) Beyond that, cleaning solution that is too hot can remove carpet dyes and protectors. What does that mean? There is no perfect temperature, but budgets are better spent on better chemicals and the education to use them than on equipment that can make cleaning solutions hotter.
Carpet cleaning chemicals and stain removers have complex jobs to do: they must separate soil and grime from carpet fibers, hold that soil, grime, grease and whatever caused the stain in suspension or solution, cancel the electrostatic charge that binds dirt to carpet fibers, and penetrate every nook and cranny of every carpet fiber to get out dirt. Then it has to be capable of being thoroughly extracted without leaving a residue. Oh, and if it was safe for kids, pets and the environment and preserved the color and texture of the carpet, that would be good, too.
If a single detergent exists that can do all of that and remove every type of stain exists, no one has yet seen it. Instead, effective carpet cleaning, stain removal and odor control typically requires a variety of chemical tools, including pre-sprays, detergents, surfactants, stain treatments, carpet protectors and static reducers. Unfortunately, the inexpensive chemicals that line the shelves at most home stores don’t meet those rigorous requirements: they’re cheap for a reason. A skilled carpet cleaner must learn the differences between organic and synthetic stains, why more pH is good and too much is very bad, and while the same stain calls for different treatments on different types of rug fibers.
Pro tip: without taking courses and understanding the basic chemistry and physics behind carpet cleaning, the odds of reading the label on a jug of detergent and using it correctly to clean a carpet (and generating great results) are very slim.
There’s a reason why a clothes washer agitates and tumbles clothes in a soapy solution for 20-30 minutes or more: agitation loosens dirt more effectively than just detergent (or other chemicals) alone. Otherwise, you could just squirt soap on your hands when they’re at their grimiest, stick them under the water, and, without scrubbing, have them magically become clean.
Agitation accomplishes three goals: it lifts matted and crushed fibers, helps cleaning agents penetrate the carpet, and then holds solid particles of dirt in suspension without allowing them to settle back into the carpet.
For wet carpet cleaning, agitation typically means using rotary shampoo extraction or hot water extraction (otherwise known as steam cleaning). Cleaning machines can use high pressure, vacuums, rotating pads or other technology to agitate the cleaning solution. No method is inherently “better.” However, properly used “wet” equipment with the right cleaning chemicals is almost always a better choice than dry carpet cleaners, which typically involves putting a cleaning compound into the carpet, cleaning it with a brush and then vacuuming it. Dry methods often do not work well on heavily soiled carpets and certain types of stains.
One last tip: agitation also means extraction. If cleaning solutions aren’t effectively extracted from carpets, drying time is greatly increased. Carpets that are wetter longer attract more dirt and odors, and also make for unhappy clients.
Time is a carpet cleaner’s ally: in most cases, the more time a cleaning solution has to work, the more effective it is. Pre-treating stains and using other pre-sprays are, among other things, great ways to put time on your side. The longer a cleaning solution has to work on soil, the more soil it can remove.
On the flip side, allowing cleaning solutions to soak into the base of the carpet for hours leads to other problems, and isn’t an effective cleaning strategy. The key is to take the time to thoroughly clean the carpet, moving slowly enough so that the cleaning solutions can do their work. This can be difficult in some situations, such as a commercial establishment that must have dry, clean carpet within a shorter time frame (such as a restaurant that needs to open at a certain time). There, the only solution may be to take the time to do a thorough cleaning job, then use fans or other blowers to dry the carpet faster.
The bottom line: a thorough understanding of the four factors that go into carpet cleaning is critical for great results. Otherwise, you’re just pushing a wand around and wasting water.
Randy Pierce is president of Worldwide Cleaning Industry Resources, LLC, an educational resource for carpet and upholstery cleaners. He is an I.I.C.R.C. approved Instructor for CHEMSPEC and Certified Master Cleaner and Water Restorer, holds a number of other professional certifications, and has travelled the country teaching textile cleaning courses for the past several years. He was the owner/operator of a successful textile cleaning and restoration company for 17 years; that company is still successful and being managed by his son.