To many housekeeping employees, cleaning is the series of tasks they’ve learned to perform over the course of a shift – trash removal, dusting, vacuuming or mopping. These tasks, and many more, essentially are done to make their areas look presentable and reduce customer complaints.

However, workers also should look at cleaning from the perspective of all that it does for the environment in which they are working. Every housekeeping employee should understand that cleaning actually is the process of locating, identifying, containing, removing and properly disposing of unwanted substances from an environment. A clean environment can be an object as simple as a floor or shelf, or a structure as complex as a school or a ten-story office building.

Ironically, cleaning staff do much to enhance the quality of life without really grasping the extent to which they contribute to occupant health and well-being. So providing them with the right chemicals and tools, as well as teaching them how to use these products, is not enough. They also must understand cleaning’s purpose and the science behind their actions. Without this knowledge, workers could misuse products, causing more harm than good to the indoor environment.

Why apply products?
First, employees need to understand the science behind the cleaning products they apply – how the solution affects what they are trying to clean from a surface.

When workers apply a cleaning solution to a surface, they help create a chemical action. Cleaning solutions often either are a mixture of water containing soaps or detergents, or an organic solvent in liquid or gaseous form. Polluting substances differ widely in their tendency to dissolve in various solutions, but a common assumption is that likes dissolve likes.

For example, oil will not dissolve in water but only in another organic solution. Sodium chloride (table salt) will dissolve in water but not in gasoline.

In cleaning, it’s always important to understand the process of how things dissolve and become suspended before they become removable. If microorganisms aren’t dissolved enough to safely remove, they will remain and create a host of avoidable headaches for housekeeping managers.

Soap breaks down and helps remove oils and fats in fabrics and surfaces because like dissolves like.

A more detailed explanation is that the hydrocarbon tails of the soap ions dissolve in the hydrocarbons of an item soiling a surface. This reaction then gradually breaks apart the soil as the charged, water-loving, head of the ion is drawn toward surrounding water molecules. The attractive forces of the water molecules and the head of the long hydrocarbon chain literally pull the soil apart.

As the breakage occurs, bits of unwanted substance are held in suspension by the soap solution. Because the charged heads of the soap ions are the same charge, they repulse each other, thereby keeping the soil from reforming. Wash water then emulsifies and carries away the soil.

Removing pollutants from a surface often requires the help of mechanical action such as scrubbing with a brush. Workers always have to use some degree of agitation and mechanical force because the agitation makes the molecules of the cleaning solvent interact faster with the molecules of the substance being dissolved.

Agitation also helps particles separate by providing the initial momentum for the charged particles to separate and then rearrange themselves according to electrostatic charges. So, for instance, simply pouring toilet cleaner into a bowl and flushing after a few minutes will not remove bacteria as well as agitating that solution with a brush can.

The elements that aid cleaning
While water is important in the cleaning process, so is air. Like water, air is a fluid. As air flows, it carries suspended materials — gases and small-suspended particles called aerosols — with it. Air is beneficial to cleaning when it helps direct unwanted substances to a desired location for removal and disposal, such as in a vacuum.

Airflow also is necessary to achieve drying. While drying seems like a simple enough concept, many times tasks such as carpet extraction can do more harm than good because employees don’t fully understand what is involved in thoroughly drying a surface. Drying occurs only when suspended moist air is displaced by dry air on, above and through an environment that has been cleaned. Many cleaning problems occur when environments do not dry, creating breeding grounds for potentially harmful organisms. A classic example is over-wetting a fabric, then not drying it adequately, which creates an opportunity for mold to grow.

Time is another critical element. If workers must capture dirt or microorganisms in a solution that then breaks them down for removal, all those steps obviously take time. But cleaning workers need to remember that individual steps require individual time considerations. Applying a solvent to break down oil and then wiping it off right away, will not allow ample time for a chemical reaction to take place.

What is necessary is adequate “dwell time” — the time it takes for the chemical to sit on the surface and break down the substance before wiping it up.

In trying to increase productivity, workers may wipe off chemicals before they can take effect, leaving behind the microorganisms they’re supposed to remove. This not only is less productive, but can lead to workers having to clean that area more often, due to a building up of microorganisms building on that surface, which can lead to health risks.

Temperature also is an important element in cleaning, especially as it affects the solvents that break down pollutants. In general, increased temperature makes particles more soluble — dirt dissolves much faster in boiling water than in ice water. Elevated temperatures, therefore, can make cleaning more efficient and allow workers to use less chemical to dissolve a given amount of substance.

But misunderstanding how heat helps the cleaning process could lead workers to overuse products, draining a department’s budget.

Heat also destroys living organisms, though critical times and temperatures vary, depending on how well each organism resists heat. This is important when workers must disinfect surfaces — cold water could void a disinfecting task.

Last but not least
Time, chemical actions, the flow of air and water, temperature and mechanical action all are elements of the cleaning process. But it is critical to address the last two steps: removal and disposal.

The more pollutants workers remove, the more effective their cleaning becomes, and the better their actions protect occupant health. An example is the vacuum cleaner that collects dust and other particles in a bag so workers can eventually remove them from the building. However, if workers mishandle the bag, they displace dust back into the environment, that will need to be recaptured.

Removal often comes into play when arguing the merits of how clean an area becomes versus how clean it looks. In modern times, many customers have greatly confused “pleasing appearance” with “healthy.” While not the same, these characteristics are compatible when the pleasing appearance results from extracting and removing the pollutant. Often hiding the unwanted substance from sight or altering its appearance can obtain a pleasing appearance, but for a shorter period of time.

An example is extracting dirt from a carpet as opposed to simply polishing the carpet fibers. In the end, the dirt that isn’t removed will attract more soil and the carpet will require more frequent cleaning than if the initial dirt had been completely removed the first time.

Disposing of pollutants is the last step of the cleaning process. Simply removing pollutants does not make cleaning effective. Cleaners must dispose of unwanted materials properly to truly improve the indoor environment.

Disposal must be logical, legal, socially acceptable, environmentally suitable and in accord with cultural tradition.

An example of socially and environmentally preferable disposal is depositing waste water in a sanitary drain that connects with a wastewater treatment facility, as opposed to putting it in a storm drain that leads to a river or lake.

Logic also helps dictate which disposal methods make the most sense. For instance, making sure trash receptacles outside of a building are not located near ventilation intakes is a way to avoid reintroducing particles into a building’s environment. Otherwise cleaners’ work is nullified by the final step in the process.

Cleaning buildings may not seem like rocket science, but it is a highly scientifically-based exercise. Understanding the science of cleaning requires a heavy emphasis on the means by which workers achieve healthy indoor environments.

Dr. Michael Berry is a research professor at the University of North Carolina at Chapel Hill where he teaches and writes about a range of environmental management topics. He serves as private consultant to businesses and institutions.




POSTED ON: 4/1/2001