Since the COVID-19 pandemic reached Canadian shores, building managers and cleaning professionals have increased cleaning frequencies significantly to remove pathogens and protect health.

Although it is now believed that the primary way the coronavirus is spread is through the inhalation of droplets from a contaminated person, the Centers for Disease Control and Prevention (CDC) adds that we cannot rule out transmission due to touching surfaces contaminated with the virus.

“It may be possible that a person can get COVID-19 by touching a surface or object that has the virus on it and then touching their mouth, nose, or possibly their eyes,” the CDC webpage stated earlier this year.

“This is not thought to be the main way the virus spreads, but we are still learning more about this virus.”

However, we know other viruses are spread by touching contaminated surfaces and then touching our face, nose, mouth, or eyes. For this reason, it is wise that managers and cleaning professionals are ramping up their cleaning routines.

But, this brings up another issue. Let us say the high-touch surfaces in an office building are wiped clean and disinfected each evening. How long does it take for those very same surfaces to become recontaminated?

Can we count on them to be contamination-free for several hours, or even most of the next day when the building is being used?

This can be extremely hard to determine because no two facilities are used in the same way. Recontamination can be faster in one facility and slower in another. This is because the facilities may differ in the number of people using the building, which surfaces are most touched, weather conditions, and several other factors.

Looking for answers to this quandary, researchers at the University of Hong Kong found that one of the best ways to determine how quickly surfaces become recontaminated is to conduct tests in, of all places, airline cabins.

Why airline cabins? Most cabins are used the same way and hold about the same number of people. Although several planes were used in the study, recontamination frequencies were about the same in all test cabins.

As to their findings, after the surfaces in the airline cabins had been cleaned and disinfected, the researchers reported the following:

• Soon after boarding, a “contamination network” began forming on aisle seat backs and toilets.
• In less than three hours, most of the just-cleaned high-touch surfaces showed traces of contamination.
• Within six hours, “nearly all touchable surfaces are contaminated.”

But then the researchers added one more thing. “Our [research] model is generally applicable to other crowded settings.”  This means in a busy office or school, for instance, most of those just-cleaned surfaces will begin collecting potentially harmful pathogens in less than three hours and possibly be fully recontaminated within six hours.

The researchers also added, “The commonly repeated advice to ‘wash hands frequently’ may be replaced in [the] future by more strategic advice such as ‘clean surfaces right now.'”

However, is that practical or possible in most facilities? Can schools or commercial office buildings afford to have custodial workers cleaning high-touch areas every hour or two? In most cases, the answer is no. Nevertheless, building managers can take steps to help minimise surface contamination and protect the health of building users.

The first step is to create a “high-touch checklist.” The second is to make sure proper cleaning methods are in place. Let’s start with the checklist.

The High-Touch Checklist

Managers should tour their facilities with their housekeeping crew or cleaning contractor. The goal here is to develop a list of high-touch items in the facility that can become “pathogen heavy” during the day. Some surfaces are apparent, such as elevator buttons, door handles, kitchen counter tops, water fountains, and light switches.

But how about the glass on doors, coffee machine handles, refrigerator door handles, time clocks, chair tops, even common-use staplers and staple removers. These become pathogen heavy very quickly, all belong on the high-touch checklist for cleaning.

With the checklist in hand, cleaning professionals know more precisely which surfaces need their time and attention. This saves time because it eliminates cleaning surfaces that do not need special attention. Building housekeepers and day porters now know where they are needed the most. 

Cleaning Methods

The cleaning workers in a 644-unit condominium building were using a high-touch checklist and cleaning program to ensure frequently touched surfaces were clean and disinfected throughout the day. As concerns mounted regarding the coronavirus, the building managers met with the cleaning professionals to review the program and determine if any changes were necessary.

During the review, a few high-touch surfaces were added to the list. However, it soon became apparent that the methods used to clean surfaces were the bigger problem.

For instance, one worker was tasked with cleaning the door handles on each apartment once per week.

He used the same cleaning cloth to clean each handle until it was saturated with moisture and soil. With this method, instead of removing pathogens, the worker was spreading them from one door handle to another.

A similar situation happened with floor mopping. Mop buckets were filled with water and cleaning solution to clean the long hallways in the building. There was no procedure in place regarding how often the mop water and mop heads were to be changed.

The result was that both were changed when they became unsightly. That is way too late. By then, the bucket water and mop heads have spread contaminants from one end of the hallway to another. (See sidebar: Touched Any Floors Lately?)

To address these situations, cleaning cloths were changed after cleaning the door handles on each floor. As for floor cleaning, the decision was made to transfer from floor mopping to a spray-and-vac cleaning method, also known as no-touch cleaning.**

No mops are used in this process, and only fresh water is applied to floors. This eliminates the dangers of floor contamination due to the cleaning process. ISSA, the worldwide cleaning association, also finds the process is faster than traditional mopping procedures.

When we look back at this difficult time, one of the few good things we may realise is that we learned much more about surface contamination than ever before. We now have a better idea how long surfaces can stay contaminated as well as how quickly they can become recontaminated. We have also learned some cleaning methods and procedures are more effective at removing and stopping the spread of infection than others.

 

Drew Bunn is Canadian Director of Sales for Kaivac Canada, manufacturers of professional cleaning tools and equipment engineered to help protect health.  He can be reached at dbunn@kaivac.com

 

* Lei H, Li Y, Xiao S, et al. “Logistic growth of a surface contamination network and its role in disease spread.” International Journal of Scientific Reports. Published Nov. 1, 2017.

** Spray-and-vac is a term coined by ISSA.

 

Sidebar: Touched Any Floors Lately?

According to Mark Warner, former education manager at ISSA, people have as many as 50 direct and indirect contacts with floors every day.

When an item is placed on the floor and then picked up from where it was in contact with the floor, it is as though we have just touched the floor.