The Facts On Disinfecting Schools


School administrators are facing perhaps their most difficult fall season ever. Getting back to school has never been more uncertain or complicated. Ensuring the safety of students and faculty during the COVID-19 pandemic has raised some challenging questions, many of them about cleanliness and disinfection. Infection control in schools is always a concern because of influenza and bacteria such as MRSA and C. diff, but COVID-19 presents new questions. Principals and school boards are seeking information and they often turn to commercial cleaning professionals for the answers.

The pandemic has created new business opportunities for those in the professional cleaning business. Not surprisingly, new companies and services have popped up, many guaranteeing to kill COVID-19. The question for school leaders is, who can you trust?

You can usually identify legitimate, experienced commercial cleaning companies because they carefully follow guidelines from Health Canada and other public health authorities. This would include proper cleaning procedures and disinfection using Health Canada approved products. They also rely on peer-reviewed, published research. For infection prevention, there is no substitute for science.

To help school officials weigh the infection control claims made by competing vendors, ServiceMaster Clean has provided some frequently asked questions we get from schools about cleaning and disinfecting.


What fogging or spraying equipment should you use against Coronavirus?

There are different devices that are used to apply antibacterial and antiviral products over larger areas. The list includes foggers, pump sprayers, electric sprayers and electrostatic sprayers. They sometimes all are incorrectly referred to as “foggers.”

An actual fogger vaporizes an antimicrobial/antiviral product to form Ultra Low Volume (ULV) droplets that destroy airborne and surface-borne pathogens. The direction of the spray and gravity are crucial to its effectiveness. It works well in large areas with few vertical surfaces, like a hallway.

Pump sprayers produce large droplets that don’t travel far and are inconsistent in size. Electric sprayers produce a more uniform spray pattern and are generally more effective than pump sprayers. Pump and electric sprayers work best for disinfecting small spaces like a desk or table. While dwell time of the disinfectant solution is important, there is a fine line between wet enough and too wet as it’s important not to over wet the surface when using a sprayer.

Electrostatic sprayers utilize an electrode to initiate an attractive charge that atomizes the solution, releasing charged droplets that are actively attracted to surfaces. The mist reaches and wraps around surfaces regardless of the direction of the spray. Electrostatic sprayers are considered the fastest, most effective method for disinfecting large spaces with many different surfaces.

Note that all of these devices can be effective for disinfecting if they are applying the right product in the proper setting with the correct technique. A cleaning professional will be able to recommend the proper spraying method and product for your facility. 


Is ultraviolet light an effective disinfectant?

The short answer is yes, but it’s not that simple. Ultraviolet C (UVC) light has been used for decades to disinfect surfaces. It’s actually used in some sewage treatment facilities to destroy pathogenic organisms. UVC light is produced by the sun but filtered out by the ozone layer, which is good because it can cause cancer in humans and damage our corneas.

Though effective as a germicide, there is a catch when using it for disinfecting rooms and surfaces. The intensity of the light and exposure time are critical to its effectiveness. Simply shining a UVC light on a surface won’t thoroughly disinfect it unless it is close enough and strong enough to kill the pathogen.

UVC light can be very useful for smaller surfaces such as keyboards, cell phones, tools and so forth. It is not very effective for deactivating COVID-19 in a classroom.


Do residual antimicrobial products work?

When evaluating residual antimicrobial products, look for those that provide protection from bacteria, mould and fungi for a minimum of 90 days. You can find this information on the product label, along with a Health Canada PMRA registration number. Health Canada, through its Pesticide Management Regulatory Agency (PMRA), verifies the claims of pesticides, which include products that kill pathogens, moulds and fungi.

As part of our Protect-3 AdvanceTM system, ServiceMaster Clean uses AEGIS®, a residual antimicrobial protectant that lasts up to one year.

Evidenced-based studies conducted by independent laboratories, including peer-reviewed studies in the American Journal of Infection Control, support the protection claims of residual antimicrobial products.¹ Once application and drying are complete, residual antimicrobials add a layer of protection to help prevent contaminants adhering to the surface.

Residual antimicrobials help to create a cleaner, safer and healthier environment by offering long-lasting protection from organisms associated with serious illnesses like MRSA, staph and meningitis. Although these products do not protect specifically against viruses, they do enhance protection by providing an inhospitable environment for viruses.   Residual antimicrobials do not eliminate the need for regular cleaning and disinfecting, but provide protection between scheduled cleaning and disinfection periods.


How often should we clean our facility?

The answer: there is no such thing as too much cleaning, especially during a pandemic. The better question is, how much cleaning is practical in a normal school environment?

To help break the chain of infection, you should clean high touch points frequently, 3-4 times a day, if possible. This would include doorknobs, handrails, bathroom fixtures, shared keyboards, and countertops. Unless they are grossly soiled, wiping with a disinfecting agent is usually sufficient, but make sure you allow for adequate dwell time — the amount of time necessary for the product to kill bacteria and deactivate viruses.


A final word

Remember that infection control begins with thorough cleaning followed by disinfecting with products approved by Health Canada. It is imperative that label directions and Health Canada guidelines are followed carefully. Facility management teams with questions about cleaning and infection control are advised to seek advice from a professional commercial cleaning service.

All educators know that homework is important. This is especially true when seeking the right protocols for keeping students and faculty free of infection. Safe schools are no accident.


1 “Long-acting water-stable organosilane agent and its sustained effect on reducing microbial load in an intensive care unit,” American Journal of Infection Control, 2017