Disinfection After a Coronavirus Outbreak

Successful disinfection and decontamination of a building that has had a recent outbreak of coronavirus, or any virus, requires a thorough understanding of that virus.  The newest species of coronavirus disease (COVID-19) is still being researched for its means of transmission and best disinfecting and decontamination procedures.  Understanding COVID-19 allows us to create better coronavirus disinfection and decontamination protocols, use better chemicals and better understand the needs for quarantine, which ultimately allows for more successful decontamination and preventing contamination in the first place.

Disinfecting and Decontaminating COVID-19

How can you decontaminate COVID-19 when an outbreak occurs in a commercial building?  How can you decontaminate for a new virus we know so little about? Until further information is produced, the CDC has directed cruise ships, hospitals, schools, and businesses to rely on interim guidance for disinfection based on the past successful decontamination techniques used for previous strains of coronavirus.  It would be best to consider worst case scenarios and use the best-known decontamination practices, equipment, and personal protective equipment. Cutting corners could be risking infection.

Some of the questions to ask with any virus decontamination project are:

  • What areas where infected people in?
  • Who have they come in contact with, and what areas do those people occupy?
  • What type of HVAC system is in the building?
  • What is the design of the ductwork?
  • What are the high traffic areas in the building?
  • What are the main areas of ingress and egress?
  • How quickly does the building need to be operational?

Bringing in the proper industry experts would be advised.  These experts should include an engineer who is familiar with the construction of the building including the HVAC system, an HVAC company that follows the National Air Duct Association Standards (NADCA) and is familiar with decontaminating ductwork, an industrial Hygienist who is specialized in virus and bacteria decontamination to write the overall protocol and provide testing services, and a decontamination company that has experience with proper personal protective equipment (PPE) use and proper training including OSHA Disaster Site Worker and HAZWOPER 40 certificates.  HAZWOPER training is a requirement for all workers completing the decontamination.2 These companies should also be familiar working with multiple materially interested parties on commercial projects to facilitate efficient communication.

The method of cleaning, decontamination process, personal protection equipment, and other items will vary based on guidance from the CDC and the protocol developed by the Industrial Hygienist.  However, the moving parts of the project should be generally completed in this order:

  • Secure the property and set Hot, Warm, and Cold contamination zones
  • Turn off HVAC system and seal the ducting
  • Set equipment to control the ambient conditions
  • Thorough cleaning of the contaminated areas
  • Disinfecting of the contaminated areas
  • Cleaning of the HVAC and duct system
  • Testing of areas as they area cleared

What Should Be Used To Kill The Virus?

While the use of a hospital-grade disinfectant should make the coronavirus inert, the EPA is currently not endorsing any product, even for List N.  It is important to follow the label of any of these products, which includes the important step of cleaning the surface before disinfecting.  By pre-cleaning, much of the SARS-CoV-2 virus is physically removed.  The cleaning rags used should be disposed of properly to maintain compliance.  Also, the dirtier a surface is, the less effective the disinfectant will be.  Deep cleaning of surfaces prior to disinfecting is the correct way to decontaminate and will result in a more successful decontamination project.  After deep cleaning, applying the right disinfectant to the surface will kill any virus that might remain.   According to current research, other strains coronavirus can be killed on non-porous surfaces with readily-available solutions that contain the following concentrations of chemicals1,3, among others:

  • 78% Ethanol inactivates SARS-CoV Isolate FFM-1 in 30 seconds
  • .5% Hydrogen Peroxide inactivates HCoV Strain 229E in 1 minute
  • 5%-6% Sodium Hypochlorite diluted 5 tablespoons per gallon of water in 1 minute

Additional list of EPA approved products can be found on their website.4 These chemicals can be found in various cleaning products available to consumers, but it is important that they are the proper concentration.  We also recommend making sure the product has an emerging pathogen claim which can be found on list N.  If you decide to attempt disinfection yourself, be sure to read the product’s label and follow the instructions, use the proper protective gear, and remember to keep the product wet on the surface for the recommended dwell time.  For public buildings, especially in the case of severe outbreaks, it’s best to contact a professional virus decontamination company.

Can Heat Kill Coronavirus?

There has been some research on the effect of temperature and previous coronavirus strains.  This research has shown that viruses tend to spread more easily and survive longer in cooler temperatures. Higher temperatures could reduce the duration for which certain strains of coronavirus can survive, specifically 86 to 104 degrees Fahrenheit, or 30 to 40 degrees Celsius.  The same article from Infection Control Today stated that at 39.2 degrees Fahrenheit, or 4 degrees Celsius, the virus could survive on surfaces for up to 28 days or longer. 3

What To Do

Because COVID-19 is so new, researchers and the government do not have all the facts and are relying on past figures to determine how to manage COVID-19.  However, based on historical coronaviruses with similar characteristics and following the interim guidance provided by the CDC, we can make educated decisions and there is no reason to panic. By treating COVID-19 with slightly more caution than the flu, practicing good hygiene by washing hands frequently, and staying home if you are sick, you can help prevent infection.

If you have an outbreak at your business, don’t treat it lightly and call the right people with the right training and certifications to help with decontamination. Hiring a company that is not osha HAZWOPER certified could actually increase risk if someone becomes ill.  Should you attempt virus decontamination and disinfection on your own, make sure to use the right disinfectants and allow enough dwell time. This strain could live for extended periods of time on surfaces, so clean and disinfect frequently touched areas such as doorknobs daily.