COVID-19 Pandemic and HVAC Filter Replacement Safety Precautions
By now everyone is clearly aware of the ongoing COVID-19 pandemic first identified in Wuhan, China in December 2019. The world is also beginning to accept that this global health crisis isn’t going away on its own.
In the meantime, organizations must adapt to operate in this “new normal.”
The CDC and the World Health Organization state that: “Although most people who have COVID-19 have mild symptoms, COVID-19 can also cause severe illness and even death. Some groups, including older adults and people who have certain underlying medical conditions, are at increased risk of severe illness.” “This requires further study, as well as to know whether there is neutralizing immunity after infection.”(1,2)
Essentially, there is a lot we still don’t understand about COVID-19.
One thing we do know: The novel coronavirus likely spreads more easily between people in close contact, primarily through respiratory droplets. High occupancy indoor spaces with inadequate or under-maintained ventilation systems present a high level of risk.
Have you checked your air handling system lately?
The CDC encourages building owners and operators to “evaluate the building and its mechanical and life safety systems to determine if the building is ready for occupancy and ensure that ventilation systems in your facility operate properly.”(3) The American National Standards Institute (ANSI), the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), and the Air Conditioning Contractors of America (ACCA) Standard 180-2018: Standard Practice for Inspection and Maintenance of Commercial Building HVAC Systems offers guidance to ensure that ventilation systems in your facility operate properly.(4)
The ASHRAE Coronavirus (COVID-19) Response Resources page has additional online resources to address many aspects of managing HVAC systems during the pandemic.(5) The “Filtration/Disinfection” tab outlines the PPE recommended to use while performing facilities maintenance on air handling units (AHU) that support COVID-19 patient areas. This includes the use of N95 filtering facepiece respirators or a silicone half mask respirator with N95 or better cartridges, eye protection, disposable gloves, and disposable coveralls during filter removal and replacement; and after maintenance to wash hands with soap and water or alcohol-based sanitizer.(6)
Filtration, air quality, and environmental infection control
Even though the risks associated with handling AHU filters potentially contaminated with the COVID-19 virus have not been thoroughly studied, ASHRAE also recommends that additional safety precautions be added to the facility’s standard maintenance procedure. ASHRAE recommends, when feasible, that filters exposed to the virus be disinfected with a 10% bleach solution or another appropriate disinfectant (approved for use against SARS-CoV-2) before removal.(7)
The CDC states that gaps in and around filter banks with heavy soil / debris upstream of poorly maintained filters have also been implicated in healthcare associated outbreaks of aspergillosis.(8) So, by implication, gaps in filter banks may also lead to infection control issues with COVID-19 on recirculated air or allow excessive wildfire smoke into the building. Therefore, when replacing final AHU filters, look into increasing the filtration efficiency of your AHUs to MERV 13 or as high as the filter racks and fan pressure drop will allow, and make sure that the new filters are tight to their housings with no gaps. (9,10)
Higgins and Associates industrial hygienists can team with your Facilities and EHS departments to review operation and maintenance plans, review current ventilation systems for COVID-19 preparedness, perform bioaerosol assessments, conduct indoor air quality evaluations, and much more.
Contact us for more information.
1) Centers for Disease Control and Prevention (CDC), Coronavirus Disease 2019 (COVID-19, Updated Sept. 1, 2020, https://www.cdc.gov/coronavirus/2019-ncov/cdcresponse/about-COVID-19.html
2) World Health Organization (WHO), Report of the WHO-China Joint Mission on Coronavirus Disease 2019 (COVID-19); https://www.who.int/docs/default-source/coronaviruse/who-china-joint-mission-on-covid-19-final-report.pdf
3) CDC, Employer Information for Office Buildings, Updated Sept. 11, 2020, https://www.cdc.gov/coronavirus/2019-ncov/community/office-buildings.html
4) The American National Standards Institute (ANSI), the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) and the Air Conditioning Contractors of America (ACCA) ANSI/ASHRAE/ACCA Standard 180-2018, Standard Practice for Inspection and Maintenance of Commercial Building HVAC Systems, 2018, https://www.ashrae.org/File%20Library/Technical%20Resources/Bookstore/previews_2016639_pre.pdf
5) American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), Coronavirus (COVID-19) Response Resources, updated August 20, 2020, https://www.ashrae.org/technical-resources/resources
6) ASHRAE, Facilities/Maintenance – PPE Basics, updated as of October 10, 2020, https://www.ashrae.org/technical-resources/filtration-disinfection
7) ASHRAE, HVAC System Maintenance and Filter Replacement during the COVID-19 Pandemic, updated as of October 10, 2020, https://www.ashrae.org/technical-resources/filtration-disinfection
8) CDC, Guidelines for Environmental Infection Control in Health-Care Facilities, revised 2019, https://www.cdc.gov/infectioncontrol/pdf/guidelines/environmental-guidelines-P.pdf
9) CDC, Guidelines for Environmental Infection Control in Health-Care Facilities, Infection Control Impact of HVAC System Maintenance and Repair, revised 2019, https://www.cdc.gov/infectioncontrol/guidelines/environmental/background/air.html
10) American Conference of Governmental Industrial Hygienists (ACGIH), White Paper on Ventilation for Industrial Settings during the COVID-19 Pandemic, August 2020, https://www.acgih.org/docs/default-source/vent-committee/iv_position-test.pdf?sfvrsn=4b10ba0d_2