*This blog contains updated information from a previous version*
Stay at home orders from government officials in response to the SARS-CoV-2 virus and the resulting COVID-19 disease has resulted in closure of numerous business and buildings. Closing buildings abruptly could have unintended consequences if building owners and operators did not take proactive steps before closure or staff reductions.
In some scenarios, building owners and operators were able to close using appropriate methods that will make eventual re-opening more streamlined. However, because of the fast-moving nature of the mass closures, many buildings may have been left in an “as-is” condition. This means that minimal preparation may have occurred when closing. Changes in building use patterns for a facility that is designed to be used daily can impact the indoor environment. These changes can manifest as degradation in water quality or increased indoor humidity levels.
Buildings and supportive systems were designed to be used while occupied. Water, HVAC, and electrical systems are intended to maintain equilibrium with the people inside the building. Because of an unexpected closure, a building could be operating in a scenario that greatly changes the loads on the mechanical systems. These changes could have negative impacts on the building’s systems. For example, a building that was designed to have hundreds of gallons of water flowing through potable water pipes when occupied will now have stagnant water flow conditions. Low or no flow of water in premise plumbing and associated water heaters will consume disinfectant (e.g., chlorine) quickly and result in conditions where waterborne pathogens may grow, especially Legionella. Additionally, less water will likely be used in utility water mains, contributing to stagnant conditions throughout the system.
Opportunistic pathogens like Legionella do not discriminate and can benefit from conditions where their growth is allowed to occur unabated. Interruptions in water use, similar to what is occurring in response to COVID-19, have been previously associated with outbreaks of Legionnaires’ disease, but on a smaller scale. Because of larger system-wide changes in water quality conditions, there is potential for Legionella growth within the plumbing of buildings that have closed for extended periods of time. Individuals re-occupying a building after closure could be exposed to the Legionella bacteria and may be at an increased risk of developing Legionnaires’ disease, a reportable illness, unless procedures are established to ensure the safe re-start and operation of the facility. Identifying Legionnaires’ disease cases following re-occupancy may be complicated because individuals with the disease and COVID-19 may have similar health issues (e.g., fever and pneumonia). This may lead to misidentification of the real reason behind the cause of disease and could result in ongoing issues linked to the building.
The current standard of care has placed the management of waterborne pathogens on building owners and operators. It is up to the owner and operator, not the local water utility, to manage the safety of the water within a facility.
Cooling towers are also under the control of building owners and operators and are a potential exposure point for Legionella. Changes in heat loads from lack of typical building operations may negatively impact heat transfer mechanics at a facility. Health departments have identified cooling towers as sources of Legionnaire’s disease outbreaks. Changes in operational capacity and limited or absent maintenance staff during this time may result in cooling tower conditions that may be favorable for Legionella bacteria growth to occur.
Continuity of indoor environmental operations will also be essential when bringing a building back into service. Indoor humidity levels may be higher than are prescribed if HVAC systems were turned off or were adjusted beyond recommendations before vacating a building. Elevated relative humidity can lead to mold and moisture problems on building materials or equipment left in place at the time of closure.
Cleaning surfaces that people will contact will become an important step in ensure the safe re-start of a facility. Building owners will have to understand that cleaning may not be a one time event, but rather a continuous effort. A one time cleaning for the “Coronavirus” may give a false sense of security. Limited studies have suggested that different surfaces can harbor the virus longer than others, showing the importance of routine cleaning protocols once people are again routinely interacting with the building environment. Further, a building owner or operator receiving a “certification” from a company showing elimination the virus via testing will need to have the certification reviewed to understand how the contractor established cleanliness of the surface (e.g, surrogate testing or otherwise). Currently, the EPA lists disinfectants that meet the criteria for use against SARS-CoV-2. It is important to understand the safety of the disinfectant, ensure that it is being used in accordance with its registered uses, and that they are being handled by employees in a safe way.
As a quick summary to the main points covered above:
Buildings closed as a result of COVID-19 can have water stagnation in potable water pipes.
Water stagnation can quickly deplete residual disinfectants and can allow waterborne pathogens, like the Legionella bacteria, to grow uncontrolled.
The current standard of care focuses on building owners and operators for the management of waterborne pathogens in a facility.
Cooling towers can also be negatively impacted by changes in building conditions, like allowing Legionella to grow if not maintained during non-occupancy.
Changes in indoor humidity levels can result in mold and moisture issues on building materials and internal fixtures.
Ensuring the safe function and cleanliness of key systems and areas, including internal surfaces, is vital to maintain the safety of occupants entering a building after a closure.
Guidance documents by governmental organizations and professional groups (some available below) have been issued on this topic and others are being developed due to the fast moving nature of COVID-19 response.
Exposure Assessment Consulting can aid in evaluating site conditions when reoccupying a building. We can help identify the steps owners and operators can take to address stagnant water conditions, how to deal with changes in the indoor building environment, and can assist owners and operators in evaluating the effectiveness of cleaning procedures. Dr. Alex LeBeau is a toxicologist, certified industrial hygienist (CIH), and a human health risk assessor that has over twelve years of experience evaluating exposures and identifying high risk exposure scenarios that require mitigation. He has performed Legionella risk assessments at facilities, for both proactive measures and following outbreaks of Legionnaires’ disease. He has also evaluated the effectiveness of cleaning procedures following contamination and remediation. Together with our other professionals, we can assist building owners and operators identify scenarios that could lead to unsafe conditions for occupants. Please feel free to reach out and let us know if we can be of assistance or if you have any questions.
Alex LeBeau, PhD, MPH, CIH
Email: alexlebeau@exposureconsulting.com
Phone: 321-263-1333
Useful links for on topics covered above:
Guidance from the American Industrial Hygiene Association (AIHA)- Recovering from COVID-19 Building Closures:
CDC Guidance for Building Water Systems: https://www.cdc.gov/coronavirus/2019-ncov/php/building-water-system.html
EPA Disinfectants meeting the criteria for use against SARS-CoV-2:
