Important Steps to Take During Building Shutdowns and Low Occupancy to Minimize Legionnaires’ Disease Risk

Important Steps to Take During Building Shutdowns and Low Occupancy to Minimize Legionnaires’ Disease Risk

By Spenser Johnson, Lead Environmental Group Manager 

The COVID-19 pandemic has created unprecedented new challenges including those for your building’s water systems. With many facilities currently at reduced occupancy or shutdown altogether, and as talks begin of plans to reopen, facilities need to consider the risks of stagnant water and the potential for increased levels of waterborne pathogens. The Centers for Disease Control and Prevention (CDC) recognizes this and has released important guidelines for ensuring the safety of your building water system components after a period of prolonged shutdown. 

Here are the CDC’s recommendations for ensuring the safety of your building water systems and minimizing the risk of Legionnaires’ Disease:

I. Develop a comprehensive and site specific Water Management Program.

i. If your site already has a Water Management Program, check Barclay’s list to make sure it includes all the vital elements


II. Confirm your water heater is maintained and the temperature is correctly set.

i. Guidelines, like ASHRAE Guideline 12, recommend that the temperature at the hot-water storage tank be maintained at or above 140°F and implement an additional control or adjustment, such as a thermostatic mixing valve, to prevent scalding at the point of use.


III. Flush your water system.

i. Barclay can help your facility validate that your flushing procedures are working. Chlorine Mapping is a tool that can be used to confirm that there are sufficient disinfectant residuals throughout plumbing system and identify areas that might need increased flushing.

ii. The Ohio Department of Health recommends sampling for Legionella bacteria to evaluate a flushing procedure. Specifically, they recommend collecting 2 to 4 samples per hot water loop and per level of the facility, samples from the hot water tank and hot water return and a sample from the cold water main to the building.


IV. Ensure equipment including cooling towers, decorative water features, ice machines, fire sprinkler systems, eye wash station, safety showers and any equipment or devices with water reservoirs are clean and well-maintained.


Before reintroducing the water systems, consider testing for Legionella bacteria to validate water quality. Barclay is here to help you through these challenging times with all your building water safety needs.

Stay Safe!


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