Legionella Risk When Buildings Reopen – How to Detect and Prevent

Legionella bacteria exist in lakes, streams, and other bodies of freshwater. While they thrive in many natural environments, they can also transfer to buildings through plumbing systems. This bacteria causes an infection of the respiratory system called Legionnaires’ disease which can be fatal in some cases. Legionella risk increases after buildings sit empty for long periods. For example, a building forced to shut down due to the COVID-19 outbreak creates a higher risk than a building that remained open. The bottom line is that building managers need to have a plan in place to respond to Legionella risk.

Legionella Risk

Legionnaires’ disease is a form of atypical pneumonia. Although it is a milder form, some symptoms are similar. The symptoms of Legionnaires’ disease include:

• Fever
• Muscle pain
• Headaches
• Coughing
• Shortness of breath
• Nausea
• Vomiting
• Diarrhea

According to the World Health Organization, in the U.S. about 10-15 cases of Legionnaires’ disease get detected per one million people, although many cases go unreported. Smokers and the elderly face higher Legionella risk as do immunocompromised individuals.

The Spread of Bacterial Infections

Legionella bacteria thrive in the microbial growth found on pipe walls and that creates a health risk for building occupants. When the bacteria are present in building systems, staff and visitors face exposure when they drink water from faucets and drinking fountains. The bacteria travel in tiny water droplets that get dispersed by cooling towers, HVAC systems and decorative fountains. These droplets enter the lungs and cause infection. Legionella risk increases when the bacteria spread around the buildings as a mist by cooling towers. 

ASHRAE offers resources on how to deal with Legionella outbreaks, but the best way to deal with an outbreak is to prevent it from happening in the first place.

Preventing Legionnaires’ Disease

To prevent an outbreak of Legionnaires disease, facilities managers need to conduct an assessment of their buildings. This includes inspections of water and air systems by qualified experts. Testing for the bacteria gives managers actionable data on potential outbreaks. A Legionella test kit collects water samples which are sent to an environmental lab for analysis. Building managers should have a plan for water-borne pathogens in place based on the findings. Facility managers, as well as any outside contractors, should know how to recognize bacteria-causing conditions and how to deal with them.

Steam Cleaning and Disinfecting

A cleaning method, such as PURE-Steam, uses high temperatures to disinfect evaporator coils, drain pans, and the air handling unit. It kills bacteria but also molds and allergens. Steam, heated up to 350° F, pushes dust and debris through the coil which also improves airflow. Disinfecting HVAC systems once or twice a year lowers Legionella risk.

Cooling towers also present a risk. Building engineers should ensure that towers sit a minimum of 33 feet away from outdoor air intakes and further is even safer. Towers should also be located away from parking lots, sidewalks, and other high-traffic areas. Environmental cleaning of cooling towers is also recommended. 

Tracking building conditions is an effective way to lower Legionella risks as well. For example, IAQ Guard monitors conditions and provides data on temperature and relative humidity as well as gases and VOCs. Around-the-clock monitoring of building conditions improves the overall indoor air quality of buildings too.

Learn More About Legionella Risk

Pure Air Control Services helps healthcare facilities, schools, spas, gyms, and commercial businesses with their Legionella response. Protect your staff and visitors from bacterial infections, call us today at 1-800-422-7873 or email us.