Preventing and Mitigating Legionnaires’ disease

We talk with chemical and cleaning expert Ray Field on Legionnaires' disease. We discuss what it is, its history, and what we can do to prevent it proactively.

Cooling towers host all kinds of microorganisms, including harmful bacteria like Legionella. Legionella is a natural bacteria that you can find in bodies of freshwater, including lakes, but it was discovered relatively recently, in the 1970s. We become susceptible to Legionnaires' disease when we inhale droplets that contain Legionella. Legionnaires' disease causes pneumonia-like symptoms and is potentially fatal. Cooling towers, unfortunately, provide perfect conditions for Legionella to survive and aerosolize. Decorative fountains and evaporative coolers also provide ideal conditions for Legionella to grow and thrive.

Unsurprisingly, cleaning with special attention to microbe control helps mitigate Legionella bacteria growth. Bleach and anti-microbial peroxide help keep the water clean, but the bulk water is just one part of the system. When Legionella-filled water sprays beyond the tower, slime and water accumulations may also harbor Legionella.

Inspecting and cleaning towers monthly are the best practices. Vacuum the basin and descale the tower each time you clean the tower; when you clean slime, deposits, and scale, you give Legionella fewer places to hide. You can also disinfect the tower exterior. Pressure-washing works well as a starting point and can be followed up with chemical technology. Overall, the key to preventing Legionnaires' disease is proactivity; safety begins with a regular maintenance regimen, use of proper PPE, and thorough training for cleaning procedures.

Ray and Bryan also discuss:

• Legionella growth assistance
• History of Legionnaires' disease
• Ideal Legionella growth conditions
• ASHRAE Standard 188P
• Fill deposits
• Goodway products to combat Legionella
• Legionella testing and CDC guidelines