AHU Condensate Pans and the Petri Dish Effect
Published January 12, 2016, by Christine Parrington
We’ve all seen the national headlines concerning the outbreak of Legionnaires’ Disease in New York City, resulting in 12 deaths and sickening over 100 people to-date as a result of poorly maintained mechanical systems. Could the condensate pans in your air handling units be a potential source of pathogenic agents like Legionella? Consider this…
According to the Centers for Disease Control, Legionnaires’ Disease is considered “fairly common and serious”, resulting in more than 25,000 cases per year and with nearly 25% of all cases (approximately 4,000) being fatal. These are concerning statistics when you consider that hundreds of thousands of people have been afflicted by Legionnaires’ Disease since its presence became known nearly 40 years ago, and even more concerning that it is a largely preventable illness caused by a bacteria most often found in poorly maintained manmade systems.
Specifically, there are more than 34 species of Legionella bacteria, and more than 20 of them linked to human diseases. Legionella bacteria and other forms of toxic mold and fungus, such as Aspergillus, prefer and actually thrive in pooling, stagnant water – much like what’s found in many air handling unit condensate pans. If an air handling unit (AHU) is leaking condensate, the purpose of the condensate pan (a/k/a “drip” or “drain” pan) is to catch and effectively drain the water. However, more often than not in older, larger buildings with multiple AHUs, many condensate pans are decades old and worn with age, rusted, corroded, poorly sloped or clogged, and not draining properly. Standing water in condensate pans works much like a petri dish, cultivating bacteria and potentially dangerous microorganisms. If left unchecked or unmaintained, the environment can become a hazardous breeding ground for potentially toxic pathogenic agents, creating a “petri dish effect” within your HVAC system’s components. Contaminated droplets dispersed through the air stream by the system’s blowers may become vaporized, conveyed downstream, and ingested by unsuspecting building occupants.
According to the Department of Labor’s Occupational Safety & Health Administration (OSHA), stagnant water often creates ideal conditions to promote growth of Legionella. In fact, the Legionnaires’ Disease page onOSHA’s website specifies that improperly draining condensate pans may produce the ideal, tepid conditions that can encourage microbial and fungal growth.
In light of the national statistics and recent events, perhaps it’s worth taking a closer look at your air handling unit floors and condensate pans to not only ensure that they are draining properly, but for peace of mind that your facility isn’t unknowingly posing a risk to its occupants.
If your air handling unit floors and condensate pans are plagued with standing water, scale, rust and corrosion – all of which are collectively creating a literal breeding ground inside your facility – then why take the risk? AQUIS can eradicate these problems and leave you peace of mind.