Legionnaires Disease 101

If you are the owner or a perspective owner of cooling towers, one risk that you should be fully aware of is the potential for the development of Legionnaire’s disease in the pools of your towers. With the water disaster in Flint, MI (which is absolutely tragic and inexcusable) awareness of Legionnaires disease is on the climb because so many are currently being affected by it. While the development of Legionnaires disease is easily avoidable, understanding the disease is still important.


Legionella is the bacteria that involved with outbreaks of Legionellosis, which can develop into Pontiac Fever or Legionnaires disease. While Pontiac Fever tends to pass through your system on its own, Legionnaires disease is a form of pneumonia that requires a hospital stay to eradicate. The mortality range of Legionnaires disease is 5%-30% which is alarming enough to take every measure to avoid its development.

Spreading Legionnaires:

The most common way that Legionnaires Disease is transmitted through water that has been aerosolized, which is why cooling tower owners need to be educated and aware of this disease. A less common way that it can be transmitted is via drinking water. While it is possible to become fatally ill, most people who actually come into contact with the disease do not fall ill and the disease cannot be passed from one person to another.

Legionella occurs naturally in fresh water, but it isn’t pervasive enough to cause illness. It’s when Legionella starts to prop up in artificially heated and contained bodies of water. These environments accelerate the growth of Legionella and are almost ideal for it to develop enough to become problematic for humans.

Performing regular maintenance on your cooling tower is the easiest and most effective way to avoid experiencing any problems related to Legionella, especially Legionnaires Disease.

Effectively Retrofitting HVAC Chillers 2016

effectively retrofitting HVAC Chillers 2016

Replacing chillers is something typically avoided for as long as possible by engineering and maintenance managers. Chiller equipment is very expensive (most expensive piece of building equipment).

Chiller repair or chiller replacement can be very disruptive to other processes sometimes requiring piping systems to be replaced, removal of entire ceilings or walls. It is very time consuming and typically requiring 1 year or longer from the time the replacement/repair decision is made until the replacement chiller is installed. If companies have a need for chilled water year-round, managers and maintenance crew much use temporary cooling systems.

These factors and others make it understandable why some managers don’t act as quickly when faced with replacement chiller decisions. It’s not that simple to replace so most managers wait as long as possible using the old saying, “leave well enough alone”.

While this approach may sometimes work with other equipment, taking this chance can end of costing your tons of money and leave you without a chiller for a longer period of time.

It’s wise to move cautiously when facing potential disruption and cost attached to chiller repair and replacement but there are also other factors that should be taken into consideration. Knowing these factors and how you should apply them to your particular chiller installation is important to make your decision.

Keep Your Eye Focused On Efficiency

Manufacturers of chillers have made all types of improvements in chiller unit operating efficiencies over the past 20 years. Example: Many of today’s higher efficiency chillers have a load efficiency rating of (.50 kilowatts (kW) per ton. Very few chiller models have range of .40kW per ton.

Chillers, 10 years ago had load efficiency ratings of (.75  – .85 kW per ton). 20 years ago chillers were in range of (.85 – 1.00 kW per ton) efficiency ratings. This means that there is newer high efficiency chillers require about 60% of the energy that would of typically been used by a twenty year old chiller.

Chillers operate at full capacity less than 3% of the time, this improvement in load ratings serves as a measure of the improvement in chiller efficiencies. Even the most moderate improvements to chiller efficiency can result big savings for managers. More savings for facilities where chillers are operated for more than 2,000 hrs per year.