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Legionnaires' Disease

Water cooling systems and evaporative condensers can be essential requirements in a commercial or industrial application, yet they have received notoriety because of outbreaks of Legionnaires disease.

Legionnaires’ Disease

Legionnaires’ is a type of bacteria that mainly lives in water. Outbreaks occur from purpose-built water systems where temperatures are warm enough to encourage growth of the bacteria, e.g. in cooling towers, evaporative condensers, whirlpool spas and from water used for domestic purpose in buildings such as hotels.

It is critical to keep these types of systems in good repair and maintain the water treatment, used to prevent scale, corrosion and biological problems.

The problems caused with a cooling system are due to a combination of system design and the quality of the water supplied to the tower. All of these can be controlled and overcome but first it starts with a risk assessment. This is a key part of L8 as it identifies all the risks and resolutions to issues within a cooling system. This risk assessment needs to be carried out at least every two years or whenever there is a reason to suspect it is no longer valid. There are several routine tasks that need to be carried out regularly; these include weekly, monthly and quarterly legionella testing and six monthly clean disinfections.

Water Treatment

The essential task of water treatment is to maintain and extend the life expectancy of the plant. Well chosen water treatment chemicals will;

•    Minimise corrosion
•    Keep the system from scale
•    Prevent biofouling
•    Decrease pumping
•    Decrease energy costs
•    Minimise potential plant shutdowns
•    Prevent complete failure of system

Most problems can be predicted using aids such as Langelier or Ryznar, which predicts if there is scaling or corrosive water inside the system. These tools allow a water treatment specialist to identify the most appropriate products to help protect the system.