Other risk systems

In addition to evaporative cooling systems, hot and cold water systems and spa pools, there are a number of other risk systems, eg humidifiers, air washers, emergency showers, eye wash sprays, indoor ornamental fountains, aqueous tunnel washers etc that could potentially be a source for legionella bacteria growth.

Any water system is potentially a reasonably foreseeable legionella risk if it has any of these factors:

  • The presence of legionella bacteria in the system water
  • where the water temperature may be between 20-45 °C,
  • a means of creating and/or spreading breathable droplets, (aerosols)
  • stores and/or re-circulates water
  • likely to contain a source of food for the organism, such as contaminants from the surroundings or process including presence of sludge, rust, scale, organic matter or biofilms

The actions you need to take with regard to other risk systems are detailed in HSG274 Part 3: Legionnaires' disease: The control of Legionella bacteria in other risk water systems.

You will need to carry out a risk assessment as described in What you must do to decide whether further actions are needed. These systems and any others found to present a risk should be maintained in a clean state and monitored on a regular basis, where appropriate. There is also a duty to maintain records of all maintenance carried out together with monitoring results.

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Updated 2022-05-17