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Legionella Risk Assessment

Legionella Risk Assessment


What is Legionnaire’s Disease?
Legionnaires’ disease is a serious lung infection caused by Legionella bacteria.
Initial symptoms usually include flu-like symptoms, such as: mild headaches, muscle pain, high temperature (100.4F) or above, chills, tiredness, changes to your mental state, such as confusion. Once bacteria begin to infect your lungs, you may also experience symptoms of pneumonia.

During 2011 to 2013, there were 84 deaths from Legionnaires’ disease in England and Wales according the NHS. Some people (such as old people) are more susceptible than others so workplaces like residential care homes may have a stronger need to prioritise this safety issue.

What type of Legionella risk could there be in your workplace?

  • a cooling tower or evaporative condenser
  • hot and cold water systems
  • spa pool
  • humidifiers
  • air washers
  • emergency showers
  • eye wash sprays
  • indoor ornamental fountains
  • aqueous tunnel washers

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 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.

You have a responsibility to your workforce to ensure that any legionella risk is investigated by a competent person. If you are a commercial tenant, it is your responsibility to work together with your landlord to conduct risk assessments and take any consequential actions.

Our recommendation is annually but this will be dependant upon the severity of the risks involved.It will also need to be done if the water system in question is altered in any way.

You will be provided with recommendations on how to manage the risk – and this will be depend on the nature of the water system, how many people are exposed to it and in what ways. This may require daily, weekly or monthly management and monitoring.



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