Legionella Assessments

Environmental Evaluation can provide a full Legionella risk assessment, risk management and training service.

In line with the HSE guidance publication L8 “Legionnaires’ disease. The Control of Legionella bacteria in  water systems” our risk assessments primarily address the following:

  • the potential for droplet formation;
  • water temperature;
  • the likely risk to those who will inhale water droplets;
  • means of preventing or controlling the risk.

Background to Legislation and Guidance relating to the Control of Legionella 

Legionellosis is the term used for infections caused by Legionella pneumophila and other bacteria from the family Legionellaceae. Legionnaires’ disease is a pneumonia that principally affects those who are susceptible due to age, illness, immunosuppression, smoking, etc. and may be fatal. Legionellae can also cause less serious illnesses which are not fatal or permanently debilitating but which can affect all people.

Infection is attributed to inhaling Legionellae, either in those water droplets which are small enough to penetrate deeply into the lung, or in droplet nuclei (the particles left after the water has evaporated). Legionellae are widespread in natural sources of water.
They may enter man-made systems or water services, where they can multiply under certain conditions, and if there is a means of creating and transmitting water droplets people in the vicinity may be at risk. Most cases and outbreaks of legionellosis have been attributed to water services in buildings, cooling towers and whirlpool spas. Other sources have been identified in foreign outbreaks including a humidification system, industrial coolants and respiratory therapy equipment.

A reasonably foreseeable risk of exposure to Legionella bacteria exists in:

  • water systems incorporating a cooling tower;
  • water systems incorporating an evaporative condenser;
  • hot and cold water systems; and
  • other plant and systems containing water which is likely to exceed 20oC and which may release a spray or aerosol (i.e., a cloud of droplets and/or droplet nuclei) during operation or when being maintained.