Legionella Risk Assessment
What is Legionnaires’ disease?
- Legionnaires’ disease is an acute form of pneumonia.
- The bacteria are found in most water supplies at some time.
- Traditional water disinfection processes do not remove it.
- It cannot be prevented from entering a water system without further treatment – therefore often the emphasis will be on controlling the conditions that allow it to proliferate to dangerous levels. Temperature, time and nutrients are all areas that can be controlled.
- It only enters a human through inhaling water droplets in which the bacteria are present.
- Cooling towers, showers, spa baths, jet washes and misting machines are examples of processes in which water is aerated and can be inhaled.
- On average 10% of those infected die (age, sex, smoking and general health are all relevant to survival rates).
- On average there are 150 cases of infected people annually in Great Britain.
What does the law state?
Legionnaires’ disease comes within the Health & Safety Act 1974 and the Management of Health & Safety at work regulations 1999, but is more specifically detailed in the COSHH 2002 regulations.
Schedule of required actions
- Identify Duty holder, responsible person (day-to-day management – must have control of a suitable budget to act upon recommendations)
- Identify / employ a competent person to carry out a risk assessment.
Risk assessment:
- Scope of what is covered / not covered.
- Communication structure / emergency procedures.
- Schematic diagram of the water system.
- Inspection / condition reports on main elements – tanks, calorifiers, pipework, TMV’s, showers etc.
- Assessment of existing control measures / records.
- Identification of risk(s) and the level of severity.
- Recommendations of remedial works to remove / reduce risks.
- Recommendations of control measures / monitoring.
After the risk assessment:
- Implement recommendations of risk assessment (using internal / external competent person(s) as required).
- Implement control measures / monitoring – internal or external competent person(s).
- Implement management level oversight of the entire process.
Annually review action required:
- Full risk assessment is only required every two years unless: major changes have been made to the water system, change of use of the water system, recorded legionella outbreak.
- Annual inspection required of tanks and general system so recommendations can be made on monitoring and controls (tank cleaning etc).
- Implement comprehensive record-keeping of all works associated with legionella control
Fulfilling the legal duty of protecting employees and end users from the threat of Legionnaires’ disease is an ongoing process of monitoring, inspecting, controlling measures and reviewing the processes and systems to ensure the correct conditions are kept to prevent the proliferation of the bacteria.
