Legionella Control in Water Systems
Legionnaires’ disease is a potentially fatal form of pneumonia. People may get infected when they breathe in tiny water droplets (aerosols) or droplet nuclei (particles left after the water has evaporated) contaminated with elevated concentrations of Legionella bacteria.
Legionella bacteria grow best between temperatures of 20°C – 45°C with optimum growth temperature being 35°C – 40°C. High temperatures (minimum 60°C) kill the bacteria. Legionella bacteria are found in low numbers in natural aquatic environments, for instance, lakes, rivers and ground water. As a result it is virtually impossible to prevent Legionella bacteria entering man-made water systems.
In low numbers the bacteria are generally considered harmless. With the correct conditions, for example, warm water, the presence of micro-organisms and nutrients in the water or materials such as rust, the
bacteria can grow and multiply to high levels which increase the risk of exposure.
The bacteria tend to grow in biofilms (slime). Biofilms are likely to form on surfaces where there is low water flow or water is allowed to stagnate. However the growth of the bacteria can be controlled.
The Legislation & Guidelines
HBI adhere to & utilise the following documents when devising legionella control programmes:
- UK HSE document L8 – Legionnaires
- Disease, The control of legionella bacteria in water systems: Approved Code of Practice and Guidance
- Safety, Health and Welfare at Work Act 2005 (No. 10 of 2005)
- Safety, Health and Welfare at Work (Biological Agents) Regulations 1994, as amended in 1998 (S.I. No. 146 of 1994 and S.I. 248 of 1998)
- Safety, Health and Welfare at Work (General Application) Regulations, 2007 (S.I. No. 299 of 2007)
- National Disease Surveillance Centre:
- The Management Of Legionnaire’ Disease in Ireland
- CIBSE TM13 – Minimising the risk of Legionnaires’ Disease
- HTM 04-01
All of the documents listed giving advice specific on legionella follows a similar format on how to control this risk:
- Identify and assess sources of risk using competent help and advice;
- Prepare a scheme for preventing or controlling the risk;
- Implement, manage and monitor precautions;
- Keep records of the precautions
- Appoint a person to be managerially responsible.
The HBI Legionella Management Solution
HBI provide the following services to help the building manager discharge their duties and obligations relating to the control of legionella bacteria in water systems:
Legionella risk assessments
- Qualified consultants
- Schematic drawings
- Priority Of Risk
- Soft & hard copies
Remedials
- Clean & disinfection of domestic hot & cold water systems, old or new
- Clean & disinfection of new mains pipework and reservoirs
- Tank replacement programmes
- Precommisioning of closed circuits
- Treatment and monitoring of closed circuits
- Showerhead cleaning programmes
- Deadleg flushing programmes
- On –line dosing systems
Monitoring
- Provision of either hardcopy or electronic logbooks
- Provision of technicians to carry out sentinel temperature monitoring &
- logbook maintenance
- Bar-coding of outlets
- Legionella and microbiological sampling programmes
For more information about Legionella assessments and how to implement a Legionella Management programme call Healthy Buildings International, email sales@hbi.ie.
Download more information about Legionella here
