Legionella Risk Assessment | HSE’s Legionnaires’ disease guide for employers
Health and safety Executive (HSE) has published a guide for employers so that they can understand the health risks associated with legionella. The Legionnaires’ disease guide explains in general terms how to control those risks. Employers are advised to consult the Approved Code of Practice (ACOP) and guidance on Legionnaires’ disease: The control of legionella bacteria in water systems for the technical detail on how to manage and control the risks in water systems. The Legionnaires’ disease guide is intended for employers who manage premises with hot/cold water services and/or wet cooling systems (eg cooling towers and evaporative condensers).
Under general health and safety law, all employers should consider the risks from
legionella that may affect their staff or members of the public and take suitable precautions. As an employer or a person in control of the premises (eg a landlord), you must:
- Identify and assess sources of risk
- Prepare a scheme (or course of action) for preventing or controlling the risk
- Implement and manage the scheme - appointing a person to be managerially responsible, sometimes referred to as the ‘responsible person’
- Keep records and check that what has been done is effective
- If appropriate, notify the local authority that you have a cooling tower(s) on site
Assessing the risk
The risk assessment is the employers’ responsibility. Employers may be able to carry out the assessment themselves but, if not, they should call on help and advice from within their own organization or if this is not available, from outside sources, eg consultancies, like Howlett Associates Water Treatment Ltd. Employers need to find out if their water
systems (including the equipment associated with the system such as pumps, heat exchangers, showers etc) are likely to create a risk. An assessment will consider:
- Are conditions present which will encourage bacteria to multiply? For example - is the water temperature between 20-45°C?
- Is it possible that water droplets will be produced and, if so, could they be dispersed over a wide area? For example, consider showers and aerosols from cooling towers
- Is it likely that anyone particularly susceptible will come into contact with the contaminated water droplets?
Employers should know:
Assessment and Prevention against legionella bacteria
What water treatment methods to be used