Preventing or controlling the risk.

You should consider whether you can prevent the risk of Legionella in the first place.

If a risk is identified which cannot be prevented, you must introduce proper controls.  Risks from legionella in water systems can be controlled but careful planning, a successful management policy, competent staff and attention to proper control strategies are all essential.  You should consider whether you can prevent the risk of legionella in the first place by looking at the type of water system you need. For example, is it possible to replace a wet cooling tower with a dry air cooled system?

You need to prepare a written scheme which sets out how you intend to control the risk from legionella. You should describe:

■  Your system – an up-to-date plan or schematic diagrams are sufficientlegionella prevention
  Who is responsible for carrying out the assessment and managing its implementation
■  The safe and correct operation of your system
■  What control methods and other precautions you will be using
■  What checks will be carried out on the control scheme and how often.

The key point is to design, maintain and operate your water services under conditions which prevent or control the growth and multiplication of legionella. You should:

■  Ensure that the release of water spray is properly controlled
■  Avoid water temperatures and conditions that favour the growth of legionella and other micro-organisms
■  Ensure water cannot stagnate anywhere in the system by keeping pipe lengths as short as possible or by removing redundant pipe work
■  Avoid materials that encourage the growth of legionella
■  Keep the system and the water in it clean
■  Treat water to either kill legionella (or other micro-organisms) or limit their ability to grow