How To Manage Legionella?

How To Manage Legionella?


In this article, we answer the question “how to manage legionella?  It covers what should be contained in the risk assessment and the steps you should take to manage your system.

Legionella pneumophila and associated bacteria are the cause of a collection of pneumonia like diseases, of which Legionnaires’ Disease is probably the best known.

Everyone who comes into contact with the bacteria in sufficient numbers is at risk of developing one of these diseases. It occurs in natural water sources and reservoirs, but in low numbers. Unfortunately if not properly designed and maintained, artificial water systems can provide ideal breeding conditions for the bacteria to multiply to dangerous levels.

Both employers and people in control of a premises are legally obliged to take suitable precautions to prevent or control the risk of exposure to legionella. Carrying out a risk assessment is your responsibility and should help to establish any potential risks and implement measures to either eliminate or control risks.

Your responsibilities

The most common places where legionella can be found include purpose-built water systems, cooling towers, evaporative condensers, hot and cold water systems and spa pools. In addition it is most likely to be found in systems where water is stored or recirculated, where the temperature is between 20–45 °C or if droplets are produced and can be dispersed over a wide area, e.g.showers.

Duty holders must carry out a risk assessment of their water systems to identify any areas where the risk of the bacteria multiplying is high. The risk assessment must be carried out by a competent person. In some instances this will require the input of external consultants if there are no suitably competent members of staff within the company able to carry out the assessment. The risk assessment should include the following:

  • the name of the competent person and a description of the water system being assessed
  • any potential risk sources
  • any controls currently in place to control risks
  • monitoring, inspection and maintenance procedures
  • records of the monitoring results, inspection and checks carried out
  • a review date

The main control measure for water systems that pose a risk of harbouring Legionella is that they should be properly maintained and managed. This includes steps such as:

  • properly controlling the release of water spray
  • avoiding water temperatures and conditions that favour the growth of Legionella and other micro-organisms
  • avoiding stagnant water by keeping pipe lengths as short as possible or by removing redundant pipework
  • avoiding use of materials in the system that encourage the growth of Legionella
  • keeping the system and the water in it clean
  • treating water to either kill Legionella bacteria or limit their ability to grow

All control measures implemented should be documented as part of a safe system of work. Records should be kept of the competent person’s qualifications, instructions for safe operation and maintenance of the system and any checks made such as temperature checks.

Using External Specialists

Be aware that if you employ an external specialist company to either carry out your risk assessment or manage your water system this does not mean that you have transferred the duty holder’s responsibility. Ultimately the responsibility for the safety of the system still lies with the duty holder and as such, you must ensure that the company you employ is competent to carry out these functions.

Training Available

Envesca offers a two specific Legionella management courses.  For further details on these courses and information on forthcoming training courses, simply click on the links below:

Legionella Awareness

Legionella Risk Management for the Responsible Persons

6 Step Guide to Legionella Management

Ensure that you are fully protected and aware of how to minimise the risks and prevent the spread of a legionella outbreak in your business.

If you would like to discuss the various options with our friendly team just give us a call on 01452 898180

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