Legionella FAQs

Legionnaires’ Disease is a potentially fatal form of pneumonia, contracted by inhaling water droplets that are carrying legionella, a bacteria present in natural water sources. Your building’s water infrastructure may in certain conditions provide the perfect environment for legionella to build up and pose a life-threatening risk to your building users.

What causes legionella build-up?

Elements that may affect your susceptibility to legionella build-up include:

  • Water temperature – legionella survives and flourishes in water temperatures between 20°C and 45°C
  • Storage – water that is stored, recirculated, or left to stagnate has an increased chance of legionella build-up.
  • Breathability – situations in which water is formed into breathable droplets – e.g. showers or evaporative condenser – allow legionella bacteria to be airborne, increasing the chances of inhalation.
  • Deposits in the system – a build up of rust, sludge, organic matter or biofilms in your system can support bacterial growth, meaning dangerous bacterial strains such as legionella can thrive.

What laws affect legionella?

Health and safety laws in the UK place the responsibility of ensuring against legionella on building owners, landlords and facilities managers. While there are no specific laws regarding legionella and legionnaires’ disease (unlike asbestos and lead) there are overarching obligations under sections 2 & 3 of the Health and Safety at Work Act (1974) and the Control of Substances Hazardous to Health Regulation (1994).

How often should I get a legionella risk assessment done?

HSE no longer provides specific guidance on how often risk assessments should be carried out. The best timescales will vary depending on the type of business, the nature of your facilities, and the level of risk they pose. Our highly trained and experienced legionella team will be able to advise based on your facilities, network and water use.

Who can conduct legionella risk assessments?

 Legionella risk assessments must be carried out by a competent and experienced individual – that is, somebody who has both the right level of training, and previous experience in conducting risk assessments. If a legionella risk assessment is carried out by somebody who doesn’t meet these criteria, your business could be put at risk of legal action in the event of a breakout, so it’s important to be sure that your risk assessment is conducted by somebody with the right knowledge and experience. Our legionella team are all fully qualified and have extensive experience in conducting legionella risk assessments.

 Do my team members need Legionella training?

There are two main types of legionella training: City and Guilds qualifications to become a legionella risk assessor, and more general legionella awareness training. Businesses do not need their own legionella risk assessor – in fact, the qualification alone is not enough to fulfil the requirements of a risk assessment, as the assessor must also have an appropriate level of experience to qualify. However, more general legionella awareness training can help your team to understand their responsibilities for preventing legionella build-up, and can help to ensure that legionella management processes are followed.

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