What is Legionella and Legionnaires disease?

Legionella are bacteria that are common in natural (rivers and lakes etc.) and artificial water systems, e.g. hot and cold water systems (storage tanks, pipework, taps and showers). We usually associate legionella with larger water systems e.g. in factories, hotels, hospitals and museums, and cooling towers, but they can also live in smaller water supply systems used in homes and other residential accommodation. Other potential sources of legionella include spa and whirlpool baths, humidifiers (in factories) and firfighting systems (sprinklers and hose reels). Legionella can survive in low temperatures, but thrive in high temperatures between 20c and 45c. High temperatures over 45c will kill them.

Legionnaire’s disease is a potentially fatal form of pneumonia caused by the legionella bacteria. It can affect anybody, but some people are at higher risk including those over 45, smokers and heavy drinkers, those suffering from chronic respiratory or kidney disease, and people whose immune system is impaired.

Year 2007 2008 2009 2010 2011 2012 2013
Cases 442 362 344 355 235 333 268
Travel 199 148 163 144 135 167 108
Deaths 53 34 45 38 20 26 11

What do I have to do to comply with the law?

Legionella bacteria can multiply in hot or cold water systems and storage tanks in residential properties and then be spread e.g. spray from showers and taps. Although the generally high throughput and relatively low volume of water held in smaller water systems reduces the likelihood of the bacteria reaching dangerous concentrations, you must still have a risk assessment carried out to identify and assess potential sources of exposure. You must then introduce a course of action to prevent or control any risk that has been identified.

Legionella: Assess, Control & Prevent

Gemini Safety Consultants provide a range of Legionella safety services, including risk assessment, controlling the risk and preventing the risk in future. For information on our Services, click the link.

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