Following an outbreak of Legionnaires’ disease in Melbourne, Australia, with six cases now diagnosed, the race is on to find the source of the infection. Attention is focused on the cooling towers of nearly 100 buildings in the city’s central business district, after tracking the movements of the six patients, all of whom worked in or visited the area in the days before they became ill. The enormous investment of time and resources invested in tracking down and eliminating the Legionella bacteria demonstrates the urgency of the situation and acts as a warning to us here in the UK as the weather begins to warm up with the arrival of spring.

Already we have seen temperatures over 20°C in some parts of the country following a generally mild winter, hot on the heels (literally!) of 2016 being declared the warmest on record globally. Warmer temperatures increase the risk of Legionella for several reasons so, with summer in the offing, make sure you’ve assessed and controlled the risk adequately.

Warm water breeds bacteria

Legionella thrives at temperatures between 20°C and 40°C, so when the weather hots up it can raise the ambient temperature of stored cold water. It’s important to check temperatures during spells of warm weather and if your thermometer reading is on the rise invest in improved insulation on pipes and tanks. This will help to regulate and reduce the temperature even on very hot days. Remember, heat rises so loft spaces can get particularly warm during a heat wave. Alternatively, if your water storage tank is outside make sure it isn’t in direct sunlight by installing an adequate shade.

Beware air conditioners and humidifiers

Air conditioning systems and humidifiers are the perfect delivery mechanism for Legionella bacteria as they create and disperse a fine mist of water into the air. If this water is contaminated with bacteria, it goes straight into your lungs where it can cause Legionnaires’ disease. Therefore, it’s very important to be scrupulous about servicing and regular cleaning of air conditioning units and humidifiers, hence the focus on cooling tower disinfection in Melbourne.

Ice warning

Given that Legionella thrives in warm water, you’d be forgiven for thinking that an ice machine doesn’t present a risk. Think again. Ice machines actually contain a water reservoir next to a compressor which, when it heats up, can warm the water in the reservoir and promote bacterial growth. There was a case in Pittsburgh a few years ago where hospital ice machines were found to be the source of a Legionnaires’ disease outbreak and, when tested, 20% of the hospital’s icemakers contained Legionella. We’re currently working with a customer to eliminate Legionella from an industrial ice machine after a positive test, so we know from first-hand experience that this can be an area which is overlooked. Again, regular cleaning and servicing are the key to ensuring the safety of your ice machine.

Swimming pools and hot tubs

Water hygiene measures are particularly important in large bodies of warm water such as swimming pools and hot tubs. Due to the agitation of the water, Jacuzzis present a notably higher risk, hence the publication recently of revised guidelines for the control of Legionella in hot tubs by the Health & Safety Executive. A scrupulous programme of water testing, chemical dosing, cleaning and maintenance are essential to ensure that pools are safe and clean for swimmers and people in the vicinity alike.

While we don’t want to put a damper on your summer, it’s important to recognise the increased risk of Legionella during warmer weather. So stay safe and enjoy the sunshine by taking our advice. If you want to know more, browse our blog or get in touch.