Legionella Risk Assessment


Under the Health and Safety at Work Act of 1974, all business owners are obliged to perform regular risk assessments for Legionella, a bacteria which thrives in water systems and which causes Legionnaire’s Disease, a potentially fatal form of pneumonia. During 2016, almost 500 individual cases of Legionnaire’s Disease were reported in the UK- a worrying number, and a clear sign that more needs to be done to combat this dangerous disease.

What is Legionella?

Legionella bacteria thrive in temperatures between 20 and 45 degrees Celsius- temperatures which can be found in countless water systems across the country. To survive and reproduce, they only need impurities in the water to feed off of. Contrary to popular belief, water doesn’t have to be “dirty” to contain impurities. Even trace amounts of limescale or rust can be enough to feed a whole colony of Legionella, and put everyone using that water supply at risk of a potentially lethal disease.

What’s more, the risk of Legionella is increased in areas which use air conditioning systems, since this can easily transport the contaminated water droplets across a wider area. Since most modern offices use such a system, it’s vital that businesses keep their Legionella risk assessments up to date, so that their employees aren’t at any risk.

How often do I need to perform a Legionella risk assessment?

HSE guidelines recommend that you carry out a full Legionella risk assessment every two years, to ensure that your employees are always safe and protected. Since Legionella are microscopic, the only way that they can be spotted is by carrying out a thorough assessment of the whole water system.

Although it’s recommended that you have a Legionella risk assessment carried out every two years anyway, it’s also necessary to perform one whenever there is a significant change to the water supply, such as widespread pipe replacement. If you have any large-scale plumbing work done on your company’s premises, then it’s a good idea to have another risk assessment carried out- after all, it’s better to be safe than sorry.

Is there any way of spotting Legionella?

While Legionella bacteria are microscopic, there are some visible warning signs to watch out for that can help you tell whether your water is contaminated. The most obvious of these is sludge or biofilms in your water supply, which give the bacteria a hearty food supply that will help them reproduce rapidly. Rust and limescale in the water can also act as a food source, though, so it’s important to keep your water supply as clean as possible to deny Legionella the chance to grow.

What if Legionella is found in my water supply?

While the chances of this happening are relatively small, so long as your employees are all healthy and uninfected, Legionella can be dealt with quickly. The same companies that perform Legionella risk assessments will also offer a remedial action service, and can immediately start working on fully cleaning out your water system. Any malfunctioning or underperforming equipment will be repaired or replaced, and the water will all be completely disinfected. By acting fast, the problem can be easily resolved, and you’ll know that your staff aren’t at any risk of getting sick.

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