Legionella Health and Safety Concerns

It is important for all health and social care providers to carry out a full risk assessment of their hot and cold water systems, so that they can control the risk of spreading Legionella bacteria. Legionella is a group of bacteria that is common in many soil and aquatic environments. Inhaling airborne water droplets that contain Legionella bacteria can cause Legionnaire’s disease, which is a potentially fatal type of pneumonia. These water droplets could be created by atomisers, wet air conditioning systems, hydrotherapy baths, whirlpools or hot and cold water outlets. Legionnaire’s disease can be contracted by anyone, but it is smokers, the elderly, alcoholic and those with chronic respiratory problems, diabetes or cancer that are most at risk. Most people with a health immune system are able to fight off the disease, but those whose immune systems are compromised are more likely to be affected. The disease and the bacteria get their name from a July 1876 outbreak that sickened 221 people and caused 34 deaths in Philadelphia. The outbreak took place among people attending a convention of the American Legion, an association for military veterans.

What are the Symptoms of Legionnaires’ Disease?

When a person is infected with the bacteria, it will take approximately 2-10 days for the first symptoms of the disease to show up. The first symptoms will be rapid-onset headaches, a general feeling of being unwell and muscle pains. As the disease develops, this will be followed with a high fever and pneumonia. The patient will cough excessively and will feel short of breath. Some patients also suffer from diarrhoea and vomiting. The disease can be very serious and requires administration of antibiotics immediately.

What Are the Conditions Suitable for Legionella to Multiply?

The bacteria that causes the disease legionella is found in the water and in the ground in very small quantities. This bacteria is more likely to multiply when it is in water than has a temperature of between 25 and 55 degrees Celsius that is stagnant for a long period of time. Having a strong flow to the water will prevent the growth of the bacteria, but if the flow is not constant throughout the entire system then it could become stagnant in particular spots (called “dead corners”) where growth could occur.

How to Prevent Legionella Growth

One of the most effective ways to control the risk of Legionella is with the water temperature. Water services should be operated at temperatures that will prevent the growth of Legionella. If water is being stored in hot water storage cylinders, it should be stored at 60 degrees Celsius or higher. Hot water should always be distributed at 50 degrees Celsius of higher, with thermostatic mixer valves at the outlets to protect against a scald risk. Cold water should always be kept and distributed at below 20 degrees Celsius. The water system should always be kept, checked, inspected and cleaned by a competent person on a regular basis. It is also important to remove the risk of stagnant water gathering within the pipe work. For example, there should be no dead ends in the pipe work and all infrequently used outlets such as taps and shower-heads should be flushed out at least weekly. Shower heads should be cleaned out to make sure that water is not trapped inside. Samples can be taken and tested for Legionella periodically. The frequency with which these samples are taken will be determined by your Legionella Risk Assessment.

Related Content