Legionella bacteria, legionellosis, legionnaires disease, Pontiac fever, what does it all mean? How are they different? You may have heard of these terms when it comes to your legionella control programme, the sheer number of words you come across when looking into this crucial part of your health and safety can seem baffling. Luckily however, BrodexTrident can make it easy for you to understand everything to help keep the risk of legionnaires disease in your place of work as low as possible... Without confusing you along the way!

In very simple terms, here is what legionella and legionnaires disease is from the authority in the UK, Health and Safety Executive;

Legionellosis is the collective name given to the pneumonia-like illness caused by legionella bacteria. This includes the most serious legionnaires’ disease, as well as the similar but less serious conditions of Pontiac fever and Lochgoilhead fever. Legionnaires’ disease is a potentially fatal form of pneumonia and everyone is susceptible to infection. However, some people are at higher risk, including

- people over 45 years of age;

- smokers and heavy drinkers;

- people suffering from chronic respiratory or kidney disease; and 

- anyone with an impaired immune system.

If any of these describe someone within the vicinity of your premises, whether it be a care home, office, hospital or school, you will need to ensure a legionella control programme is put in place, but what does one look like and how can you get started?

The first thing to do if you're are just starting out is to appoint a 'competent person.' This is someone who is responsible for managing the risk of legionella and who will be active in taking steps in controlling the risk to be as low as possible. This competent person must be someone with the correct knowledge, skills and experience to manage health and safety and the relevant control measures.

Great, I have a responsible person in place, now what?

In HSE458 (Legionnaires disease, a brief guide for duty holders), Health and Safety Executive relay the following information:

You should consider whether you can prevent the risk of legionella in the first place by considering the type of water system you need, eg consider whether it is possible to replace a wet cooling tower with a dry air-cooled system. The key point is to design, maintain and operate your water services under conditions that prevent or adequately control the growth of legionella bacteria.

In essence, this means you must identify the type of water system in operation, this can include different things but as well as those mentioned above, can also include water systems with water storage units such as a water tank or a calorifer. If, for example you are the appointed person at a school that has five calorifiers and two cold water storage tanks then these must be identified and records kept of their temperatures to ensure you are meeting the correct guidelines for legionella control every month. Such as keeping the water stored in a hot water heater to 60°C, or below 20°C in a cold water storage tank,

I'm doing my monthly checks, what else do I need to do?

If you operate a premises that employs more than five people, the next stage will be to conduct a legionella risk assessment. This should be done by a suitable and qualified engineer and can be carried out by a contractor. HSE explain:

The purpose of carrying out a risk assessment is to identify and assess any risks in your water system. The responsible person should understand your water systems and any associated equipment, in order to conclude whether the system is likely to create a risk from exposure to legionella.

Simply put, this is a full examination of your water system from a legionella-risk point of view. What are the potential problem areas that could lead to a legionella outbreak? Even if you are not storing water, a legionella risk assessment is still a legal requirement in the UK. A summary of information should be assembled from surveys of your stored water assets such as those mentioned above, any showers on-site, whether the checks are being carried out regularly and any major high risk areas such as dead legs and dead ends (a branch of pipework that has become isolated from the normal flow of water and may contain stagnant water under the right circumstances). If these are found, the next step is to take any 'remedial action' against the potential high risk areas that have been discovered and lower the risk of these having an effect, or simply removing them entirely.

A legionella risk assessment should also take into account any persons who may come into contact with water within your premises. For example in a care home. One major area to consider is scald risks. This is when hot water comes out at 60°C+ and could potentially do harm to the user, those in a care home are especially vulnerable, so what can be done to prevent this? A scald risk survey may identify areas where this could be a problem and the solution could lie in TMV's.

A TMV, or thermostatic mixing valve is a device that is installed below a sink or faucet and intercepts the scalding hot water before it reaches the tap and mixes it with cold water to quickly lower the temperature to a recommended and more tolerable 38-43°C. The hot water can still be stored at a safe and compliant 60°C in a hot water calorifier/cylinder without the risk of scalding the end user and causing a legionella risk with lower temperatures.

Do I need to do anything else?

Once your legionella risk assessment is complete, it will then depend on a myriad of factors on what your next step could be. If your risk assessment returns as high risk, there may be a number of remedials identified which you can action. These can range from the previously discussed dead legs and scald risks to areas within the hot water calorifiers and water tanks themselves such as sediment presence or missing parts.

Of course, if you are still finding things to be a little too overwhelming, there is a professional solution. By taking advantage of a water treatment provider that will not only carry out the legionella risk assessment on your behalf but also provide you with regular temperature checks and a general overview of your water system condition for the ultimate peace of mind.