Legionella is a potentially harmful bacteria, it exists in natural water sources like lakes and rivers, places we often draw our water supplies from. Legionella can often be found in mains water and because of this, and it can get into the water systems in our buildings.
In natural water sources, the numbers of legionella bacteria are very small, but in buildings these numbers can rise significantly, as many conditions found in our water systems can help support its growth.
If the Legionella bacteria is allowed to grow in the water systems in a building, someone may become infected and contract Legionellosis. Legionellosis is an umbrella term for several different conditions, Legionnaires Disease, Pontiac Fever and Lochgoilhead Fever (which can all be caused by Legionella Bacteria). This is similar to how Cancer is an umbrella term for several different conditions uncluding skin Cancer, Lung Cancer and Breast Cancer.
In general, people contract legionellosis by inhaling tiny droplets of water, that we call aerosols, that contain the Legionella bacteria. Once the bacteria get into the body, in particular the lungs, it begins to multiply and spread. If people contract the most serious form of Legionellosis, Legionnaires Disease, the effect can be fatal.
Legionnaires Disease has an approximately 12% mortality rate, it can be treated with antibiotics, but the damage it can do to your lungs can be serious and permanent if you do survive. As a result of these serious outcomes, the Government has placed an emphasis on preventing people from contracting Legionellosis.
If you are an employer, or someone responsible for a building, you are required under the Health and Safety at Work Act 1974 to manage the risk from Legionella to your employees, customers and the general public. The Health and Safety Executive has produced several documents to help give advice in doing this, the ACoP L8 and the HSG274 Parts 1 -3. There is also a set of more specific guides produced by the Department of Health for healthcare environments, HTM 04-01.
These guidance documents all give instructions on how to minimise the risk of someone becoming infected with Legionella bacteria by telling you how to avoid the conditions that can lead to it multiplying, and on how to reduce aerosol sprays that can spread the bacteria.
The main factors in the growth of Legionella are temperatures between 20-45°C, where water is stored or re-circulated, where there are deposits like sediment, scale, rust or biofilm that can support and provide nutrients. Legionella management is all about trying to minimise these factors.
The first part of Legionella management is having a risk assessment carried out, without a risk assessment, you won’t know where there are potential problems in your water system, we can then put a plan in place to fix any issues and begin to manage the water system. There then needs to be a management structure and procedures in place to help control the ongoing risk. The HSG274 Part 2 has a very helpful table (Table 2.1) that details all of the different monitoring and maintenance tasks that should be carried out to help manage the risk of Legionella in a water system.
There are other important factors to consider when thinking about Legionella management. An important one which has not been addressed yet is susceptibility, some people are at a greater risk from Legionella than others. Those with compromised immune systems, existing medical problems, particularly lung conditions, smokers, people over the age of 45, heavy drinkers and men are all at an elevated risk.
Healthcare sites are much more likely than other buildings to have many susceptible people, particularly hospitals with ICU and Oncology wards, these are likely to have some of the most vulnerable people.
In order to help protect these people, the Department of Health’s HTM 04-01 places more stringent requirements on healthcare settings for the management of Legionella than in regular buildings.
One of the most significant differences between healthcare and regular buildings is the requirements regarding temperature controls. Healthcare buildings must circulate hot water to outlets above 55°C, whereas regular buildings only need to reach 50°C. The HTM 04-01 also states that temperature control has to be the main way of controlling risk from Legionella in healthcare buildings, in regular buildings you are allowed to use system disinfectants like chlorine dioxide instead of temperature.
Such disinfectants can still be used in healthcare; however, they can only be used as a “belt and braces” support to temperature control, there are also extra considerations as departments such as renal units cannot be supplied water with these disinfectants in it.
There are several other differences in the way water systems in healthcare settings should be designed and operated, but the greatest difference is in how they are managed.
HTM 04-01 Part 2 goes into detail regarding the Water Safety Group (WSG) and Water Safety Plan (WSP) which are required at healthcare sites. The WSG is a multidisciplinary group whose job it is to manage all aspects of the water systems on site, it should consist of representatives from all relevant departments such as estates, microbiology, SSD, nursing, housekeeping and specialist water use departments like endoscopy.
They are responsible for creating and developing the WSP, which is a document that covers the management of all the water systems on site. It will identify potential hazards on site, consider practical aspects and detail control measures.
If you are a healthcare practice or run a healthcare environment Euro Environmental can help you strategise your Legionella assessments and regular testing to safeguard any patients and their visitors. Find out more.