During these challenging pandemic times, several buildings are not being used as usual. This is the case with schools, sport centres, offices, holiday parks and museums. Water services that have a low usage level as well as stagnant areas have an increased risk for the growth of Legionella bacteria.
On the other hand, nursing homes, residential care institutions and hospitals are obviously in operation and are absolutely focused on the care and health of their patients during this pandemic. In either situation (lockdown or not lockdown buildings) extra precautions need to be taken in order to protect their exposure to Legionella bacteria.
Legionella bacteria can cause Legionnaire’s disease. This is a serious lung infection that is on the rise in many countries around the globe. It can happen when an individual inhales a water droplet contaminated with Legionella bacteria. Typically, the majority of Legionella outbreaks take place when cooling water systems in corporate or commercial buildings are not appropriately cleaned and sanitised. Individuals in the building may inhale contaminated water droplets from the systems and become sick with an illness similar to pneumonia that can actually be life-threatening.
Industrial water systems provide the ideal environment for Legionella bacteria to grow and spread. Very often, such outbreaks don’t occur because of negligence, simply because the building’s management did not know the building was actually at risk, and hence did not take the necessary precautions and did not have the necessary systems in place to prevent it.
In case you hold a building management responsible position, managing and controlling risks to the health and safety of people who occupy your building is one of the most (if not the most) important aspects of your role as a facilities maintenance responsible. Taking a preventive approach is the key to reducing the risk of Legionella infection in the water system of your building.
Where can we find Legionella?
Legionella is a type of bacteria that can occur naturally in rivers, soil, lakes and other water bodies, and can successfully colonise manmade water storage systems, In fact, these very often provide ideal nutrition and temperature conditions for Legionella growth. Legionella bacteria have an optimum pH of between 5.0 and 8.5, and frequently flourish inside sediment and scale, since there they are protected from chemical disinfectants and high temperatures.
Preventing Legionella from spreading
Proper maintenance of plumbing systems and cooling towers is truly imperative to keep Legionella at bay, but it is also true that no maintenance system or water treatment is guaranteed to completely and permanently eliminate the organism. Continuous chlorination, the system used for most cooling towers, is not an option for potable water supplies.
A primary control strategy for Legionella in large buildings is to keep the water systems at temperatures outside the bacteria’s growth range of twenty-five degrees Celsius to forty-three degrees Celsius. Warm water makes a water system particularly vulnerable to Legionella growth and colonisation. A number of studies across multiple scales, countries, and building settings, have proven the benefit of high temperatures when it comes to Legionella risk control.
Water heater settings of higher than sixty degrees Celsius are the key threshold for minimising positive detection of Legionella and consequently for reducing Legionnaires’ disease infections as well as outbreaks.
Maintenance of a disinfectant residual is an integral part of a large building’s water management plan (or WMP) for control and management of Legionella risk. Disinfection systems need to be paired with programmed water testing to guarantee that the system maintains a residual.
Water is utilised in different ways nowadays in offices, different premises and factories, and each use needs to be risk assessed as advocated by the authorities. To comply with all the legal duties in managing and reducing Legionella risk, the managers of the premises have a legal responsibility to:
- Identify as well as assess sources of Legionella risk
- Prepare a program for preventing the identified risks
- Implement and monitor precautions as well as control measures, for example frequently opening outlets that are not in use.
- Keep records of all the control measures
- Appoint a responsible individual to hold the managerial responsibility
Local authorities provide guidance when it comes to Legionella control, such as the UK HSE or Health and Safety Executive guidance.