Legionella: Are you aware of the risks of returning to an unused building?
The Closure of buildings has been a method used worldwide to reduce the spread of COVID-19; however, the prolonged closure of buildings may have unexpected implications for some.
Whilst buildings have remained empty, the water and HVAC systems within offices and other public buildings have been largely unused, which poses additional risks for public health, through diseases such as Legionnaires.
The recent lockdown created an optimum environment for the bacteria to proliferate within water systems, due to stagnant water and warm temperatures. The bacteria can exist in any water system but will specifically cause issues in large plumbing systems, showerheads, sinks and hot water tanks. Upon opening of buildings the bacteria-infected water can then be released and inhaled by those in the vicinity.
It is important that the water systems are adequately checked and cleaned prior to reopening, especially those systems holding stagnant water for some time. Those buildings that already had Thermostatic Balancing Valves (TBV) installed within the building prior to the lockdown have an easier task on their hands.
Thermostatic Balancing Valves are designed for use in Domestic Hot Water Systems to accelerate hot water delivery to taps, reduce water wastage and conserve energy and are now being specified in public building installations to protect against the growth of the Legionella bacteria.
In its optimum environment the Legionella Pneumophila bacteria will multiply rapidly, this usually occurs when subjected to temperatures between 32°C and 42°C. Therefore, HSE requires the temperature of stored hot water to be at least 60°C. This is where Thermostatic Balancing Valves are required; by design they provide thermostatically controlled regulation of flow and thermal disinfection and therefore assisting with protection against legionella. TBV’s come with an Automatic Legionella Disinfectant module.
The European Society of Clinical Microbiology and Infectious Diseases (ESGLI) has issued guidance for managing Legionella in building water systems during the COVID-19 pandemic, giving instructions on how to safely reopen.
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