BSEE
BOILERS & HOT WATER Legionella: the risks of returning to an unused building
The closure of public buildings has been a method used worldwide to reduce the spread of COVID19; however, the prolonged closure of buildings may have unexpected implications for some, Albion Valves explains.
have been largely unused which poses additional risks for public health, through diseases such as Legionnaires.
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Thermostatic Balancing Valves are designed for use in Domestic Hot Water Systems (DHWS) to accelerate hot water delivery to the tap, reduce water wastage and conserve energy, though they are now being specified in public building installations to help protect against the growth of the Legionella Pneumophila bacteria.
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Legionnaires disease is a lung infection caused by the bacterium named Legionella Pneumophila, which is commonly found in water. The recent lockdown created an optimum environment for the bacteria to proliferate within water systems. The bacteria can exist in any water system but will specifically cause issues in man-made water systems such as large plumbing systems, showerheads, sinks and hot water tanks. Upon reopening of buildings, and without proper precautions, the bacteria- infected water in an aerosolised form can then be released into the surrounding space when the water systems are used, this can then be inhaled by those in the vicinity.
Symptoms of Legionnaires disease are similar to the symptoms of COVID-19, with a high temperature / fever and a cough being amongst the common symptoms for both. Whilst having similar symptoms both illnesses are transmitted in different ways and require different treatments, so it is imperative to get an accurate diagnosis from a medical professional. Legionella is not thought to be transmitted from person to person, however because of the way that the disease is spread it is not uncommon to see localised outbreaks.
To prevent a localised outbreak of Legionnaires Disease, it is important that the water systems are adequately checked, inspected, and cleaned in line with the building’s guidelines, prior to reopening, especially systems that have not been used, as these will have been holding stagnant water for some time. Buildings that had Thermostatic Balancing Valves (TBV) installed prior to the lockdown may have an easier task on their hands, when compared to those that did not.
Thermostatic Balancing Valves are designed for use in Domestic Hot Water Systems (DHWS) to accelerate hot water delivery to the tap, reduce water wastage and conserve energy, though they are now being specified in public building installations to help protect against the growth of the Legionella Pneumophila 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. Many high quality TBV’s would come with an Automatic Legionella Disinfectant feature and a temperature verification port and gauge as standard, allowing the engineers to easily follow any temperature logging procedures and alerting them to any potential issues at an early stage.
18 BUILDING SERVICES & ENVIRONMENTAL ENGINEER JULY 2020
hilst buildings have remained empty, the water and HVAC systems within offices and other public buildings
A Thermostatic Balancing Valve: designed for use in Domestic Hot Water Systems (DHWS) to accelerate hot water delivery to the tap, reduce water wastage and conserve energy, though they are now being specified in public building installations to help protect against the growth of the Legionella Pneumophila bacteria.
Due to the buildings being unoccupied, there has been no demand for the water supplies meaning the water within the systems will have remained stagnant throughout this period, pair this with the recent warm weather and it has created an ideal environment for the bacteria to proliferate.
If Thermostatic Balancing Valves are present within the water systems, the engineers will be able to utilise the thermal disinfection function which will increase the temperature of the system to temperatures above 60°C – often to around 70°C – running the system at this temperature for a period of time will eliminate the Legionella bacteria that has been able to exist.
Whilst thermal disinfection is said to be one of the most easy and reliable ways to eliminate Legionella bacteria within water systems, other options are available such as water chlorination, these may be the preferred option for those with systems without a Thermostatic Balancing Valve installed. However, these methods do have their disadvantages, the added chemicals can affect the water quality and also cause corrosion.
Whilst many large premises will have engineers who oversee the day-to-day maintenance and as such, will be aware of the issues that stagnant water creates and how to overcome these, the smaller premises and businesses amongst us may be facing an unprecedented challenge. However, 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, and gives instructions on how to safely reopen these systems.
Darren Baxter, Albion’s sales and marketing director, comments “It is likely that many small businesses will not have engineers overseeing the maintenance of facilities on a day-to-day basis, this lack of knowledge and dedicated personnel, combined with the nature of some of these businesses, means that they could be most at risk of causing an outbreak of Legionnaires disease.
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For example, hairdressing salons are particularly vulnerable, being one the industries that have been closed the longest, alongside having facilities such as showerheads, which is a prime outlet for dispersing the infected water.” Professionals within the building services industry would recognise the importance of preparing water systems before use, however, the average business owner is going to be focused on ensuring that social distancing can be adhered to and the correct equipment and procedures are in place, preventing further spread of COVID-19. With so many factors to consider before reopening, something that is out of sight, such as water systems, could easily be forgotten.
Baxter adds “It would be wise for small businesses to appoint a reputable engineer or company to oversee their reopening procedures, there are many aspects that business owners may overlook and some work that may need to be undertaken in which they are not qualified to do. When public health is in doubt, it is best to leave it to the professionals.”
Albion Valves (UK) Ltd offer a comprehensive range of public health valves including, thermostatic balancing valves to decrease the risk of Legionella, amongst others that omit risks such as scalding and back siphonage.
For more information please contact us by phone on 01226 729900 or by email on
sales@albionvalvesuk.com
www.albionvalvesuk.com
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