Monday, August 3, 2020


The closure of public 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. Actually, 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. 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 th e 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 aerosolized 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 localized outbreaks. To prevent a localized 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. The 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 TB'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. 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 utilize 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. Professionals within the building services industry would recognize 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.

Cimberio has recently introduced a Thermostatic Regulator for domestic hot water recirculation loops which has a disinfection function against Legionella, Cim 778.
Cim 778 is made of a “CR” – “DZR” brass alloy that complies with standard EN 12165-CW602N-M and it is available in ½”, ¾” and 1” size.
Cimberio TBV is WRAS approved and available with temperature gauge and insolating case.