What is Legionella?
Legionnaires’ disease is a potentially fatal form of pneumonia caused by the inhalation of small droplets of contaminated water containing Legionella. All man-made hot and cold-water systems are likely to provide an environment where Legionella can grow.
Where conditions are favourable (i.e. suitable growth temperature range; water droplets (aerosols) produced and dispersed; water stored and/or recirculated; some ‘food’ for the organism to grow such as rust, sludge, scale, biofilm etc) then the bacteria may multiply thus increasing the risk of exposure. It is a simple fact that the organism will colonise both large and small systems so both require risks to be managed effectively.
Legionella and COVID-19
Some people will be more vulnerable than others to COVID-19. Generally, these infections can cause more severe symptoms in people with weakened immune systems, older people, and those with long-term conditions like diabetes, cancer and chronic lung disease – not unlike the susceptible groups for Legionnaires’ disease.
There are no vaccines that can prevent Legionnaires’ disease. Instead, the key to preventing Legionnaires’ disease is to make sure that building owners and managers maintain building water systems in order to reduce the risk of Legionella growth and spread.
Advice for Legionella Control During the COVID-19 OutbreakDuring the current Coronavirus pandemic attention has appropriately been on the safety and well-being of employees and the general public with regard to confronting the spread of the virus, it is all too easy to lose focus on general day to day priorities. However, as our work practices, actions and behaviour changes this can have a substantial bearing on aspects of the safety of our properties and this includes the risk associated with Legionella bacteria. Health and Safety regulations continue to apply, and Duty Holders maintain a legal obligation to protect those in and around their properties from exposure to Legionella bacteria.
HSE Regulation HSG274 Legionnaires’ Disease Part 2: The Control of Legionella Bacteria and Cold-Water Systems (page 24. 2.5 Buildings temporarily taken out of use) – Where a building, part of a building or a water system is taken out of use (mothballing), it should be managed so that microbial growth, including Legionella in the water, is appropriately controlled.
If you do decide to temporarily shut down your premises (mothball), the following advice is recommended:
- Do not drain down the water system or part of it, as moisture will remain within the system allowing biofilm to develop where there are pockets of water or high humidity. It will also help to avoid other problems associated with the drying out of the system, including failure of tank joints and corrosion in metal pipework.
- Lock off, place signage on doors / outlets to advise potential users that the system has been taken out of use.
- Have a plan in place for the recommissioning of the water system.
While controls in place may need to be adapted to changing circumstances, Duty Holders must still be able to demonstrate control of risk to a reasonably practicable level.
Legionella bacteria can grow and colonise water systems at temperatures between 20°C and 45°C, where a suitable nutrient source is available, and where turnover of water is low. As many businesses increasingly move to homeworking arrangements during the Coronavirus pandemic the demand for water in many commercial buildings will be significantly reduced. As demand is reduced the risk of low turnover and stagnation increases. With lower turnover we can also see increases in water temperatures as pipes warm to ambient levels. This risk can be further increased as the availability of maintenance staff and engineers is reduced through illness, isolation or travel restrictions.
You are therefore advised to continue to provide access to your site to enable your preferred engineer to maintain Legionella testing service visits and, whether or not the engineer is provided access, to continue to communicate with service provider, they can advise you on appropriate adaptations to your control scheme in response to the change in circumstances and increase in risk.
Recommissioning of Water Systems
If over this interval where your water system has been mothballed or partially mothballed, it is vital that any water system is not immediately put straight back into use, this can be highly dangerous if not undertaken by a qualified engineer. It is advised, before any work is undertaken, that you speak with your water engineers to devise a plan to recommission the system to allow for the speedy and safe start-up.
Cleaning and Disinfection
Thorough cleaning and disinfection is required followed by proper sampling to determine that the water system is safe, and Legionella is being controlled, before being returned to use.
Depending on the concentration of contamination that has built-up within the system during the mothballing period, it will have an effect on the success of the disinfection. It may be necessary, therefore, to repeat the disinfection and sampling process in order to achieve control. The levels of contamination and subsequent disinfection can only be assessed by someone with the relevant qualifications and experience.
For more information about Legionella testing and specific concerns relating to your business get in touch with our expert Health and Safety Consultants today.