Measures to control the spread of coronavirus mean that many local businesses are closed or partly closed.
This means that many hot and cold water systems will not be running, and this increases the chances of bacteria forming. This can cause Legionnaires’ disease - a potentially fatal type of pneumonia. Legionnaires’ disease is caused by inhaling droplets of contaminated water from things like air-conditioning, showers, water sprays, whirlpool or hydrotherapy baths.
Legionella bacteria, commonly found in water, multiply when the water temperature is between 20 and 45ºC.
There are steps businesses can take to prevent potentially-deadly legionella bacteria from getting into their water systems:
- Hot water systems should maintain water temperatures of at least 60ºC in storage cylinders and above 50ºC through the distribution system
- Cold water should be below 20ºC
- Make sure that water systems are flushed through at least weekly. More frequent flushing may be needed for some systems
- Flush all of the system outlets – it’s not good enough to just flush one or two outlets on a large system
- Reduce the water levels in bulk tanks so there is less standing water
- Keep records of how you’re preventing legionella during closure
- If evaporative cooling systems are in use, these must be maintained as usual or switched off safely
- Where water systems have control measures built into the system, these should be maintained and kept working (if feasible) during the closure period
At some point, the lockdown controls will be lifted and there will be pressure to quickly return to normal operation. It's important for businesses to have a plan in place which addresss the risks relating to a return to normal operations.
Where water systems have been unused for a prolonged period, you should take advice from a competent heating/ventilation engineer about pre-start checks and maintenance.
It might be appropriate to have a system service, including cleaning and disinfection, before bringing complex systems back into use.
You might need to clean and disinfect even simple systems such as spray taps and showers before using them again.
If you’re not sure about the steps that need to be taken in relation to your businesses then please seek competent advice.
Links to further information
- HSE: Legionnaires' disease: The control of legionella bacteria in water systems
- HSE: Control of legionella bacteria in water systems: Audit checklists
- Legionella Control Association: Safe Management of Water Systems in Buildings During the COVID-19 Outbreak
- European Society of Clinical Microbiology and Infectious Diseases: Guidance on Maintaining Safe Water Systems
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