Page 10 - inPRINT Issue 63

inDEPTH

Legionnaires’ disease has an incubation
period of 2 to 10 days *

environment LEGIONELLA – REOPENING

YOUR SITE SAFELY

hen buildings reopen Legionella risk factors
Wafter lockdown, it During the lockdown,
is essential that water there are two risk factors
systems are not put that may have increased,
back into use without creating ideal conditions
considering the risks of for Legionella bacteria to
Legionnaires’ disease. grow in your water system.
There is an increased risk of These are temperature and
waterborne pathogens such time for stagnation to occur.
as Legionella bacteria being Legionella bacteria thrive
present in consequence at temperatures between
of the conditions that 20°C and 45°C, so one of the
lockdown may have key control measures for
created. As a result of the minimising the risk is to
COVID-19 pandemic, there ensure that your cold water
is also the potential for is cold (i.e. below 20°C) and
an increased number of the hot water is hot (above
people to be susceptible 45°C). Actions to take before Legal requirements
to Legionnaires’ disease When water is below 20°C reopening: and guidance
due to a compromised or above 45°C, Legionella » Flush through simple hot/ Employers must manage
respiratory system during bacteria will not grow. cold water systems with the risks of exposure
or after infection with But water between these fresh mains water for to Legionella bacteria,
COVID-19. temperatures presents several minutes especially where buildings
Legionnaires’ disease a greater degree of risk, » Increase the temperature are closed, subject to
is a type of pneumonia particularly where it is left of hot water systems to low use or due to reopen.
that can cause serious to stagnate. Generally, if above 60°C if possible Guidance on how to do this
respiratory illness. It can water remains in a system and draw it through is provided in these (HSE)
occur when tiny droplets of without movement for more to all hot water outlets documents:
water (aerosol) containing than a week, the risk of (a temperature over L8 Approved Code of
Legionella bacteria are growth will increase. 60°C will kill Legionella Practice and guidance on
breathed into the lungs of bacteria over time) Legionella regulations
susceptible people, and Control measures » Flush through larger HSG274 Part 2 – The
is therefore very similar For simple hot/cold water hot/cold water systems Control of Legionella
to COVID-19. Preventing systems, a review could (including those with Bacteria in Hot and Cold
Legionnaires’ disease be straightforward. The tanks and showers) for a Water Systems
is typically achieved by main objectives should be significant period of time
limiting the growth of to prevent stagnation and » Ensure the system is For more information
Legionella in building keep water temperatures capable of delivering about Legionella, please
water systems. outside of 20-45°C. If water at safe contact Phil Ashcroft,
Legionella bacteria will possible, aim to ensure temperatures by checking HS&E Adviser, at
inevitably enter man- the turnover of any water temperatures ahead of [email protected]
made water systems, but stored in tanks every 24 reopening
the degree of risk it poses hours, and movement of » Undertake a chemical *https://www.who.int/news-
will vary. All hot and cold water through pipework and disinfection of the water room/fact-sheets/detail/
water systems need to be outlets at least once a week, system legionellosis
considered, including those to prevent it from becoming » Undertake microbiological
in hand washing facilities stagnant. sampling for Legionella
and shower units. bacteria

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