Legionella and COVID-19

21st April 2020

Guidance produced by the European Society of Clinical Microbiology and Infectious Diseases released a document highlighting actions needed for companies prior to them putting their water systems back into use safely.  Many people aren’t sure of how to deal with re-opening their buildings.  The water systems in buildings have been left and unattended, and even flushing probably hasn’t been sufficient enough to prevent the stagnation and bacteria growth in water systems.  Legionella and waterborne infections fall under the health and safety at work act and as such,  needs to be taken seriously and in a timely manner.  A flush and disinfection of the system is required, followed by some water samples to ensure the system is free from issue.

To see a full study, please see the below guidance:

COVID Building Water Guidance PDF Guide

The bits to pay attention are:

When restarting,

14. Carry out a full system disinfection of the cold-water system, flushing through to all outlets to achieve 50 ppm free chlorine or equivalent biocide for at least an hour checking that this level is achieved at the furthest outlets, top up when required.

15. Flush out and refill the system to achieve maximum normal operating target levels of disinfection (equivalent to at least 0.2 ppm free chlorine).

16. Refill and reheat the calorifier to 60 °C. and when the calorifier/ storage water has been heated to 60 °C throughout, open the valves and flush through all outlets taking care to avoid any scalding risk.

17. Monitor temperatures and biocide levels where applicable, adjust where necessary, for at least 48 hours and then take Legionella samples from the sentinel outlets (microbiological samples taken before 48 hours following disinfection may give false negative results).

18. When you are satisfied the hot and cold-water systems are under control then reopen the building.

19. Ensure you keep all documentation for inspection: including the review and update of risk assessments (these can be annotated by hand) including monitoring data etc., with evidence of who carried out the monitoring, add time date and signature.

20. Follow the advice for other additional waters systems or equipment as above.

For nationwide coverage DS Water can provide you with everything to put your building back online safely, and hassle free.

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