Guidance from the LCA
With the COVID-19 pandemic continuing to evolve, a lot of questions have been asked surrounding what needs to be completed regarding Legionella Compliance. As a company, we are constantly reviewing measures and consulting external bodies, such as the Legionella Control Association (LCA) for support in these matters.
The Legal responsibility lies with the Duty Holder who must make their own determination for each circumstance, but the following principles should be considered when making decisions on what to do to control legionella during the current COVID – 19 outbreak. The below is based upon LCA guidance issued 25/03/2020:
- The expectation for evaporative cooling systems is that they will be maintained as usual or switched off safely – there is no leeway in this
- The expectation for water systems supplying critical services, for example, hospitals, is that they will be maintained as usual – there is no leeway in this
- Hot and cold-water systems in buildings that are empty or with under-occupancy must address the issue of stagnation:
- If the building is still partially in use take additional measures to keep the remaining occupants safe:
- If possible, drop stored water levels in tanks to maintain <24 hours storage
- Flush to simulate use – weekly flushing may not be sufficient
- Monitor temperature to ensure thermal gain in cold water is controlled
- If controls are lost (temperature, biocide levels, etc.) the guidance in HSG274 is to sample for legionella weekly
- Buildings that are temporarily shut down (mothballed) should follow the guidance in HSG274 Part 2 paragraphs 2.50-2.52:
- Do not drain down pipework
- If possible, remove sources of heat and external thermal gain
- Lock-off, place signage on doors and otherwise advise potential users that the system has been taken out of use
- Have a plan in place for recommissioning the water system
With all the above actions considered a plan for recommissioning the water systems should be in place once the current situation starts to change, again advice has been provided by the LCA:
Recommissioning Water Systems
It is essential that when buildings reopen following the lifting of COVID-19 restrictions, that any water system is not simply put straight back into use. During the period of shutdown, it would be sensible to formulate a recommissioning plan for each water system to allow safe start-up and assurance to users that it is safe.
Evaporative cooling systems should already have a robust start-up and shut-down procedures in place, and the expectation is that these must be followed.
The minimum expectation for small, simple hot and cold-water systems would be flushing through with fresh mains water. Larger buildings, those with tanks, showers, calorifiers and more complex pipework the expectation is likely to be for more extensive flushing followed by cleaning and disinfection.
During flushing, all valves should be operated in the fully open position so that any particulate matter can be flushed through. Of particular importance are float-operated or other restrictive valves that need to be manually opened to ensure the clearing of particulates and prevent fouling of the valves. Where a clearing velocity cannot be achieved, consideration should be given to the removal of valves to enable an effective flush.
Where buildings have been empty for some time and during warm weather, it is likely that some increase in bacteria levels and biofilm will occur. These water systems may require more than a simple disinfection to be successful. Be prepared for the need to repeat some disinfections to achieve success.
In all cases where systems are being recommissioned, it is sensible to have evidence to prove/reassure that the recommissioning process has been effective. Legionella sampling to BS7592 should be considered for recommissioning plans to validate the effectiveness of the process.
While each individual water system is likely to need individual consideration, it will be helpful to be aware of the bigger picture with regard to demand on services. There will be an increased demand for flushing and disinfection, sampling and other system recommissioning work.
There is potential for multiple outbreaks of Legionnaires’ disease following the COVID-19 outbreak if actions taken now are not carefully considered.