Legionella Control during Covid-19 Outbreak

For all of us in the UK and around the world Coronavirus is greatly affecting all aspects of our lives, from our health, to our work, to our families and how we operate in our day to day lives.

First and foremost, it is essential that everyone’s focus and efforts are actioned towards minimising spreading the infection to keep people safe in accordance with the latest advice from the Government and the NHS. Whilst this is of the utmost priority we need to make sure that we do not lose sight of other significant threats to our health in the workplace.

Legionella bacteria and Legionnaires’ disease is one possible threat that needs to be addressed and considered in these changing times.

We are reviewing the situation and guidance we are giving to clients on a regular basis and also consulting with external bodies such at the Legionella Control Association.

The following information is based on guidance from the Legionella Control Association 23rd March 2020 and is important information for Duty holders during the COVID-19 outbreak.

What the expectation is for management of water systems during this period of COVID-19 precautions? 

The Health and Safety at Work Act still applies and Dutyholders must be taking reasonably practicable steps to control risk from legionella throughout this time.  Dutyholders implicated in an outbreak of Legionnaires’ disease resulting from actions taken for COVID-19 precautions are not likely to have any exemption from prosecution.

The LCA cannot make sweeping statements about what is critical, what can be deferred for a few weeks and what can be deferred for longer.  The legal responsibility for legionella control lies with the Dutyholder, but LCA members should be providing expert advice to their customers to assist them in compliance.  Each Dutyholder must make their own determination for each circumstance.

What principles should be considered when making decisions on what to do to control legionella during the COVID-19 outbreak?

1) The expectation for evaporative cooling systems is that they will be maintained as usual or switched off safely – there is no leeway in this

2) 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

3) Hot and cold water systems in buildings that are empty or with under occupancy must address the issue of stagnation:

a. If the building is still partially in use take additional measures to keep the remaining occupants safe:

i. If possible, drop stored water levels in tanks to maintain <24 hours storage

ii. Flush to simulate use – weekly flushing may not be sufficient

iii. Monitor temperature to ensure thermal gain in cold water is controlled

iv. If fitted, consider temporarily increasing levels of potable water treatment dosing – consider other consequences of this such as corrosion and make the decision on balance of benefit

v. If controls are lost (temperature, biocide levels, etc.) the guidance in HSG274 is to sample for legionella weekly

vi. Consider other short term measures to keep remaining occupants safe such as point of use filters at designated locations with other areas shut off

What if a building is temporarily shut down (mothballed)?

b. Buildings that are temporarily shut down (mothballed) should follow the guidance in HSG274 Part 2 paragraphs 2.50-2.52:

i. Do not drain down pipework

ii. If possible, remove sources of heat and external thermal gain

iii. Lock off, place signage on doors and otherwise advise potential users that the system has been taken out of use

iv. Have a plan in place for recommissioning the water system

For all of the work above there should be a task risk assessment in place to ensure operatives are working safely.

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 for duty holders 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 robust start-up and shut-down procedures in place and the expectation is that these will 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.

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 at 50ppm of chlorine for an hour to be successful.  The duty holder should 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.  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.