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WITH BUILDINGS STANDING EMPTY SINCE THE START OF LOCKDOWN, THERE ARE LOTS TO CONSIDER WHEN OPENING THEM UP AGAIN AS LIFE SLOWLY BEGINS TO RESTART... Assessing risk post-covid reopening CONTROL MEASURES The following will likely need to be considered as part of a control strategy, but there may be others.
R eopening a building that has stood idle without addressing the safety of its water system is unacceptable and is likely to be in breach of the law. If duty holders are not able to put in place a proper recommissioning process to use the water system safely, they should not reopen the building. In addition to legionella risk, drinking water retained within buildings may no longer be potable following a period of prolonged stagnation. Buildings that have remained empty with static water systems, or those that have been subject to flushing that does not represent normal usage, are likely to require recommissioning. Those that have remained in normal use - or where flushing has approximated normal usage - may still require additional control measures due to the additional risk factors below. The requirements for recommissioning a building water system will vary and the level of work and investment should be appropriate for the risk. During the Covid-19 period there may have been several factors that will increase both
legionella risk in water systems and the risk of legionellosis. These may need to be considered in the risk assessment process: • Rushed shutdown of buildings • Stagnation • Bacterial growth • Degradation of system components • Mechanical deterioration as a result of corrosion and settlement of system debris • Temperature increases within buildings aiding the growth of harmful bacteria • General thermal gain particularly in buildings with large amounts of glass where the air conditioning has been switched off • Water left in hot water systems that has cooled and aided growth • Cold water systems suffering thermal gain
Flushing a water system will change the bulk water and, depending on flow velocity, may have a shearing effect on biofilm and move other contaminants through the system. Flow velocity is likely to be reduced by outlet fittings and flow restrictors. These will reduce the effectiveness of flushing and consideration should be given to temporarily removing these during the process. Flushing activities need to consider: Correct volume of water change Circulation of all hot water services, including return pipework Flushing all dead legs and dead ends Remove all fouling such as scale within system components including exposed outlets (tap ends etc) You should always consult industry experts if in any doubt in carrying out firstly risk assessments and then the system maintenance and flushing.
• Stand-alone water systems • Point of use water dispensers • Vending machines.
Covid-19 increases the risk of legionellosis as a secondary infection. Consider this risk before allowing people back inside of the building.
For more information, contact Chris Reilly, Country Manager for Ireland, on +353 (0)85 215 2288 or e-mail chris.reilly@altecnic.co.uk or Gary Swann, Northern Ireland Sales Manager on +44 (0)7760 596727 or e-mail gary.swann@altecnic.co.uk or visit the website at www.altecnic.co.uk
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