As places of work begin to consider a return to work after lockdown, businesses are being reminded to flush out their pipes before reopening to prevent the possibility of Legionnaires disease spreading.
Legionella, the bacteria which causes the sometimes fatal disease, grows and thrives in stagnant water. Pipework and tank systems that have been unused for many weeks may contain water that has been lying within since lockdown began in mid-March, providing optimal conditions for legionella to form.
The solution for removing legionella lies in letting water run through pipes for anywhere between 10 and 30 minutes depending on the size of the business premises in question.
This fresher, cleaner water will safely flush out any older, contaminated water which has been lurking in pipes, removing the legionella with it. Tanks – especially those which supply hot water – should be drained and refilled with fresh water.
The speed with which legionella develops can be accelerated by temperature. If any water on your premises has been subjected to temperatures in the ‘danger zone’ between 25°C and 45°C, then the growth of the bacteria will have been enhanced.
Hot water tanks which have cooled down are prime candidates for providing these conditions, which is why it is important that tanks are emptied before businesses return to work.
Guidance from the Health and Safety Executive says the easiest way to prevent legionella forming is by keeping cold water cold and hot water hot. The bacteria are largely dormant when cold water is under 20°C and hot water temperatures in excess of 50°C kills it.
People contract Legionnaires disease when they inhale droplets of water containing legionella through mist or vapour. Legionella was first discovered in 1976 during a convention of the American Legion.
The bacteria had bred in the pipework system of a hotel in Philadelphia. By the end of the convention, over 200 people had contracted Legionnaires disease from the hotel’s pipes.
Individuals with underlying health conditions, weakened immune systems or existing respiratory problems are most at risk from Legionnaires disease. The elderly, smokers and those with lung disease are also susceptible and, in some cases, it can cause severe problems for the healthy.
According to the Centre for Disease Control and Prevention, one in 10 people who gets sick with Legionnaires’ disease will die due to complications from their illness.
Legionella isn’t the only threat posed by water left stagnant over lockdown. If a premises’ pipework system features lead piping, then there is a great chance of lead leaching into water. Flushing pipes also removes water contaminated with lead.