Nemco Utilities provides a guide to Legionella Mutating

May 12, 2011 - PRLog -- Typically, the approach taken to Legionella Management is a Legionella risk assessment followed by strict maintenance of a temperature regime (sometimes referred to as the old Kingston controls). The essence being that by keeping hot water hot and cold water cold the, critical temperature range which supports Legionella growth (20 – 50 C) can be avoided. Where this is not possible, it then falls to some type of water treatment, usually in the form of UV or chlorine dioxide to manage bacterial levels.

However, recent claims have suggested that bacteria have been discovered surviving temperatures well in excess of 50 C and also at biocide levels well in excess of those expected to kill off most bacteria. It is well known that bacteria contained within a biofilm or in another organism, such as amoeba, are far more resilient than those free floating. In some circumstances it can take up to 1000 times the usual concentration to kill bacteria in a biofilm and it is known that Legionella within an amoebal cyst can survive 50 ppm chlorine overnight.

Unfortunately, even new buildings do not always escape the formation of biofilm. Due to phased occupation, complex design, infrequent use or inadequate / poorly timed commissioning biofilm can form within weeks.

These are worrying trends and, combined with falling facilities budgets, all does not bode well for the already under reported Legionnaire’s Disease. Experts still agree that proper application of the government guidance, ACOP L8, is sufficient to prevent Legionella bacteria from multiplying and posing a significant risk. Not only this, if the principles in L8 are followed, the risk from other water borne pathogens such as e-coli.

Development of more advanced biocides is underway, especially those with the ability to penetrate biofilm, but it is unlikely there will ever be a ‘cure all’.

For more information please visit our website www.nemco-utilities.co.uk or call the office on 01284 724 503.

Contact Details:

Nemco Utilities Ltd
12 Hillside Road
Bury St Edmunds
Suffolk
IP32 7EA

Telephone: 01284 724503
Fax No.: 01284 724826

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Nemco are independent building risk management consultants specialising in assisting organisations in the prevention and control of the risks associated with fire, air quality and waterborne pathogens including those responsible for causing Legionnaires’ disease.