Legionella - Managing the Hidden Threat
“What exactly could the construction, installation and maintenance industries be doing to prevent the spread of Legionella?”, asks Geoff Mann.
We are all aware of the recent case of Legionnaires' disease in Barrow-in-Furness , Cumbria , reportedly originating from an air-conditioning system. But why do these outbreaks repeatedly arise, precipitated by similar circumstances, and what should the construction, installation and maintenance industries be doing to lower this risk?
Legionella, the bacteria causing Legionnaires' disease, is ubiquitous in natural fresh water. There are currently 250 cases reported in Britain every year, of which around 10% result in death. In light of this continued problem, the Health and Safety Commission (HSC) published the Approved Code of Practice (ACOP) L8 “The Control of Legionella bacteria in water systems” in 2000, which provides practical advice on several previously published regulations with regard to the risk posed by Legionella. These most recent guidance notes demand more comprehensive risk assessments, management strategies and record keeping, but highlight additional responsibilities for manufacturers, importers, suppliers and installers to reduce the risk of the proliferation of Legionella bacteria in working environments.
To a certain extent, Legionnaire’s disease is a product of the built environment, and it therefore follows that design or construction firms can have an impact on the level of risk in developments. The guidelines state that to control the multiplication of the bacteria, suitable design, manufacture, installation, operation, maintenance and treatment of water systems should be used. Many firms have been following these guidelines themselves for years, and consequently the modern built environment is at a substantially lower risk from Legionella bacteria than ever before.
What is becoming clear is the extent to which we can ‘design out the risk’ of the problem in the construction phase. Simple measures can be employed for example cut down as far as possible on wet cooling systems, segregate or insulate of cold water system pipes to avoid temperatures of above 20ºC, or install de-stratification pumps on hot water generators, all of which should reduce the proliferation of the bacteria. Obviously, these measures can incur higher costs for the client, but these should be balanced against the reduced cost of legionella control measures resulting from correctly designed and installed systems. However, awareness ofthe responsibility that suppliers and service providers now bear in relation to Legionella has increased, and the ethical selling of goods and services has also been highlighted.
Breach of Legionella control regulations can lead to immediate closure of premises and anything up to six figure fines, and in cases where a member of the public or employee becomes infected the cost can be much higher. Although the penalties will initially fall on the building’s owner or manager, if a construction company is found to have failed in its responsibilities, the costs, both financially and to its reputation, could be serious.
More specifically, suppliers of products and services should ensure that any limitations on their expertise or products with regard to legionella are clearly defined and made known to the owner or responsible person. Furthermore, they should also make the responsible person aware of any deficiencies in the water systems or control measures under consideration which are likely to increase the risk of exposure to legionella bacteria. This should cut down on the risk of opportunist contractors cashing in on the problem and allow legitimate companies to further improve the situation.
It is obvious that the Legionella problem won’t disappear entirely and these changes in guidelines can’t be implemented overnight, but with the recommendations for contractors and suggestions to employers to bring in specialist agencies for professional advice, perhaps we can all reduce the prevalence of the bacteria in environments such as schools and hospitals that house those most susceptible to contracting diseases associated with Legionella.
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