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Review of Legionella Risk Session at IHEA conference

Tuesday 2 December, 2014

Dr Vyt Garnys was in good company at the Institute of Hospital Engineers Australia (IHEA) Conference held in Brisbane in October with all presenters singing from the same CETEC hymn sheet.

Vyt was speaking at the conference in a session dedicated to Legionella risk with an emphasis on the hospital environment. Vyt presented jointly with Mark Collen of Veolia Water Technologies with their topic “Control of Legionella in Potable Water”. Other presenters were Stuart Lloyd of Jacobs (SKM), Alex Mofidi of AECOM and Les Szabo of Hydrochem.

In each case, the message from the presenters was consistent – Legionella risk from potable water in Australia is real with the local water supply authorities under no obligation to monitor or treat the water they supply to large institutions, such as hospitals, for the presence of Legionella. In response to this risk, the Queensland Government released their “Guidelines for Managing Microbial Water Quality in Healthcare Facilities” late last year. This document will soon be supplemented by enHealth's National Legionella Control Guidelines for potable water developed by CETEC for the Federal Government.

While the Queensland Guidelines are specific in their intent, the broader Facility Management discipline leaders are now attuned to their wider implications and are beginning to apply them to identifying Legionella risk in a range of non-health facilities and monitoring water quality more closely.

Consistent with this new awareness, each speaker emphasised the need to apply the water quality guidelines to these other facilities, while also stressing the need to apply similar controls to both HOT and COLD water. This message was especially relevant to Queensland where “cold” water can be delivered to site by the local authority at elevated temperatures and, after on-site storage, enter the facility at 30°C. Typically, this on-site storage is in unshaded steel tanks which, because of these elevated temperatures, facilitates the growth of biofilm and increases the attendant risk of Legionella development. To reduce this risk, Stuart Lloyd recommended that such storage tanks be housed in a cool place within the facility and insulated.

Two of the speakers explained the relationship between microbial activity and temperature with higher microbial growth occurring in the 30 to 40°C temperature range. Typical “tempered” hot water systems are often set at the upper level of this range and represent an elevated risk of biofilm growth and microbial activity even in domestic situations. It was also emphasised that cold water needed to be continually monitored for residual chlorine disinfectant within a facility, particularly at the distal outlets.  

The joint presentation by Vyt Garnys and Mark Collen was well received by the audience who were a broad cross section of facility managers, consultants and specialist trade representatives from across the country.

To learn more about Legionella & water quality risk and mitigation strategies