Legionella is a lingering, ever-present bacterium which, in the right breeding conditions, poses a significant health risk. 

The disease causing bacteria is found in potable water supplies and flourishes at temperatures between 25 and 45 ºC and in stagnant water storage volumes. Unfortunately, this means hospitals are one of the highest risk environments for Legionella as they have large and complex water systems with various dead-leg lengths that are difficult to monitor, filter, temper and flush. Couple this with the vulnerability of those using the systems and the threat of Legionella in hospitals intensifies. 

The ongoing threat of Legionnaire’s Disease is a very real one and something which must be addressed by the building and design sector. There is a responsibility for those entrusted with the design, construction and maintenance of Australian hospitals and care facilities to challenge the status-quo in relation to the systems used within the facilities to transport and treat water.

Currently, The National Plumbing and Drainage Code stipulates hot water be stored at no less than 60ºC to help prevent the growth of Legionella. But this temperature can cause scalding, so water temperature in most Australian healthcare environments is required (AS/NZS3500.4) to be controlled through the use of thermostatic mixing valves set to a maximum temperature of 45°C– unfortunately a perfect temperature for Legionella to thrive in. 

ALLEVIATING THE RISKS

Australia’s inadequate and inconsistent regulation on the issue of Legionella control in water systems is in high-contrast to aligned markets such as the UK and major parts of Europe such as Germany.
 
The UK Department of Health provides the following comprehensive advice and guidance in a code of practice for the control of Legionella in health water systems. The code stipulates that:
•    The entire water storage volume should be capable of being heated to 60 ºC without permanent pockets of lukewarm water 
•    Temperature maintained within the hot water circulating system and minimum temperature of water leaving the heater should be 60 ºC, and 55 ºC at the supply to the furthest most draw-off point in the circulating system. 
•    In non-recirculating systems, the minimum 55 ºC should be maintained by electric trace heating
•    Dead-leg lengths should be as short as practicable, and electric trace heating (if used) be taken up to the mixing device (1)

These practices are focussed around keeping water hot at all times which requires a device for safe delivery and avoiding potential scalding is of serious concern.

For safe delivery, thermostatic mixing valves which mix  hot and cold water at the point of use ensuring the water can be kept hot for as long as possible, without the risk of scalding.

Enware Australia has developed the first point-of-use sequential Thermostatic Mixing Valve (TMV) range purpose designed for high risk applications such as hospitals are care facilities. 

For more information on how this technology is working to address the threat of Legionella in Australian hospitals, all the while offering superior scald protection as well as water and energy-saving features, download this free whitepaper: ‘Eliminating Legionella Risk in Healthcare’.

1 Water systems: Health Technical Memorandum – The control of Legionella, hygiene, “safe” hot water, cold water and drinking water systems  – Part A: Design, Installation and testing 2006