How a French hospital eliminated legionella with Alfa Laval heat transfer solution

Legionella bacteria pose a serious health risk, particularly in large buildings and institutions where hot and cold water systems can become breeding grounds for these bacteria. The bacteria thrive in temperatures between 20°C and 45°C and can cause Legionnaires' disease, a severe form of pneumonia. The hospital needed a solution that could continuously disinfect circulating water, ensuring the safety of patients and staff.

Our solution: continous maintain, low maintenance

Alfa Laval’s anti-Legionella tap water system was chosen for its ability to maintain water at a disinfecting temperature of 70°C, its low maintenance requirements, and its space-saving design. The system replaced eight 500-liter tanks with a single 300-liter tank, significantly reducing the space needed in the boiler room.

The compact system design from Alfa Laval requires low maintenance and is very easy to use and monitor.

Philippe Raquin, the Technical Service Manager at the Iris hospital

The decision was influenced by positive feedback from a similar installation in another clinic in Lyon and the longstanding relationship with Alfa Laval.

How the heat process is implemented in the hospital

The installation was carried out by Cofély, an experienced installer with 13,000 employees.

The system uses two gasketd plate heat exchangers: the first heats the water to 70°C for disinfection. Once heated to 70°C, the disinfected water needs to be maintained at this temperature for a given period of time to ensure eradication of any bacteria.

The hospital chose to install a standard storage tank to ensure the holding time. The disinfected water flows to heat exchanger II for the cooling process. The second heat exchanger cools it to the required network temperature of 60°C.

The mixing valve C ensures the requested network temperature by mixing the disinfected water coming directly from the storage vessel at 70°C and the disinfected – but cooled down – water coming from heat exchanger II.

This design ensures that only disinfected water is circulated throughout the hospital’s water system. Regular water samples are taken and tested to ensure the system's effectiveness, and since its installation, no Legionella infections have been detected.

Impact and benefits to Les Iris hospital

Alfa Laval's anti-Legionella tap water system has provided numerous benefits to the Les Iris hospital:

• Safety: Continuous disinfection of all circulating water ensures the eradication of Legionella bacteria.
• Efficiency: The system is energy-efficient, using recovered heat for disinfection without additional energy input.
• Maintenance: The system requires low maintenance and is easy to operate and monitor.
• Space-saving: The compact design saves significant space in the boiler room.
• Compliance: The system can adapt to comply with local regulations and water hardness levels.

The successful implementation of the system has not only ensured the safety of the hospital’s water supply but also demonstrated the effectiveness of Alfa Laval’s solutions in preventing waterborne diseases.

By prioritizing safety and efficiency, the Les Iris hospital has set a benchmark for other institutions looking to safeguard their water systems against Legionella.