WHY IS LEGIONELLA A RISK?
Low concentrations of Legionella bacteria can be found in natural waters and ground water everywhere.
Problems arise when a specific sub-set of Legionella Pneumophila bacteria are allowed to multiply in water pipes, fittings, air conditioning systems, air washers, warm water systems, cooling towers, water reservoirs and cooling circuits. Legionella bacteria multiply in warm water systems where temperatures are between 20°C and 45°C, but can survive in temperatures up to 60°C. In cold water systems they can appear in summer as result of high outside temperatures and when there is poor isolation of the cold water pipes and the temperatures in the piping become greater than 20°C. The bacteria thrive where there is also a nutrient source and where water flows are low or the water is stagnant.
Legionella and Pseudomonas are increasingly found in care homes, hospitals, schools, day cares, hotels, swimming centres, sports facilities, camping grounds etc. Old and infrequently serviced or infrequently used warm water pipes and tanks carry a higher risk of being a source and support strong reproduction of the Legionella bacteria.
Biofilm plays a key role in the reproduction process, because it protects and feeds the Legionella. The protection of the bacteria by the biofilm is also a reason why methods like thermal disinfection are very often not sustainable and can not solve the problem!
