In order to minimize the risk of microbial proliferation, especially by legionella in the water of evaporative cooling systems, cooling towers and wet separators, the 42nd BImSchV, which came into force in August 2018, specifies comprehensive monitoring of these systems.
Furthermore, the ordinance contains a notification requirement for all plants to the competent authority. This can be done nationwide in the Portal.


The following installations fall within the scope:

• Wet separators/ evaporative cooling plants (≤ 200MW).
• Cooling towers (cooling capacity > 200MW)

Important questions regarding the scope of application are clarified in the LAI's interpretative questionnaire on the Ordinance on Evaporative Cooling Plants, Cooling Towers and Wet Separators (42.BImschV).

Our offer to operators of evaporative cooling plants, cooling towers and wet separators:

• Investigations of the feed water before commissioning of the plant
• Examinations of the feed water within the first 4 weeks after commissioning for selected microbiological parameters (determination of the general colony counts at 22°C and 36°C as well as the Legionella concentration)
• Reference value determination (determination of the general colony counts at 22°C and 36°C for the service water)
• quarterly examinations of the service water (determination of the general colony counts at 22°C and 36°C as well as the legionella concentration)
• if the test or measure values are exceeded, the test interval may be changed