The mass application of antibiotics and extensive use of chemical disinfecting methods has had led to a whole list of problems. Bacteria has become resistant and in general people have side-effects and follow up problems.

The growing awareness of hygiene has now borne fruits with the corresponding guidelines and laws like the HACCP (Hazard Analysis and Critical Control Point) or the German norm VDI 6022 (Hygienically Focused Planning, Design, Operation and Maintenance of HVAC Systems). With the limitations of chemical disinfecting in certain areas the UVC disinfecting technologies have again today their renaissance.