However, the commissioning of the new central security checkpoint has given rise to previously unknown problems with electrostatic discharges. Employees have complained extensively about unpleasant electric shocks, particularly at the roller tables used to transport luggage. After intensive analysis of possible causes, low humidity in the new building was identified as the decisive factor. Measurements showed that the steam humidification in the supply air of the ventilation and air conditioning system, with a regulated relative humidity of 30 percent, was insufficient. Only at a constant relative humidity of 40 percent or higher does a natural, conductive moisture film form on poorly conductive materials such as rubber or plastic. This also makes the insulating surfaces of the roller tables more conductive. Friction contact during baggage transport and subsequent separation then allows a complete exchange of charge between the materials without dangerous charging and painful electric shocks. “Once we knew how to solve the electrostatic problems, we decided in 2018 to retrofit additional air humidification. The positive effects on well-being and health were further arguments in favour of this,” says Thomas Harrer, summarising the situation at the time.

Since 2019, 37 TurboFog high-pressure nozzle humidifiers have been in use at the security checkpoint at Albrecht Dürer Airport Nuremberg. The systems, which are suspended from the hall ceiling, are individually positioned above the check-in area and baggage conveyor. The micro-fine mist with a droplet size of less than 15 μm is achieved by high-pressure technology that forces the water through high-performance nozzles at an operating pressure of up to 85 bar. Compared to compressed air-powered nozzle or steam humidifiers, only a fraction of the energy costs are incurred. In addition, the adiabatic cooling effect of cold water evaporation ensures a pleasant indoor climate: 100 litres of water from high-pressure nozzle humidification absorb around 70 kW of heat with an energy consumption of only 0.6 kW. The desired minimum humidity of 40 percent is regulated by room sensors that continuously monitor the climate situation in the security control area and ensure a consistently constant humidity level. The high-pressure humidifiers are activated precisely when the setpoint value is not reached. The new system was connected to the BACnet building management system via Modbus, so that all operating conditions can be monitored at all times and the humidity levels can be recorded.