Monitoring air quality in lift cars with CO2 sensors

To reduce the risk of Corona infection in lifts, RST Elektronik has developed the IMC-2 Pro Air, which permanently monitors the CO2 concentration in the car by means of a new sensor technology.

By Michael Maas

An important indicator for the risk of COVID-19 infection risk is the CO₂ content in the air, since it reflects the quantity of exhaled infectious aerosols. A study by the TU Berlin on the risk evaluation of virus-contaminated aerosols determined a high air exchange can reduce both CO₂ as well as the aerosol concentration. This also lowered the risk of infection, according to the study (see Risk evaluation of virus-contaminated aerosols on the basis of CO₂ concentration of virus-contaminated aerosols (tu-berlin.de) retrieved on 15.12.2021).

The CO₂ traffic lights in schools or offices operate on this principle. They optically indicate the respective limits of the CO₂ concentration in the air with the colours red, orange and green and announce when ventilation is needed.

Due to their low air volume, closed rooms, which include lift cars, involve a special risk of infection, (see Infectious aerosols in interiors | German Environmental Agency retrieved on 15.12.2021).

Operators often react to this by reducing the number of users, but this unavoidably reduces the lift’s conveyance performance. Moreover, many lift users nevertheless retain a certain anxiety regarding infection.

Lowering CO₂ concentration

Photo: © RST Elektronik GmbH

This is why RST Elektronik decided to develop a solution for lift builders. The result was the IMC-2 Pro Air. In combination with the IMC-2 PRO 2 lift controller from RST Elektronik with an adjustable CO₂ advance warning threshold, controller-related measures, such as phased increase of the open-door times, are carried out to improve the air quality in the car.

Upon exceeding a set maximum value, the car can travel to a “ventilation stop” where it remains with open doors until the CO₂ value has fallen below the limit. Additional fans or shaft ventilation flaps can be activated via a digital output. The current CO2 concentration is shown in the TFT display for the information of the passengers and if so desired can also be colour highlighted.

Guaranteeing barrier freedom

To ensure barrier-freedom, the hazard level and instructions to the passengers can be provided to the passengers at every stop or upon reaching limits via a voice announcement. To achieve an optimal measurement result, there is the additional option of recording the air quality at different points in the lift shaft.

The IMC 2 lift controller and controller add-on IMC-2 PRO Air can be linked to numerous products on the market, which rid the cabin air of viruses in various ways. Thanks to the flexibility and versatility of the IMC 2 products, project-related adjustment and system expansion is achievable at any time.

The author is the head of controller projects at RST Elektronik.

More information:rst-elektronik.de