Recent studies, on the airborne transmission of the SARS-CoV-2 and the new CDC guidelines confirming the aerosol transmission of the virus, make immediate attention to the airflow in elevators imperative. While several versions have been thought of for contactless rides, there is little that has been considered for lessening the anticipated viral load in the elevator car.
In this paper, a two-step approach is used. The first is the risk assessment, and the second is the risk mitigation through an improved lift car ventilation design. The risk is assessed by computing the probable viral load during the journey in a lift car. It is seen that the ventilation typically provided as per the minimum permissible requirements by codes is inadequate to handle the current situation.
The computations show that one-minute exposure, to a coughing high emitter in the lift car, creates a viral load to dangerous levels well above the possible acceptable level of 10,000 virus copies/m3. To come up with the risk mitigation strategies, the required ventilation in the car was computed. The main recommendation suggests the use of forced ventilation using pressure fans and 3 to 6 air changes per minute depending on the operating environment. Such a design will help us achieve our objective of bringing the density of virus copies in the lift car to an acceptable level. A properly designed ventilation system for the elevator car will benefit in both pandemic situations as well as non-pandemic situations.