Health based IAQ design: Comparison among different approaches

Politecnico di Milano, Energy Department, 20156 Milan, Italy

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Abstract

In designing any system that must achieve and maintain a certain indoor air quality (IAQ), a ventilation system or an air cleaning system, it is necessary to know the required clean air flow rate they must provide, where clean air means free of pollutants. Herewith a methodology is provided for defining the minimum clean air flow rate able to keep the infection probability due to a pathogen presence below a target value. A program has been developed to calculate such target values for any available pathogen infectious capacity, expressed in quanta, which allows us to specify all boundary conditions, such as the activity and activity level of both infectious and susceptible individuals, their numbers, the room size, etc. At the same time several others standardised air quality design method as described in EN 16798-1, ASHARE 62.1, ASHARE 241 have been employed to check the difference in the required clean air flow rate between them and the health-based approach. What emerges from a preliminary analysis carried out using such tool is that if we constrain the comparison to the most common and frequently spread virus, seasonal influenza, the design flow rate required by the perceived IAQ method is enough in several cases.