To limit the probability that main entrance doors will have inadequate control of air leakage, which could lead to transfer of air or air contaminants induced by air pressure differences in vestibules.
This is to limit the probability of the generation of pollutants from biological growth or from materials that become unstable on wetting, which could lead to negative effects on the air quality of indoor spaces.
This is to limit the probability of harm to persons.
To limit the probability that main entrance doors will have insufficient protection against the ingress of insects and vermin, which could lead to unsanitary conditions.
This is to limit the probability of negative effects on the air quality of indoor spaces, which could lead to harm to persons.