Forum of Ventilators
The xxx:
I was always concerned with the question about the phrase "20 m3/h per visitor, and 60 m3/h per survey. It is ".
And how do you make it so that the service staff gets exactly 60 cubes, and the visitor gets their 20? Or do they give shutters with cybers at the entrance?

YYYY :
You can give anti-gases with a calibrated reducer at the entrance. They breathe on the hole, by counting.