Hi Yellowbird
I agree I don't know how teaching facilities can work without proper ventilation.
Not sure what you mean by "first photo with the fan"?
This is the link to the pictures of my fan
https://www.facebook.com/photo.php?f...70195476525497
and here the label with the tech details
https://www.facebook.com/photo.php?f...70195479858830
I think 1 m³/h = 0,58867 CFM
Just as an example: If the room is 6 by 2 meters with a height of 2.5 meters (1 Meter = 3.2 foot) which is 30 m³
Using my fan with full power would exchange the air in the room 40 times per hour or every 1.5 Minutes. Even if ducting etc. will reduce this, it will we sufficient. You shouldn't do that in Winter, when it is cold outside, because if you transport the air outside the building, the same amount of fresh/cold air will replace it in the room.
PerlenFlo