You enter a building, the doors slide open- you walk about 16 feet and another set of slideing doors open. The glass room is about 16'x16'. It has supply air enering it from a stainless steel floor grating.
You are now in the building. You leave the same way. This is a public entrance to a hospital. Would it be a) vestibule-b)air lock-c)anteroom?
A link with your response would be nice. I say anteroom. the other 2 answers are what two others say.