How fast does the fog fill a space? The Density 900 will fill 735 sq ft with a 12 ft ceiling in 10 seconds. The Density 2400 will fill 1,030 sq ft with a 12 ft ceiling in 10 seconds. By Admin|2021-11-30T03:52:02+00:00September 27th, 2021|Security Fog| Share The Virtual Reality Post! FacebookXLinkedInEmail