Animation

This animation shows how the HVAC system spreads contamination through part of a building. The animation runs at faster than real-time, and shows the spread of gas after a very rapid release of gas (not from a continuous source). The times shown are for the building that is being illustrated — the rate of spread and exhaust depend on the details of the building the ventilation system.

The exhaust damper and mixing box (air intake) at the top of the building are schematic; the actual devices may look different, and may be positioned elsewhere on a building.