With the codification of smoke control, the central air-handling system now also has a smoke system mode. Many tests and evaluations of actual fire-fighting experiences conclusively show that with little reengineering, the HVAC system can provide very effective, low-cost smoke and fire safety and can aid fire fighting. Economical integration of suppression systems and smoke control is now the state of the art. In some spaces, where cooler smoke is likely, smoke control may be at least as and dampers that were important for life and property protection as sprinklers. Selective pressurization around the fire zone now requires fans that are left on originally designed to function in point-of-origin fire conditions. Evolving from only physically blocked heat containment in compartments to smoke containment by air pressure for the estimated 30-minute maximum evacuation period requires additional damper operations, which can adapt to the preexisting air system type actuators and controls.

One new multifunctional type damper can mean damper cost reductions, as it displaces possibly three separate air control, fire, and balancing dampers. It would have acceptable airflow and control characteristics while providing elevated temperature low-leakage capability through the smoke control phase and, as necessary, making the transition to the fire damper mode. It is desired that all the dampers (operating with power sources intact) would then operate to provide smoke purging.