Not too long ago, a mechanical engineer could size the smoke management system for an atrium by simply calculating the volume of the atrium. The building codes were prescriptive when determining the capacity of smoke management systems, and there was never a need to consult with another consultant or specialist.

Today, a more complex set of equations and methodology is mandated by both building and fire codes to determine the design fire size, its resultant smoke generation capacity, and the corresponding size and operation of a building's smoke management equipment.