What does the term 'plenum' refer to in HVAC systems?

The term 'plenum' in HVAC systems refers to a compartment connected to ducts. In building ventilation, a plenum is an air distribution space that allows air to flow between the heating, ventilation, and air conditioning systems and the occupied spaces within the building. It typically functions as a passageway for conditioned air from the HVAC system to reach different parts of the structure. In addition to serving as supply plenums that distribute air to various spaces, there are also return plenums that collect air from those spaces to be cycled back into the HVAC system.

Understanding the role of plenums is crucial in high-rise fire safety, as these areas can also influence smoke control and air movement during a fire emergency. Proper design and management of plenums can help mitigate smoke spread and enhance the effectiveness of fire protection systems.