What does "Plenum" refer to in fire safety?

The term "Plenum" in fire safety specifically refers to the space that carries air between the ceiling and the floor above. This area is crucial in the context of heating, ventilation, and air conditioning (HVAC) systems, as it often serves as a passageway for air distribution throughout a building. Because plenums are used to facilitate airflow, understanding their role is essential for fire safety professionals, particularly in relation to fire behavior and smoke movement during an emergency. In the event of a fire, the plenum can become a conduit for smoke and heat, potentially spreading fire beyond its source. Therefore, recognizing the importance of the plenum helps in managing fire risks and ensuring appropriate safety measures are implemented in building design and emergency response strategies.