What type of space is referred to for environmental air-handling purposes above a hung ceiling?

The term used for environmental air-handling purposes above a hung ceiling is "plenum." In this context, a plenum refers to the space that is specifically designed to facilitate the movement of air throughout a building, particularly where heating, ventilation, and air conditioning (HVAC) systems are involved. This space allows conditioned air to circulate and helps return air to the system for heating or cooling, making it essential for efficient climate control.

Plenums are typically located above suspended ceilings and below the structural ceiling. They must be designed and constructed to comply with specific codes to ensure adequate airflow and safety, as they may also carry electrical wiring and ductwork. Proper identification of this space is crucial as it can impact the fire rating, and any materials used in this area must comply with fire safety standards.

Other types of spaces listed, such as restricted space, service space, and utility space, do not specifically refer to air-handling functions. Restricted spaces are more about access limitations, while service spaces generally refer to areas designated for equipment or maintenance. Utility spaces may house building systems but are not primarily intended for air handling. Hence, the identification of the term "plenum" is crucial in understanding the proper classification for spaces used for air distribution above ceilings