What is fully ducted as used in NFPA?

In the context of the National Fire Protection Association (NFPA) standards, "fully ducted" refers to a system where air is transported exclusively through ducts, as opposed to using a combination of ducts and open spaces. This design is critical for ensuring proper air management, smoke control, and fire protection in buildings. Fully ducted systems help in maintaining smoke-free environments during a fire event by efficiently directing smoke and heat to designated areas. This concept is often applied in fire protection systems, HVAC, and smoke control systems.