Which statement about raised or sunken floors under a total flooding system is true?

• A. The space under raised floors only must be protected
• B. The room only must be protected
• C. Both the room and the raised or sunken floor must be protected simultaneously
• D. Neither requires protection

Answer: (C)

Total flooding aims to saturate the entire protected volume with the design concentration of clean agent. When a floor is raised or sunken, it creates a floor void that communicates with the room and can harbor air or resist mixing if left out of the flooding design. To ensure the agent reaches every part of the protected space, the room and the floor void must be flooded together, treated as a single volume. Protecting both simultaneously prevents pockets of under- or over-concentration, which could compromise the system’s effectiveness. In practice, this means the design accounts for the floor void in addition to the room, so the agent distributes throughout the entire space.