When a room with a raised or sunken floor is served by a total flooding system, how must protection be applied?

• A. The room and raised or sunken floor must be simultaneously protected
• B. The room only
• C. The raised or sunken floor only
• D. The space under the raised floors only

Answer: (A)

Total flooding requires that the entire protected volume be filled with the clean agent to reach the design concentration. A room with a raised or sunken floor includes an underfloor plenum that is part of the same space the agent must saturate. If protection is applied only to the room, the underfloor plenum can remain unprotected or become a bypass path, preventing the agent from achieving uniform concentration throughout all areas. If protection were only for the underfloor space, the occupied room could still harbor insufficient agent levels. To guarantee complete, uniform distribution and avoid pockets of lower concentration, protection must cover both the room and the raised or sunken floor simultaneously.