In illustration D035SA below, viewing the bridge level of your vessel's fire control plan, what do the two symbols within the machinery casing represent?

Correct Answer: Option A — CO2 and Halon protected spaces

Enclosed boundary symbols inside the machinery casing on bridge deck fire control plans delineate spaces protected by total flooding CO2 and Halon fixed fire-extinguishing systems. These boundaries ensure airtight containment required for effective gaseous smothering agent concentrations.