In spaces protected by a carbon dioxide system, what must be present for crew safety?

In spaces protected by a carbon dioxide (CO2) suppression system, an audible warning device is essential for crew safety. The reason this is critical is that CO2 systems work by flooding the space with carbon dioxide to displace oxygen and extinguish fires. This rapid change can create an immediate hazard for anyone present in the area, as the environment quickly becomes unsafe for human respiration.

The audible warning device serves as an important alert mechanism. It notifies personnel of the activation of the CO2 system, giving them the necessary warning to evacuate the area before the discharge occurs. This device enhances situational awareness and allows crew members to take appropriate actions to ensure their safety.

While other options, such as an emergency exit, manual override switch, or ventilation fans, contribute to safety in different contexts, they do not specifically address the immediate dangers posed by the deployment of a CO2 system in a timely manner. The primary function of the audible warning device is to ensure crew members are aware of the hazardous conditions created by CO2 flooding, making it a vital component of safety measures in these protected spaces.