Every space protected by a CO2 system that is normally occupied must have what feature?

When considering spaces that are protected by a CO2 fire suppression system, it is essential to prioritize occupant safety, especially since CO2 can displace oxygen in a space, leading to potential asphyxiation. An audible warning device is crucial in such areas because it alerts occupants to evacuate before the CO2 system is activated. The sound serves as a clear signal that a fire hazard exists and that an immediate response is necessary to ensure their safety.

In contrast, while automatic sprinkler systems, manual pull stations, and emergency lighting are important safety features in various contexts, they do not directly address the specific needs of spaces protected by CO2 systems. The audible alarm specifically communicates a need for immediate action due to the hazardous conditions created by CO2, which is not something that the other features effectively accomplish in this scenario. Therefore, having an audible warning device in spaces that are normally occupied and protected by a CO2 system is a critical safety measure.