In a fixed fire-extinguishing system, what does the missing yellow indicator disc signify?

In a fixed fire-extinguishing system, the absence of a yellow indicator disc signifies that the system has normally discharged. This indicator is designed to provide a visual cue regarding the status of the system. When the disc is missing, it indicates that an intentional discharge of the fire suppression agent has taken place, meaning the system has successfully done its job in suppressing or extinguishing a fire.

The yellow indicator disc is crucial for maintenance personnel and safety officers to quickly assess the status of the fire suppression system. A missing disc serves as an alert that action may need to be taken, such as refilling or resetting the system, but it primarily indicates that the system has functioned as intended during a fire event.

This concept is important within the context of safety and emergency response protocols in powerplants, ensuring that fire detection and suppression systems are appropriately monitored and maintained for continued effectiveness.