What is the function of the yellow disk in a CO2 fire extinguishing system?

The function of the yellow disk in a CO2 fire extinguishing system serves as a system discharge indicator. This disk provides a visual cue to operators and maintenance personnel about the status of the fire extinguishing system. When CO2 is discharged from the system, the yellow disk is designed to release or change in some manner to indicate that the system has been activated and the agent has been expelled.

This feature is crucial for safety and operational purposes. It allows easy identification of whether or not the system has been used in a fire emergency, which can inform maintenance decisions and ensure that the system is recharged and made ready for future use.

The other options, while relevant to fire suppression systems, do not accurately describe the primary function of the yellow disk. Monitoring pressure levels, indicating system operational status, or displaying expiry dates are separate functionalities that may be provided by other components of a fire extinguishing system.