How large is the CO2 symbol?

The CO2 symbol is standardized to be an 18-inch white circle. This size ensures visibility and consistency across various contexts, particularly in aviation environments where clear identification of emergency equipment is crucial. The 18-inch diameter allows for the symbol to be easily recognized from a reasonable distance, which is essential in emergency situations where quick action may be needed. The standardization of such symbols aids in safety and compliance, ensuring that personnel can reliably identify and respond to equipment like carbon dioxide fire extinguishers, which play a vital role in fire suppression in aviation settings.