What indicates that the cylinder is ready for regular use?

A fully charged air supply is a significant indicator that a cylinder is ready for regular use in the context of an SCBA. This means that the cylinder has been filled to the appropriate pressure level, providing the user with the necessary air supply for extended operations. Having a charged cylinder is essential to ensure that firefighters and emergency responders can rely on their breathing apparatus while in potentially hazardous environments.

While a green safety light, basic inspection, and a passed pressure test are all important factors in the overall safety and functionality of the SCBA, they do not alone confirm that the cylinder is adequately prepared for immediate use. For example, a green safety light signifies that the unit is operational, but it does not specifically indicate whether the cylinder is filled to the required pressure. A basic inspection ensures that the equipment is in good condition, and a passed pressure test guarantees that the cylinder structure is sound, but none of these factors ensure an adequate air supply. Therefore, ensuring that the air supply is fully charged is the key readiness indicator for operational use.