When should an SCBA cylinder typically be replaced?

An SCBA (Self-Contained Breathing Apparatus) cylinder should typically be replaced during inspection if it contains less than 90% of its capacity. This guideline is rooted in safety and operational effectiveness. Maintaining a sufficient air supply is crucial for firefighters, as being caught in a situation with inadequate air could lead to life-threatening consequences. Ensuring that the cylinder has at least 90% of its capacity before use helps guarantee that personnel can perform their duties safely without the risk of running out of air while in hazardous conditions.

This proactive measurement is part of standard safety protocols, ensuring that all equipment is maintained to the highest safety standards. An SCBA cylinder that's below this threshold may not provide adequate air supply for the duration of its intended use.

The other options do not align with safety practices established for SCBA usage. For example, replacing a cylinder after every use could lead to unnecessary waste and cost, as many cylinders may have more usable air left. Replacing it once a year regardless of capacity can be wasteful as well, potentially discarding cylinders that are still functional. Similarly, waiting until the gauge indicates half full does not provide an effective measure for ensuring adequate air supply and could jeopardize the safety of the user.