Before donning SCBA, what safety check should a crew member perform?

When preparing to don a Self-Contained Breathing Apparatus (SCBA), it is crucial to ensure that the regulator gauge and cylinder gauge read within approximately 10% of the same pressure. This check is essential because it confirms the integrity of the air supply system. A discrepancy between the two gauges might indicate a malfunction, such as a leak in the system or issues with the regulator, which could compromise the user's ability to breathe safely while fighting a fire or in a hazardous environment.

Verifying that both gauges are aligned ensures that the crew member has a reliable air supply, critical for safety during firefighting operations. If the gauges are not within this range, it may mean that the cylinder is not full or that the breathing apparatus is not functioning properly, which would be a significant risk in an emergency situation. This check is a fundamental part of SCBA safety protocols, ensuring personnel can rely on their equipment when they need it most.