At what pressures do the first and second low-pressure warning alarms occur?

The first and second low-pressure warning alarms are designed to alert the mine rescue team about decreasing air pressure in breathing apparatus, which is critical for their safety during operations. The correct choice indicates that the first low-pressure warning alarm occurs at 55 bar, and the second at 10 bar.

This is significant because the first alarm (55 bar) gives responders an early warning that they need to monitor their air supply closely. The lower second alarm at 10 bar serves as a final alert, prompting immediate action to either exit the hazardous situation or replenish air supplies.

Understanding these pressure thresholds is vital for ensuring the safety and effectiveness of rescue operations, as it allows miners and rescue personnel to operate within safe limits and respond adequately to air supply concerns.