What is the flowrate of the minimum valve used in mine rescue operations?

In mine rescue operations, the minimum flowrate of the valve is crucial for ensuring that rescuers have an adequate supply of breathable air while navigating hazardous environments. The correct flowrate often specified for mine rescue is 80 liters per minute. This rate is established to meet the oxygen demands of an individual working in potentially life-threatening conditions, where rapid and efficient breathing can be vital for survival.

A flowrate of 80 L/min provides a balance between ensuring enough oxygen is supplied and managing the amount of air available for a sustained period. This is particularly important in emergency scenarios, where rescuers may exert themselves physically, thus increasing their oxygen needs.

The other flowrates suggested, such as 50 L/min, may not deliver sufficient oxygen in high-stress situations, while higher rates like 100 L/min or 120 L/min, though theoretically adequate, can lead to inefficiencies, increased weight, and bulkiness of the equipment, making it less practical for the rapid response required during mine rescues. Therefore, 80 L/min is deemed the optimal minimum flowrate for effective mine rescue.