How long can an SSR last during moderate physical activity at a draw of 30L/min?

The duration that a Self-Contained Self-Rescuer (SSR) can last during moderate physical activity depends on its design and the rate of oxygen consumption by the user. At a draw of 30 liters per minute, it is crucial to understand the specifications of the SSR being used.

Typically, SSRs are designed to provide breathable air for a certain amount of time during emergency situations, which includes consideration for moderate physical exertion. In this case, SSRs generally can sustain use for about 90 minutes when engaged in moderate activity at a consumption rate of 30 liters per minute. This duration takes into account both the volume of breathable gas stored in the device and the metabolic rate of the user during physical exertion.

Aside from the correct choice, the other options suggest either an overestimation or underestimation of the time the SSR can function effectively at that draw rate, which would not align with the operational guidelines established for these devices. Understanding the performance metrics and limitations of SSRs is essential in ensuring the safety and preparedness of miners in emergency situations.