What is the general principle of the SCSR?

The general principle of the Self-Contained Self-Rescuer (SCSR) is that oxygen is supplied to the wearer while exhaled carbon dioxide is absorbed. This mechanism is critical for ensuring the safety of miners in an emergency situation where the atmosphere may become unbreathable due to smoke, toxic gases, or lack of oxygen.

The SCSR contains a supply of oxygen that is available to the user, allowing them to continue breathing safely for a limited period of time. At the same time, the device has a means to absorb carbon dioxide, which is produced by the wearer's respiration. This absorption is crucial to prevent the build-up of carbon dioxide in the enclosed space, which can lead to unconsciousness or suffocation.

This principle distinguishes the SCSR from other systems that focus on different methods of gas safety. For example, options that mention combustion or filtration do not capture the essential function of supplying breathable oxygen and removing exhaled carbon dioxide, which is the primary operation of an SCSR.