A breathing apparatus simulator unit (BASU) comprises a mouthpiece/noseclip subassembly and a cartridge subassembly. The mouthpiece/noseclip subassembly includes the same mouthpiece/noseclip subassembly that is utilized in an actual self-contained self-rescuer (SCSR) device. The cartridge subassembly comprises a container containing a reactionary material. The reactionary material reacts with at least one product of a user's exhalation to generate heat and resistance, thereby providing sensations to simulate the use of an actual SCSR.