The autoclave is a machine that will sterilize all contents. Sterilization refers to a total eradication of all life forms; including all endospores, all viruses, all prokaryotic and eukaryotic cells. After the autoclave has finished it's work, there will be no contagion or any other life form present. The formula:

PV = nRT

reveals the mechanism by which it works. n and R are constants, and do not change. When the door is closed the volume of the autoclave compartment does not change. Therefore, as the temperature increases, the pressure increases.

Moist heat is applied until the chamber reaches 15 lbs /sq inch. At this pressure the temperature will have reached 121°c. If the contents of the chamber are in contact with this temperature for 15 minutes, the items held within will be sterile and therefore safe for disposal or reuse.