Steam sterilization is a commonly used means of eliminating bacteria, fungi and other transmissible agents. Autoclaves are used in many different fields, for many different applications. Examples include: microbiology laboratories, research laboratories, hospital sterilization suites, pharmaceutical industry, food processing, dental offices, tattoo parlors and beauty salons.
Under ordinary circumstances (at standard pressure), liquid water cannot be heated above approximately 100°C. In autoclaves, water is heated in a pressurized vessel, and can reach higher temperatures. In order for the sterilization to be efficient, air must be removed from the chamber. This may be achieved by gravity displacement or by first generating vacuum in the chamber. Sterilization occurs by direct contact of the pure dry steam with the material. In case of materials that are wrapped (such as, for example, surgical instruments), the autoclaving time must be longer than for unwrapped objects. Commonly used autoclaving conditions are: 121°C for 15 min; or 134°C for 3 min.