An autoclave is a pressurized steam sterilizer. It is used to sterilize surgical instruments, lab equipment, or other items that may be contaminated with microorganisms. An autoclave applies pressure and heat to water to create superheated steam that is able to kill potentially pathogenic microorganisms. The parameters for effective sterilization specify a steam temperature of at least 250 degrees F (121 degrees C) and a pressure of at least 15 to 20 psi. The time required to sterilize an item depends upon the amount of contamination as well as the temperature and pressure applied.