industry are grown in autoclaves. Packing of parachutes for specialist applications may be performed under vacuum in an autoclave, which allows the chutes to be warmed and inserted into their packs at the smallest volume. A thermal effluent decontamination system functions as a single-purpose autoclave designed for the sterilization of liquid waste and effluent. Air removal It is very important to ensure that all of the trapped air is removed from the autoclave before activation, as trapped air is a very poor medium for achieving sterility. Steam at can achieve a desired level of sterility in three minutes, while achieving the same level of sterility in hot air requires two hours at . Methods of air removal include: Downward displacement (or gravity-type) As steam enters the chamber, it fills the upper areas first as it is less dense than air. This process compresses the air to the bottom, forcing it out through a drain which often contains a temperature sensor. Only when air evacuation is complete does the discharge stop. Flow is usually controlled by a steam trap or a solenoid valve, but bleed holes are sometimes used. As the steam and air mix, it is also possible to force out the mixture from locations in the chamber other than the bottom. Steam pulsing air dilution by using a series of steam pulses, in which the chamber is alternately pressurized and then depressurized to near atmospheric pressure. Vacuum pumps a vacuum pump sucks air or air/steam mixtures from the chamber. Superatmospheric cycles achieved with a vacuum pump. It starts with a vacuum followed by a steam pulse followed by a vacuum followed by a steam pulse. The number of pulses depends on the particular autoclave and cycle chosen. Subatmospheric cycles similar to the superatmospheric cycles, but chamber pressure never exceeds atmospheric pressure until they pressurize up to the sterilizing temperature. Stovetop autoclaves used in poorer or non-medical settings do not always have automatic air removal programs. The operator is required to manually perform steam pulsing at certain pressures as indicated by the gauge. In medicine A medical autoclave is a device that uses steam to sterilize equipment and other objects. This means that all bacteria, viruses, fungi, and spores are inactivated. However, prions, such as those associated with Creutzfeldt–Jakob disease, and some toxins released by certain bacteria, such as Cereulide, may not be destroyed by autoclaving at the typical 134