The autoclaves work at different temperatures and pressures depending on the height of the canning plant. For example, at sea level, an autoclave heated to 120°C (248°F) will have a gauge pressure of 14.1 PSI. However, at 1219 meters (4000 feet) above sea level, at the same temperature of 120°C (248°F), the autoclave pressure gauge will register a pressure of 16 PSI.
In the case of overpressure autoclaves, the pressures inside the equipment may be higher. For example, at 120°C (248°F), they can reach 28 PSI. These autoclaves are used to thermally process canned and other soft packaging, such as pouches, jars, plastic and cardboard, and typically use atomized, cascade or flood water.