The quality of standard process steam is not sufficient for the sterilization of installations in the pharmaceutical industry because the portion of contaminants, particles, hydrazine, phosphates and similar components (corrosion inhibitors) is too high. A special process steam must be used for drugs in compliance with relevant regulations e.g. FDA (Food and Drug Administration). This process steam must not contain any of these components and in addition it must be free from volatile matters which cannot be removed by filtration.