Page 16 - ISCC'22
P. 16

                    October 11-13,   ON CONTAMINATION CONTROL AND
           Antalya TURKIYE  |  2022  CLEANROOM TECHNOLOGY

                                Necessary for set-up
                                f   2 lifting device (scissors lift)
                                f   Assembly time: appr. 1 working day; 3 persons
                                f   Framework structure + fabric
                                f   4 CAPE-modules, 400 kg each; 12 FFUs, 80 kg each
                                2. VARIANTS DUE TO THE AIR FLOW TECHNOLOGY USED
                                Depending on whether the product to be manufactured or processed must be kept
                                clean, or whether the product poses potential hazards to the environment outside the
                                cleanroom system, different air pressure conditions must be built up compared to the
                                surrounding environment.
                                Positive pressure mode
                                For most applications of cleanroom technology, such as for the semiconductor industry,
                                an overpressure to the environment is built up inside the cleanroom system. This has
                                the advantage that contaminants from the environment cannot penetrate into the
                                interior, as the higher interior pressure prevents this (see figure 4, left side).

                                Negative pressure mode
                                If, on the other hand, active substances or samples that are potentially harmful to the
                                environment are processed, as is common in the pharmaceutical industry, for example,
                                the interior area must be operated with a slight negative pressure compared to the
               CAPE –           surrounding environment( see figure 4, right side). In the CAPE system, this constellation
                                ensures that air can flow in through the open textile walls and that no environmentally
                                harmful particles can escape through the textile walls to the outside. The FFUs, which
                                are mostly connected − by means of wall ducts − close to the floor and flanged to the
         CLEANROOM              outside of the CAPE, must be used with high-end filter systems to retain particulate
              SYSTEM            and chemical contaminants. If biological material is also used, e.g. UVC irradiation to
                                remove viruses, microorganisms, bacteria, etc., an irradiation unit of suitable dimensions
                                and irradiation characteristics must be implemented in the exhaust airflow. This unit
                                must be connected after the air has passed through the CAPE, i.e. after the air has
                                left the CAPE and before it enters the FFU. If the filters are intact, the exhaust air from
                                the FFU can be blown off into the ambient air or fed to a higher-level disposal system
                                via a piping system.

                                Figure 4; Left side: the design sketch shows the overpressure mode. Right side: the
                                design sketch shows the negative pressure mode in combination with UVC irradiation.
                                Circulating air mode
                                For highly efficient and cost-reduced operation, a set-up is recommended that allows the
                                recirculation mode (see figure 5, left side). Here, the majority of the air is not constantly
                                cleaned from the very high outdoor concentrations to the very low indoor concentrations,
                                so that in recirculation mode only relatively small air volumes need to be cleaned. The
                                facts described above for the operation of the system with biologically active material
                                also apply here, that an integration of e.g. UVC irradiation units can be realized into
                                the recirculation system.
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