Page 16 - ISCC'22

25 th INTERNATIONAL S YMPOSIUM
October 11-13, ON CONTAMINATION CONTROL AND
Antalya TURKIYE | 2022 CLEANROOM TECHNOLOGY
16

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
FLEXIBLE,
harmful particles can escape through the textile walls to the outside. The FFUs, which
PORTABLE,
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.