User Manual

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Siemens Building Technologies
Cerberus Division
01.2002
2 An introduction to clean room
technology
Clean room technology protects products, processes and the workforce from the harmful
influence of contamination in a clean workplace. It is a key feature of modern production
processes in:
D The semiconductor and microelectronics industry
D Microcircuitry and precision mechanics
D The pharmaceutical industry
D Biotechnology
D The health care and surgical products industry
D Food processing
D Satellite and space technology
D Research and development
D Operating theatres
D etc.
Clean room technology is designed to provide:
D Clean air at the workplace by eliminating extraneous particles
D Clean product and work surfaces as well as packing materials through the use of high-
purity process media (gases, liquids, chemicals).
The cleanliness of the air at the workplace is assured in the following ways:
D Air filtering and air flow control
D Room equipment and structure optimally adapted to the movement of material and per-
sonnel
D Under and overpressure gradation between rooms and types of rooms
D Organization of operational sequences
D etc.
Clean rooms with overpressure or underpressure are based on two fundamentally different
clean room concepts.
Clean rooms
with overpres-
sure
In order to prevent the transport of air contamination from one room
to another (so-called cross-contamination), pressure differences are
maintained between adjacent workrooms. If the room has to be pro-
tected from processes in the surrounding area an overpressure sy-
stem is set up in that room. Clean rooms with overpressure are found
especially in high-tech industries such as the semiconductor and mi-
croelectronics industry, microcircuitry and precision mechanics, sa-
tellite and space technology etc.
Clean rooms
with under-
pressure
If, on the other hand, the surrounding area has to be protected from
extraneous particles released into the air in the workroom (micro-or-
ganisms), then an underpressure system must be set up in that
room. Clean rooms with underpressure are frequently found in the
pharmaceutical and medical industry and similar fields of activity.
However, the monitoring of clean rooms with a fire detection system is very difficult due to
the extremely powerful air handling systems. A basic knowledge of air filtering and flow
control as well as the pressure gradation in clean rooms is absolutely essential.
The examples and recommendations given, apply to clean rooms with overpressure as are
found in the semiconductor and microelectronics industries.
Other criteria apply to clean rooms with underpressure for the planning of air sampling
smoke detection systems.
You will find more detailed information on clean room technology in section 6.