Rarely has a line of business been stimulated by a process engineering subject of overriding importance the way clean room engineering has done for various industrial sectors in recent years.  Production under special ambient conditions has been continuously increasing from year to year. 
Quality not only depends on one's production equipment but also to a very great degree on the production environment at hand.  There are special requirements concerning purity and suitability for:

• Atmospheric surroundings
  
• Technical media in solid, liquid and gaseous states
  
• Surfaces
  
• Technical facilities, manufacturing equipment and production processes

Put simply, the aim of clean room engineering is to protect manufacturing processes and the products made by them from even minute impurities.  This means, on the one hand, limiting the particles released during production, and on the other hand, expelling them immediately.  As simple as this might sound, in actual practice an extensive range of not only high-tech but also organisational measures are required.  This starts with building measures, continues with equipment for regulation, ventilation and air-conditioning, and is by far not done with rules for the staff's behaviour.