Managing the dust balance in clean rooms (clean room filters)
1993
Feliers, R. (Camfil, Brussels (Belgium))
The principal parameter characterizing a clean room is the dust level. Dust levels are internationally standardized and should permit to improve the product quality and to make a production process more efficient. The lay-out of the production lines, the concept of the room, the inventory of the dust generators, the aerodynamic function and the discipline of the individual workers in the room determine the property of each clean room. Putting the above mentioned parameters into a mathematical model makes it possible to simulate the cleanliness level that shall be obtained. Terms such as "cleansing - decontamination - recontamination cross contamination - dust level" are clearly defined in the simulation. Varying the different parameters has an influence on the dust level and gives a clear look into the dynamic function of the system when changing i.e. the number of air changes or the number of people working in the clean room. Simulation permits to define the values necessary to reach a cleanliness level and it also permit to fix the limits of use within which the dust level will be under control. The computer model is not only useful to set up a new clean room, it also helps restore the balance when it should be disturbed after a certain running time. When a cleanliness level is no longer reached, the parameters from the simulation report can be checked in order to recover the cleanliness class without extra cost for expertises or analyses. Calculations made with in situ values will give the same results as those obtained with the simulation, as far as the preliminary information given by the customer is clear enough to put real values in the simulator.
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