Design Calculation of Cleanroom
Both the uniform and nonuniform distribution theories of cleanroom have been introduced. In order to meet the need of practical application, the method and procedure of specific analysis calculation will be given in this chapter.
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Design Calculation of Cleanroom
Both the uniform and nonuniform distribution theories of cleanroom have been introduced. In order to meet the need of practical application, the method and procedure of specific analysis calculation will be given in this chapter.
13.1
Determination of Indoor and Outdoor Parameters for Calculation
13.1.1 Atmospheric Dust Concentration Through the discussion about atmospheric dust in Chap. 2 and the at-rest state characteristics of the cleanroom in Chap. 12, the following two points should be clear: 1. Generally, the corresponding atmospheric dust concentrations for three typical areas at present are 0.75 105 #/L, 105 #/L, and 2 105 #/L, respectively. The highest is about 106 #/L, which is the concentration with the situation of most severe pollution. Since the beginning of this century, the concentration reduces about one third. 2. For the cleanroom with air cleanliness level equal to or lower than Class 100, when the atmospheric dust concentration is under 106 #/L, the effect of the variation of this concentration on the particle concentration in the cleanroom can be ignored. Therefore, the atmospheric dust concentration for design of cleanroom can be determined as follows: (1) For HEPA cleaning system with air cleanliness level equal to and higher than Class 5, in order to ensure the safety of the cleanroom in whatever outdoor situations (except the situation with extremely severe pollution), the design value of atmospheric dust concentration ought to be M ¼ 106 #/L. When three-stage Z. Xu, Fundamentals of Air Cleaning Technology and Its Application in Cleanrooms, DOI 10.1007/978-3-642-39374-7_13, © Springer-Verlag Berlin Heidelberg 2014
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Design Calculation of Cleanroom
filtration systems are placed on the passage of fresh air (see Chap. 12), the local specific atmospheric dust concentration can be used for calculation. As for the atmospheric dust concentration for HEPA cleaning system, there is no single value given explicitly in foreign literatures, and it was pointed out that the variation results in the inconvenience of the design process. However, the single value 106 was suggested in the past by author (see the research report “Calculation of cleanroom” printed in 1977 at Institute of HVAC, China Academy of Building Research), which brings convenience for design calculation and also has high safety coefficient. When the explicit single value of atmospheric dust concentration is given for the HEPA cleaning system, there is no need to search for the data in this aspect. (2) For a non-HEPA cleaning system, it is not economic to use M ¼ 106 #/L for design since the atmospheric dust concentration affects the concentration of cleanroom a lot. It is better to choose the actual concentration. Of course, filtration of fresh air should be strengthened. This chapter will not repeat discussing other problems about atmospheric dust.
13.1.2 Particle Generation Rate per Unit Volume of Indoor Air 13.1.2.1
Indoor Particle Source
The main generation sources of indoor
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