Air duct design in cleanrooms

Definition of clean room in ISO standarts is, "A room in which the concentration of airborne particles is controlled, and which is constructed and used in a manner to minimise the introduction, generation, and retention of particles inside the room and in which other relevant parameters, e.g. temperature, humidity, and pressure, are controlled as necessary". To provide these conditions air quality is the most important thing in clean rooms. That's why design and implementation process of the ventilation system is extremely important. This study starts with the explanation of clean room concept and terms. Later definitions in automatic control systems are told and automatic control types are considered. In the last part of the first section general sound information is given. In the next section the importance and reason of the pressure control are explained in clean rooms.Single blade dampers' work priciples and their usage results are considered which are used to ensure this systems. After that, for critical environments which single blade damper can not provide a good solution, an alternative device "venturi air valve" is considered. After that a duct design in a pharmaceutical factory is considered. In the last section, to see the acoustic effects of this ventilation system in the spaces, air handling unit-1 supply duct's sound generation is considered with an acoustic calculation. In this study two different calculations are completed. First calculation is done with single blade damper with silencer. In second calculation single blade damper is replaced with venturi air valve with silencer.