Clean room system

Astronet co., Ltd. specializes in design consulting, construction and installation of clean room systems in the factory.

The clean room is a room in which the concentration of suspended particles in the air turn and it was built and used in a texture so that presence, the produce and maintain the seeds they are reduced to a minimum and other factors such as temperature, humidity , the pressure can control and controls ".
1.Select the filter clean filtered gas-level 
principles According filter, to filter through 3 clean rooms have filtering levels: 
First: Filter Primary G2, G3, G4 Standard EN779, filter out larger particles size 10 microns, this kind should choose G4 can use cotton dust filter G4 
Secondly secondary filter as standard EN779 F5-F8-filtering 0,5micron particle size should be choose F8. These filter bags 
Third: Selection HEPA & ULPA 
Class 100,000 (Level D according to GMP) choose HEPA H13 
Class 10,000 (Level C according to GMP) selected H14 HEPA filtration levels. 
Class 1000 to 100 (Level A & B) selected ULPA Filter U15 level 
Class 1 to 10 selected ULPA Filter U17 level. 
Note: 
The total pressure loss across 3 levels of filtering approximately -1000 Pa 800Pa. attention when choosing pressure blower through filtration column.

          

2.Select wind flow air filter according to 
formula I have clean air flow required for system 
Q = V x AC in which 
Q: clean air flow to the system (m3 / h) 
A / C: (Air change) number of air changes / hour 
V: (Volume) clean room volume 
at each filter are recorded flow (capacity) filter. Thus the amount of filtering should use = Q / flow filter. 
For example: 
I have = W x D cleanroom x H = 5 x 4 x 2 = 40 m3 
Hits changed at the request of 25 times / hour 
Flow need filters in 1 hour = 40 x 25 = is 1000m3 / h (Flow filter to choose must be greater than 1000m3 / h) 
according to the standard size and the secondary filtration is: 
Size: 12 "x 24" x thickness = 1700 m3 / h 
Size: 20 "x 24" x thickness = 2800 m3 / h 
Size: 24 "x 24" x thickness = 3400m3 / h. 
So we choose one primary G4 size 12 x 24 x 2 "and 1 secondary filter F8 size 12 "x 24" x 21 "mm. 
Select if the level is Class 100,000 clean wind speed at the request oral 0.5m / s, we choose a HEPA filter, H13 x 1219 x 610 size 66mm , flow of 1205m3 / h or 610 x 610 x two filter flow 66 603m3 / h
In the absence of required wind speeds, we only choose 1 HEPA 610 x610 X150, H13, flow 1305m3 / h is given. 
The communication Some consider when selecting HEPA filter: Flow filter = section x velocity. If the wind speed requirement is 0.45m / s at the mouth filter traffic by filtering tandard of the following: 
The size and flow of HEPA standards 
If the wind speed is 1m / s and 2.5m / s (applies at AHU), the flow will change. Wind speed the greater the total cost for the lower filter and vice versa. But in reality people often choose mouth-level wind speeds at about <1m / s. If the wind speed is high, dust itself in the room and to affect levels of cleanliness. Request type wind speed 0.45m / s, the usual initial pressure drop <= 150Pa.The other type is 250 Pa. Sinking affect their original lifespan, flow and cost of filtration.

          

3.Cleanroom Standards 
The first standard of clean room dust content, ie the concentration of dust particles suspended in the air under control to the extent (of course the more you have to clean up dust and then). If one compares an image, the diameter of a human hair in size 100μm, dust in the room may have a diameter of 0.5 to 50μm (see picture comparison).


The clean room standards were first launched in the US in 1963, and today has become the common standard for the world. It is the quantitative criteria particulates per unit volume of air. It is divided into the size range dust and room type is determined by the number of particles larger size 0,5μm on a volume of 1 cubic foot (ft3) of air in the room. 
a) Federal Standard 209 Standards (1963) [1] 
This standard was first defined in 1963 (called 209), and then continually improved, finishing the 209 version A (1966), 290 B (1973 ) ..., to 209 E (1992).


b) Federal Standard 209 E Standards (1992) [2-3] 
This standard to determine the amount of dust in the air according to the standard unit (the unit's air volume m ^ 3). The clean room classification is determined by the amount of dust logarithmic scale with larger diameter 0.5 \ mum. Below is a standard FS 209 E.


c) ISO 14644-1 [3,4] 
The International Organization for Standardization (International Standards Organization - ISO) has defined standards for clean rooms of international standard. ISO 14644-1 was released in 1999 titled "Classification of air cleanliness" (Classification of Air Cleanliness). The clean room type is specified based on the expression: 
Cn = 10n [0,1D] 2.08 
to: 
Cn¬ is the maximum allowable concentration (measured in particles / m3) of air suspended dust greater than or by size into consideration. 
N is the ISO classification number, not exceeding 9 and only allows the minimum number of 0.1 
D is calculated according micron particle diameter 
of 0.1 here is a constant with the dimension of the micron . 
Thus, we can easily determine the concentration limit dust from the above formula and easily categorize each level clean room (table 3).


Noting that the level of contamination of the air depends on the dust particles generated in the activities in the room, not just a fixed number of rooms. Therefore, in the standard of room, always require continuous cleaning systems and other regulations on the size and number of rooms, number of possible activities in the clean room. 
In addition to these criteria, each branch There may be additional requirements for their own, such as making the semiconductor IC industry requires different with medicine ... I remember the semiconductor industry with the elements manipulation of materials to micron size , hence the very stringent requirements of small dust content, while the health sector requires high level of cleanliness and air conditioners to combat bacterial infections ...