The term "cleanroom" is initially used in the medical field. A cleanroom requires factors such as dust, temperature, sound, light, pressure, etc controlled within a certain standard. The particle density in the air is controlled in a specified manner according to the specified parameter requirements. The first standard of the cleanroom is concentration. Particularly in the operation, the types of particles are more concerned than the number of particles for a cleanroom.

Cleanroom standards were first introduced in 1963 in the United States and are now common standards.

a. Federal Standard 209(1963)

This standard was first specified in 1963 and then continuously improved to complete versions 209A (1966), 290B (1973)... until 209E (1992).

b. Federal Standard 209E(1992)

This standard defines the concentration of suspended particles in the air according to the standard unit (air volume unit is m3).

 

Class

Maximum

particles

/m3

 

 

 

ISO Class

≥0.1µm

≥0.2µm

≥0.3µm

≥0.5µm

≥5µm

1

35

7

3

1

 

ISO3

10

350

75

30

10

 

ISO4

100

 

750

300

100

 

ISO5

1000

 

 

 

1000

7

ISO6

10000

 

 

 

10000

70

ISO7

100000

 

 

 

100000

700

ISO8

 

c. ISO 14644-1 Standard

The International Organization for Standardization has defined the international standard for clean rooms, ISO14644-1 was released in 1999 called "Classification of air cleanliness". Cleanroom types are specified based on the expression where Cn is the maximum permissible content (number of particles / m3) of air-suspended dust greater than or equal to the considered size. N is the ISO rating, not exceeding 9 and the minimum allowable index of 0.1. D is the particle diameter in tínhm 0.1 here is constant with the dimension µm.

Class

Maximum particles / m3

0.1 um

0.2 um

0.3 um

0.5 um

1 um

5 um

ISO 1

10

2

 

 

 

 

ISO 2

100

24

10

4

 

 

ISO 3

1,000

237

102

35

8

 

ISO 4

10,000

2,370

1,020

352

83

 

ISO 5

100,000

23,700

10,200

3,520

832

29

ISO 6

1,000,000

237,000

102,000

35,200

8,320

293

ISO 7

 

 

 

352,000

83,200

2,930

ISO 8

 

 

 

3,520,000

832,000

29,300

ISO 9

 

 

 

35,200,000

8,320,000

293,000

It should be noted that the degree of air pollution in the room depends on the particles produced in the operations of the room, not just the fixed number of the room. It always requires continuous cleaning systems and regulations on room size and number of people, the number of possible operations in the cleanroom.

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