What are the principles of a clean environment?
In many fields of FA, represented by the electronic components ・ assembly industry, which is constantly evolving with miniaturization and high integration, and the pharmaceuticals ・ food industry that have an impact on the human body, a clean environment is required. This special feature will illustrate clean environment and pollution management with examples. This is an important technology that affects quality. Provides 3 principles for creating and maintaining this clean environment.
[3 Principles of Clean Environment]
1. No pollution
2. No pollution
3. No accumulation of pollution
※Pollution: refers to pollutants such as floating trace particles and microorganisms.
In addition, it is said that in pollution management, if the following classification standards are adopted, it is easy to take countermeasures.
[Classification Standards for Pollution Management]
1. What is the object of pollution?
→The countermeasures vary depending on the gas, liquid, and solid (internal or surface). Gas spreads faster than other forms and is widespread at manufacturing sites. Therefore, gas pollution management is very important for maintaining a clean environment.
2. What is the nature of the pollutant?
→The physical ・ chemical properties must be confirmed. Because pollutants will change the physical ・ electrical properties of the polluted object, or chemical reactions are used to remove pollutants.
3. What is the source of pollution?
→ There will be no pollutants if there is no source of pollution. It can effectively specify and remove the pollution source, or cut off the pollution path.
Relevant standards for clean environment
When it comes to clean environments, I think many people think of clean rooms. Next, confirm the definition and standards of the clean room.
[What is a clean room]
Refers to the limited space for pollution management. Through management, the floating fine particles and microorganisms in the air are controlled to below a limited cleanliness level, and the cleanliness required for the materials, medicines, and water supplied in the space are also maintained. It also manages environmental conditions such as temperature, humidity, and pressure as needed. (JIS Z 8122 Pollution Control Terminology)
The clean environment technology is mainly developed in the United States, so the United States Federal Standard FED-STD-209D has been generally used for many years. The standard stipulates that the standard volume is 1 cubic foot (1 foot = 30.48cm). After that, the standard was changed to FED-STD-209E, which uses 1 cubic meter as the standard. In Japan, the JIS B 9920 clean room air cleanliness evaluation method standard was established in 1989. In addition, in the process of global transfer to international units, the ISO 14644-1 standard was formulated in 1999. The particle size and standard volume of the target fine particles generally adopt JIS standards. Therefore, the American standard was abolished, but FED-STD-209D was used habitually.
Standard volume and standard particle size of each standard
Standard table (FED-STD-209)
|
Grade identification |
Upper limit of grade
|
||||||||||
|
0.1μm
|
0.2μm
|
0.3μm
|
0.5μm
|
5μm
|
|||||||
|
Volume unit
|
Volume unit
|
Volume unit
|
Volume unit
|
Volume unit
|
|||||||
|
209E |
209D |
m3 |
ft3 |
m3 |
ft3 |
m3 |
ft3 |
m3 |
ft3 |
m3 |
ft3 |
|
M1 |
350 |
9.91 |
75.7 |
2.14 |
30.9 |
0.875 |
10 |
0.283 |
– |
– |
|
|
M1.5 |
1 |
1,240 |
35.0 |
265 |
7.5 |
106 |
3.00 |
35.3 |
1 |
– |
– |
|
M2 |
3,500 |
99.1 |
757 |
21.4 |
309 |
8.75 |
100 |
2.83 |
– |
– |
|
|
M2.5 |
10 |
12,400 |
350 |
2,650 |
75 |
1,060 |
30 |
353 |
10 |
– |
– |
|
M3 |
35,000 |
991 |
7,570 |
214.4 |
3,090 |
87.5 |
1,000 |
28.3 |
– |
– |
|
|
M3.5 |
100 |
– |
– |
26,500 |
750.4 |
10,600 |
300 |
3,530 |
100 |
– |
– |
|
M4 |
– |
– |
75,700 |
2,140.4 |
30,900 |
875 |
10,000 |
283 |
– |
– |
|
|
M4.5 |
1,000 |
– |
– |
– |
– |
– |
– |
35,300 |
1,000 |
247 |
7.00 |
|
M5 |
– |
– |
– |
– |
– |
– |
100,000 |
2,830 |
618 |
17.5 |
|
|
M5.5 |
10,000 |
– |
– |
– |
– |
– |
– |
353,000 |
10,000 |
2,470 |
70.0 |
|
M6 |
– |
– |
– |
– |
– |
– |
1,000,000 |
28,300 |
6,180 |
175 |
|
|
M6.5 |
100,000 |
– |
– |
– |
– |
– |
– |
3,530,000 |
100,000 |
24,700 |
700 |
|
M7 |
– |
– |
– |
– |
– |
– |
10,000,000 |
283,000 |
61,800 |
1,750 |
|
Standard table (JIS B 9920/ISO 146441-1)
|
Grade identification |
Upper limit of grade
|
|||||
|
0.1μm
|
0.2μm
|
0.3μm
|
0.5μm
|
1μm
|
5μm
|
|
|
Level 1 |
10(101) |
2 |
||||
|
level 2 |
100(102) |
twenty four |
10 |
4 |
||
|
Level 3 |
1,000(104) |
237 |
102 |
35 |
8 |
|
| level 4 |
100,000(105) |
2,370 |
1,020 |
352 |
83 |
|
| Level 5 | 23,700 |
10,200 |
3,520 |
832 |
29 |
|
|
Level 6 |
237,000 |
102,000 |
35,200 |
8,320 |
293 |
|
|
Level 7 |
352,000 |
83,200 |
2,930 |
|||
|
Level 8 |
3,520,000 |
832,000 |
29,300 |
|||
|
Level 9 |
35,200,000 |
8,320,000 |
293,000 |
|||