1. Clean room: The concentration of suspended particles and bacteria in the air are controlled to meet certain requirements or standards.
2. Air cleanliness: the amount of suspended particles in the air in a clean environment. Dust concentration is high and low.
3. Clean room air concentration level:
(1) Vacant state: The facilities have been built, all the power is connected and operated, but there are no production equipment, materials and personnel.
(2) Static: Facilities have been built, production equipment has been installed and operated under the unified state of owner and supplier, but no personnel.
(3) Dynamics: Facilities operate in a prescribed state, with prescribed personnel present and operating under agreed conditions.
4. Classification of pollutants:
(1) Solid and liquid particles suspended in air.
(2) Microorganisms suspended in the air, such as fungi and pathogens; and (3) gases harmful to human body or production process.
5. Particle classification:
Formation: dispersibility and cohesion.
Source: Inorganic, organic, living.
(3) Size: Visible, microscopic, ultramicroscopic.
(4) General purpose: dust, smoke, fog, smoke.
6. Expressions of atmospheric dust concentration:
(1) Counting concentration: expressed by the number of particles in the air per unit volume.
(2) Mass concentration: expressed by the mass of particles contained in the air of a unit volume.
(3) Settlement concentration: expressed by the number or quality of particles naturally settled per unit area of time.
7. Classification of clean rooms:
(1) According to the use: industrial cleanroom (positive indoor pressure, with inanimate particles as the control object, the main parameters are temperature, humidity, wind speed, flow field, cleanliness); biological cleanroom (general positive pressure, biological safety negative pressure).
(2) According to the flow pattern: unidirectional flow (single flow direction, uniform velocity, no eddy current); non-unidirectional flow (turbulent flow, variable direction, uneven velocity, accompanied by eddy current); mixed flow (non-unidirectional flow + unidirectional flow); radial (loss) flow (airflow passing through longitudinal section, radiation-like non-uniformity of outlet outflow).
8. Clean room standards:
International Clean Room Standard: ISO 14664-1 Cn = 10 ^ N* (0.1/D) ^ 2.08
Large Permissible Concentration of Cn-Air Suspended Particles with Particle Size Considered (pc/m3)
N-graded ordinal number (1-9), the intermediate number between integers can be specified, and the small allowable increment of Zui is 0.1
D-Considered Particle Size (um)
(2) Federal FS-209E Standard of the United States: M = 10 ^ M (0.5 d) ^ 2.2
M - Indicated value of cleanliness grade when adopting international unit system. M1-M7, 13 levels, 0.5 per level
D-Consider the radius (um)
M-the upper limit concentration of particles larger than or equal to (d) (pc_m3)
(3) Clean room standards in China: Code for Design of Clean Workshops GB 50073-2001
9. Control of noise requirements in clean rooms:
The noise level specified in the Code for Design of Clean Workshops (GB 50073-2001) is as follows:
The noise level in the clean room should not exceed 70 dB (A) in dynamic testing.
(2) In the empty state test, the non-unidirectional flow clean room should not be greater than 60dB (A); the unidirectional flow and mixed flow clean room should not be greater than 65dB (A).
10. Filtration efficiency: Percentage of the difference between the air dust concentration before and after the filter and the ratio of the air dust concentration before the filter under rated air flow. _=(1-C2/C1)*100% in series: 1-(1-1) (1-_2)
11. Permeability: Percentage of the ratio of the dust concentration of the filtered air to that of the pre-filtered air is 1-_.
12. Filter surface velocity: The airflow velocity passing through the cross section of the filter reflects the performance index of the filter passing capacity and installation area.
Filtration speed: The air velocity passing through the area of the filter material reflects the passing capacity of the filter material (filtration performance).
13. Filter resistance: resistance of filter material + resistance of filter structure.
Initial resistance: The air flow resistance of the newly manufactured filter under rated air volume.
End resistance: Resistance value of filter scrap (initial resistance 2-4 times).
Design Resistance: Representative Resistance in Design (Average of Initial Resistance and Final Resistance)
