Clean room pollution source knowledge
The amount of dust generated in the clean room from the equipment can be considered to be discharged through local exhaust and will not flow into the room; Compared with the amount of dust generated by human body, the dust generated by products and materials during transportation is generally very small and can be ignored; Due to the application of metal half wall (color steel sandwich panel), there is little dust from the building surface, generally accounting for less than 10%, and the dust mainly comes from people, accounting for about 90%. In terms of human hair dust, due to the improvement of clothing materials and styles, the absolute amount of hair dust is also decreasing.
A. Material: cotton has the largest amount of dust, followed by cotton, dacron, antistatic pure polyester and nylon.
B. Style: large hanging type has the largest amount of dust, followed by upper and lower sub assembly type, and the full cover type is the least;
C. Activity: the amount of dust generated during action generally reaches 3-7 times of the static time;
D. Cleaning: the amount of dust washed with solvent is reduced to one fifth of that washed with ordinary water.
The dust emission on the surface of indoor maintenance structure is subject to the ground. The dust emission on the surface of about 8 square meters of ground is equivalent to that of a stationary person.
Amount of bacteria
Pollution caused by workers:
1) Skin: humans usually complete complete skin replacement every four days. Humans shed about 1000 pieces of skin per minute (with an average size of 30 * 60 * 3 microns)
2) Hair: human hair (about 50-100 microns in diameter) has been falling off.
3) Saliva: including sodium, enzyme, salt, potassium, chloride and food particles.
4) Daily clothing: particles, fibers, silica, cellulose, various chemicals and bacteria.
5) Humans standing still and sitting will produce 10000 particles larger than 0.3 microns per minute.
6) Humans will produce 1000000 particles greater than 0.3 microns per minute when they move their head and trunk.
7) When humans walk at a speed of 0.9m/s, they will produce 5000000 particles greater than 0.3 microns per minute.
Based on the analysis of foreign test data, it can be considered that:
(1) When the staff in the clean room wear sterile clothes:
The amount of bacteria at rest is generally 10-300 / min
The amount of bacteria during general physical activity is 150-1000 / min
When walking fast, the amount of bacteria is 900-2500 / min
(2) One cough is generally 70 ~ 700 / min
A sneeze is generally 4000 ~ 62000 / min
(3) When wearing ordinary clothes, the amount of bacteria is 3300 ~ 62000 / min. person
(4) Bacteria amount without mask: bacteria amount with mask: 1:7 ~ 1:14
(5) Bacteria amount: dust amount: 1:500 ~ 1:1000 according to domestic examples:
(6) The number of bacteria in the operation was 878 / min
Therefore, it can be seen that the static quantity of bacteria in sterile clothes in the clean room is generally no more than 300 / min. people, and the dynamic quantity of bacteria is generally no more than 1000 / min / person, which is feasible as the calculation basis.