1) Filtration efficiency: under the condition of air flow (85 ± 2) l / min, the filtration efficiency of sodium chloride aerosol with median diameter (0.24 ± 0.06) μ m in aerodynamics shall not be less than 95%, that is to say, it shall meet the grade of N95 (or FFP2) and above. It can block the air-borne infectious factors with a diameter of less than 5 μ m or close contact with the infectious factors transmitted by droplets.
2) Suction resistance: under the above flow conditions, the suction resistance shall not exceed 343.2pa (35mmh2o).
3) When the sample is sprayed to the mask under the pressure of 10.9kpa (80mmHg), the inner side of the mask shall be free of penetration and other technical indicators.
4) The mask must be equipped with a nose clip, which is made of bendable plastic material with a length of more than 8.5cm.
5) Synthetic blood is sprayed at 10.7kpa (80mmHg) pressure to the mask sample, and there should be no penetration inside the mask.