Medical protective mask indicators are as follows:
Including non-oil particles filtration efficiency and airflow resistance.
(1) filtration efficiency: under the condition of air flow (85±2) L/min, the filtration efficiency of aerodynamic median diameter (0,24±0,06) μm sodium chloride aerosol is not less than 95%.
(2) tightness: the total fit factor of the mask should be not less than 100.
Expanded Information
Classification
N series: protection against non-oil suspended particles without time limit.
R series: protection against non-oily suspended particles and sweat oil suspended particles time limit of eight hours.
P series: protection against non-oily suspended particles and sweat oil suspended particles without time limit.
Some particles of the carrier is oily, and these substances attached to the electrostatic nonwoven fabrics will reduce the electrical properties, so that fine dust penetration, so for the prevention of oily aerosol filter media should be a special electrostatic treatment, in order to achieve the purpose of preventing fine dust.
So each series is divided into 3 levels: 95%, 99%, 99, 97% (i.e., referred to as 95, 99, 100), so *** there are 9 small categories of filter media.
Baidu Encyclopedia - Medical Masks