5.2 “United States” American NIOSH standard [15] Filter material for masks
The quality and filtration efficiency are graded, and the standard is recognized all over the world Degree is the highest. According to the filter material of the middle layer of the mask, there are three types: N, R, P series, each can be divided into three levels according to the filtration efficiency Don’t (see Table 2). N is used to protect against non-oily suspended particles, usually Non-oily particulate matter refers to coal dust, cement dust, acid mist, microorganisms, etc., speak Or droplets from coughing are not oily. The smog that is currently raging During dyeing, most of the suspended particles are also non-oily. Oily particles refer to oil Smoke, oil mist, asphalt smoke, etc., such as cooking fume produced by cooking is oily particles Things. R and P are used to protect non-oily and oily aerosols, relative Compared with the R series, the P series has been used for a relatively long time. The time used is based on the label of different manufacturers. N95 mask is N In the series, a type of mask with a filtration efficiency ≥ 95%, and is passed through the wearer’s face When testing the tightness, make sure that the air is close to the edge of the face. Only those who can enter and exit through the mask will be issued N95 certification number if they meet this test code all clean china set wipe face. During the special period of SARS prevention, WHO temporarily recommends medical staff Use N95 masks certified by the US NIOSH. N95 masks vary For medical protective masks, medical protective masks stipulate the filtering efficiency of masks If it meets the requirements of N95, and has surface moisture resistance and blood barrier ability. “ASTM” F2100 standard [16] is a medical standard, the standard Divide masks into three levels: low protection (level 1), medium protection (Level 2) and high protection (Level 3). The higher the level, the protection performance The better. Level 1 and Level 2 masks are usually called procedure Mask; Level 3 masks can be used in the operating room, also called surprise Mask. When the chance of exposure to the virus is particularly high, the level should be selected Higher protection. ASTM certification requires masks to filter The four aspects of filtration efficiency, synthetic blood penetration resistance and pressure difference are all up to To the relevant standards, see Table 1. Level 1 can block 95% of bacteria Even if it only meets the low protection standard, it is enough to protect the general society. District users; Level 2 and Level 3 (medium to high protection standards) Masks are required to block at least 98% of bacteria and particles all clean china pogies dog wipes, and the pressure difference is It only needs to be lower than 49.0Pa/cm2, and the lower protection standard is a little looser. Because it is difficult to achieve better protection while maintaining breathability. The main difference between medium and high protection standards is high protection (Level 3) Chinese Journal of Infection Control, Vol. 19, Issue 2, February, 2020 “Chin” J “Infect” Control “Vol” 19 “No” 2 “Feb” 2020 ·113· Standards have higher requirements for the ability to block liquids all clean china wet floor wipes. Medical N95 mask Need to meet the requirements of FDA” Surgical “Masks-Premarket” Notification [510(k)] Submissions Guidance for Industry AND FDA Staff standard [17], and also meet NIOSH For the requirements of N95 masks, it is resistant to synthetic blood penetration and surface moisture Performance has been tested, and the FDA standard basically follows ASTM” F2100 standard.
