Disposable mask is made of 28 g non-woven fabric with more than three layers; The nose is made of environmentally friendly plastic strips, free of any metal, and is breathable and comfortable, especially suitable for electronic factories and daily use. Disposable mask (
Medical Mask) can prevent respiratory infection to a certain extent, but it can not prevent haze. When purchasing, please pay attention to the selection of masks clearly marked "medical surgical masks" on the outer packaging.
Disposable masks have many types, which must be selected according to different working requirements and working conditions.
First, it should be based on the concentration and toxicity of dust. According to gb/t18664 "selection and application and maintenance of respiratory protection equipment", as dust masks, all dust masks are suitable for environments with harmful substances concentration not exceeding 10 times the working touch limit, otherwise, the mask or protection grade shall be completely used with advanced respirator.
If the particles have high toxicity, carcinogenicity and radioactivity, the filter data with high filtration efficiency should be selected.
If the particles are oil-like, please ensure that the appropriate filter data is selected.
If the granular material is needle like fiber, such as slag wool, asbestos, glass fiber, etc., dust mask can not be cleaned with water, and the mask attached to the sealing part of the face with micro fiber is easy to cause facial irritation and will not be suitable for use.
For high temperature, high humidity environment, it is more comfortable to select the mask with air vent valve. The selection of masks that can remove ozone for welding can provide additional maintenance, but if the ozone concentration is 10 times higher than the working health specification, it can be replaced by dust-proof, poison combination filter elements. For environments without particles but only some peculiar smell, for example, in some laboratory environments, selecting dust masks with activated carbon layer is much lighter than wearing gas masks, but for normative reasons, the use of such masks is not controlled.
How long can N95 mask be worn? It is not clearly stated, but said: "when N95 mask becomes dirty, damaged or difficult to breathe, it is necessary to leave contaminated area and replace it with a new mask."
Practical experience shows that N95 mask can be used continuously or intermittently within 8 hours to maintain the effect. Whether N95 mask can be used for a long time depends on whether it is dirty, whether it can be sealed continuously and whether it affects the smooth breathing. The repeated use of N95 mask requires attention to cross contamination, and because of different conditions, it is impossible to determine the safe reuse times of N95 mask.
Using N95 masks over a long period of time is better than removing and wearing from scratch, which reduces the possibility of contamination. Especially in the air where there are epidemic bacteria, if the lower cover is taken, it is difficult to ensure that the bacteria will not stick to the inside of the mask.
N95 masks have many different colors, shapes and styles. Some shapes and styles are designed to be better suited to the face of some people and to the individual.
As long as the standard requirements of the occasion, and users after the test wear masks to ensure air density, no matter the N95 mask color, shape or style, can achieve the same expected maintenance effect. That is to say, "the filtration efficiency of non oil particles with diameter greater than 0.3 microns in air is more than 95%.".
May 11, 2021
