currently*Viral pneumonia epidemicAlthough there has been improvement, the situation remains severe. In addition to minimizing outings and gatherings, we also need to wear respiratory protection measures such as masks when going out. So, how to choose respiratory equipment to ensure proper protection?

Today, based on《GB/T 18664-2002 Selection of respiratory protective equipmentThe selection method of respiratory protective equipment in the "Usage and Maintenance" standard is excerpted for the convenience of readers. We hope to provide assistance to everyone. For specific selection, please read GB/T 18664-2002 carefully and choose according to the standard, or consult a professional.

Selection of respiratory protective equipment

1、 General principles
1. Without protection, no one should be exposed to air environments that can or may harm health.
2. According to relevant occupational health standards, the air environment during work should be evaluated (various factors to be considered in the evaluation can be found in Appendix A), identifying the nature of harmful environments and determining the degree of harm.
3. The possibility of taking engineering measures to control harmful environments should be considered first. If engineering control measures cannot be implemented for various reasons, or cannot eliminate harmful environments, and during the period when engineering control measures are not effective, they should be implemented in accordance with Section 4 of this standard 2, 4. Choose appropriate respiratory protective equipment according to the provisions of 3 and 4.4. The classification of respiratory protective equipment is shown in Table 1. Select the program as shown in Figure I
4. Approved respiratory protective equipment that meets standard requirements should be selected.
5. When choosing respiratory protective equipment, one should also refer to the technical specifications in the user manual and meet its applicable conditions.
6. If respiratory protective equipment is needed to prevent harmful environmental hazards, the employer should establish and implement a standardized respiratory protection plan.

2、 Choose based on harmful environment
1. Identify hazardous environmental properties
Harmful environments in homework should be identified and the following situations should be understood:
a) Can harmful environments be identified;
B) Whether there is hypoxia and oxygen concentration value;
c) Whether there are air pollutants and their concentrations;
D) The forms of air pollutants, whether they are particulate matter, gas or vapor, or a combination thereof, and further understanding of the following situations:
1) If it is particulate matter, it should be understood whether it is solid or liquid, its boiling point and vapor pressure, whether it evaporates significantly at the operating temperature, whether it is radioactive, whether it is oily, possible dispersion, whether there are occupational health standards, whether there is an ID LH concentration (see Appendix B), whether it can still be absorbed through the skin, whether it is allergic to the skin, whether it irritates or corrodes the skin and eyes, etc;
2) If it is a gas or vapor, it should be understood whether it has obvious odor or irritant warning signs (see Appendix C), whether there are occupational health standards, whether there is IDLH concentration (see Appendix B), whether it can still be absorbed through the skin, whether it is allergic to the skin, whether it irritates or corrodes the skin and eyes, etc.
2、 判定危害程度
Determine the degree of harm according to the following method:
a) If the nature of the harmful environment is unknown, it should be considered as an IDLH environment;
If there is hypoxia or it is uncertain whether there is hypoxia, it should be considered as an IDLH environment;
c) If the concentration of air pollutants is unknown, reaches or exceeds the IDLH concentration, it should be considered as an IDLH environment;
d) If the concentration of air pollutants does not exceed the IDLH concentration, the hazard factor should be determined according to formula (1) based on the relevant occupational health standards; If there are more than one air pollutant present at the same time, the hazard factor of each air pollutant should be calculated separately, and the value with a higher ZUI value should be taken as the hazard factor
3. Choose respiratory protective equipment based on the degree of harm
1) Protection against IDLH environment
The respiratory protective equipment suitable for IDLH environment is:
a) Positive pressure SCBA with full face mask;
B) Under the premise of equipped with suitable auxiliary escape type respiratory protective equipment, positive pressure air supply respiratory protective equipment with full face mask or air delivery head mask should be provided.
Note: Auxiliary escape type respiratory protective equipment should be suitable for IDLH environmental properties. For example, in environments with unknown harmful properties, oxygen deficiency, and oxygen deficiency, the selected auxiliary escape respiratory protective equipment should be gas carrying and filter type should not be allowed; In an environment where there is no oxygen deficiency but the concentration of air pollutants exceeds the IDLH concentration, the selected auxiliary escape respiratory protective equipment can be air carrying or filtering, but should be suitable for the type and concentration level of the air pollutant
2) Protection against non IDLH environments
Respiratory protective equipment with an APF greater than the hazard factor should be washed. The APF of various respiratory protective equipment is shown in Table 2

3、 Choose respiratory protective equipment based on the type of air pollutants
1. Protection against particulate matter
Isolation or filtration respiratory protective equipment can be selected (see Table 3). If choosing a filtering type, the following points should be noted:
a) Dust masks are not suitable for protecting against volatile particulate matter. Respiratory protective equipment that can simultaneously filter particulate matter and its volatile gases should be selected;
b) Suitable dust masks should be selected based on the dispersion of particulate matter;
c) If the particulate matter is liquid or oily, respiratory protective equipment with suitable filtering elements should be selected;
d) If the particulate matter is radioactive, a dust mask with a filtration efficiency of ZUI high level should be selected.
2. Protection against toxic gases and vapors
Isolation or filtration respiratory protective equipment can be selected (see Table 3). If choosing a filtering type, the following points should be noted:
a) Suitable filter elements should be selected based on the types of toxic gases and vapors. For filter element types not included in current standards, they should be selected according to the instructions provided by the respiratory protective equipment manufacturer;
b) For toxic gases or vapors without warning or with poor warning, respiratory protective equipment with failure indicators or isolated respiratory protective equipment should be prioritized.
3. Simultaneous protection against particulate matter, toxic gases or vapors
Isolation or filtration respiratory protective equipment can be selected (see Table 3). If a filtering type is chosen, effective filtering elements or a combination of filtering elements should be selected.

4、 According to the selection of homework personnel
1. Head and facial features
When choosing a half face mask or full face mask, attention should be paid to:
a) If respiratory protective equipment manufacturers or distributors can provide suitability testing to users, they can help users choose suitable tight fitting masks. The suitability testing method can be found in Appendix E;
b) Beards or excessively long hair can affect the fit between the mask and the face. Users should shave their beards in advance to avoid getting their hair caught between the mask and facial skin;
c) The facial features of the user should be considered. If the tight fit between the face and the mask is affected by (ba) scars, sunken temples, very prominent cheekbones, skin wrinkles, nasal deformities, etc., a mask unrelated to facial features should be selected.
2. Comfort level
The work environment should be evaluated to determine whether the workers will be affected by physical factors (such as high temperatures), and respiratory protective equipment that can alleviate these adverse effects and provide comfort should be selected, such as air supplied respiratory protective equipment with cooling function.
3. Vision correction
Vision correction glasses should not affect the fit between respiratory protective equipment and the face. If respiratory protective equipment provides structural components for using corrective lenses, suitable vision correction lenses should be selected and operated according to the instructions
4. The physical condition that is not suitable for the use of respiratory protective equipment should seek advice from industrial hygiene physicians. For individuals with a history of cardiovascular and pulmonary diseases, severe psychological stress reactions to confined spaces, and respiratory loads, their ability to use respiratory protective equipment should be considered.