Both the United States and the European Union have standards for chemical protective clothing. The EPA has classified chemical protective suits into four different grades of protection
Class A: gas sealed protective clothing;
Class B: protective suit against liquid sputtering;
Grade C: protective clothing with enhanced functions;
Grade D: general protective clothing.
It can be argued that, since many products are imported from the United States, the classification of chemical protective clothing used in China is also based on the classification of EPA, and the classification of these 4 is also based on the classification of NFPA protective clothing. Specific can refer to the standard nfpa_1991-2005_ hazardous chemical accident with steam protection kit, which is divided into four levels as above.
According to the classification, the chemical protective suits/protective suits at all levels have the following characteristics.
Class A: air-tight protective clothing, the highest level of existing respiratory, skin and eye protection.
The grade A protective suit meets the requirements of NFPAl99l. It is generally believed that such chemical suits can resist the threat to human body from almost all kinds and all forms of hazardous chemicals (including gaseous, liquid and solid substances) or other dangerous substances encountered in conventional industrial production. Therefore, grade A air-tight chemical protective clothing is generally regarded as the most protective chemical protective clothing internationally. This type of protective clothing is equipped with internal or external positive pressure self-contained air breathing apparatus or long tube breathing apparatus, and the clothing is completely airtight in order to effectively prevent the invasion of toxic and harmful gases. Therefore, the clothing must conduct strict air tightness performance testing according to ASTM F 1052.
The complete outfit also includes a hard hat and double protective gloves (with a special protective glove inside), anti-chemical boots, anti-chemical face screen and dual-use radio communication facilities. Such protective clothing is mainly used in environmental pollution are difficult to determine the chemical composition and concentration of occasions, or known these substances may pose a threat to life and health immediately occasions, such as entering the harmful to the environment may have a high concentration of steam, gas, solid particles or liquid, and the material may cause respiratory tract, eyes or skin suffered serious damage. All the protective components of the garment must be tested with a series of chemical substances after a certain number of bending and friction tests. The maximum penetration of chemical substances in the protective clothing tested shall not exceed 0.1 in the 60min test time. G/cm2, min. These substances include: acetone, acetonitrile, anhydrous ammonia (gas), l, 3 butadiene, carbon disulfide, methylene chloride, chlorine gas, diethylamine, DMF, ethyl acetate, ethylene oxide, n-hexane and hydrogen chloride gas, methanol, chlorinated methane gas, nitrobenzene, sodium hydroxide, sulfuric acid, tetrachloroethylene, tetrahydrofuran, toluene.
Where applicable: the composition and concentration of chemical substances in the polluted environment are uncertain, and a high concentration of steam, gas and dust is detected. It may pose A great threat to respiratory system, skin and eyes. It may be accidentally splashed, immersed or exposed to steam, gas and dust. The working environment is poorly ventilated and requires class A protection.
Class B: the same respiratory protection as class A, slightly inferior skin protection, the lowest level of protection for handling dangerous goods;
The b-class protective suits meet the requirements of NFPA1992. The main body of the suits includes joint or separate protective suits, as well as the head cover with hard hat, anti-chemical face screen, anti-chemical gloves with inner and outer layers, anti-chemical boots, positive pressure self-contained air breathing apparatus or long tube breathing apparatus, dual-use radio communication facilities, etc. The protective ability of the respiratory system can reach level A, while the protection level for the skin and eyes is lower than level A, which can prevent the infiltration of liquid chemicals, but cannot prevent the infiltration of the vapors or gases of toxic chemicals. The environment (inhaled only) does not cause serious skin damage or does not qualify as a filter. Substances with known contact properties and concentrations require high respiratory protection and low skin protection, with oxygen concentration lower than 19.5%. The instrument cannot fully detect the vapor or gas, but it is harmless to the skin or is not absorbed by the skin. Class B protection prevents any liquid from entering the protective clothing, but gas and wet vapor can penetrate. Protective clothing must be resistant to penetration of chemicals and their mixtures. All parts and connecting parts of the garment shall meet the corresponding protection requirements.
Provide breathing gas SCBA (self-contained breathing apparatus, self-contained breathing apparatus) or gas pipeline, chemical proof, splash proof clothing; Chemical protective gloves on the inner and outer layers; Chemical; Hard hat.
Application: it is mainly used for the occasions where the chemical composition and concentration in the polluted environment do not require a high level of skin protection. For example, the occasions where the gas chemical in the known environment is harmless to the skin or is not absorbed through the skin, only causing harm to the respiratory system. The chemical composition and concentration in the environment do not require a high level of skin protection. A situation involving only liquids and not vapors.
In addition, grade B protective clothing is divided into two types: joint and separate. When breathing, you can use an oxygen bottle or a compressed air duct. Thus suitable for long time operation.
The use of grade A and B protective clothing must be trained. Fit for military purposes, not for medical purposes.
The level of protection for the skin is the same as grade B, but the level of protection for the respiratory system is lower than grade b. it meets the requirements of NFPA1993, which can prevent the harmful effects of the injection of toxic liquid substances on the human body, but cannot prevent the vapors or gases of toxic chemicals. Protective clothing must be resistant to penetration of chemicals and their mixtures. The concentration of toxic chemicals in the air must be below the IDLH(immediate hazard to life and health) standard. Including: full cover air filter respirator; Filter respirators with canisters, gloves and boots against toxic chemicals, dual-use communications systems, helmets, chemical protective suits; Chemical protective gloves on the inner and outer layers; Chemical protective boots; Hard hat.
Applicable occasions:
Where the composition and concentration of chemical substances in the polluted environment have no effect on the skin: where the composition and concentration of toxic substances in the polluted air are determined; All characteristics of toxic substances in a contaminated environment are defined for the occasion. The type and concentration of pollutants in the air are known, and the filter can effectively filter them. Oxygen is no less than 19.5%; The gas environment is lower than IDLH.
Grade D: general protective clothing
Minimal skin protection does not protect the respiratory system. Protective clothing includes: protective coveralls; Safety boots/shoes, goggles or anti-sputter goggles. Optional: gloves, breathing devices for escape, protective mask; Chemical protective gloves; Chemical protective boots; Safety glasses or eye patches; Hard hat.
Applicable occasions:
There is no known harmful gas in the atmosphere; No liquid spatter at work, immersion in liquid or possible exposure to any harmful chemicals. There is no obvious danger in the air that is known to pollute the environment. Should not be worn where there is danger to the respiratory tract and skin. This level of protective clothing cannot be used in a hot environment. Oxygen content in the operating environment must not be lower than 19. 5%. It is not suitable for dealing with sudden emergencies.
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