Eye and face protection classification

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Classification of eye and face protection: Occupational eye (face) injuries account for about 5% of all industrial injuries. To effectively protect the eyes and face from damage, it is necessary to choose appropriate eye and face protection gear based on the specific hazards present, and to use that gear correctly. 　　During the work process, employees in enterprises often suffer damage to their eyes and face due to flying objects, chemicals, or light. According to statistics, occupational eye (face) injuries account for about 5% of all industrial injuries, yet the area of the eyes constitutes only 1/600 of the total body surface area. In other words, compared to other human organs, the eyes are more susceptible to occupational injuries. 　　How to effectively protect the eyes and face from injury at work? Improving the working environment and conditions is the most effective approach. When the working conditions cannot be changed temporarily, it is necessary to select appropriate eye and face protection gear based on the different hazard factors, and to use them correctly. 　　Occupational factors causing eye and facial injuries Common occupational factors that cause eye and facial injuries include five categories: foreign body injuries, chemical injuries, non-ionizing radiation injuries, ionizing radiation injuries, as well as microwave and laser injuries. 　　Foreign body injury: During operations in industries such as casting, machining, construction, and quarrying, it is possible for foreign objects such as sand particles and metal shavings to enter the eyes or strike the face. Some solid foreign objects can fly out at high speed (such as metal fragments from rotational cutting or particles resulting from grinding metal objects); if they strike the eye or face, they can cause severe eye rupture or penetrating injuries, as well as damage to the facial skin or fractures of the nasal bone. 　　Chemical injuries: Acidic or alkaline liquids, or corrosive fumes generated during the production process, can enter the eyes or come into contact with the facial skin, causing burns to the cornea or facial skin. In industrial production, chemical injuries to the eyes and face are common, with burns caused by alkalis being the most severe, as alkalis can penetrate the skin more easily than acids. 　　Damage from non-ionizing radiation: In areas such as electrical welding, oxygen cutting, furnaces, glass processing, hot rolling, and casting, heat sources operating at temperatures between 1050°C and 2150°C can generate intense light, ultraviolet rays, and infrared rays. Ultraviolet radiation can cause burns to the superficial tissues of the cornea and conjunctiva, leading to symptoms in victims such as photophobia, pain, tearing, and blepharitis. Infrared radiation produces a thermal effect on eye tissues, causing chronic inflammation of the eyelids and lens opacity (occupational cataract). It can be seen that strong light can cause eye fatigue, eyelid spasms, and conjunctivitis. 　　Damage from ionizing radiation: In industries related to nuclear energy, nuclear power plants and submarines, nuclear explosions, and high-energy physics experiments, there are often various types of radiation such as alpha particles, beta particles, gamma rays, X-rays, thermal neutrons, slow neutrons, fast neutrons, protons, and electrons. When the total dose absorbed by workers exceeds 22 Gy, some of them begin to develop cataracts, and the incidence increases as the total dose rises. 　　Microwave and laser injuries Microwave and lasers are types of electromagnetic waves and constitute non-ionizing radiation. Microwaves are widely used in fields such as radar, communications, medicine, detection, **, and food processing. The damage of microwaves to the human eye is mainly caused by the thermal effect, which leads to lens opacity and the development of cataracts. In recent years, the application of lasers in industry, medicine, and scientific research has developed rapidly, especially in **. When lasers are directed at the retina of the eye, they can cause burns; lasers with a power of more than 0.1 μW may also lead to bleeding in the eye, coagulation or melting of proteins, resulting in permanent blindness. 　　Classification and Selection of Eye and Face Protection Equipment Eye and face protection equipment refers to gear designed to protect the eyes and face from harm caused by smoke, chemicals, metal sparks, debris, and dust. Based on their structural design, they are divided into three types: protective glasses, protective goggles, and protective face shields. 　　Impact goggles: Impact goggles protect the eyes from impacts caused by flying particles such as metal, sand, and debris, and are commonly used in tasks involving machining, milling, planing, and grinding. The lenses and frames of such protective glasses must be very sturdy and not easy to break, and the edges that come into contact with the eyes should have no sharp corners. 　　When choosing impact-resistant glasses, opt for those with side shields (as shown in Figure 1) to protect against impacts from the sides. The lenses should also be anti-fogging to prevent them from becoming blurry due to the wearer’s breath. 　　Protective eye masks 　Protective eye masks not only prevent various impacts from harming the eyes, but also offer protection against liquid splashes. To maintain air circulation inside and outside the eye shield, the protective eye shield is equipped with indirect ventilation holes on the sides (as shown in Figure 2). In work areas where liquid chemicals are used, and there is a risk of liquid splashes causing damage to the eyes, protective goggles should be used to safeguard the workers’ eyes. 　　But it should be noted that when protection against dust, smoke, and various harmful gases is required, a protective eye mask without ventilation holes must be chosen, one that fits tightly against the face, with frame materials that are resistant to acids and alkalis. However, this type of protective eye mask is suitable for use in environments with mild toxicity and low irritation. It should be used in conjunction with a gas mask in environments with high toxicity. 　　Impact and liquid splash protection face shield: This type of face shield covers the eyes and entire face, providing good protection against impacts and liquid splashes. If the face shield can be lifted to expose the eyes, impact goggles must also be worn. If the workplace is also exposed to risks such as object strikes, dust, and noise, when choosing impact-resistant and splash-proof face shields, it is necessary to consider ones that can be worn alongside safety helmets, masks, and earplugs (as shown in Figure 3). 　　Welding eye and face protection: In welding environments, it is necessary to use protection against welding arc light. The welding eye and face protection devices available on the market currently include ordinary welding goggles (as shown in Figure 4), welding eye shields (as shown in Figure 5), and welding face shields (as shown in Figure 6). Welding protection face shields include helmet-mounted, handheld, and helmet-equipped face shields. 　　In practical use, it is advisable to use welding protective goggles or face shields as much as possible. When ordinary welding safety glasses are worn, ultraviolet rays can penetrate the eyes through the gaps between the face and the glasses, failing to provide effective protection against the ultraviolet rays and intense light emitted by the welding arc, thereby causing damage to the eyes. Furthermore, welding workers who also engage in dust-producing tasks such as grinding should wear dust masks as well ； When welding in areas where objects may fall, a helmet-type face shield should be worn. 　　Heat radiation shielding screen: A heat radiation shielding screen is made from materials with high reflectivity and good heat resistance, such as aluminum foil; alternatively, a metal film or coating (such as aluminum or gold plating, with gold plating providing better results) can be applied to plexiglass to reflect infrared radiation. goggles are then used for observation, for example, to measure the temperature of flames inside a furnace. Therefore, it is required that the protective lens be able to show the red filament under an incandescent lamp. Operators of industrial furnaces should wear heat-radiation protective face shields (as shown in Figure 7). 　　Full-face respirator: A full-face respirator covers the user’s mouth, nose, eyes, and forehead, thereby providing effective protection against impacts from objects, splashes of liquids, toxic and harmful gases, dust, etc. In workplaces with high levels of danger, especially those with high concentrations of toxic and harmful gases, a full-face respirator should be used (as shown in Figure 8). 　　Selection and Usage Precautions for Eye and Face Protection Equipment The key to choosing protective glasses is to try them on; since everyone has a different face shape and pupil distance, it is necessary to select glasses that suit one’s own features by trying them on. When trying them on, check the side to ensure that the safety glasses can protect against damage from the side. 　　Furthermore, when choosing eye and facial protective equipment, it is also necessary to select products that meet the requirements for **special protective equipment. When purchasing, pay attention to the labels and markings on the product and its packaging to confirm that it is a qualified product. Qualified products should have on their packaging: the product name, the manufacturer’s name, and the production date ； There are functional indicators: such as indicators for impact resistance, protection against liquid splashes, etc. 　　Impact-resistant eye and face protection, welding eye and face protection gear, full-face respirators, etc., are products subject to safety mark regulations; they must have safety marks (i.e., LA, which stands for labor safety, as shown in Figure 9) on their packaging or on the products themselves. 　　The safety sign diagram features a green background on a white base, with the numbers in black font assigned using a numbering system that combines three digits and letters. The two digits in the first layer represent the year in which authorization to use the security identifier was granted ； The two digits in the second layer represent the administrative region code of the provincial-level area to which the manufacturing enterprise authorized to use the safety mark belongs (for imported products, the codes in the second layer are two-letter abbreviations indicating the country of origin of those imported products) ； The first three digits of the third-layer code represent the product’s name code; for example, welding face shields are 301, welding goggles are 302, and impact-resistant goggles are 303. The last three digits indicate the order in which authorization to use the safety label was granted. 　　Eye and facial protection gear must be maintained and replaced regularly during use; users should follow the product instructions for maintenance to ensure it remains clean. When the surface is dirty, it should not be cleaned with organic solvents, nor should it be wiped directly with a dry cloth to avoid scratches on the lens; instead, it should be rinsed with a small amount of detergent and clean water. When the lenses or frame develop cracks, deformation, or damage, they must be replaced promptly.