Electrical performance protective shoes are protective […]
Electrical performance protective shoes are protective shoes used to protect the feet in personal protective equipment, including anti-static shoes, conductive shoes and electrically insulating shoes, which can prevent static electricity injuries and electric shock injuries.
The harm of static electricity to human body
The damage of static electricity to the human body is caused by psychological obstacles and fear, which can lead to accidents. It can also cause skin burns and dermatitis due to electrostatic shock. The main hazard of static electricity is the occurrence of flammable and explosive accidents in the industry, thereby endangering the lives of operators and causing major losses in production facilities.
Electric shock injury is a common industrial injury accident, which can be divided into contact electric injury and non-contact electric injury. The former is mainly caused by electric current, which can damage the internal tissues of the human body, such as the heart, respiratory system, nervous system and so on. The mild ones have acupuncture, shock, tremor, cramps, increased blood pressure, irregular heart rate and coma; the severe ones may have ventricular fibrillation, cardiac arrest, respiratory arrest and even death. The latter is mainly caused by arc damage, which is manifested by electric branding, electric burns, and skin carbonization. In severe cases, it can reach the muscles, bones and internal organs.
Researches on human electrophysiology showed that the average current of humans is 1.1mA for adult males and 0.7mA for adult females; the current is 16mA for adult males and 10.5mA for adult females. When the electric shock current is greater than the escaping current, the electric shocker cannot take the initiative to get rid of the power source. If there is no external help, the electric shock time will be prolonged and the risk of death will occur. The hands and feet are the most vulnerable parts of the human body when current passes through the body.
Classification of electrical performance protective shoes
Anti-static shoes and conductive shoes can be divided into leather shoes and cloth-soled shoes according to material. Leather shoes can be divided into adhesive type, injection type and molded type according to the production process. Electrically insulating shoes can be divided into leather shoes, cloth rubber shoes, rubber shoes and plastic shoes according to the material. According to the manufacturing process, leather shoes can be divided into adhesive type, molded type, injection type and seam type. Anti-static shoes are protective shoes that can eliminate the accumulation of static electricity in the human body and prevent electric shock from power supplies below 250V. Conductive shoes have good conductive properties, can eliminate the accumulation of human body static electricity in a short time, and can only be used for protective shoes in places without electric shock hazards. Electrically insulated shoes are protective shoes that can insulate human feet from charged objects and prevent electric shock injuries.
Technical requirements for electrical performance protective shoes
Anti-static shoes and conductive shoes are in accordance with GB4385-1995 "Technical Requirements for Anti-static Shoes and Conductive Shoes", with resistance values ranging from 100k to 1000M and not more than 100k, respectively. Among them, leather shoes should meet the requirements of GB1002-1005; cloth-soled shoes should meet the requirements of HG / T2495. The main technical properties of anti-static shoes and conductive shoes are not only electrical properties, but also the standards of outsole wear, the adhesion strength of the girdle and the upper, the outsole fold resistance, the outsole wear resistance, and the finished shoe peel strength.
Electrically insulated shoes shall comply with the provisions of GB12011-2000 "General Technical Conditions for Electrically Insulated Shoes". The electrical properties of electrically insulating leather shoes and electrically insulating cloth shoes are: when the leakage current is 0.3mA / kV, the requirements of Table 1 should be met.
The electrical properties of electrically insulating rubber boots and electrically insulating polymer material boots are: when the leakage current is 0.4 mA / kV, the requirements of Table 2 should be met.
In addition to electrical performance, the main technical properties of electrically insulating shoes include the adhesion strength of the upper and the girdle, the tensile properties of the upper, the adhesion strength of the upper and the fabric, the outsole fold resistance, the outsole wear resistance, the finished shoe peel strength, and water penetration Sex and so on.
Selection of electrical performance protective shoes
The provision of electrical performance protective shoes should be in accordance with the national standard GB11651-1989 "Rules for the selection of labor protection articles" and the "Standards for the Provision of Labor Protection Articles (Trial)" issued by the State Economic and Trade Commission on March 6, 2000 or the relevant regulations of local and industry It can also be selected according to the type of protection injury and the working environment. If the risk factor in the working environment is mainly electrostatic damage and the working ground is conductive, conductive shoes may be considered; and there may be low voltage (250V or less) electric shock If the work place is hazardous, and the working ground is anti-static ground, anti-static shoes may be considered. Anti-static shoes and conductive shoes are mainly used in petrochemical, pharmaceutical and electronic industries. If the main risk factor in the working environment is electrocution injury, electrically insulated shoes should be used when live working. In addition, users can choose protective shoes with different materials according to the working environment. For example, in most electronics and pharmaceutical industries, the environment is neat and the working intensity is relatively low (less walking). You can choose cloth anti-static shoes or conductive shoes, which are light, comfortable and breathable. In the petrochemical industry, including gas (gas) stations, the working environment is more complicated and the working intensity is relatively high (more walking). Antistatic leather shoes or conductive leather shoes can be selected, which are more resistant to dirt and wear. Similarly, in live working places with a power frequency voltage below 1kV and a relatively dry environment, electrical insulating leather shoes or electrical insulating cloth rubber shoes with a voltage resistance below 15kV can be selected. In the working place where the power frequency voltage is more than 1kV, or the environment is relatively humid, you can choose electrically insulating rubber boots or electrically insulating plastic boots with a voltage of more than 15kV. In use, it must also strictly abide by the provisions of the electrical safety work regulations (DL408 and DL409).
Leather footwear electrical performance protective shoes can also choose products with different manufacturing processes and appearance quality according to user preferences. At present, glued and injection leather shoes are more common. Seam leather shoes are mostly car tire soles and suede insulated leather shoes. Molded leather shoes are now rarely used. The appearance quality is generally easier to judge, such as whether the help surface is disabled, the color is different, the parallel thread is heavy, the needle is skipped, the thread is broken, and the needle code is uneven.