The performance of protective footwear should be carried out in accordance with national standards or local and industrial regulations. It can also be selected according to the type of protective injury and working environment. For example, the risk factors in the working environment are mainly electrostatic damage, and the working ground is conductive ground. , consider the use of conductive shoes.
Electrical performance protective shoes are protective shoes for protecting the feet in personal protective equipment, including anti-static shoes, conductive shoes and electrically insulated shoes, which can prevent static damage and electric shock.
The harm of static electricity to the human body
The harm of static electricity to the human body is: causing psychological obstacles, generating fear, causing accidents, and skin burns and dermatitis due to electrostatic shock. The main hazard of static electricity is that industrial flammable and explosive accidents endanger the lives of workers and cause significant losses in production facilities.
Electric shock is a common industrial accident and can be divided into electrical contact and non-contact electrical damage. The former is mainly current injury, which can damage the internal tissues of the human body, such as the heart, respiratory system, and nervous system. Lighter people have a sense of acupuncture and percussion, and there are tremors, convulsions, high blood pressure, and arrhythmia until coma; in severe cases, ventricular fibrillation, cardiac arrest, respiratory arrest, and death may occur. The latter is mainly arc injury, which is characterized by electrocautery, electric burns, carbonization of the skin, and severe muscles, bones and internal organs.
The electrophysiological physiology of the researchers showed that the human perceptual current was 1.1 mA for adult males and 0.7 mA for adult females; the current for adults was 16 mA and the average for adult females was 10.5 mA. When the electric shock current is greater than the current, the electric shock can not actively get rid of the power supply. If there is no external force, the electric shock time will be prolonged and the risk of death will occur. Hands and feet are the most vulnerable parts of the body through the body.
Classification of electrical performance protective shoes
Anti-static shoes and conductive shoes can be divided into leather shoes and cloth rubber sole shoes according to materials. Leather shoes can be divided into adhesive type, injection type and molding type according to the production process. Electrically insulated shoes can be divided into leather shoes, cloth rubber shoes, rubber rubber shoes and plastic shoes according to the material. Leather shoes can be divided into adhesive type, molding type, injection type and seam type according to the production process. Anti-static shoes are protective shoes that can eliminate static electricity accumulation in the human body and prevent electric shock from power supply below 250V. The conductive shoes have good electrical conductivity and can eliminate the static electricity accumulation in the human body in a short time, and can only be used for the protective shoes without the danger of electric shock. Electrically insulated shoes are protective shoes that can insulate people's feet from live objects and prevent electric shock.
Technical requirements for protective footwear
Anti-static shoes and conductive shoes according to GB4385-1995 "anti-static shoes, conductive shoes technical requirements", the resistance value range is 100k ~ 1000M and not more than 100k. Among them, leather shoes should meet the requirements of GB1002-1005; cloth rubber soles should meet the requirements of HG/T2495. The main technical performance of anti-static shoes and conductive shoes, in addition to electrical performance, there are also the outsole wear, the adhesion of the strip and the upper, the folding of the outsole, the wear of the outsole, the peel strength of the shoes and so on.
Electrically insulated shoes shall comply with the provisions of GB12011-2000 "General Technical Conditions for Electrically Insulated Shoes". The electrical properties of electric insulating shoes and electric insulating cloth shoes are as follows: When the leakage current is 0.3 mA/kV, the requirements of Table 1 should be met.
The electrical properties of the electrically insulating rubber boots and the electrically insulating polymeric shoe are: when the leakage current is 0.4 mA/kV, the requirements of Table 2 should be met.
In addition to electrical properties, the main technical performance of electrically insulated shoes is the adhesion strength of the upper and the strip, the tensile properties of the upper, the adhesion strength of the upper and the fabric, the folding resistance of the outsole, the wear of the outsole, the peel strength of the shoes, and the water seepage. Sex and so on.
Choice of electrical performance protective shoes
The installation of electrical performance protective shoes shall be in accordance with the National Standard GB11651-1989 "Rules for the Selection of Labor Protection Products" and the "Standards for the Provision of Labor Protective Equipment (Trial)" issued by the State Economic and Trade Commission on March 6, 2000 or the relevant provisions of the local and industry. Execution can also be selected according to the type of protection injury and working environment. For example, the risk factors in the working environment are mainly electrostatic damage, and the working ground is conductive ground, you can consider the use of conductive shoes; and there may be low voltage (250V or less) electric shock For workplaces that are 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 electronics industries. If the main risk factor in the working environment is electric shock, electrical insulation shoes should be used during live working.
In addition, users can choose different performance electrical protective shoes according to the working environment. For example, in most electronics and pharmaceutical industries, the environment is relatively clean and the work intensity is relatively low (less moving). The anti-static shoes or conductive shoes on the rubber surface can be used, which is light, comfortable and breathable. The petrochemical industry, including refueling (gas) stations, the working environment is more complicated, the work intensity is relatively high (more walking), anti-static shoes or conductive shoes can be used, which is more resistant to dirt and wear. Similarly, in a live working place with a power frequency voltage of 1 kV or less, and the environment is relatively dry, electric insulating shoes or electric insulating cloth shoes with a withstand voltage of 15 kV or less can be selected. In the workplace where the power frequency voltage is above 1kV, or the environment is damp, you can use electric insulation rubber boots or electric insulation plastic boots with a withstand voltage of 15kV or higher. In use, the regulations for electrical safety work procedures (DL408 and DL409) must also be strictly observed.
Leather footwear electrical performance protective shoes can also be selected according to the user's preferences, different production processes and appearance quality products. At present, the most common ones are adhesive and injectable leather shoes. Most of the seam-type leather shoes are tire bottom and anti-wool insulated shoes, and molded shoes are rarely used now. Appearance quality is generally easier to judge, such as whether there is disability, uneven color, heavy needle, jump stitch, broken thread, uneven stitch code, whether there is open glue, off-line, sole and rubber surface Persulfur, under sulfur, sulfur spray, etc. The intrinsic quality needs to check the factory inspection certificate of the product. It is best to check the inspection report issued by the third party inspection agency approved by the national government department as the basis for judging the quality of the product.
Electrical performance protective footwear logo
Anti-static shoes, conductive shoes and electrically insulated shoes are all special protective equipment. The State implements a safety mark management and production license system for special labor protection articles. The production enterprises of such products must obtain the safety mark certificate and industrial product production license issued by the National Special Labor Protection Products Safety Sign Management Center before they can produce and sell during the validity period of the certificate. In addition, the manufacturer must also bear the mark on the product and packaging in accordance with the standard, with the product manual and certificate, as well as the safety mark and QS mark.
The outsole, insole or upper surface of anti-static shoes and conductive shoes shall have the following signs: "anti-static" / "conductive" on the sole; "GB4385" standard code; inspection seal; trademark; shoe-type shoes. The product package should have a standard code, factory name, product name, mark,
Shoe size, trademark, instructions for use, date of manufacture and production batch number. Electrically insulated shoes (boots) products shall have the following markings: on the upper or sole of each pair of shoes, there shall be a standard number, electrical insulation type (or English EH), lightning mark and withstand voltage value; manufacturer name, shoe size, Product or brand name, production date, and electrical insulation performance, factory inspection and seal. The product package should have the standard number, manufacturer name, product name (example: 6kV cow leather face insulation shoes), shoe number, trademark, instructions for use, etc.
When purchasing the above products, the company shall require the dealer to produce the test report of the batch of products, as well as the safety mark certificate and production license of the manufacturer of the product, and file the record.
Wear protective footwear
When wearing anti-static shoes and conductive shoes, you should not wear insulated wool stockings or padded insulated insoles at the same time. The place where the anti-static shoes are used should be an anti-static floor, and the place where the conductive shoes are used should be a conductive floor. During the wearing process, the resistance test should be performed once for less than 200h. Store in a dry, well-ventilated place to avoid contact with oil, acids, alkalis or other corrosive materials. Calculated from the date of production, products that have been in use for more than 18 months shall be tested for electrical performance in accordance with the standards and shall be sold and used in accordance with the requirements.
When wearing electric insulating shoes and electric insulating cloth shoes, the working environment should keep the upper dry. Wear any electrically insulated shoes to avoid contact with sharp objects, high temperature and corrosive substances, to prevent the shoes from being damaged and affecting electrical performance. Where there is corrosion or damage at the bottom, it can no longer be used as an electrically insulated shoe. Calculated from the date of production, products that have been in use for more than 24 months must be subjected to electrical performance preventive inspections. Only those that meet the requirements can be electrically insulated and sold. Each preventive test result is valid for no more than 6 months.
In addition, users can choose different performance electrical protective shoes according to the working environment. For example, in most electronics and pharmaceutical industries, the environment is relatively clean and the work intensity is relatively low (less moving). The anti-static shoes or conductive shoes on the rubber surface can be used, which is light, comfortable and breathable. The petrochemical industry, including refueling (gas) stations, the working environment is more complicated, the work intensity is relatively high (more walking), anti-static shoes or conductive shoes can be used, which is more resistant to dirt and wear. Similarly, in a live working place with a power frequency voltage of 1 kV or less, and the environment is relatively dry, electric insulating shoes or electric insulating cloth shoes with a withstand voltage of 15 kV or less can be selected. In the workplace where the power frequency voltage is above 1kV, or the environment is damp, you can use electric insulation rubber boots or electric insulation plastic boots with a withstand voltage of 15kV or higher. In use, the regulations of the Electrical Safety Work Regulations (DL408 and DL409) must also be strictly observed.