One question per week (6): Case studies for safety professionals

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A mechanical processing enterprise whose main production equipment consists of metal cutting machines such as lathes, milling machines, grinders, drilling machines, punching machines, and shearing machines. In addition, the enterprise’s workshops are equipped with a 3-ton bridge crane and 2 forklifts. Based on an analysis of the company’s accident statistics from recent years, the majority of accidents were mechanical injuries and object strikes; in 2008 alone, there were 14 incidents of finger amputations caused by punching machines. 01 Based on the above scenario, answer the following question: Briefly describe the main dangers and hazard factors present in the machinery industry. Q&A: Reference Q&A: The main dangers and hazard factors in the machinery industry include: (1) object strikes. It refers to the movement of an object under the effect of gravity or other external forces, which impacts the human body and causes injuries or deaths. It does not include object strikes caused by main mechanical equipment, vehicles, lifting machinery, collapses, etc. (2) Vehicle injuries. It refers to injury and death accidents caused by the movement of a company’s motor vehicles, such as falls of people, collapse or falling of objects, and crushing. Accidents that occur during lifting, towing of vehicles, or when vehicles are stationary are not included. (3) Mechanical injury. It refers to injuries such as compression, collision, impact, shearing, entrapment, entanglement, ejection, cutting, severing, and puncture caused by the direct contact between moving or stationary parts of mechanical equipment, tools, or workpieces with the human body; it does not include injuries caused by vehicles or lifting machinery. (4) Lifting injuries. It refers to crushes, falls, and impacts by objects (lifting devices, lifted loads), etc., that occur during various lifting operations (including the installation, maintenance, and testing of lifting machinery). (5) Electric shock. This includes electric shock from various devices and facilities, electric shock during electrical work, lightning strikes, etc. (6) Burns. It refers to burns caused by flames, scalds from hot objects, chemical burns (burns inside or outside the body caused by acids, bases, salts, or organic substances), and physical burns (burns inside or outside the body caused by light or radioactive substances). Burns caused by electrocution and fires are not included. (7) Fire. Including burns and deaths caused by fires. (8) Fall from height. It refers to injury accidents caused by falls during work at heights. Accidents caused by electric shock or falling are not included. (9) Collapse. It refers to accidents that occur when an object, under the effect of external forces or gravity, exceeds its strength limits or experiences a loss of structural stability. Such as soil and rock collapse during trenching, scaffolding collapse, collapse of piled materials, building collapse, etc. Not applicable to roof and slope failures in mines, nor to collapses caused by vehicles, lifting equipment, or blasting. (10)**Explosion. Refers to explosion accidents that occur during the production, processing, transportation, and storage of **, **, and their products. (11) Chemical explosion. It refers to explosion accidents that occur when flammable gases, dusts, etc. mix with air to form explosive mixtures and come into contact with an ignition source (including gas decomposition, spray explosions, etc.). (12) Physical explosion. This includes boiler explosions, container overpressure explosions, etc. (13) Poisoning and asphyxiation. Including poisoning, asphyxia due to lack of oxygen, and toxic asphyxia. (14) Other injuries. It refers to injuries other than those mentioned above, such as falls, sprains, contusions, abrasions, etc. 02 Based on the scenarios above, answer the following question: What effective safety measures should be taken to prevent or reduce the occurrence of mechanical injuries? Q&A: Reference Q&A: Preventing mechanical injuries involves two aspects: (1) Achieving the intrinsic safety of machinery ① Eliminating the causes of hazards ； ②Reduce or eliminate the frequency of exposure to dangerous parts of the machine ； ③Make it difficult for people to access the dangerous parts of the machine (or provide safety devices so that accessing these dangerous parts does not cause injury); ④ Provide protective devices or personal protective equipment. The above measures are listed in order, but can also be applied together. (2) Protecting the safety of operators and relevant personnel ① Improving people’s ability to identify hazards through training ； ②By redesigning the machine to make dangerous areas more visible, or by using warning signs ； ③Improve the ability to avoid harm through training ； ④Take the necessary actions to enhance awareness of avoiding harm. 03 Briefly describe the safety measures to prevent electric shock. FAQ: Refer to the FAQ: The safety measures to prevent electric shock mainly include: (1) Protection against direct contact, which primarily involves insulation, shielding, and proper spacing. Insulation refers to the use of insulating materials to enclose and isolate live electrical components ； Protection is a means of isolating factors that pose a risk of electric shock; it involves using barriers, guards, covers, enclosures, etc. to separate dangerous live parts from the outside world, thereby preventing electric shock accidents caused by human contact or proximity to those live parts ； Clearance refers to the necessary safety distance between a live conductor and the ground, between a live conductor and other equipment and facilities, and between live conductors themselves. (2) Protective measures against indirect contact electric shock mainly refer to the grounding system. There are three types of grounding systems: the IT system, the TT system, and the TN system. The IT system is also known as protective grounding, while the TN system is known as protective neutral grounding.