Summary of safety technical rectification measures

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Appropriate safety technical rectification measures shall be taken according to different accidents and their causes. For corrections regarding work safety incidents and key technical, management, education, and training measures, please refer to the article below. ” (1) Technical measures for fire and explosion prevention There are many factors that can trigger fires and explosions; once an accident occurs, the consequences are extremely serious. To ensure safe production, it is first necessary to carry out preventive measures to eliminate the risk factors that could cause fires and explosions. Theoretically, by controlling either of the two measures—keeping combustible materials in a non-hazardous state or eliminating all ignition sources—it is possible to prevent the occurrence of fires and chemical explosions. In practice, however, due to limitations in production conditions or the influence of certain uncontrollable factors, it is insufficient to take just one measure; multiple measures are often required to enhance the safety of the production process. In addition, other auxiliary measures should also be considered to minimize the extent of harm and reduce losses in the event of a fire or explosion. These are all issues that must be comprehensively addressed in fire and explosion prevention efforts. 　　1. Prevent the formation of flammable and explosive systems: Prevent the simultaneous presence of flammable substances, oxidizing substances (air, strong oxidizers), and ignition sources (open flames, impacts, hot objects, heat generated by chemical reactions, etc.); prevent the coexistence of explosive mixtures formed by the mixing of flammable and oxidizing substances (within their explosion limits) with ignition sources. 　　To prevent combustibles from reacting with air or other oxidizing agents and thus creating hazardous conditions, during the production process, it is necessary first to strengthen the management and control of combustibles. Non-flammable or flame-retardant materials should be used to replace combustible ones, thereby preventing any leakage or accumulation of combustibles that could form explosive mixtures. Secondly, steps must be taken to prevent air and other oxidizing substances from entering the equipment, as well as to prevent leaked combustible materials from mixing with air. 　　(1) Substitution or control of the amount used. 　　(2) Strengthen sealing. 　　(3) Ventilation and exhaust. 　　(4) Inerting. 　　2. Eliminate or control ignition sources
To prevent fires and explosion hazards, controlling ignition sources is an important measure to avoid the simultaneous presence of the three elements required for combustion. The main sources of energy that can cause fire and explosion accidents include open flames, hot surfaces, friction and impact, adiabatic compression, heat generated by chemical reactions, electrical sparks, static sparks, lightning strikes, and thermal and optical radiation. In production areas where there is a risk of fire and explosion, due attention must be paid to the following ignition sources, and strict control measures should be taken: (1) Open flames and hot surfaces. 　　(2) Friction and impact. 　　(3) Prevent electrical sparks. (II) Electrical safety technical measures
To prevent direct, indirect, and step-voltage electric shocks (electric injury), the following measures shall be taken:
1. Neutral grounding and earthing protection systems
Depending on whether the neutral point of the power supply system is grounded or not, either a protective neutral grounding system or a protective earthing system shall be adopted. In construction projects, the TN-S and TN-C-S protection systems should be preferentially adopted for low-voltage power networks with a grounded neutral point. 　　2. Leakage protection: In accordance with the requirements of \"Installation and Operation of Leakage Protectors\" (GB/13955—1992), in TN and TT protection systems where the power supply neutral point is directly grounded, leakage protectors (referred to as residual current devices in some standards) must be installed within specified equipment and locations, and a hierarchical protection system using such leakage protectors must be implemented. In devices and locations where a power outage can lead to accidents and significant financial losses in the event of a leakage current, alarm-type residual current devices should be installed. 　　3. Insulation: Depending on the environmental conditions (humidity, high temperatures, conductive dust, corrosive gases, work environments with a high metal content, such as machining, riveting, electric furnace electrode processing, forging, casting, pickling, electroplating, dyeing and printing workshops, as well as pump rooms, air compressor stations, boiler rooms, etc.), electric tools, equipment, and wires with enhanced insulation or double insulation (Class II) should be used. Insulating protective equipment (insulated gloves, insulated shoes, insulating mats, etc.) should be employed, and a non-conductive environment should be created (with floors and walls made of non-conductive materials). Such equipment and environments must not have any protective grounding or earthing systems. 　　4. Electrical isolation: An isolation transformer with equal primary and secondary voltages is used to achieve electrical isolation between the working circuit and other circuits. A grounded isolation circuit (operating circuit) is formed on the secondary side of the isolation transformer, which can block the path of the electric shock current in the event of a single-phase electric shock to a person working on the secondary side. 　　There must be enhanced insulation between the primary and secondary sides of an isolation transformer. The secondary circuit must not have any connections to other electrical circuits, the earth, or protective grounding/earthing wires. It is necessary to ensure that the voltage in the isolated circuit (secondary side) does not exceed 500 V, the length of the wiring does not exceed 200 m, and the product of the secondary voltage and wiring length, U·L, does not exceed 100,000 Vm. When the secondary circuit is relatively long, an insulation monitoring device should also be installed. In cases where multiple electrical devices are connected to the isolated circuit, equipotential bonding measures must be taken between the metal enclosures of these devices; the sockets used must have dedicated terminals for such equipotential bonding. 　　5. Safe voltage (or safe ultra-low voltage): DC power supplies should use voltages below 120V. 　　A dedicated safety isolation transformer for AC power (or a generator with equivalent isolation capability, a converter with separate windings, electronic devices, etc.) is used to provide a safe voltage supply (42 V, 36 V, 24 V, 12 V, 6 V). Class III equipment, power tools, and lighting fixtures are utilized. The rated value of the power-frequency safety voltage should be selected based on the working environment and conditions (that is, in environments such as humid, narrow metal containers, tunnels, and mines, a safety voltage of 12V is advisable). 　　Plugs and sockets used in low-voltage safety circuits shall be dedicated ones, and must not have neutral or ground plugs and sockets; fuses shall be installed on both the primary and secondary sides of the low-voltage power supply for short-circuit protection. 　　When electrical equipment uses a safe voltage of 24V or higher, protective measures must be taken to prevent direct contact with live parts. 　　6. Barriers and safe distances
(1) Barriers include shields and obstacles; they refer to devices such as fences, covers, enclosures, and boxes that prevent people from intentionally or unintentionally touching or getting too close to live parts. These are simple and effective safety devices that isolate energized parts from the surroundings and prevent individuals from accidentally entering areas with live electrical components. For example: switch boxes, busbar guards, enclosures for high-voltage equipment, barriers for power transformation and distribution equipment, etc. 　　Metal shielding devices must be connected to neutral or ground. The height of the shielding, the minimum safety distance, the mesh diameter, and the spacing between the fences shall meet the requirements specified in (Safety Requirements for Protective Screens) (GB/8197—1987). 　　Warning signs corresponding to the characteristics of the protected objects shall be posted on the barriers. When necessary, audible and visual alarm signals as well as interlock protection devices should also be installed. When a person crosses the barrier and approaches energized parts, an audible and visual alarm is triggered, and the energized parts under protection are automatically de-energized. 　　(2) The safety distance refers to the minimum electrical safety spacing that must be maintained, as specified in relevant regulations, between live parts and the ground, buildings, human bodies, other equipment, other live parts, and pipelines. The size of the safety distance depends on factors such as voltage level, device type, and installation method. It is essential to strictly adhere to the regulations regarding safety distances during design; when it is not possible to maintain such distances, other safety measures must be implemented. 　　7. Interlock protection: Install safety interlock protection devices to prevent electric shock accidents caused by misoperations or accidental entry into live areas. For example: program-operated control locks for substations, automatic transfer interlock protection devices for dual power sources, alarm systems and automatic power-off protection devices that activate when the protective covers of high-voltage hazardous equipment are opened, devices that cut off power or reduce no-load voltage in welding machines when they are idle, etc. (III) Protective measures against mechanical injuries
1. Apply inherent safety techniques
(1) Avoid sharp edges, sharp corners, and protrusions. Without compromising their intended functions, mechanical equipment and their components should, as much as possible, be designed to avoid having sharp edges, points, rough or uneven surfaces, as well as protruding parts that could cause damage. The edges of metal sheets shall be deburred, folded, or rounded; open ends that could cause scratches shall be covered. 　　(2) Principle of safe distance. Using a safe distance to prevent people from touching hazardous parts or entering hazardous areas is one way to reduce or eliminate mechanical risks. When determining the safe distance, it is necessary to take into account various conditions that may arise during machine operation, measurement data related to the human body, as well as technical and practical factors. 　　(3) Limit the physical quantities of relevant factors. Without affecting the functional capabilities, certain physical values that may pose a risk are restricted based on the distinct characteristics of various machines, in order to reduce such risks. For example, limiting the operating force to its minimum value prevents mechanical hazards resulting from damage to the control elements; restricting the mass or speed of moving parts reduces their kinetic energy; and limiting noise and vibration as well. 　　(4) Use intrinsically safe processes and power sources. For machines intended for use in explosive environments, fully pneumatic or fully hydraulic control systems and operating mechanisms should be used, or “intrinsically safe” electrical devices. It is also permissible to use power supplies with a voltage below the “functionally low voltage” level, as well as flame-retardant and non-toxic fluids in the machine’s hydraulic systems. 　　2. Limiting mechanical stress: The performance data of the materials used in machinery, as well as the design guidelines, calculation methods, and testing rules, must all comply with the professional standards or specifications for machinery design and manufacturing. This ensures that the mechanical stress on the components does not exceed allowable levels, thereby maintaining a safety factor and preventing damage or failure due to excessive stress on the components, and avoiding malfunctions or accidents. Stress is also controlled by managing the conditions of connection, loading, and motion. 　　3. Safety of materials and substances
The materials, fuels, and processing materials used to manufacture machines must not pose any risk to the safety or health of personnel during their use. 　　4. Implementation of safety ergonomics principles
In mechanical design, safety ergonomics principles should be applied through aspects such as the rational allocation of functions between humans and machines, adaptation to human characteristics, design of the human-machine interface, and arrangement of the working space. This helps improve the operability and reliability of machines, minimize the physical exertion and psychological stress on operators, thereby reducing operational errors. 　　5. Safety principles for designing control systems Typical hazardous conditions during the operation of machinery include accidental startup, uncontrolled changes in speed, inability to stop movement, projection of moving machine parts or workpieces, and failure of safety devices. The design of the control system should consider the operating modes for various tasks or incorporate fault indication devices, so that operators can safely take intervention measures. The following principles and methods shall be observed: (1) The method of initiating and varying the speed of the mechanism. The initiation or acceleration of a mechanism should be achieved by applying or increasing voltage or fluid pressure; if binary logic elements are used, this should be done by changing the state from “0” to “1”. Conversely, stopping or deceleration should be achieved by removing or reducing voltage or fluid pressure; if binary logic elements are used, this should be done by changing the state from “1” to “0”. 　　(2) Principles of restarting. When power is reconnected after an interruption, if the machine starts up on its own, it can be dangerous; therefore, measures should be taken to ensure that the machine does not start automatically upon power restoration, and it can only operate when the start button is pressed again. 　　(3) Reliability of components. This should serve as the foundation for the completeness of safety functions; the components used must be able to withstand various disturbances and stresses under the intended operating conditions, so as to prevent dangerous malfunctioning of the machine due to failure. 　　(4) Directional failure mode. This means that the main failure modes of components or systems are known in advance; therefore, preventive measures can be taken beforehand for those failure modes, provided that it’s always these components or systems that fail. 　　(5) Duplication (or redundancy) of critical components. The key components of a control system can be backed up, meaning that if a component fails, a backup can take its place to ensure the desired functionality is maintained. When combined with automatic monitoring, automatic monitoring should employ different design techniques to avoid common-cause failures. 　　(6) Automatic monitoring. The function of automatic monitoring is to ensure that when the ability of a component or element to perform its function deteriorates, or when changes in processing conditions give rise to hazards, the following safety measures are activated: halting the hazardous process, preventing automatic restart after a fault-induced shutdown, and triggering an alarm. 　　(7) Protection of safety functions in reprogrammable control systems. In critical safety control systems, reliable measures should be taken to prevent stored programs from being intentionally or unintentionally altered. If possible, a fault detection system should be used to check for errors caused by changes to the program. 　　6. Safety protection measures Safety protection refers to safety technical measures that involve the use of safety devices, protective gear, or other means to prevent various mechanical hazards; its purpose is to avoid any harm to people that may occur as a result of the machine’s operation. Protective devices and safety devices are sometimes collectively referred to as safety protection devices. The focus of safety protection lies in the mechanical transmission parts, the operation area, the areas where work is carried out at heights, other moving parts of the machinery, the areas within which mobile machinery moves, as well as special protections required for certain machines due to their specific types of hazards. The measures to be taken for protection should be determined based on the results of a risk assessment of the specific machine. 　　Safety protection devices must meet the safety technical requirements appropriate to their protective functions, and their basic safety requirements are as follows: (1) The structure and layout design should be reasonable, providing effective protection to ensure that human bodies are not harmed. 　　(2) The structure should be sturdy and durable, not prone to damage; it should be reliably installed and difficult to disassemble. 　　(3) The surface of the device should be smooth, free of sharp edges or corners, not introduce any additional hazards, and should not become a new source of danger. 　　(4) The device should not be easily bypassed or avoided, and there should be no unprotected areas. 　　(5) Meet the requirements for safety distance to prevent various parts of the body (especially hands or feet) from coming into contact with hazards. 　　(6) It shall not affect normal operation, must not come into contact with any movable parts of the machinery; it should cause minimal obstruction to human vision. 　　(7) Easy to inspect and repair. (IV) Safety measures for lifting operations The potential hazard in lifting and hoisting operations is being struck by objects. If the objects being lifted are flammable, explosive, toxic, or highly corrosive materials, any accidental drop of these items due to broken slings and rigging, damaged hooks, or violation of operating procedures could not only result in direct injury to personnel, but also damage the packaging containing such materials. This would lead to leakage of the substances, causing pollution and even resulting in accidents such as fires, explosions, corrosion, or poisoning. During inspection and maintenance, lifting equipment poses risks such as electric shock, falls from heights, and mechanical injuries, while truck cranes carry the potential risk of causing traffic accidents while in operation. (V) Safety countermeasures for internal transportation (1) Focus on proposing countermeasures regarding safety distances and safety signs, signals, pedestrian passages (including underpasses and overpasses), protective railings for railways, roadways, buildings, equipment, the edges of doors, power lines, pipelines, etc., as well as safety facilities related to vehicles, level crossings, and loading/unloading methods. 　　(2) In accordance with the “Safety Regulations for Railway and Road Transportation within Industrial Enterprises” (GB/4387—1994), the “Safety Standards for Railway Crossings in Industrial Enterprises” (GB/6386—1986), the “Safety Specifications for Powered Industrial Trucks” (CB/10827—1989), and the requirements of relevant standards in various industries, other countermeasures and measures are proposed. (3) Safety countermeasures for the storage and transportation of chemical hazards. 　　①Packaging for dangerous goods shall be marked in accordance with the “Marking for Packaging of Dangerous Goods” (GB/190—1990); ② The transportation of packaged dangerous goods shall comply with the “General Technical Requirements for Packaging of Dangerous Goods for Transport” (CB/12463—1990); ③ Labels for hazardous chemicals shall be prepared in accordance with the “Guidelines for Preparing Labels for Chemical Hazardous Substances” (GB/T 15258—1994); ④ Such substances shall be properly stored and managed in accordance with the “General Rules for Storage of Commonly Used Chemical Hazardous Substances” (GB/15603—1995); ⑤ Safety data sheets for hazardous chemicals shall be prepared in accordance with the “Regulations on Preparing Safety Data Sheets for Hazardous Chemicals” (GB/16483—1996). These sheets must include eight main sections: identification, composition and physical/chemical properties, fire and explosion hazards, toxicity and health hazards, first aid measures, protective measures, packaging, storage and transportation, as well as leakage handling and disposal. The operation, management, and use of chemical hazardous substances shall be carried out in accordance with Appendices 1 to 4 of the “Regulations on the Preparation of Safety Data Sheets for Hazardous Chemicals” (GB/16483–1996). ⑥ In accordance with Decree No. 344 issued by the State Council, “Regulations on the Safety Management of Hazardous Chemicals”, hazardous chemicals must be stored in dedicated warehouses. The storage methods, procedures, and quantities must comply with relevant **standards, and such storage must be supervised by designated personnel. When hazardous chemicals are received or dispatched, inspection and registration must be carried out. Stockpiled hazardous chemicals should be inspected regularly. For example, highly toxic chemicals such as cyanides must be stored separately in dedicated warehouses, with a system of dual-person receipt, dispatch, and custody in place. Storage facilities shall report to the local public security authorities and the department responsible for the comprehensive supervision and management of the safety of hazardous chemicals, the quantity and location of cyanide stored, as well as information regarding the personnel in charge. 　　Special warehouses for hazardous chemicals shall meet the **standards regarding safety and fire protection, and shall be marked with clear signs. The storage equipment and safety facilities in specialized warehouses for hazardous chemicals should be regularly inspected. (VI) Safety management corrective measures (1) Establish safety management systems ； (2) Establish and improve the safety management organizational structure and staffing in production and business entities ； (3) Establish and improve a long-term guarantee mechanism for safety production investment in production and business operations entities. (7) Safety training and education (1) Safety training and education for the main persons in charge of the unit and safety production management personnel ； (2) Safety training for employees ； (3) Special operation personnel must receive specialized safety operation training in accordance with **relevant regulations.