Interim Provisions on Safety and Health Design for Metallurgical Enterprises

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Interim Provisions on the Safety and Health Design of Metallurgical Enterprises (issued on January 26, 1988, by the Ministry of Metallurgical Industry under Document No. (88) Ye An Huan Zi No. 80) 1 General Provisions 1.1 These provisions are formulated in order to implement the principle of \"safety first, prevention first,\" to create suitable working conditions, to ensure the safety and health of employees, to improve labor productivity, and to promote the development of production and construction in metallurgical enterprises. 　　1.2 These regulations apply to the design of new construction, expansion, renovation, and major repair projects in large and medium-sized metallurgical enterprises. Any entity responsible for the engineering design of metallurgical enterprises shall, in addition to complying with these provisions, also adhere to the relevant **standards, specifications, and regulations regarding safety and health. For the design and equipment of imported projects, as well as those designed through Sino-foreign joint ventures or cooperation with foreign parties, the safety and health standards of that country may be adopted provided they are approved by our side. 　　Small metallurgical enterprises with severe occupational hazards shall also comply with these regulations. 　　1.3 In the preliminary design of construction projects, a section on safety and health must be included, and its content shall be prepared in accordance with the requirements and level of detail specified for the preliminary design of metallurgical enterprises. 　　Special safety and health projects such as safety education rooms, testing stations, first aid facilities, and occupational disease treatment facilities require separate design and cost estimates, while the cost estimates for other safety and health facilities are included in the cost estimates of their respective specialized designs. 1.4 Safety and health requirements should be integrated into the design of all relevant specialties, ensuring safety and reliability, advanced technology, and economic Rationality, as well as mutual coordination. Where possible, intrinsic safety should be achieved, and ergonomic principles should be followed in order to reconcile economic benefits with safe production. 　　1.5 When selecting a process flow, safety and health requirements must be met. The level of safety and hygiene technical equipment should be commensurate with that of the process equipment; where necessary, it should be higher than the technical standards specified for the process equipment. For tasks that remain hazardous even after technical measures have been implemented, safety protection measures should be adopted, or manual operation should be replaced by automation or remote control. 　　1.6 A safety and hygiene assessment should be conducted during the preliminary design. The main aspects of this assessment include whether indicators such as fire prevention, explosion prevention, safety distances, and dust and toxin concentrations at work sites meet the relevant safety and hygiene standards and regulations ； Compared with the safety and hygiene conditions of similar process equipment and facilities already in operation domestically, have the identified safety and hygiene issues been effectively resolved? ； Compared to before the expansion, renovation, or major repair, have there been significant improvements in safety and hygiene conditions? 　　1.7 Safety and health facilities must be designed, constructed, inspected, and put into use simultaneously with the main project. At the preliminary design review and the completion acceptance of the project, departments at the same level responsible for labor, health, public security, as well as trade union organizations must be present. Those that do not meet safety and hygiene requirements will not be accepted nor put into operation. Factories (workshops) that produce silica bricks, which pose particularly severe occupational hazards, as well as products containing tar, asphalt, and asbestos, must obtain approval from the higher-level safety authority before they can begin operations. 2 General Provisions 2.1 Design Basis and Original Data The design shall be based on sufficient and reliable evidence as well as original data. Abnormal weather conditions such as heavy rain and thunderstorms, poor engineering and hydrogeological conditions, harmful components in the ore that can affect human health, as well as problematic building materials, must all be verified before they can be used as a basis for design. 　　2.2 Site Selection 2.2.1 When selecting a site for the plant, heavy rainfall should be taken into consideration. The impact of natural disasters such as thunderstorms and typhoons, as well as special geological conditions like landslides, mudslides, karst caves, faults, and earthquakes, on the site location is considered an important factor. 　　2.2.2 The site should be avoided in areas threatened by floods or suffering from severe endemic diseases, and it should not have any adverse effects on existing or planned airports, radio stations, communication and television facilities, radar navigation systems, or other industrial buildings in the vicinity. When a factory must be built in an area where the ground level is below the flood (tidal) level, reliable flood control measures must be in place. 　　2.2.3 When selecting a site near a mining area, the collapse zones of the ore bodies should be avoided. If it is necessary to build (expand or renovate) a facility within the collapse zone of the ore body, a technical and economic comparison must be conducted; only after obtaining approval from the competent authorities may design work proceed. 　　2.2.4 The locations of facilities outside the plant, such as residential areas, water sources, slag dumps, waste rock piles, **storage areas, and tailing dams, should be determined simultaneously with the location of the plant itself, as part of an integrated planning process. Water intake points for factories (mines) must not be located in areas contaminated by pollution sources or areas where endemic diseases are common. 　　2.3 Layout of the plant (mine) area 2.3.1 The layout of facilities such as industrial areas for plants and mines, mine entrances, ventilation shafts, waste disposal sites, and residential areas should take into account factors such as the frequency of wind directions, pollution sources, and the impact of floods. 　　2.3.2 The overall transportation layout of the plant site, while meeting the requirements of the production process, shall also comply with relevant regulations regarding safety, hygiene, fire prevention, etc. Strive for short transportation distances, fast turnaround times, and fewer loading/unloading operations; avoid or minimize intersections in transportation routes as much as possible, and separate main pedestrian flows from larger freight flows. 　　2.3.3 Based on the nature of the main and auxiliary workshops in the production process flow, the functional zones of the plant area should be determined reasonably. The areas in front of the plant, the steel rolling area, and the machine repair area should preferably be located on the downwind side of the wind direction with the lowest frequency of occurrence throughout the year, and near residential areas to facilitate employees’ commutes ； Stockpiles and production facilities that consume large amounts of raw materials and fuels and cause significant pollution should be located as close as possible to the external transportation routes and docks, away from residential areas. 　　2.3.4 The planar and spatial layout of the building complex in the factory area should meet the requirements for natural ventilation and natural lighting; high-temperature workshops should avoid exposure to westward sunlight as much as possible, and the layout should be harmonious and aesthetically pleasing. 　　2.3.5 Industrial sites should take into account the slope for draining rainwater, and should have drainage and flood control measures. 　　2.3.6 The renovation and expansion project should address the issue of overcrowding in the plant area, as well as the hazards posed by highly toxic, flammable, and explosive substances. Asphalt products, foundry work, electroplating, oil depots, and other such facilities should be arranged in groups according to their category. 　　2.4 Safety and Hygiene of Production Process Equipment 2.4.1 The design of production process equipment should meet safety and hygiene requirements as well as those related to the physiological and mental health of operators. 　　2.4.2 Dust and toxic substances should be eliminated during the production process; new processes, technologies, and equipment that cause little or no harm should be developed, while outdated processes and equipment that pose serious dust and toxicity risks and are difficult to manage should be phased out. 　　2.4.3 It is advisable to use non-toxic or low-toxic raw materials in place of toxic and highly toxic ones. When toxic raw materials must be used, effective preventive measures should be taken during storage, processing, packaging, transportation, and use to minimize the risks. 　　2.4.4 The design of specialized metallurgical equipment shall take into account the requirements of the production process and be carried out in accordance with GB5083–85 \"General Principles for the Safe and Hygienic Design of Production Equipment\". The equipment manufacturing task order should include information on safety and health. The general mechanical and electrical equipment selected shall comply with ** or the technical standards of the competent authorities. The technical requirements specified in these regulations should be submitted to the manufacturer at the time of placing an order; if there are difficulties, they shall be resolved through consultation. 　　2.5 Workshop Layout 2.5.1 The workshop layout should be designed in accordance with the process requirements, so as to minimize the distance material needs to be transported, ensure smooth coordination between different processing steps, and facilitate operation and maintenance. 　　2.5.2 Equipment that generates dust, toxic gases, noise in the workshop, as well as those that use flammable and explosive materials, should be separated from one another as much as possible to reduce the scope of their impact. 　　2.5.3 Raw materials, semi-finished products, and spare parts shall have sufficient storage space as well as appropriate storage and transportation methods. Waste should be stored in designated containers, and containers for toxic waste must be sealed. 　　2.5.4 The location, quantity, and dimensions of doors and passages within the workshop should be adapted to the process equipment, walkways, transportation methods, and transportation routes. In areas where hazardous operations such as casting are carried out, there should be two or more safety exits, and safety walkways should be installed if necessary. Its width shall not be less than 1 m, and vehicle lanes should be separated from pedestrian paths as much as possible. The distance between the outer edge of the railway rail and the equipment must be no less than 1.5 m. The distance between the edge of the road for motor vehicle traffic and gates, equipment, sidewalks, as well as other buildings and structures must be no less than 1 m. Transportation routes and walkways should be indicated on the workshop floor plan. 　　2.5.5 Signals and alarm devices shall be installed at the intersections of pedestrian paths with motor vehicle lanes or mobile machinery within the workshop. 　　2.5.6 The distance between the outer edge of the equipment and the building should generally be no less than 1 m; in cases where it is difficult to meet this requirement, it must still be at least 0.8 m. 　　2.5.7 The opening of windows must not hinder the workers’ operations or the smooth flow of transportation routes. 　　2.6 Control Room 2.6.1 The design of the control room should facilitate observation and communication, ensuring that the operator can directly control all the equipment that needs to be operated from their seat. Prioritize seated posture, and use alternating sitting, standing, and walking postures when necessary. For workrooms exposed to cold, high temperatures, intense radiation, harmful gases, noise, and other factors that may pose a threat to human health, appropriate protective measures must be taken, and there must be sufficient space to ensure the operators can move around freely. 　　2.6.2 Operating rooms in high-temperature areas should be equipped with double-layer tempered glass or heat-insulating anti-fogging glass windows, with an air gap between the glass layers of not less than 0.05 m. At the bottom of the control room spanning the heat production line, insulation materials or cooling measures such as water circulation should be used. When the thermal radiation intensity is greater than 10.5 J/(cm2·min), an aluminum wire mesh or water curtain should be installed at a distance of 0.2–0.5 m outside the window. 　　2.6.3 The cab of the crane shall be designed in accordance with the provisions of Article 1.4 in GB6067–85 \"Safety Regulations for Lifting Machinery\". 　　2.7 Buildings and Structures 2.7.1 The design of buildings and structures shall, in addition to complying with building regulations and structural codes, ensure that the shape and colors of the buildings within a factory (mine) complex are harmonious with each other. 　　2.7.2 The design of buildings and structures should take full account of the characteristics of metallurgical plants. Where explosions of molten steel and slag may occur, strict waterproofing and moisture-proofing measures must be implemented ； Heat-resistant and insulating measures should be in place in areas subject to high-temperature baking ； For areas affected by shocks and vibrations, shock and vibration protection measures should be taken ； Corrosion protection measures should be in place for areas prone to corrosion ； For areas affected by acid oil erosion, acid and oil resistance measures should be taken. 　　2.7.3 The design shall specify clearly the clear height of bridge cranes, safety walkways, maintenance platforms, etc. 　　2.7.3.1 In workshops equipped with heavy and medium bridge cranes, the clear height between the top of the columns or the lower chord of the roof truss and the top of the crane trolley must be not less than 0.4 m. With a good foundation, low ground loads, and a span of less than 15 m, the clear height can be reduced to 0.22 m. Through the safety walkway at the column, the clear height from the top edge of the column to the outer edge of the bridge crane’s end should be no less than 0.55 m ； If passing through the access hole from the upper column, the width of the access hole should be no less than 0.4 m, and the height should be no less than 1.9 m. The clear height dimensions of the bridge crane are as shown in the figure below. 　　　　　　　　　　　　　The distance between the platform of the bridge crane operator’s cab and the bottom of the bridge crane beam shall be not less than 1.9 m. Each bridge crane shall be equipped with a ladder leading to the climbing operation room. When there are safety walkways on both sides, ladders should be installed evenly on each side, with the distance between the ladders not exceeding 200 m. 　　　　　　　　　　　　　The elevation of the tracks for bridge cranes must ensure safety during the lifting and lowering of the tallest equipment; the clear distance between the lower edge of the lifting mechanism and the tallest equipment should be no less than 0.5 meters. The safe distance from the lower edge of the bridge crane operator’s cab to the safety passage platform, material stacks, or vehicle facilities. It should be no less than 2 m, and the distance from the operating platform should be no less than 3 m. 2.7.3.2 For bridge cranes operating under heavy duty conditions, double-sided safety walkways should be provided; the width of these walkways must be at least 1 m. Additionally, continuous walkways spanning the entire length of the crane should be installed at both ends of the building’s gable walls. 2.7.3.3 For bridge cranes operating under moderate duty conditions, single-sided safety walkways can be used when there are two or more cranes; the width of such walkways must be at least 0.8 m. At the other end of the crane, a maintenance platform should be provided, with a length of at least 12 m. If possible, two-sided safety walkways can also be installed. 　　2.7.3.4 When no safety walkway is provided, one should be installed at each end of the bridge crane, with a length of not less than 12 m. 　　2.7.3.5 The lifting method for the maintenance bridge crane and the facilities required for maintenance shall be clearly specified in the design, and the maximum lifting capacity shall be indicated on the drawings. 　　2.7.4 Buildings with significant safety hazards should be included in the renovation plan and rectified within a specified time frame. Structures and buildings that are in use but pose safety risks must undergo technical evaluations; they may only be put back into use after being reinforced to meet safety standards. 　　2.8 Fire Protection 2.8.1 The design of metallurgical enterprises must strictly comply with the \"Fire Protection Regulations of the People’s Republic of China\", the \"Code for Fire Protection Design of Buildings\" and other relevant fire protection regulations, as well as the provisions regarding fire separation distances in the \"Code for General Layout and Transportation Design of Steel Enterprises\". 　　2.8.2 The overall layout of the plant area and the arrangement of the factory buildings must ensure unobstructed access for fire trucks, with the fire water supply network and fire hydrants arranged reasonably. And ensure there is sufficient water volume and water pressure. Buildings in metallurgical enterprises should be equipped with fire hydrants in accordance with regulatory requirements. Underground oil depots and hydraulic stations should be equipped with automatic fire detection alarms and fixed fire extinguishing systems. 　　2.8.3 Factories, station buildings, and warehouses shall have no fewer than 2 safety exits. The safe evacuation distance and the width of stairs, corridors, and doors must comply with current fire safety codes. Safety evacuation doors must open outward. 　　2.8.4 Metallurgical enterprises located in cities must establish a dedicated fire brigade in accordance with regulations if the local fire trucks are unable to reach the production facilities within 5 minutes of receiving an alarm. Large and medium-sized mines located more than 15 km away from the city should have full-time fire brigades, while small mines should establish part-time fire brigades. 　　2.8.5 The stations and warehouses of metallurgical enterprises shall store items separately according to their categories, and appropriate fire prevention measures shall be taken in accordance with different requirements. Flammable materials such as oils and chemical substances should be equipped with automatic alarm and fire suppression systems. 　　2.8.6 In pump rooms and combustible gas compression stations, in addition to a fire hydrant system, portable chemical fire extinguishers should also be installed. In addition to a fire hydrant system, the oxygen production station should also be equipped with fire extinguishing facilities; firewalls should be installed around liquid oxygen pumps and oxygen compressors. 　　Large raw material and fuel storage areas, lumber yards, as well as storage sites for semi-finished and finished products, should be equipped with a fire hydrant system. 　　2.8.7 Large rolling mills and large motors should be equipped with necessary fire extinguishing facilities. 　　2.8.8 Computer rooms in the main production workshops of large and medium-sized enterprises should be equipped with automatic fire alarm systems and fixed fire extinguishing devices ； Computer rooms in small workshops should be equipped with chemical fire extinguishers. Substations, electromagnetic stations, and control rooms should be equipped with automatic fire alarm systems and portable fire extinguishing devices. Large cable tunnels should be equipped with automatic fire alarm systems and dry spray fire extinguishing systems ； Medium-sized cable tunnels should be equipped with an automatic fire alarm system and portable fire extinguishing equipment. All cable tunnels and cable ducts shall be equipped with a fire partition every 100 meters. Fire compartments should also be provided at the cable tunnel access to the substation and electrical room. The cable shafts should be sealed off every 6 to 8 meters using non-combustible materials. When cables pass through the walls, ceilings, or floors of electrical rooms, or emerge from distribution cabinets, they should be sealed with non-combustible materials. 　　2.8.9 Transformers with a capacity greater than 1600 kVA shall be equipped with heat detectors and fixed carbon dioxide fire extinguishers. Cable structures that may be splashed by molten steel or iron should be protected with refractory materials. 　　2.8.10 The fire protection design must be approved by the local fire department. The fire-fighting equipment selected must be products that have passed **qualification testing**. 　　2.9 Explosion Protection 2.9.1 Protection against explosions caused by liquid metals and slag. 　　2.9.1.1 The water cooling equipment for blast furnaces, melting furnaces, open-hearth furnaces, converter furnaces, and electric furnaces must ensure sufficient strength and tightness during design, manufacturing, and installation, in order to prevent water from entering the high-temperature furnaces. 　　2.9.1.2 In areas where liquid metals and slag are stored, the floor must not have any pits or ditches that could easily accumulate water. If it is necessary to create trenches or pits on the ground in the production process, strict waterproofing measures must be implemented to ensure the area remains dry. The floor level in the workshop should be at least 0.3 m higher than the floor level of the factory area. 　　2.9.2 Protection against gas explosions. 　　2.9.2.1 The flanges and shaft seals of combustible gas equipment must be highly airtight, and the effective height of the water seal shall comply with GB6222–86 \"Safety Regulations for Gas in Industrial Enterprises\". 　　2.9.2.2 Nitrogen should be used for the displacement of flammable gases. 　　2.9.2.3 The electrical equipment in the gas-blowing room and the primary instrument room for combustible gases shall be of explosion-proof type. 　　2.9.3 Prevention of dust explosions. 　　2.9.3.1 Efforts should be made to control the dispersion of dusts such as aluminum, magnesium, silicon, calcium, and coal dust in the production process. Crushing operations should be carried out via remote control or inside an isolated protective chamber. 　　2.9.3.2 Interior walls should be smooth, and the floor should be level, to facilitate cleaning and prevent dust accumulation. Electrical equipment should be of explosion-proof type. 　　2.9.3.3 In closed devices or circulation systems, filling with nitrogen can be employed when conditions permit. 　　2.9.3.4 Pressure relief vents shall be provided on buildings and structures; except for aluminum and magnesium powder, the ratio of the area of these vents to the volume of the building (m2/m3) shall be 0.05–0.10. For buildings and structures with a volume exceeding 1000 m3, the pressure relief ratio may be appropriately reduced, but it must not be less than 0.03. 　　2.9.4 For workshops containing flammable gases or explosive dusts, the design shall comply with GBJ16–87 \"Code for Fire Protection Design of Buildings\". 　　2.9.5 The processing, storage, and transportation of blasting materials shall comply with the provisions of GB6722–86 \"Safety Regulations for Blasting\". 　　2.10 Antifreezing Necessary antifreezing facilities should be available in cold regions. In other regions where temperatures drop below 0°C for an extended period, antifreezing measures should also be implemented as required by production needs. 　　2.11 Boilers and Pressure Vessels The design of boilers and pressure vessels must comply with relevant regulations such as the \"Safety Supervision Regulations for Steam Boilers,\" the \"Safety Supervision Regulations for Pressure Vessels,\" and the \"Design Specifications for Steel Pressure Vessels Used in the Petrochemical Industry.\" 　　2.12 Dust and Toxic Substance Control 2.12.1 The hazards caused by dust and toxic substances should be eliminated to the greatest extent possible during the production process. For dust and toxic substances that are difficult to eliminate, process measures must be put in place to address them. 　　2.12.2 For the control of dust and toxins, the principle of unified control both inside and outside the workshop should be adhered to; the concentrations of dust and harmful gases at the work sites must comply with TJ36–79 \"Hygienic Standards for Industrial Enterprise Design\". 　　2.12.3 The sealing of gas facilities must be tight. Areas with gas, blast furnace hot blast stoves, and workplaces where leaked carbon monoxide may accumulate should be well-ventilated, and automatic carbon monoxide alarm devices should be installed wherever possible. 　　2.12.4 As much as possible, asbestos and its products should be used as little as possible or not at all. Bulk asbestos shall not be used directly. At work sites where asbestos products are handled, ventilation and purification systems as well as misting systems must be installed. 　　2.12.5 Harmful bulk materials should be handled using enclosed methods and transported via pipelines whenever possible. 　　2.12.6 For operations that generate dust, measures such as humidification or misting to reduce dust should be adopted whenever the production process permits it. 　　2.12.7 Effective dust source control measures shall be adopted at dust-generating points such as crushing, screening, and grinding wheels. 　　2.12.8 Workplaces that emit toxic and harmful substances shall be equipped with ventilation. Local exhaust airflow must not pass through the breathing zone. 　　2.12.9 In workshops that generate dust, fumes, and toxic gases, the walls, doors, windows, and floors must meet the requirements for washing and cleaning. 　　2.12.10 When the concentrations of dust, fumes, or toxic and harmful gases in the workplace are high and it is difficult to carry out centralized purification, a sealed operation room should be installed to supply fresh air. 　　2.12.11 After the dust and pollutant purification system is completed, no-load and load tests should be carried out, and the air flow distribution of the system shall meet the requirements. Three months after normal operation, an effectiveness test should be conducted, and its main technical parameters must exceed 90% of the design values. 　　2.13 Cooling in workplaces 2.13.1 The design for cooling in workplaces shall comply with TJ36–79 \"Hygienic Standards for the Design of Industrial Enterprises\". 　　2.13.2 High-temperature workshops shall take the following measures to ensure a rational layout of heat sources and proper dissipation of heat. 　　2.13.2.1 For single-span or double-span factories, the heat source should be located on the upwind side of the wind direction with the lowest frequency throughout the year. 　　2.13.2.2 In multi-span factory buildings, heat sources should be concentrated in one or two spans as much as possible. Various hot finished products, whether cooled naturally or by forced cooling, should be gathered in a designated area. 　　2.13.2.3 The time that hot finished products and semi-finished products remain in the workshop, as well as the distance they have to be transported, should be minimized as much as possible. 　　2.13.3 Thermal insulation measures shall be taken for various furnaces, equipment, and pipelines that generate heat. 　　2.13.4 The control rooms in the high-temperature operation areas of high-temperature workshops shall be equipped with air conditioning, and break rooms fitted with cooling facilities shall be provided. 　　2.13.5 Metallurgical enterprises in the local summer zone where the design calculation temperature for ventilation is above 32°C shall have high-temperature shift rest rooms equipped with cooling facilities, along with sufficient sleeping beds. The area per bed should be 2–4 cm2 (the upper limit for single beds, and the lower limit for double beds). 　　2.13.6 Large and medium-sized metallurgical enterprises should establish plants (or workshops) for producing salt-containing refreshing beverages, as well as complete facilities for health monitoring. Its production volume should meet the requirement of 3–5 liters per person per shift for workers in high-temperature environments. 　　2.14 Noise and Vibration Protection 2.14.1 Low-noise process equipment should be selected during design, and its layout should be optimized. Make full use of the terrain, sound source directivity, landscaping, etc., to separate high-noise areas from low-noise areas as much as possible. For noise sources that exceed the noise standards, measures should be taken to minimize the noise hazards. 　　2.14.2 Regarding the noise limit values for various locations within the factory area, as well as the noise emitted from noise sources within the factory to its perimeter, the provisions of GB187-85 \"Code for Noise Control Design in Industrial Enterprises\" shall be followed during design. 　　2.14.3 Ventilators, blowers, compressors, and systems for exhaust or ventilation that generate excessive noise must be equipped with silencers. Equipment such as oil grinders, diesel engines, crushers, and vibrating screens should have sound-absorbing or sound-insulating measures in place. A sound insulation wall or barrier should be installed between the high-noise span and the adjacent low-noise span within the same building. 　　2.14.4 In work areas where it is still difficult to reduce noise to 115 dB(A) even after taking measures, automated equipment or remote control should be used. For work positions requiring 8 hours of operation, where the noise level exceeds 90 dB(A), sound-insulated operation rooms or duty rooms should be provided. 　　2.14.5 In forging, heavy machinery, and other areas where vibration control is required, vibration reduction measures such as shock absorbers, vibration pads, vibration isolation trenches, or flexible connections should be employed. When it is difficult to reduce the vibration of the equipment itself, vibration isolation measures can be taken at the workers’ operating positions, or vibration-damping workbenches and anti-vibration chairs can be provided. 　　2.14.6 Electrical equipment and components with significant vibration shall have vibration prevention and reduction measures. Fuses should be installed in locations free from vibration. 　　2.15 Radiation Protection 2.15.1 For the design of applications involving radioactive isotopes, it is necessary to comply with the relevant provisions set out in GB4792–84 \"Basic Standards for Radiation Health Protection\" with regard to use, storage, transportation, handling, supervision, and management, and such designs must also be approved by the competent health authorities. 　　2.15.2 A radioactive work unit or facility may be designed only if it complies with the provisions of Article 9 of GB4792-84 \"Basic Standards for Radiation Health Protection\". 　　2.15.3 In facilities using sealed radioactive sources, external exposure protection must be addressed. 　　2.15.3.1 Radioactive sources should be used and stored in populated areas as little as possible. 　　2.15.3.2 The shielding design of radioactive work areas must ensure that the annual dose equivalent received by the operators does not exceed 50 mSv (5 rem) ； The annual dose equivalent received by personnel in adjacent work areas shall not exceed 50 mSv (0.5 rem). 　　Principles for selecting shielding materials Radioactive type Type of shielding material Examples α Ordinary materials Paper β Light materials + heavy materials Aluminum or plexiglass + iron γ Heavy materials Lead, iron, ordinary concrete Neutrons Light materials Water, paraffin 2.15.3.3 Determine the scope of the radiation source control area based on the intensity of the radiation source. Red iron cables or fences should be installed around the radiation area, with a height of over 1.5 meters. Clear signs should be installed within the radiation source control area, indicating the location, type, and intensity of the radiation source. There should also be indicator lights that show the open or closed status of the container holding the source, as well as provide hazard alerts. 　　2.15.3.4 Design the ventilation system appropriately based on the characteristics of the equipment using radioactive isotope sources. 　　2.15.4 The design of mining, concentrating, and processing enterprises for ores containing associated natural radioactive elements shall comply with the provisions of Articles 10 and 11 of GB4792-84 \"Basic Standards for Radiation Health Protection\". 　　2.15.5 Radioactive sources shall be stored in a dedicated source vault. The source and storage sites must be located far away from residential areas. The source database should be equipped with fire, water, and theft prevention facilities. The storage tank should be of the underground pit type, with cement walls having a thickness of not less than 0.3 m. The indoor floor level is 1 meter higher than the outdoor floor level. The interior should be equipped with exhaust and mechanical lifting facilities. A fence should be installed 5 meters away from the source reservoir. 　　2.16 Natural Light and Lighting 2.16.1 The design should make full use of natural light; all buildings, unless there are special requirements or constraints that prevent it, should have windows that open outward to allow natural light to enter. 　　2.16.2 The illuminance for factory building lighting shall be designed in accordance with the requirements of TJ34–79 \"Design Standards for Lighting in Industrial Enterprises\". Pedestrian walkways, work areas, and major transportation routes should all be illuminated. 　　2.16.3 According to production and maintenance requirements, where a disruption in the lighting power supply could lead to accidents, emergency lighting should be installed in the following locations, with an illuminance of not less than 1 lx. 　　2.16.3.1 Areas where work interruptions or operational errors can cause explosions, fires, or personal injuries. 　　2.16.3.2 Power plants, enterprise substations, main workshop substations, important water pump stations whose operation must not be interrupted, automatic telephone stations, and iron smelting blower stations, etc. 　　2.16.3.3 Production workshops without lighting where work-related accidents are likely to occur, or areas where danger is likely during passage. 　　2.16.3.4 Office buildings of large enterprises and crowded places such as large clubs, as well as stairways, passages, and exits. 　　2.16.3.5 Underground production lines and corridors. 　　2.16.4 For fixed and mobile lighting fixtures that are easily accessible and lack protection against electric shock, and whose installation height is less than 2.4 m, the voltage shall not exceed 36 V: (1) Areas with high humidity ； 　　(2) High-temperature areas ； 　　(3) Areas with conductive dust ； 　　(4) In areas with conductive floors (metal or particularly moist soil, brick, concrete), the voltage of hand lamps used in such areas should not exceed 12 V. 　　2.16.5 When installing lighting fixtures or laying wiring for illumination on the roof trusses of workshops, facilities that can be maintained using cranes, or maintenance walkways and platforms, should be considered. 　　2.16.6 Lighting switches shall be installed at entrances/exit points or near conveyor lines, at appropriate locations that are easily identifiable. 　　2.17 Dust and Toxic Substances Testing 2.17.1 For the hazards posed by dust and toxic substances generated during the production process, as well as the safety risks that require testing in accordance with **relevant regulations, appropriate testing equipment must be installed ； At the same time, the testing items, methods, and frequency should also be specified. 　　2.17.2 Fixed measurement holes shall be provided at the inlets and outlets of the dust purification pipeline system as well as at the dust collectors and purifiers ； In explosive dust purification systems, continuous automatic detection devices should also be installed. 　　2.18 Safety walkways, ladders, platforms, guardrails, and protective measures for other hazardous areas 2.18.1 Safety walkways. 　　2.18.1.1 Sidewalks should be provided on both sides of the main roads within the premises of large and medium-sized factories. 　　2.18.1.2 Safety walkways must be provided within the production workshop buildings; their width should be greater than 1 m, and they should be marked on both sides with yellow paint 0.08 m wide. The safety walkway installed should be equipped with railings and anti-slip steel plates, and a protective plate should be placed at the bottom of the railings. 　　2.18.1.3 The width of the safety walkway in transmission and transportation facilities should be greater than 1.2 m. 　　2.18.1.4 The clear height of overhead walkways and platforms shall generally be not less than 2.2 m. 　　2.18.1.5 For belt conveyor systems with a length of more than 100 m, a transverse pedestrian bridge should be installed every 70 m. 　　2.18.1.6 On the roller tables of steel rolling production lines, walkways equipped with insulation and protection against scale particles should be provided at locations where personnel need to cross them. Guardrails at least 1.5 meters high should be installed on bridges for pedestrians. At pedestrian bridges over the wire rolling line in areas where metal shavings and iron oxide scale may splash, protective steel railings at a height of 1.5 m or more should be installed. The pedestrian bridge should be installed at a safe location far away from the rolling mill. 　　 　　2.18.1.7 When a series of equipment is arranged in a longitudinal configuration, a bridge should be installed every 40 m. 　　2.18.2 Ladders 2.18.2.1 For equipment that requires regular inspection and maintenance at heights, steel inclined ladders should be used instead of straight steel ladders. 　　2.18.2.2 When designing steel ladders, the provisions of GB4053.1–83 \"Fixed Steel Straight Ladders\" and GB40532–83 \"Fixed Steel Sloping Ladders\" shall be followed. 　　2.18.3 Platform. 　　2.18.3.1 The location where the platform is installed and its dimensions should be determined with the principle of facilitating operation and maintenance in mind. 　　2.18.3.2 When designing fixed industrial platforms, the provisions of GB4053.4–83 \"Fixed Industrial Platforms\" shall be followed. 　　2.18.3.3 The outdoor platforms are equipped with appropriate measures to prevent water leakage. 　　2.18.4 Guardrails 2.18.4.1 Guardrails, fences, or covers must be installed in areas where people may enter and where there is a risk of falling, such as platforms, walkways, the edges of pits, and openings for access. 　　2.18.4.2 Safety barriers shall be provided for rotating bodies without protective covers, continuously movable mechanical equipment, and high-voltage hazardous areas. 　　2.18.4.3 When designing fixed industrial protective railings, GB4053 shall be followed. 3‑83 Provisions for “Fixed Industrial Guardrails”. 　　2.18.5 Protective measures for other hazardous locations. 　　2.18.5.1 Insulation protection measures shall be applied to high-temperature pipes and high-temperature materials that are within 2.5 m above platforms, walkways, and ladders and within reach of people. 　　2.18.5.2 Equipment that generates sparks, such as flame cleaners and grinding wheels, as well as equipment for straightening objects on straightening machines that may produce flying debris, shall be equipped with protective covers or shields. 　　2.18.5.3 At the openings formed by the horizontal movement of the equipment, a cover that moves with the equipment or a detachable lid should be installed. If there are difficulties, barriers that do not interfere with operations can be installed. 　　2.18.5.4 Protection covers shall be provided for drive chains, V-belts, open gears, or any rotating parts that could easily entangle people. 　　2.18.5.5 On the moving parts of machinery that perform reciprocating motion, where there are elements that could pose a risk to human safety, protective covers or safety guards must be installed. 　　2.19 Safety Colors and Safety Signs 2.19.1 Safety Colors. 　　2.19.1.1 Safety colors shall comply with the provisions of GB2893–82 \"Safety Colors\". 　　2.19.1.2 Fire hydrants, fire extinguishers, fire buckets, fire alarms, firefighting equipment, and barriers in hazardous areas where entry is strictly prohibited shall be red. 　　2.19.1.3 Yellow should be used at hazardous locations such as cranes, all types of lifting devices, winches, control panels, low beams, the edges of pits, and equipment drive shafts. 　　The frames of electric vehicles, ground crawlers, and lift trucks, the center of cranes and their beams, the pulley frames of hooks, as well as locomotive crash buffers and protective railings, should feature yellow and black alternating stripes. 　　2.19.1.4 Safety passages and emergency exits in the workshop should be painted green. 　　The main supports of the factory building, fixed equipment, toolboxes, **boxes, etc. should be green. 　　2.19.1.5 The painting and marking of various pipelines shall comply with GB7231–87. 　　2.19.2 Safety signs 2.19.2.1 Safety signs shall comply with GB2894–82 \"Safety Signs\". 　　2.19.2.2 In explosive areas such as oil depots, **warehouses, and workshops handling flammable chemical products, there must be clear, permanent signs stating “No Smoking”. 3 Professional Requirements 3.1 Mining 3.1.1 Each mine (including those with horizontal shafts) shall have two safety exits leading to the surface, with a distance between them of not less than 100 m. Wellheads and horizontal openings must be located in safe areas to avoid landslides, mudslides, floods, toxic gases, and other hazards. 　　In large mines where the ore body conditions are complex and its strike length exceeds 1000 m, safety exits should be provided at the end of the ore body or on the lower side of that end. 　　From the first intermediate section to the upper intermediate section and each mining area, there should be at least two safety exits, which should be connected to the safety exits leading to the surface. 　　3.1.2 Safety facilities such as vehicle stoppers and metal guardrails with a height of not less than 1.5 m must be installed at the shafts, inclined shaft entrances, and the head gates in the intermediate sections ； Guardrails, grills, covers, or safety barriers must be installed separately at the ceiling, chutes, and funnel openings ； Level and grade intersections should all be equipped with prominent signs and lighting. 　　3.1.3 For horizontal tunnels with a length exceeding 1000 m, and for inclined shafts with a slope of less than 30° and a vertical depth exceeding 90 m, as well as for inclined shafts with a slope greater than 30° and a vertical depth exceeding 50 m, special vehicles must be used to transport personnel. Manned transportation equipment must have comprehensive control signals. 　　New large and medium-sized open-pit mines whose distance to the main working site is over 3,000 meters, or whose vertical depth in deep pits is greater than 100 meters, or whose vertical height on slopes is greater than 150 meters, shall be equipped with transportation facilities to take workers to and from work. 　　3.1.4 The mine shaft cage lifting system and the mine and stope drainage systems must both have two independent power sources that can switch automatically to ensure a stable power supply. The cage lifting system must have two sets of reliable braking devices and fall prevention measures. 　　3.1.5 Mines must employ mechanical ventilation and establish a comprehensive ventilation system. In large mines with complex ore bodies, zoned ventilation is advisable. Mines with a fire hazard should be equipped with return air facilities and fire alarm systems. 　　When the temperature underground is above 27°C, cooling measures should be taken. Mines in cold regions should consider anti-freezing measures. 　　3.1.6 Mining designs must include provisions for ventilation and dust control. 　　3.1.7 Mining operations should be carried out using wet methods, and appropriate comprehensive control measures must be in place at locations where there is a risk of toxic dust and radiation exposure. A dust-suppression water supply system should be installed in the mine. 　　Diesel equipment must be equipped with effective exhaust gas purification systems. 　　Diesel equipment should not be used in mines containing radioactive elements and free silica, as well as in mines containing radioactive radon and its progeny products. 　　3.1.8 In mining areas subject to ground pressure hazards, treatment measures shall be determined in the design. The ground is allowed to settle, but where it may cause flooding, a drainage and flood control design must be in place. 　　3.1.9 Shafts and tunnels must determine appropriate support measures and roof management strategies based on the stability of the surrounding rock. 　　3.1.10 In areas where mineral extraction has an impact on the surface, the construction of buildings and structures should be considered carefully. 　　3.1.11 The surface waterproofing works in mining areas must be planned in conjunction with mine drainage and the dewatering of ore deposits, emphasizing prevention while combining preventive measures with drainage solutions. 　　Mines at risk of sudden inrushes of water must have effective and reliable safety measures. 　　3.1.11.1 When a river flows across the surface above an ore body, and mining underground—even with the use of safety pillars or backfilling methods—cannot ensure mining safety, special measures must be taken. 　　3.1.11.2 When mining takes place by the sea or lakes, and seawater or lake water may penetrate large amounts into the shafts or mining areas, 3.1.13 In mines where there is a risk of spontaneous combustion, reliable fire prevention and extinguishing measures must be included in the design. 　　3.1.14 Safe voltage shall be used for electrical power supply for underground lighting and lighting lamps. 　　3.1.15 In open-pit mining design, slope stability lines shall be determined and a comprehensive safety assessment shall be carried out. Buildings and structures that must be located within blast hazard areas should have reliable explosion-proof measures. 　　3.1.16 Open-pit mining should be equipped with safety blast protection facilities. 　　3.1.17 The fixed power supply lines in the stope should be installed outside the blasting hazard area; a circular power supply arrangement is preferred. Low-voltage electrical equipment in the stope shall not be grounded at zero. All kinds of handheld lighting devices should be equipped with leakage protection mechanisms. 　　3.1.18 Comprehensive dust control measures shall be taken at all dust-generating points in the open-pit mine. Air quality controllers should be installed in the cockpits of various mining equipment and vehicles. 　　3.1.19 The selection of the waste rock dump shall meet safety and health requirements. 　　3.1.20 Mines that transition from underground to open-pit operations, from open-pit to underground operations, or operate both simultaneously must have comprehensive safety measures in place. 　　3.2 Mineral Processing 3.2.1 The crushing and screening systems in the processing plant must have dust prevention measures in place. 　　3.2.2 Ventilation should be provided for the gases generated by toxic chemicals used in the flotation process. The preparation area for mineral processing chemicals should be set up separately and equipped with ventilation and purification measures. 　　3.2.3 Tailing ponds should be located away from densely populated residential areas. 　　3.3 Raw Material Yard 3.3.1 The raw material yard should be located in a centralized area to reduce the steps involved in transporting raw materials and fuels. 　　3.3.2 The car dumper cab shall be equipped with the following safety measures. 　　3.3.2.1 Signal devices 3.3.2.2 Exit accident switches, dual-limit switches, and brakes. 　　3.3.2.3 Spraying and watering device for dumping dry materials. 　　3.3.3 When a chain bucket unloader or screw unloader is used, the shaft path shall have no slope, and stoppers shall be provided. 　　3.3.4 Large powder ore piles and coal piles in areas with strong winds and heavy rainfall should be equipped with facilities for spraying a covering agent. 　　3.3.5 Mechanical loading and unloading should be used for raw materials and fuels, and the loading and unloading equipment shall be equipped with track clamps. Anchoring facilities are installed at both ends of the material yard. 　　3.3.6 Washing facilities should be installed at the main entrances and exits for vehicles in large raw material yards. 　　3.3.7 The drainage in the raw material and fuel areas should be adequate. 　　3.3.8 Flammable materials and coal storage areas shall have measures to prevent spontaneous ignition. 　　3.3.9 Bulk raw materials and fuels should preferably be transported using belt conveyors. The direction of the unloading port of the conveyor belt should be consistent with the direction of its operation, and a sturdy guide railing should be installed at the receiving end of the conveyor belt. A device for removing large pieces and metal debris should be installed in the conveyor belt input system. The tape conveyor should also be equipped with devices to prevent deviation, slipping, overload, emergency shutdown, start-up alarms, cleaning functions, and protection against longitudinal tearing. 　　Funnels that are prone to clogging should be equipped with anti-clogging devices. Chutes used for handling viscous materials should be equipped with devices to prevent material buildup and blockages. 　　Open-air long belt conveyors should be equipped with water removal devices, and the conveying section of the belt conveyor should have enclosed dust removal and purification systems or spray watering systems. 　　3.3.10 When the inclination angle of the belt conveyor corridor exceeds 6°, anti-slip measures shall be provided ； Stairs should be provided when the angle is greater than 12°. Anti-slip measures should be provided in the inclined sections of both underground passages and open-air trestles. 　　3.3.11 The clear width of the walkways in the belt conveyor corridors shall be not less than 0.8 m. The clear width of the access passage for maintenance should be no less than 0.6 m. 　　3.3.12 Fire-fighting equipment shall be installed in all buildings of the coal transportation system, and such fire-fighting equipment shall not be shared with the water supply systems used for flushing the plants. Explosion protection for electrical equipment should be considered based on specific circumstances. 　　3.3.13 When the conveyor belt passes over the following locations, drop shields should be installed: above roads or railways ； Above the water surface ； Located above the transmission device on the ground ； Above buildings and structures. 　　3.3.14 Ventilation systems shall be installed in the underground areas such as transfer sections, corridors, dump cars, and receiving tanks. Underground corridors shall have exits and entrances leading directly to the ground surface. The inclined corridor shall be provided with entrances and exits at the point where it extends above the ground, and shall have a separate lighting switch. 　　3.3.15 Metal grating plates shall be installed above all types of receiving bins and troughs. The shape of the feed trough should be hyperbolic, and a level indicator should be provided. 　　3.4 Sintering 3.4.1 The sintering production process should be changed from using hot ore to using cold ore. Belt cooling or ring cooling is recommended as the cooling method. 　　3.4.2 Equipment that generates dust or fumes must be properly sealed, and high-efficiency dust collectors should be used for dust removal. 　　3.4.3 Belt conveyors are preferred for transporting sinter, while car conveyors should be phased out. 　　3.4.4 Quicklime should be transported using sealed tank trucks or pipelines, stored in sealed mine carts, and equipped with dust removal and recovery systems. When using a conveyor belt for transportation, it should be properly sealed, dust removal equipment should be installed, and strict waterproofing measures must be taken. 　　3.4.5 For sintering machines over 75 m in length, it is advisable to use electronic scales for automatic batching. 　　3.4.6 The mix transport system in cold regions shall have measures to eliminate water mist. When there is no hot return ore, anti-freezing measures should be in place. 　　3.4.7 Dust generation sources such as the tail, nose, cooling systems, feeding systems, return ore systems, and belt conveyor loading/unloading areas must all be enclosed to prevent dust emission. 　　3.4.8 The funnel under the main flue should be equipped with a water seal zipper. 　　3.5 Coking 3.5.1 Coal storage areas and tar processing workshops should be located on the upwind side of the wind direction with the lowest frequency of occurrence throughout the year in the plant area ； The asphalt production facility should be located at the edge of the plant area. 　3.5.2 Newly built, expanded, and renovated chemical recovery processes should include naphthalene removal, ammonia removal, sulfur removal, and cyanide removal. 　　3.5.3 Stabling areas and equipment shall be enclosed and cleaned to remove dust. 　　3.5.3.1 Crusher room, coking screening building, coking storage tanks, and transfer stations of the coking transportation system. 　　3.5.3.2 Coke quenching tower of the coke oven. 　　3.5.4 The coke unloading from the coke oven should be mechanized. 　　3.5.5 In areas where asphalt fumes are generated and in the workshops for asphalt refining, the concentration of toxic gases must be strictly controlled and must not exceed the health standards. 　　3.5.6 In workshops that generate dust, toxic substances, or highly corrosive media such as acids and bases that pose significant hazards, the floor should be smooth and level, and flushing facilities should be available. There should be measures in place to handle the waste liquid from rinsing. 　　3.5.7 Cooling measures should be in place at the following locations. 　　3.5.7.1 Workers’ rest rooms and tinker’s rooms on the coke oven roof and at other high-temperature work locations. 　　3.5.7.2 Cab of the coke pusher, coal loader, coke carrier, and coke quencher. 　　3.5.7.3 Operation rooms for commutator workers, coking stack coke unloading workers, coke house workers, coke screening workers, etc. 　　3.5.8 Special high-temperature work areas such as the coke car cab shall be equipped with heat insulation and cooling measures. 　　3.5.9 Vent pipes that regularly discharge coal gas shall be equipped with an ignition device. 　　3.5.10 For scrubbing tank trucks, a tank truck scrubbing station should be provided. There should be measures in place for the treatment of waste liquids and residues. 　　3.5.11 Noise reduction measures shall be applied to Roots blowers, steam turbine blowers, and pressure relief pipes. 　　3.5.12 The refined benzene workshop shall be equipped with independent lightning protection devices as well as anti-static and fire prevention facilities. 　　3.5.13 The coal preparation chute shall have anti-clogging measures. 　　3.5.14 There shall be telephone or signal communication between the coke pusher, coke quencher, and coke stopper, enabling control of coke pushing. 　　3.6 Refractory Materials 3.6.1 The areas for raw material storage, the facilities for raw material calcination and oil impregnation, etc., should be located on the upwind side of the direction from which winds blow with the lowest frequency throughout the year in the factory area and workshops. 　　3.6.2 While ensuring production volume, the design of the refractory process should simplify the workflow as much as possible and reduce the height difference of materials. At the work locations where dust is generated during production, enclosed dust suppression and purification devices must be installed. 　　3.6.3 Raw materials should be stored in centralized warehouses, and mechanical transportation should be used as much as possible. Powder materials should be transported in sealed containers to avoid additional handling. For silica bricks, lining bricks, and oil-immersed operations where dust hazards are severe, mechanization and automation should be given priority. 　　3.6.4 The batching and mixing processes must be kept tightly sealed, with efficient dust removal facilities employed. Process control should be centralized as much as possible. 　　3.6.5 Mechanical equipment that generates significant noise, such as tube mills, ball mills, vibrating screens, and air compressors, should be equipped with noise reduction and sound insulation facilities. 　　3.6.6 For workshops that generate large amounts of heat and dust during firing, shaping, and oil dipping processes, skylights should be installed at the top, along with centralized control systems. 　　3.6.7 Brick pressing machines must be equipped with safety devices and dust prevention facilities. Where conditions permit, the brick picking operation can be automated using a robotic arm. Minimize manual shaping operations. Where possible, automatic thickness and weight inspection devices can be used for brick blank inspection. 　　3.6.8 Protective devices shall be installed on operating components such as the drive wheels of jaw crushers and the couplings in the drive sections of tube mills. 　　3.6.9 The floors must be washed with water in each process of crushing, screening, mixing, and molding. The wastewater is allowed to be discharged only after sedimentation. 　　3.6.10 Finished refractory materials should be handled mechanically as much as possible. For standardized fire-resistant standard products, transport them by container whenever possible ； Amorphous refractory materials (including bulk materials, plasticables, etc.) are packaged in bags or barrels ； Products containing tar and asphalt should be packaged in plastic bags. Bulk materials should be loaded onto vehicles using screw conveyors as much as possible, and dust control measures should be taken. 　　3.6.11 High-efficiency dust purification devices must be used in kiln operations that generate dust, as well as in processes involving tar and asphalt. 　　3.6.12 For coal gas pipelines in kilns such as rotary kilns, tunnel kilns, and drying drums, whose thermal parameters exceed the allowable values, low-pressure alarm or signal interlock devices shall be installed. 　　3.6.13 Waste generated in the production of refractory materials should be piled up in a centralized manner, and large-scale refractory manufacturing plants should be equipped with facilities for loading waste onto vehicles. 　　3.7 Ironmaking 3.7.1 The blast furnace control rooms and rest areas should be located away from the direction of the slag and tap holes, and at a certain distance from the blast furnace. It is strictly prohibited to establish offices and living/welfare facilities under the blast furnace bed. 3.7.2 The use of mine troughs for transporting materials on trains should be phased out. Conveyor belts should be used for transportation above and below the trough. When using a weighing vehicle to measure and transport materials, the vehicle should be automated. The discharge trolley above the trough and the screening system below it must be properly sealed, and dust removal and purification devices should be installed. Feed the material onto the furnace top using a glue machine. A scrap metal detection device must be installed at the discharge point at the bottom of the hopper. Protective measures to prevent the material from falling should be installed at both the feeding system and the discharge point. 　　3.7.3 The furnace top shall be equipped with lifting facilities for maintenance equipment. The furnace top equipment should be reliable in operation, flexible in material distribution, have a long service life, and good sealing performance. Flame-retardant hydraulic oil should be used in hydraulic equipment. The relief valve should be tightly sealed and operate smoothly. The blast furnace shell must be properly sealed to prevent gas leaks. 　　3.7.4 The exhaust pressure valve and vent valve shall be equipped with noise suppression devices. 　　3.7.5 The cooling water system for tuyeres in large and medium-sized blast furnaces shall be equipped with a tuyere leakage alarm device. 　　3.7.6 For the blast furnace coal powder injection system, from coal grinding to storage and transportation, reliable measures for fire prevention, explosion prevention, and dust accumulation control should be in place. Temperature, carbon monoxide, and oxygen concentration monitoring devices should be installed in the coal powder injection system. When a set value is reached, inert gas should be automatically introduced to ensure safety. The temperature at the coal powder outlet of the coal grinder must not exceed 80°C. There should be no accumulation of dead coal in the corners of the system or at the bends of the pipes. The building housing the pulverized coal injection system should be well-ventilated, and the floor should be equipped with flushing facilities. The coal crushing system should be equipped with a scrap metal detection device. Grinding equipment, conveyance pipes, and tank sections should be grounded. 　　3.7.7 Large and medium-sized blast furnaces should be equipped with automatic gas sampling devices. 　　3.7.8 When designing the tuyere platforms and slag discharge areas, due attention should be paid to improving working conditions and reducing heavy physical labor. 　　3.7.8.1 Mechanized operations should be employed in the tapping area of large blast furnaces, and the length of the slag and iron channels should be shortened as much as possible. 　　3.7.8.2 Elevators should be provided in large blast furnaces. For blast furnaces over 550 m in height, enclosed iron channels and slag channels should be used, along with one dust removal process. Local ventilation systems should be installed on the tuyere platforms, the tapping area, and the furnace top platforms. 　　3.7.8.3 When slag is punched in front of the furnace, the slag channel should be covered, and an iron accumulation pit should be provided. The slag flushing water should be filtered and reused; it must not be discharged directly. 　　3.7.9 The powdered raw materials used for grinding mud should be transported in sealed vehicles or containers. 　　3.7.10 The dust cleaning device of high-pressure gas dust collectors shall, in terms of structure, meet the requirements for safe dust cleaning under high-pressure conditions. 　　3.8 Steelmaking 3.8.1 Large and medium-sized iron and steel furnaces as well as casting facilities should be installed in separate buildings. 　　3.8.2 Dust removal facilities shall be installed at the transfer points and discharging points of the supplementary material systems in converters and electric furnaces, where dust is generated. 　　3.8.3 Newly designed converters and electric furnaces must be of the elevated type; pit-type designs are strictly prohibited. 　　3.8.4 Dust removal equipment shall be installed for off-furnace refining. 　　3.8.5 Cranes used for lifting molten iron, molten steel, and slag shall be equipped with overload alarm devices and two sets of safety protection devices to prevent exceeding limits. 　　3.8.6 The sliding nozzle of the ladle should be equipped with an automatic adjustment device for the pressure of the sliding plate. 　　3.8.7 When mold casting is used in large and medium-sized steelmaking plants (workshops), the steel pouring operation platform or position shall be equipped with cooling facilities. A safety gland device should be used for the die casting of boiling steel. 　　3.8.8 Continuous casting should be used for ingot production in large and medium-sized steel mills (workshops). If molding is used, the chassis cleaning should be carried out using a chassis tilting device and a dust removal device. Mechanized operations are advisable for tasks such as ingot mold cleaning, coating application, and insulation panel installation. 　　3.8.9 When die casting is used, a device to prevent easy ingot release should be available. 　　3.8.10 High-efficiency dust purification devices should be installed for molten iron pretreatment, slag dumping in the mixing furnace, and the mixing furnace itself. 　　3.8.11 Low-pressure gas alarms should be installed on the gas pipes used for steelmaking and on the gas pipelines of major users. 　　3.8.11 Low-pressure gas alarms should be installed on the gas pipes used for steelmaking and on the gas pipelines of major users. 　　3.8.12 The main equipment in the steelmaking plant (workshop) should be equipped with two power supplies, and major equipment such as melting furnaces and continuous casting machines should have safety measures against power outages. 　　3.8.13 Converter Steelmaking 3.8.13.1 The collection hoppers and discharge chutes in the high-level silos must be properly sealed, equipped with burst valves, and sealed using inert gas. 　　3.8.13.2 The oxygen converter body and its driving equipment shall ensure safe and continuous operation, meet the safety requirements for dealing with accidents such as converter collapse or freezing, and ensure that the converter can be reset in the event of a power outage. 　　3.8.13.3 Oxygen converters shall be equipped with dust purification devices, using water-sealed movable hoods, and shall have devices for detecting and alarming water flow differences. converters of 20t and above should be equipped with secondary dust collection and purification systems. The first-stage venturi purifier shall be equipped with an explosion relief device. When a non-combustion system is used, a device for continuously measuring oxygen content shall be installed. 　　3.8.13.4 Oxygen converters with a capacity greater than 50 t shall be equipped with a sealed converter enclosure structure and automatic furnace doors. When water cooling is used, explosion-proof measures must be in place. 　　3.8.13.5 The structural design of the oxygen lance itself should be reasonable, and the transmission equipment should be safe and reliable. There should be a backup battery power source, a mechanical automatic braking device, over-tension protection, and a wire loosening alarm device. In addition, special instruments and control devices for monitoring cooling water flow rate, temperature difference, and oxygen flow pressure should be provided. The oxygen lance hole should be equipped with a nitrogen sealing device. 　　3.8.13.6 The tilting of the converter body, as well as the lifting and lowering of the oxygen lance and auxiliary lance, as well as the lifting and lowering of the dust removal hood, shall be equipped with interlocking devices; in special circumstances, it shall be possible to disable this interlocking for independent operation. 　　3.8.13.7 The position of the converter shaking operation device shall be such that it is easy to operate. The control handle should have a safety latch and be equipped with a heat-insulating layer. Where possible, a mobile remote furnace shaking operation device should be used. 　　3.8.14 Electric furnace steelmaking 3.8.14.1 All transmission equipment in the electric furnace must ensure that it returns to its original position after one batch of steel has been produced in the event of a power outage. The electrode should be ensured to lock in place once it has been raised to a safe position or the upper limit position. The rotation and lifting of the furnace lid must ensure that it locks in its original position after returning there. 　　3.8.14.2 Transformers used for steelmaking shall be equipped with explosion-proof devices. 　　3.8.14.3 High-efficiency purification devices should be used for dust removal in electric furnaces. For ultra-high power electric furnaces, dust removal using a sealed cover should be employed as much as possible. The dust removal system should have reliable explosion-proof measures. 　　3.8.14.4 For electric furnaces of 5 tons or more, mechanical feeding is recommended. 　　3.8.14.5 When water is used to cool the walls and covers of electric furnaces, their cooling systems shall be equipped with monitoring devices for flow rate differences, temperature differences, and pressure differences, as well as alarm devices. 　　3.8.14.6 Dust removal measures shall be in place when disassembling or repairing electric furnaces. 　　3.8.15 Open-hearth steelmaking. 　　3.8 15.1 Purification devices should be installed for the dust generated in open-hearth steelmaking. Lime should be handled using mechanical means. 　　3.8.15.2 Effectively improve the working conditions for top blowing, slag removal from the slag channel chamber, and the dismantling and reconstruction of furnaces. 　　3.8.16 Continuous casting. 　　3.8.16.1 The steam generated by the cooling water of the continuous casting billet must be removed from the plant using exhaust devices. The cooling water systems for the mold and cooling section of the continuous casting machine shall be equipped with necessary instruments and alarm devices. 　　3.8.16.2 Continuous casting billets should be labeled as much as possible using a label spraying machine or an automatic printer. Purification devices should be installed for the mold of slab continuous casting machines, as well as for the dust generated by flame cutting and flame cleaning machines. 　　3.9 Steel Rolling 3.9.1 The steel rolling production process should strive to be continuous or semi-continuous, in order to reduce handling operations, and the multi-hearth conversion process should be phased out gradually. 　　3.9.2 Mechanization should be employed as much as possible for the operations before and after the horizontal rolling mill, in order to replace manual tasks such as feeding steel, turning the steel, and moving it. 　　3.9.3 Medium and large-scale rolling mills should adopt online continuous monitoring devices to replace manual inspection. 　　3.9.4 In workshops where bridge cranes are used for roll replacement, the space necessary for safe roll replacement operations must be ensured. 　　3.9.5 In large and medium-sized steel rolling workshops, an overhead safety walkway should be constructed on the side adjacent to the building. 　　3.9.6 Heating furnace. 　　3.9.6.1 Heating furnaces for steel rolling and heat treatment should preferably use liquid or gas fuels; when solid fuels are used, the feeding of such fuels and the removal of slag should be mechanized as much as possible. 　　3.9.6.2 Heating furnaces that use coal dust as fuel shall be equipped with reliable fire and explosion prevention facilities during the production, storage, and transportation of coal dust, as well as effective dust removal systems. 　　3.9.6.3 Heating furnaces that use liquid or gaseous fuels shall have a complete control system, as well as alarm and automatic shutdown devices. 　　3.9.6.4 For heating furnaces that use gaseous fuel, a venting system should be installed on the gas pipelines, and explosion-proof devices should be installed on the air pipelines. 　　3.9.6.5 The furnace’s cladding should be equipped with composite insulation measures to reduce the wall surface temperature at the furnace area and improve the operating environment. 　　3.9.6.6 The furnace shall be equipped with a safe operating platform. The operating platform in the high-temperature section should be equipped with ventilation facilities. 　　3.9.6.7 Necessary safety interlock devices shall be installed between the mechanical equipment of the furnace and the loading/unloading roller conveyors. 　　3.9.6.8 Furnaces equipped with water cooling shall have facilities to ensure safety. 　　3.9.7 Rolling. 　　3.9.7.1 Safety interlock devices shall be installed between the rolls before and after the rolling mill, the lifting platforms, the pushers, and the steel turning machines. For rolling mills controlled by automatic or semi-automatic programs, the related equipment shall have safety interlock functions. 　　3.9.7.2 Devices for removing iron oxide scale should be installed in areas where it accumulates frequently, to replace manual cleaning. Someone should pass through the metal channel, with a clear height of not less than 1.7 m and a width of not less than 0.7 m. There is a risk of remaining in areas with toxic and asphyxiating gases, so ventilation facilities should be available. 　　3.9.8 Primary rolling. 　　3.9.8.1 The spindle transfer line and spindle transfer carts shall have sufficient stability, and a safety baffle shall be installed at one end of the factory building. 　　3.9.8.2 The clamp-type crane in the soaking furnace shall have sufficient clamping force and safety protection devices. 　　3.9.8.3 The primary rolling mill shall be equipped with safety devices such as mortar-type safety pressure blocks and quick replacement mechanisms, a screw loosening mechanism for dealing with problems related to stuck steel or rolled rolls, a pressure braking device, and a pressure stroke controller, as well as safety protection facilities for the steel pipes on the lower bearing housings. 　　3.9.8.4 Safety interlock devices shall be installed between the pusher, the steel turning machine and the roller table, as well as between the ingot turntable and the roller table. 　　3.9.8.5 Facilities for removing smoke gas should be installed before and after primary rolling. 　　3.9.9 Section steel rolling mills 3.9.9.1 Mechanical and electrical interlock devices should be installed between the lifting platforms at the front and back of the rolling mill, and safety devices such as connecting guards and safety brackets should be provided between the frames. 　　3.9.9.2 Feeding devices such as elevating platforms and double-layer roller conveyors, as well as steel turning machinery, must have sufficient strength to enable smooth feeding of ingot billets, as well as to facilitate the removal of guide devices, the elimination of scale, and the handling of accidents. 　　3.9.9.3 The transfer of steel should be carried out mechanically; manual transfer is not allowed. 　　3.9.9.4 Electric or hydraulic devices shall be used for the adjustment of the rolling mill’s upper and lower pressures. 　　3.9.10 Small wire rolling mills. 　　3.9.10.1 Wire rolling should be carried out in a mechanized, continuous, and automated manner, with accident interlock devices used as much as possible. 　　3.9.10.2 Small rolling mills for finished products and wire rolling mills shall be equipped with metal guards that cover the frame from above or on the sides, to prevent the rolled products from passing through the front end. The connection parts of the protective net should be easy to remove and move. 　　3.9.11 Rolling of medium and thick plates. 　　3.9.11.1 High-pressure water or mechanical descaling should be used. 　　3.9.11.2 Mechanical and electrical interlocks shall be provided between the lifting table of the three-roll mill and the middle roll as well as the steel puller. 　　3.9.12 Cold and hot-rolled strip steel. 　　3.9.12.1 Continuous and semi-continuous rolling mills should be equipped with automatic detection devices such as online tracking, monitoring, and display systems, as well as program control, to achieve automation of the production process control. 　　3.9.12.2 The drums, guide plates, pressure rollers, swinging mechanisms, and uncoiling trolleys of hot-rolling and cold-rolling strip coilers shall be equipped with display alarms and safety interlock devices, as well as safety red lights and safety locking devices for accident handling and maintenance. 　　3.9.12.3 Automatic bundling equipment shall be provided for hot-rolled and cold-rolled sheets and coils, along with safety measures to prevent the binding straps from breaking or loosening. 　　3.9.12.4 Where possible, narrow strip mills should maximize the level of automation and install safety devices such as alarms, displays, and interlocks. 　　3.9.13 Hot-rolled thin sheets. 　　3.9.13.1 Harmless lamination coatings and roller as well as roll neck lubricants shall be used; those that use asphalt for lubrication temporarily shall be equipped with dust purification devices. 　　3.9.13.2 A panel-lifting machine should be used to replace manual panel-lifting operations. 　　3.9.14 Steel pipe rolling. 　　3.9.14.1 Major equipment such as piercing machines, tube rolling machines, and reduction machines, as well as auxiliary equipment, shall be equipped with comprehensive electrical safety interlock devices. 　　3.9.14.2 Mechanized operations should be employed for replacing the top die, push rod, and mandrel. 　　3.9.14.3 High-frequency welded pipe machines shall be equipped with protective shielding against electromagnetic fields. 　　3.9.15 Acid cleaning. 　　3.9.15.1 The acid washing and alkali washing workshops should be located separately; their foundations, floors, internal equipment, as well as the foundations of adjacent buildings, must all be equipped with acid and alkali resistance measures, and ventilation facilities should be installed. 　　3.9.15.2 Low-level acid storage tanks should be used, or acid can be pumped into the pickling tank, or it can be supplied from high-level acid storage tanks and then flow into the pickling tank. 　　3.9.15.3 The pickling tank shall be of underground type. The groove edge is more than 0.3 m above the ground level. Ventilation facilities should be installed at the edges of the troughs. 　　3.9.16 Finishing and cleaning. 　　3.9.16.1 **The cooled cold bed shall be equipped with protective covers and exhaust ventilation systems. 　　3.9.16.2 Wind shovels, shot blasting machines, and flame cleaning machines shall all be equipped with dust removal systems. Noise reduction measures, as well as protective devices such as guards and baffles. 　　3.9.16.3 The straightening machine shall use feed rollers and clamping devices for feeding, in place of manual feeding and removal operations. 　　3.10 Ferroalloys 3.10.1 Ferroalloy electric furnaces should evolve towards larger sizes, as well as semi-enclosed and fully enclosed designs; high-temperature smoke and dust should be recycled wherever possible, and microcomputer control can be utilized where conditions permit. High-efficiency purification devices should be used for the dust from ferroalloy electric furnaces. 　　3.10.2 When designing the ferroalloy raw material system and batching system, as well as systems such as electric furnaces and shaking furnaces, enclosed hoods and ventilation and purification devices should also be designed. 　　3.10.3 The hydrogen sulfide gas generated in ferroalloy slag and water-quenched ferroalloy slag must be purified. 　　3.10.4 The feeding of materials and the mixing process should be carried out in a semi-automated or automated manner. Sealing and dust removal facilities should be installed in areas where dust is generated, such as material storage bins, belt conveyors, and mixing rooms. 　　3.10.5 Raw materials for extracorporeal smelting such as aluminum granules, nitrate, and ferrosilicon powder must be stored in dedicated warehouses. Warehouse buildings and facilities within the warehouse must meet fire and explosion prevention requirements. 　　3.10.6 High- and low-voltage power lines shall not be installed above the steel scrap yard. 　　3.10.7 Center distance between two electric furnaces: For electric furnaces with a capacity greater than 12,500 KVA, this distance must be at least 30 m ； Electric furnaces with a capacity of 5,000–9,000 KVA must have a length of not less than 24 m ； Furnaces with a capacity of 5000 KVA or less must be at least 18 m in length. When installing gas purification devices between electric furnaces, the center distance between them should be increased appropriately. 　　3.10.8 For large and medium-sized ferroalloy electric furnaces, opening machines and sealing machines should be used to enable mechanized operations for tapping molten metal and sealing the furnace. The size of the taphole operation platform for electric furnaces should be determined based on the furnace type and capacity, with the principle of ensuring ease of operation for workers. 　　3.10.9 The working platform of the furnace in the workshop shall have sufficient working space and be equipped with protective railings. When designing shaking furnaces, shaking tundishes, and hot charging devices, the following safety requirements must be met ； (1) Do not block the safety passages in the workshop ； (2) Do not approach the workers’ rest room ； (3) It shall not be installed below the gas, oxygen, and water pipelines in the workshop. The horizontal distance between the pipeline and the shaking furnace must be no less than 4 m. Gas pipelines used for equipment such as stoves must be equipped with protective measures. 　　3.10.10 The floor of the pouring area within the factory building must be level, and certain sections of the floor should be covered with cast iron plates. 　　3.10.11 The casting process for ferroalloys should move toward mechanization and automation. 　　3.10.12 Large and medium-sized electric furnace workshops should have a dedicated finishing room. 　　3.10.13 Ferroalloy ingots should be mechanically crushed and transported in containers or via continuous transport, trying to avoid multiple transfers as much as possible. 　　3.10.14 The aluminum powder handling room must be constructed from materials that do not generate sparks in the event of friction or collision. The preparation of silico-calcium alloys and other flammable and explosive powders must be carried out under the protection of an inert gas. Monitoring devices for dust concentration, oxygen level, and flammable gas concentration, as well as automatic shutdown systems in case of exceeding limits, should be installed. Doors, windows, walls, etc. should meet the requirements for explosion prevention and explosion venting. Electrical equipment should be of explosion-proof type. 　　3.10.15 For the safety and health design of blast furnace production of ferroalloys, reference can be made to the provisions in section 3.7 on ironmaking. For the safety and health design of converter-based ferroalloy production, the provisions in section 3.8.13 on converter steelmaking can be referred to. 　　3.11 Carbon 3.11.1 The site should be located as close as possible to a coking plant or an oil refinery. 　　3.11.2 The process flow should be designed to minimize the amount of handling and transfer of raw materials, semi-finished products, and finished products. 　　3.11.3 Raw material warehouses should be located in a centralized area, with an effort to integrate storage and usage. The raw materials should be transported in a continuous and sealed manner. The dust point in the area should be kept under negative pressure, and dust removal and purification facilities should be installed. 　　3.11.4 Medium-temperature asphalt should be used less, while hard asphalt and modified asphalt should be used more. 　　3.11.5 Machinery must be used for loading, unloading, and transferring asphalt. The control room should be sealed. When crushing and melting asphalt, it is necessary to ensure sealing, and automation as well as remote operation should be pursued as much as possible, utilizing high-temperature rapid melting, pipeline transportation, and flue gas purification. Where possible, insulated tank trucks should be used to transport liquid asphalt. 　　3.11.6 All equipment for pre-crushing and material mixing (including all auxiliary materials) must be tightly sealed, enable automatic material feeding, and be equipped with ventilation and dust removal systems. Dust recovery and transfer should be carried out under sealed conditions. Strictly prevent secondary pollution. 　　3.11.7 Kneading, slurry, and cooling material transfer should be carried out in a continuous and sealed manner. Dust and fumes must be purified and recovered, with a flue gas collection rate of not less than 90%. 　　3.11.8 The crushing of raw products shall be done mechanically; manual breaking into large pieces is not allowed. 　　3.11.9 Except when producing extra-large varieties which require the use of reverse-flame kilns, reverse-flame kilns shall not be used for the production of other varieties. 　　3.11.10 The tank furnace should be fed in a sealed manner. Material discharge and temperature control should be carried out in the control room as much as possible. 　　3.11.11 The products after impregnation should undergo a secondary baking process. For the direct graphitization of impregnated materials, good flue gas purification facilities are necessary, with a flue gas collection rate of not less than 80%. If a forced water cooling system is used, forced ventilation must be implemented. The carbon monoxide concentration in the bridge crane operator’s cab must be strictly controlled to stay below the allowable levels. 　　3.11.12 Foundation of the graphitization furnace (including the furnace head and furnace tail); no leakage of water or steam is allowed. 　　3.11.13 The series stone blackening process is recommended. Mechanization and automation should be prioritized for roasting, graphiteization auxiliary materials, and the removal of products from the furnace. 　　3.11.14 Use mechanical means to clean carbon products, and install dust removal devices. 　　3.11.15 The control rooms for calcination and roasting, as well as the power supply control room for graphitization, shall be equipped with air purification and conditioning systems to maintain a positive pressure. 　　3.11.16 Carbon fiber production should be equipped with explosion-proof facilities and require good ventilation. Dust should be equipped with purification and capture devices. 　　3.11.17 Ingredients. Workplaces such as shaping and processing areas should be equipped with negative-pressure cleaning facilities. 　　3.12 Scrap Steel Handling 3.12.1 Scrap steel shall not be hammered by hand. 　　3.12.2 Scrap steel containing explosive, flammable, and toxic substances shall be stored in dedicated areas and processed using specialized facilities. 　　3.12.3 Special lifting equipment and grippers should be used for loading and unloading scrap steel. 　　3.12.4 Oxygen cutting of scrap steel. 　　3.12.4.1 Oxygen cutting of scrap steel should be carried out inside the factory building. When processing scrap steel blocks weighing over 10 tons, an operation room should be provided equipped with local ventilation facilities. 　　3.12.4.2 Oxygen and acetylene gases used in scrap steel processing plants (workshops) should preferably be supplied via pipelines. If bottled, separate storage chambers for the bottles should be provided. 　　3.12.5 Drop hammer treatment. Reliable protective facilities should be provided in the steel frame drop hammer chamber and the crane operator’s cab, and they must have sufficient stability and the ability to withstand impacts. 　　3.12.6 Explosion ** theory. 　　3.12.6.1 The blasting pit and cover plate shall be strong and durable; the blasting pit shall be of the \"pressure-relief type\" and equipped with \"two tunnels and exhaust holes\" – the blasting pit must have two exits. The exhaust vent should be above the floor level, and an exhaust duct should be installed behind it. 　　3.12.6.2 An electric detonator-free initiation system using detonating tubes is recommended for blasting scrap steel. If electric blasting is used, the detonation power supply should employ segmented closing. 　　3.13 Metal products, mechanical repair, and inspection (testing) – The safety and health design can follow the relevant provisions of these Regulations. 　　3.14 Electricity 3.14.1 The electrical load of enterprises should be classified, and the emergency power supply shall comply with the Provisions on the Technical Requirements for Electrical Installations in Iron and Steel Enterprises as well as GBJ58–83, Code for Design of Electrical Installations in Explosive and Flammable Areas. 　　3.14.2 The design of high and low voltage power supply and distribution systems in enterprises, as well as the lightning protection design for buildings, shall comply with the provisions of GBJ52–83 \"Code for Design of Power Supply Systems for Industrial and Civil Use\", GBJ65–83 \"Code for Grounding Design of Industrial and Civil Electrical Installations\", and GBJ232–83 \"Code for Construction and Acceptance of Electrical Installation Projects\". 　　3.14.3 The selection and installation of cables shall be carried out in accordance with the provisions of the Interim Regulations on Design Techniques for Cable Selection and Installation in Iron and Steel Enterprises. 　　3.14.4 When various conversion equipment and other nonlinear electrical devices are used in the design, they shall comply with SD126–84 \"Interim Provisions on Harmonic Management in Power Systems\". 　　3.14.5 In low-voltage circuits (AC less than 660 V, DC less than or equal to 1000 V), protective measures must be taken to prevent electric shock accidents. This type of protection can be divided into the following three categories: protection against electric shock during normal power supply ； Fault electric shock protection ； Normal power supply and fault electric shock protection. 　　The protective measures should be coordinated with the grounding method of low-voltage power grids (which are divided into TN, TT, and IT types). 　　The basic measures for protection include (1) insulation ； (2) Isolation, barriers, and protective enclosures ； (3) Grounding, neutral connection ； (4) Equipotential bonding ； (5) Safe power supplies (including isolated power supplies), etc. 　　In addition, residual current protection circuit breakers should be used as additional protection. 　　3.14.6 For the power supply of temporary or mobile equipment (including hand-held power tools), residual current protection must be used as a measure to prevent electric shock. 　　3.14.7 The color identification for protective conductors is as follows: The protective conductor (PE wire) is colored green and yellow alternatingly ； 　　The protective neutral conductor (PEN wire) is colored green/yellow, and its maintenance end should be marked with a marker that also serves as a neutral indicator ； 　　The neutral conductor (N wire) is colored light blue ； 　　To avoid accidents caused by confusion, the above two colors must not be applied to conductors used for other purposes. 　　3.14.8 Determination of the minimum cross-sectional area of the protective conductor. 　　The cross-sectional area of the protective conductor shall not be less than the value calculated by the following formula. 　　　　　　　K{1}(It) A = ------------------- K Where: A is the cross-sectional area, in mm, and must not be less than the value specified for mechanical strength ； 　　　　　I—The fault DC value (RMS of AC) caused by a fault, for which the impedance can be ignored, and which can flow through the protective device, in amperes ； 　　t — Operating time of the cutting device, s ； 　　K{1} is a coefficient that takes into account the effect of unbalanced fault current over a short period of time; it is set to 1 when t ≥ 0.25 s, and to 1.3 when t > 0.2 s. K—depends on the protection conditions, the materials of the insulation and other components, as well as coefficients for the initial and final temperatures. Copper conductor:　　　　　　　　　　　　　　　T{2} + 234 K = (116000 lg────────)　　　　　　　　　　　　　T{1} + 234
Aluminum conductor: T{2} + 228 K = (49000 lg───────)　　　　　　　　　　　　　T{1} + 228
Where: T{1} is the initial temperature of the conductor℃ ； T{2} is the final temperature of the conductor, in °C. 　　3.15 Water Supply and Drainage 3.15.1 The water supply and drainage systems and equipment shall be capable of meeting the requirements for normal water supply as well as safe water supply in the main processing operations. 　　3.15.2 Acid supply and discharge stations must be equipped with acid-resistant walls to prevent the leakage of acid in case the acid storage tanks rupture. 　　3.15.3 In the design of large-scale water pump stations (when the static water pressure is high), a safety valve must be installed behind the check valve of the water pump. 　　3.15.4 The floor elevation of the cyclone tank pump station must take into account the volume of water that will flow back into the station (into the metal channels and some pipes) in the event of a power outage, in order to prevent the station from being flooded. 　　3.15.5 The design of large pipelines must take into account emergency discharge outlets in the event of pipeline rupture. 　　3.15.6 Safety water supply pipelines shall be connected directly to the accident site using steel pipes. 　　3.15.7 The main discharge outlet of the wastewater treatment plant must be equipped with necessary monitoring and alarm instruments, as well as safety protection measures. 　　3.16 Designs involving gas such as coal gas, oxygen, steam, hydrogen, nitrogen, compressed air, and acetylene shall be carried out in accordance with current regulations and standards. 3.17 Transportation and loading/unloading 3.17.1 For the transportation of goods and the commuting of employees, appropriate transportation methods shall be selected based on the production process, volume of goods transported, characteristics of the goods, number of employees, and the distance between residential areas and the factory site; traffic flow and pedestrian flow shall be organized reasonably. At the same time, safe routes for employees to go to and from work as well as for the shuttles used in commuting should be determined, along with parking and routing areas for loading and unloading flammable and explosive goods. 　　3.17.2 Try to avoid large-scale cross-flow of people and goods. At inevitable intersections, overpasses, footbridges, underpasses, or crossing facilities should be installed in accordance with the relevant provisions of GB4387—84 \"Safety Regulations for Intra-industrial Transportation\" and \"Safety Standards for Railway Crossings in Industrial Enterprises\". 　　3.17.3 For the main rail traffic carrying hot goods and ordinary goods, level crossings should be avoided as much as possible. 　　3.17.4 The loading and unloading locations as well as the area required for storage should be determined in the design to meet production needs. The loading and unloading areas as well as storage yards should have their floors paved with suitable materials to ensure they are level, sturdy, and have good drainage. 　　3.17.5 Electric carts or trolleys that travel across spans shall be equipped with brakes, limiters, track-side cushioning devices, and protective guards. 　　3.17.6 Special lifting equipment should be used as much as possible, depending on the properties of the material. Scrap steel, billets, and steel products should be lifted as much as possible using electromagnetic cranes, and there should be a backup battery power supply along with an automatic switching device. 　　3.17.7 The main roads in large and medium-sized carbon factories and refractory factories should have concrete or asphalt pavements, along with water sprinklers or other watering facilities. 　　3.18 Living and sanitary facilities in workshops 3.18.1 The design of living facilities in workshops (rest rooms, canteens, toilets, nurseries) and sanitary facilities (health stations, bathrooms, **rooms, washrooms) shall be carried out in accordance with the provisions of TJ36—79 \"Hygienic Standards for the Design of Industrial Enterprises\". 　　The work uniforms of workers in mines and jobs involving exposure to dust and toxins should be washed in a centralized laundry facility. For outdoor work, a worker’s rest room should be provided within the work area. 　　3.18.2 The usable radius of the restroom in the workshop on the plan is 100 m. Production workshops with female employees should also have female restrooms. 　　3.18.3 Showers should be used in bathrooms. Bathtubs are prohibited in women’s bathrooms. At the same time, a women’s restroom should be provided, with 1 to 3 seats. In workshops where dust and toxins pose a serious hazard, bathrooms and **rooms should be provided simultaneously; the **rooms should be located on either side of the bathroom, with work clothes and clean clothes stored there respectively, connected by corridors. 　　3.18.4 Workers’ rest rooms should be located in areas with minimal dust and toxic pollution, as well as low noise levels. A separate smoking area should be provided in the lounge (with an area of no less than 10 m²), equipped with ventilation systems. 　　3.18.5 Mine engineering designs should include comprehensive living and welfare facilities. Each pit entrance or workshop should be equipped with nearby living and welfare facilities such as shower rooms, **rooms, workwear washing and drying areas, health stations, first-aid communication equipment, water supply stations, canteens for hot meals, worker rest rooms, female workers’ toilets, and general toilets. Underground, waiting rooms, dining halls, toilets, and water supply points should be provided at regular intervals. 　　3.18.6 The water quality of drinking water for use in factories and mines must comply with the requirements specified in TJ20—76 \"Hygienic Standards for Drinking Water\". 4 Safety and Health Institutions 　　4.1 Management Bodies and Staffing 　　4.1.1 Enterprises shall establish safety and health institutions in accordance with the provisions of Document No. Guo Fa (1979) 100, with management personnel allocated at a rate of 3–5% of the total number of employees. For enterprises with severe dust hazards and numerous safety risks, the staffing quota set during design can be appropriately relaxed. 　　4.1.2 Large and medium-sized factories (mines) and workshops should establish safety and health departments that are compatible with other management departments. 　　4.2 Training Rooms 4.2.1 Safety and hygiene training rooms are facilities where enterprises conduct centralized safety and hygiene education, training, and technical exchanges for their employees; they should consist of training classrooms, exhibition rooms, hands-on demonstration rooms, and audio-visual presentation rooms. As for its usable area, it is 1,000–2,000 m2 for large integrated enterprises ； Large mines range from 500 to 1,000 m2 ； Medium-sized enterprises are 300–500 m2 ； Small businesses cover an area of 100–300 m2. 　　4.2.2 The safety and health education room should be equipped with a video recorder/player, a radio, broadcasting equipment, photography and film developing equipment, as well as display boards. 　　4.3 Inspection Stations 4.3.1 Enterprises shall establish safety and health inspection stations to be solely responsible for conducting safety and industrial hygiene inspections within the enterprise. 　　4.3.2 The main tasks of the monitoring station are to measure and record parameters such as weather conditions, concentrations of dust and toxic substances, dust dispersion, free silica content, noise, vibration, microwave radiation, high-frequency radiation, thermal radiation, radiation dose, as well as the operating parameters of dust removal and purification equipment, along with the usage parameters of boilers and pressure vessels. 　　4.3.3 The usable area of the testing station is 800–1000 m2 for large integrated enterprises ； Large mines are 500–600 m2 ； Medium-sized enterprises are 200–300 m2. Whether a small enterprise should set up a station should be determined based on needs and collaboration conditions, but there must be a dedicated person responsible for the testing work. 　　4.3.4 The testing station should be equipped with necessary testing equipment such as safety and hygiene inspection vehicles, gas chromatographs, portable dust and toxic gas detectors, analytical balances, ultrasonic measuring instruments, X-ray flaw detectors, etc. 　　4.3.5 Testing stations can be established separately according to the needs of the enterprise, or they can be set up in conjunction with environmental protection testing stations. 　　4.4 Fire Fighting and First Aid 4.4.1 Metallurgical plants should have gas first aid stations, and the facilities within these stations shall be installed in accordance with the requirements of GB6222 \"Safety Regulations for Gas in Industrial Enterprises\". 　　The staffing and floor area of the gas rescue station in metallurgical plants are determined based on the scale of the enterprise. Large joint enterprises have 50–80 employees and a usable area of 500–700 m2 ； Medium-sized enterprises have 30–50 employees and require a usable area of 150–250 m2 ； Small businesses are set up according to the circumstances. 　　4.4.2 Mining enterprises should establish mine rescue teams based on the scale of mining operations and the potential for disasters. All mines should be equipped with ambulances, oxygen inhalers and carbon monoxide detectors, etc. 4.4.3 Enterprises’ hospitals, outpatient clinics, and health rooms should all be equipped with first-aid facilities. 　　4.5 Research Institutions and Occupational Disease Treatment 4.5.1 Large integrated enterprises should establish safety and occupational health research institutes, while medium-sized enterprises should set up institutions for the prevention and treatment of occupational diseases within their employee hospitals. 　　4.5.2 The floor area of research institutions is determined based on the established staff quota. It can be determined based on a construction quota of 50 m² per person. 　　4.5.3 The size of the Safety and Occupational Health Research Institute shall be set at 1‰ of the total number of employees. The ratio of safety and health technicians is 1:2. Each bed for occupational diseases should be equipped with 1.2 medical staff specialized in occupational diseases. The number of beds for occupational diseases is determined at 1‰ of the number of workers exposed to dust and toxins. 　　4.5.4 The Institute for Safety and Occupational Health shall be equipped with the necessary research facilities. The safety technology research section should be equipped with safety inspection vehicles, explosion-proof detectors, non-destructive testing equipment, ultrasonic thickness gauges, carbon monoxide detection devices, and more ； The industrial hygiene research section should be equipped with industrial hygiene testing vehicles, gas chromatographs, atomic absorption spectrometers, rapid detectors for dust and toxins, sound level meters, radiation detection equipment, as well as modern devices such as X-ray machines, instruments for assessing cardiopulmonary function, biochemical testing equipment, pathology and toxicology testing facilities, and ultrasound diagnostic and treatment systems. 　　4.6 Special Teams for Dust and Poison Prevention 4.6.1 Enterprises facing significant risks from dust and poisons should establish special teams for dust (poison) prevention, responsible for the operation, maintenance, and management of the technical facilities aimed at preventing such hazards within the enterprise. In mines where there is a risk of silica dust, the required number should be 5–7% of the total number of workers exposed to dust; other enterprises may determine the appropriate figure based on their own needs. 　　4.6.2 Dust (toxin) prevention workshops or sections should be equipped with work areas for sheet metal processing, component processing, filter bag cleaning and replacement, as well as the necessary working spaces. 5 Supplementary Provisions 5.1 In the event of any discrepancy between these provisions and **relevant regulations, the **regulations shall prevail. 　　5.2 The Ministry of Metallurgical Industry is responsible for interpreting these provisions.