List of 56 safe working distances

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This post was last edited by wang*nhua77020 on July 10, 2016, at 16:39. List of 56 safe distances for various operations: 1. The safe distance between oxygen and acetylene cylinders is 5 meters; the safe distance between oxygen/acetylene and any ignition source is 10 meters. 2. The safe distances from equipment when it is energized are as follows: 0.7 m for 10 kV and below, 1.0 m for 35 kV, 1.5 m for 110 kV, 3.0 m for 220 kV, and 5.0 m for 500 kV. The specified value for this safety distance refers to the condition where the equipment guards are removed, taking into account the normal range of movement of workers during their tasks. 3. The safety distance from road construction blasting debris must not be less than the minimum 200m specified in the safety regulations. 4. The distance between high-pressure gas pipelines and the foundations of buildings shall be not less than 4 meters (for medium pressures of 0.4 to 0.8 Mpa) and not less than 6 meters (for medium pressures of 0.8 to 1.6 Mpa) ； The distance from street trees shall be no less than 1.2 meters ； At least 5 meters away from railway rails ； At least 2 meters away from the tram tracks ； There are no regulations regarding the distance from other roads. 5. To prevent falls in high-altitude work, work at heights of more than 2 meters is considered high-altitude work only if no fall prevention measures are in place. 6. Safe distance between cranes and overhead power transmission conductors: When the voltage is 220 kV, the distance should be 6 meters both horizontally and vertically. When the voltage is between 60–110 kV, the horizontal distance should be 4 meters, while the vertical distance should be 5 meters. 7. In the cylinder room of the oxygen production station, empty cylinders and filled cylinders should be stored separately, with a distance of more than 1.5 meters between them, and signs should be in place. 1.5 meters mentioned by the poster is also a safe distance, right? 8. Safety protection zones for railway lines should be established on both sides of the railway tracks. The extent of the safety protection zone around railway lines starts from the foot of the embankment slope, the top of the cut slope, or the outside of railway bridges, with the following distances: (1) In urban areas, it shall be no less than 8 meters ； (II) Residential areas for suburban residents: not less than 10 meters ； (III) Residential areas in villages and towns: not less than 12 meters ； (IV) In other areas, not less than 15 meters. 9. The fire safety passage shall be 3.5m wide; in the case of a dead-end passage, a parking area shall be provided at its end. 10. The height of Guanqiao on the fire road is 5 meters. 11. The safety distance between highways and oil depots is 40 meters. 12. The working area at heights should maintain a specified safe distance from overhead power lines: at least 1 meter from ordinary power lines and at least 2.5 meters from ordinary high-voltage lines. It is also necessary to prevent the conductive materials being transported from coming into contact with these lines. Even if the height is less than 2 meters, if the work area is located on a slope with a gradient of more than 45°, if there are pits, wells, rotating equipment, or items that could cause injury in the vicinity, if the working conditions are special (such as in snowy or windy weather), or if there is mechanical vibration, work must be carried out in accordance with the regulations for working at heights whenever working inside a room where toxic gases are present. Work at heights that meets the following criteria is considered special work at heights: work performed at heights of 30 meters or more above the reference level; work conducted in environments with high or low temperatures, during rainy or snowy weather, or at night; work involving proximity to or contact with energized parts; work carried out where there are no footholds or where the footholds are unstable; emergency rescue operations in the event of sudden disasters; work in confined spaces; and work at heights in locations where the emissions of toxic, harmful gases, and dust exceed permissible concentrations. 13. The distance between bottles should be 8 meters; the minimum distance shall not be less than 5 meters. 14. Safe distance from oil depots to industrial and mining enterprises: The safe distances for oil depots of grades 1, 2, 3, 4, and 5 are 60, 80, 40, 35, and 30 meters respectively. 15. The no-fire zone at the construction site must be at a distance of not less than 15 meters from the living area, and not less than 25 meters from other areas. 16. Based on the performance, structure, and operational requirements of various electrical equipment (facilities), safety distances can be roughly divided into the following four categories: 1) Safety distances for various circuits. 2) Safe distances for transformation and distribution equipment. 3) Safe spacing between various electrical equipment. 4) Safety distance during inspection and maintenance. 500kV: 5m 220kV: 3m 110kV: 1.5m 35kV: 1m 10kV: 0.7m. 17. The minimum horizontal safety distance from buildings for 10 kV high-voltage lines is 1.2 meters, and the vertical distance is 2.5 meters. To ensure the safety of residents, the power supply department has increased the height of utility poles from the original 10 meters to 12 or 15 meters. 18. When a grounding fault occurs in high-voltage equipment, what is the safe distance for a person to stand from the point of grounding? Indoors, it should be greater than 4 m; outdoors, it should be greater than 8 m. 19. For indoor lighting in normally dry areas, the vertical distance should not be less than 1.8 meters; otherwise, a safe voltage must be used.
20. For this railway line, both parties must establish safety measures for its protection. The range of safety protection for this railway line, measured outward from the edge of the railway track and from the railways bridges at the top or sides of slopes, is as follows: 1) in urban areas, not less than 8 meters; 2) in residential areas on the outskirts of cities, not less than 10 meters; 3) in villages and small town settlements, not less than 12 meters; 4) in other areas, not less than 15 meters. 21. When installing temporary wiring, the installation height shall not be less than 2.5 meters indoors and not less than 3.5 meters outdoors. 22. When oil pipelines inevitably intersect with other pipelines, the safety distance must be no less than 0.4 meters. 23. Working at heights: 1) Definition of working at heights: Work at a height of 2 meters or more above the reference surface for falling ； 2) Safety nets should be installed on scaffolds that are 6 meters or taller. 24. Where the lower end of a steel straight ladder is more than 2.4 meters above the reference level, a protective cage must be installed on the ladder! 25. Electrical construction safety regulations: 3.2 For road construction, two-lane roads should have a width of no less than 6 meters ； Single lane: not less than 3.5m ； The clearance under the jetty and overhead lines should be at least 5 m, and storage areas for materials and waste must be at a distance of more than 0.5 m from drainage ditches. 26. Technical specifications for scaffold erection: For linear and open-type scaffolds, wall connectors must be installed at both ends. The vertical spacing between these wall connectors should not exceed the floor height of the building, nor should it be more than 4 meters. Rigid wall connectors are recommended for single-row and double-row scaffolds with a certain height. 27. Transport roads should minimize curves and intersections. The curve radius for trucks should generally be no less than 15 m; in special cases, it should not be less than 10 m, with good visibility conditions. 28. When on-site roads cross ditches, a temporary bridge with sturdy structures and reliable railings on both sides should be constructed, and it may be used only after passing inspection. The width of a pedestrian footbridge must not be less than 1 m, while the width of a trolley bridge must not be less than 1.5 m. Footbridges for carriages and vehicles must be designed with a width of not less than 3.5 m. There should be reliable railings on both sides of the bridge. 29. Construction Safety Regulations: 3.2 Roads. 3.2.7 Motor vehicles on site must be driven at a reduced speed; the speed should generally not exceed 15 km/h. 30. Electrical Safety Regulations: 3.3 Stacking and storage of materials and equipment 1) Equipment shall not be stacked close to the walls of buildings; there must be a spacing of at least 0.5 m between them, and both ends must be sealed. 2) In warehouses with vehicles coming in and going out, the width of the main passages must be no less than 2.5 m, while the passages between different materials must be no less than 1.5 m. 31. Working hours in gas-filled areas – Safe working time in such areas: Work can be carried out for extended periods as long as the CO concentration does not exceed 30 mg/m3 (24 PPm). When the CO concentration does not exceed 50 mg/m3 (40 PPm), the continuous operating time shall not exceed 1 hour. When the CO concentration does not exceed 100 mg/m3 (80 PPm), the continuous operating time shall not exceed 0.5 hours. When the CO concentration does not exceed 200 mg/m³ (160 PPM), the continuous operating time should not exceed 15–20 minutes. The interval between each time workers enter the gas leak area to work is at least 2 hours. 32. Safe distance between the normal activity range of humans (workers) and live electrical equipment: 0.35 meters for 10 kV and below; 0.6 meters for 20–35 kV; 0.9 meters for 44 kV; 1.5 meters for 60–110 kV; 3 meters for 220 kV; 4 meters for 330 kV; 5 meters for 500 kV. 33. The safe distance between a grade II gas station and ordinary civilian buildings is 12 meters, while it is 10 meters for grade III gas stations. The distance between gas stations and important public buildings must be 50 meters; such important public buildings include office buildings of Party and government agencies at the prefecture level or above ； Public gathering places such as gyms, halls, conference centers, cinemas, theaters, indoor entertainment venues, stations, and passenger terminals ； Communication and command and control buildings such as postal offices and telecommunications facilities at the provincial level or above ； Office buildings of financial institutions at the provincial level and above ； Buildings such as primary and secondary schools, kindergartens, and hospitals. Ordinary commercial premises, office buildings, mixed-use buildings, high-rise residential buildings, etc. are classified as a category of protected structures that rank just below important public buildings. The safe distance from secondary gas stations should be 20 meters, and from tertiary gas stations, it should be 16 meters. 34. Large and medium-sized hazardous chemical warehouses should have a storage area and a living area; there should be a solid wall at least 2 meters high separating the two areas. The distance between this wall and the buildings in the storage area should be no less than 5 meters, and the fire separation requirements between the buildings on either side of the wall must also be met. 35. The premises engaged in the retail business of hazardous chemicals should be located at least 500 meters away from areas with a high density of residents. 36. Large- and medium-sized warehouses for hazardous chemicals should be situated at least 1,000 meters away from surrounding public buildings, major transportation routes, and industrial or mining enterprises. 37. Technical Code for Safety of Temporary Electricity Use at Construction Sites JGJ46-2005 4.1.2 The minimum safe operating distance between the perimeter of the construction site (including scaffolds) and the outer edge of overhead power lines shall comply with the requirements specified in Table 4.1.2. Table 4.1.2 Minimum safe operating distance between the perimeter of construction in progress (including scaffolding) and the outer edge of overhead power lines
Voltage level of external power lines (KV) Minimum safe operating distance (m)
<1 4.0
1–10 6.0
35–110 8.0
220 10
330–500 16

4.1.4 Cranes are strictly prohibited from operating over unprotected external overhead power lines. When lifting operations are carried out near external overhead power lines, the minimum safe distance between any part of the crane or the edge of the load, at its maximum tilt, and the edge of the overhead lines shall comply with the requirements specified in Table 4.1.4. Table 4.1.4 Minimum safe distances between cranes and the edges of overhead lines
Voltage (KV) | Safe distance (m) – Vertical direction | Safe distance (m) – Horizontal direction
<1 | 1.5 | 1.5
10 | 3.0 | 2.0
35 | 4.0 | 3.5
110 | 5.0 | 4.0
220 | 6.0 | 6.0
330 | 7.0 | 7.0
500 | 8.5 | 8.5

4.1.5 The distance between the edges of trenches dug at construction sites and the edges of trenches containing buried power cables must not be less than 0.5 meters. 4.1.6 When the requirements specified in paragraphs 4.1.2 to 4.1.4 of these specifications cannot be met, insulation isolation measures must be taken, and prominent warning signs shall be installed. 　　When installing protective facilities, approval from the relevant authorities is required; temporary power disconnection of the circuit or other reliable safety measures must be employed, and the work must be supervised by electrical engineering technicians and dedicated safety personnel. 　　The safety distance between protective facilities and external power lines shall not be less than the values specified in Table 4.1.6. 　　The protective facilities should be sturdy and stable, and the isolation protection against external electrical lines should reach IP30 level. Table 4.1.6 Minimum safe distance between protective facilities and external power lines. Voltage level of external power lines (kV): Minimum safe distance (m): ≤10 – 1.735; 2.0110; 2.5220; 4.0330; 5.0500; 6.0.4.1.7 When the protective measures specified in Article 4.1.6 of these specifications cannot be implemented, it is necessary to consult with the relevant authorities and take measures such as shutting down power supply, relocating external power lines, or changing the location of the project. Construction is strictly prohibited without taking such measures. 　　4.1.8 When excavating trenches near overhead external power lines, it is necessary to take reinforcement measures in conjunction with relevant departments to prevent the poles of the overhead external power lines from tilting or toppling over. 　　4.2 Protection of electrical equipment　　- 4.2.1 Flammable, explosive substances, sources of contamination, and corrosive media must not be stored around electrical equipment; otherwise, they must be removed or appropriately protected. The level of protection must be commensurate with the environmental conditions. 　　4.2.2 The location where electrical equipment is installed should be free from object impact and mechanical damage; otherwise, protective measures should be taken. Protection distance for falls from height: The radius of the possible fall area for A1 is denoted by R, the base height is denoted by h, and the working height is denoted by H. 　The possible falling range radius R for A2 is as follows: a. When h is 2–5 m, R is 3 m ； 　b. When h is >5–15m, R is 4m ； 　c. When h is >15–30 m, R is 5 m ； 　d. When h is > 30m, R is 6m. 38. In evacuation passages, “Emergency Exit” signs should be installed on the walls on both sides of the passage as well as at corners; the upper edge of the sign shall not be more than 1 m above the ground level. The sign can also be placed directly on the ground, covered with a non-flammable, transparent, and sturdy protective panel. The distance between signs should not exceed 20 m, and the distance from the end of the bag-shaped walkway to a sign should not be more than 10 m. 39. Fire extinguishers should be placed firmly, with their labels facing outward. Portable fire extinguishers should be placed in fire extinguisher cabinets or on hooks or brackets, with their top being no higher than 1.50 m above the ground level ； The height of the bottom from the ground should not be less than 0.08 m. Fire extinguisher cabinets must not be locked. 40. The protective shield should preferably have a closed structure. When a mesh structure is required on site, its safety distance and the size of the mesh openings must meet the following requirements: 1) To prevent injuries caused by fingers accidentally passing through, the opening width—that is, the diameter, side length, or the minor axis of elliptical openings—should be less than 6.5 mm, and the safety distance should be no less than 35 mm. 2). To prevent injury from accidental passage of fingers, the opening width: the diameter and side length or the short axis dimension of an oval hole should be less than 12.5 mm, and the safety distance should be no less than 92 mm. 3). To prevent injury caused by the accidental passage of the palm (excluding the first metacarpophalangeal joint), the opening width: the diameter and side length, or the short axis dimension of an oval opening, should be less than 20 mm, and the safety distance should be no less than 135 mm. 4) To prevent injury caused by accidental passage of the upper limbs, the opening width – whether it is a diameter or the side length, or the short axis of an oval-shaped opening – should be less than 47 mm, with a safety distance of not less than 460 mm. 5) To prevent injury caused by accidental passage of the toes, the gap between the bottom of the protective cover and the ground (or standing surface) should be less than 76 mm, with a safety distance of not less than 150 mm. 41. During normal oil and gas well operations, the blowout preventer line is installed downwind of the local monsoons, at a distance of 25 meters from the wellhead; its diameter must be at least 62 mm. The blowout valve is placed at a distance of 3 meters from the wellhead, while the pressure gauge is connected between the internal control line and the blowout valve. When performing major repairs via sidetracking on oil and gas wells, the outlet of the blowout preventer line should be connected to a safe location at least 75 meters above the wellhead, and at least 50 meters away from various facilities. 42. Temporary lines spanning roads must be at a height of more than 4 meters. 43. During the open-pit quarrying phase, when using shallow-hole blasting, the layering height shall not exceed 6 meters; when using medium-to-deep hole blasting, the layering height shall not exceed 20 meters. 44. 1) There must be a fire separation distance of at least 20 meters between warehouses storing Class A hazardous chemicals; this distance can be reduced to 12 meters if the amount stored in each warehouse is small. 2) The distance between Class A hazardous chemical warehouses and important public buildings should be at least 30 m, while the fire separation distance from other civil buildings should be at least 25 m. 3) The distance between the wall surrounding a Class A hazardous chemicals warehouse and the buildings within that area should be at least 25 meters. 4) The distance between large warehouses and adjacent residential areas as well as public buildings should not be less than 150 meters; the distance from such warehouses to nearby industrial and mining enterprises and main railway lines should not be less than 100 meters, and the distance from them to roads should not be less than 50 meters. 5) Large warehouses are generally divided into different zones; their administrative and residential areas should be located outside the warehouse area, and separated from it by a wall at least 2 meters high. 45. Safety protection zones for railway lines should be established on both sides of the railway tracks. The extent of the safety protection zone around railway lines starts from the foot of the embankment or the top of the cut, or from the outside of railway bridges, and the respective distances are as follows: (1) In urban areas, it shall be no less than 8 meters ； (II) Residential areas for suburban residents: not less than 10 meters ； (III) Residential areas in villages and towns: not less than 12 meters ； (IV) In other areas, not less than 15 meters. 46. Open flames are prohibited within 40 meters of industrial enterprises carrying out gas-related operations. 47. Safety exits should be arranged separately from the other safety exits or evacuation exits in a building; the horizontal distance between the nearest edges of two adjacent safety exits or evacuation exits should not be less than 5.0 m. 48.1. Requirements for the installation of evacuation stairs in shops in multi-story buildings. (1) Indoor evacuation stairways in shops with more than 5 floors shall be enclosed stairways (including enlarged enclosed stairwells on the first floor). (2) In underground shops, when there is one or two underground floors and the height difference between the indoor floor level and the outdoor entrance level is greater than 10 m, smoke-proof stairwells shall be installed ； Other underground shops may be equipped with enclosed stairwells, and the doors of such stairwells should be fire-resistant doors of Class B. (3) The width of the evacuation staircase shall not be less than 1.1 m. 2. Requirements for the installation of evacuation stairways in shops within high-rise buildings: (1) Smoke-proof stairwells shall be provided in Class A buildings and Class B buildings with a building height exceeding 32 m. (2) Class II buildings with a building height not exceeding 32 m shall be equipped with enclosed stairwells. (3) The width of the evacuation staircase shall not be less than 1.2 m. 49. In petrochemical enterprises, the width of fire roads should not be less than 6 m. 1) The turning radius at the inner edge of the road surface should not be less than 12 m, and 2) the clear height above the road surface should not be lower than 5 m. 3) The distance from the center of any storage tank to the two fire truck access roads in different directions shall not exceed 120 m ； 4) When there is a fire lane on only one side, the distance from the lane to the center of any storage tank should not exceed 80 m. 5) If a fire lane is available on one side, the distance from that lane to the farthest railway track should not exceed 80 m. 6) If fire lanes are available on both sides, the distance between those lanes should not exceed 200 m; if this distance exceeds 200 m, an additional fire lane must be provided in between. 7) When the railway loading/unloading lines for liquefied hydrocarbons, flammable liquids, or solids of categories A and B are dead-end tracks, the distance from the end stop to the last parking position should not be less than 20 m. 8) In the railway loading/unloading areas for liquids of categories A, B, and C, the distance between the boom pipes of two adjacent storage tanks should not be less than 10 m ； However, the distance between the boom pipes of two adjacent loading/unloading platforms for Class C liquids should not be less than 7.50 meters. Items stored in the warehouse should be kept 20 cm away from the walls. According to the Warehouse Fire Safety Management Regulations (Order No. 6 issued by the Ministry of Public Security), inventory items should be stored in categories and in stacks; each stack should cover an area of no more than 100 square meters. The distance between stacks should be at least 1 meter, the distance between stacks and walls should be at least 0.5 meters, and the distance between stacks and beams or columns should be at least 0.3 meters. The width of main passages should be at least 2 meters. Ropes should be distributed evenly along the edges of the net, with the distance between adjacent ropes meeting the requirements specified in Table 1. The length shall be not less than 0.8 m. When the rigging ropes and tying ropes are used together, the tying rope section must be lengthened; after it is tied to the side ropes, it should be folded back and tied again, so as to form at least two layers of safety netting. The spacing between adjacent tying ropes (in meters) is as follows: for flat nets: ≤0.75; for vertical nets: ≤0.75; for closely woven safety vertical nets: ≤0.4553. The width of the walkway should not be less than 700 mm, while the vertical clearance should generally be no less than 1800 mm. 1) The width of the landing should not be less than the width of 4 flight steps, and the length in the direction of travel should not be less than 850 mm. 2) The walking platform is designed for an equivalent uniformly distributed load of 200 kg/m2. 3) The landing platforms are designed for an equivalent uniformly distributed load of 350 kg/m2. 4) The maintenance platform is generally designed for an equivalent uniformly distributed load of 400 kg/m2; when this value is exceeded, it should be designed according to actual requirements or the load coefficient of the adjacent floor. 54. The three types of safety distances in safety regulations: The first type of safety distance is the distance required when the equipment is not powered off; the specified values are as follows: 0.7 m for 10 kV and below, 1.0 m for 35 kV, 1.5 m for 110 kV, 3.0 m for 220 kV, and 5.0 m for 500 kV. The second type of safety distance: it refers to the safety distance between workers and live electrical equipment within the range of their normal activities during work. This distance takes into account the farthest positions that workers might move to during normal operations, and it represents the safety distance that must be maintained from the live electrical equipment. The specified values are as follows: 10 kV and below – 0.4 m, 35 kV – 0.6 m, 110 kV – 1.5 m, 220 kV – 3.0 m, 500 kV – 5.0 m. Third type of safety distance: the safety distance between a person and a live conductor during work at ground potential. The specified values are as follows: 10 kV and below – 0.4 m, 35 kV – 0.6 m, 110 kV – 1.0 m, 220 kV – 1.8 m (1.6 m), 500 kV – 3.6 m. 55. Classification of work at heights: Level 1: Working height of 2–5 meters; Level 2: Working height of 5–15 meters; Level 3: Working height of 15–30 meters; Special level: Working height of over 30 meters. 56. Safety distance for live working 1) Definition of safety distance: The safety distance refers to the total amount of minimum air gap that must exist between the worker and the live conductors, in order to ensure personal safety. Specifically, the safety distance includes the following five types of clearance distances: minimum safety distance, minimum ground safety distance, minimum clearance between conductors, minimum safe working distance, and minimum combined clearance. At the specified safety distance, even if the highest overvoltage occurs during live working, the probability that this gap will break down is always below the pre-determined acceptable value. 2) Minimum safety distance: The minimum safety distance refers to the smallest distance that must be maintained between personnel working at ground potential and live conductors. Table 3-16 shows the specified minimum safety distances for 10kV distribution lines in the Ministry-issued \"Safety Regulations for Electric Power Work\". Table 3-16 Safe distance between persons and live conductors – Voltage level (kV) 10 Distance (m) 0.43) Minimum safe distance from ground: The minimum safe distance from ground refers to the smallest distance that must be maintained between workers performing work at the same potential on the live conductors and the surrounding grounded objects. The Ministry’s \"Regulations on Safety Procedures in the Electric Power Industry\" stipulate that the safety distance between workers performing equal-potential work on live conductors and the ground should be equal to the minimum safety distance required for workers working at ground potential from those live conductors. 4) Minimum inter-phase safety distance: The minimum inter-phase safety distance refers to the minimum distance that must be maintained between a worker working on a live conductor and the live conductors of adjacent phases. The Ministry’s \"Safety Regulations for the Electric Power Industry\" specify the minimum safe inter-phase distances as shown in Table 3-17. Table 3-17 Minimum inter-phase safety distance by voltage class (kV) 10 Distance (m) 0.65) Minimum safe working distance: The minimum safe working distance refers to the smallest distance that ground potential workers must maintain from live parts during operations, in order to ensure personal safety and taking into account the necessary movements required for the work. The basic principle for determining the minimum safe operating distance is to add a reasonable amount corresponding to human movement to the minimum safe distance. Generally, the increment can be set to 0.5m. The Ministry’s \"Safety Regulations for Electric Power Work\" specify the minimum safe working distances when working on live power line towers; the minimum safe working distance for 10kV distribution lines is shown in Table 3-18. Table 3-18 Minimum safe operating distance – Voltage level (kV) ≤10: Distance (m) 0.76. Minimum combined clearance: The minimum combined clearance refers to the sum of the distances that must be maintained between the human body and the ground, as well as between the human body and the live conductors, when the worker is at the position corresponding to the lowest 50% operating impulse discharge voltage within the combined clearance.