Basic safety knowledge for the inspection, repair, and renovation of desulfurization towers

Thread Content

Basic safety knowledge for the inspection and renovation of desulfurization towers. Recently, a scaffold inside the desulfurization tower at Jiujiang Steel Plant in Hukou County, Jiangxi Province, collapsed suddenly, resulting in 2 deaths and 18 injuries. A desulfurization tower is a tower-type device used for removing sulfur from industrial waste gases. During inspection, repair, and modification work, accidents such as falls from heights, object strikes, electric shocks, and gas poisoning can occur, so it is necessary to take extra precautions to ensure safety during these operations. 　　Fall from height Causes: Improper installation of ladders with excessive spacing between steps; scaffolding planks that do not meet the required standards, including hollow or protruding planks; incorrect use of safety belts or failure to wear them at all; workers applying too much force while working; sitting on the railings to rest; workers being in poor mental condition. 　　Prevention: 1. The erection and dismantling of scaffolding must be carried out by professionals with qualifications for working at heights. 　　2. Scaffolding must be approved upon inspection before it can be used; when working at heights, safety belts and fall arrest devices must be worn. 　　3. The safety belt should be worn with it positioned high and used low; the hook of the safety belt should be adjusted accordingly as the height of the scaffolding changes. 　　4. Temporarily removed fences should be secured promptly with support poles, and warning signs should be placed to prevent falls from heights. 　　5. Ensure that the planks, fasteners, and scaffolding bars placed on the platform are secure, with the standard being that they do not impede movement. 　　Object impact – Causes: Chaos at work sites at heights, with tools, materials, equipment, etc. falling from above; objects being thrown carelessly from high places; inadequate securing of materials during lifting, resulting in breaks in ropes, slings, etc., and subsequent falls of the lifted items; transfer of objects by throwing them when installing or removing scaffolding; improper clothing worn by workers during sandblasting and grinding of the desulfurization tower surfaces, as well as incorrect handling methods. 　　Precautions: 1. When lifting components such as scaffold poles and planks, a fence should be used to enclose the area below; no one is allowed to stand inside that fence. 　　2. Unauthorized personnel are strictly prohibited from entering the lifting area. 　　3. Crane operators must remain focused and follow unified command signals; illegal operations are strictly prohibited. 　　4. The winch must be operated by a dedicated person under the supervision of another dedicated person. 　　5. The lifting site must have sufficient access paths for movement; a test lift at a low height should be carried out before actual lifting to verify the safety and stability of the lifting points. 　　6. The ropes used for lifting must not be worn out. 　　7. When lifting an object, the slings must be tied securely; one must not approach it until it is stable at a high altitude. 　　8. When transporting steel materials into the tower through the access hatch at the bottom of the desulfurization tower, proper communication is necessary; the people inside the tower should stand on both sides of the access hatch to avoid being injured by the materials being delivered. 　　9. Clean up construction debris at the site in a timely manner to eliminate the risk of objects falling from heights. 　　Electric shock – Causes: Exposed power cords of welding machines and explosion-proof lighting fixtures; welding machines that are not properly grounded and lack leakage protection devices; substandard power distribution panels, sockets, and switches; workers’ clothing and protective equipment that do not meet the required standards. 　　Prevention 1. Conduct safety and technical briefings prior to construction. 　　2. The power switch for electrical tools should be located outside the desulfurization tower, with clear markings. 　　3. Take rainproof measures for welding machines and power supply boxes; welding machines must have a reliable grounding system and be equipped with leakage protectors. 　　4. Low-voltage explosion-proof lighting fixtures should be used for interior lighting in the desulfurization tower, while transformers and switches should be placed outside the manhole. 　　5. Assign a supervisor outside the manhole door. 　　6. Welding shall be carried out by electrical professionals. 　　Gas poisoning – Causes: The anti-corrosion coating used in desulfurization towers is a special vinyl flake coating, whose chemical composition includes styrene. If the concentration of styrene is too high, it can irritate the eyes and skin. When inhaled by humans, it can cause inflammation of the mucous membranes and respiratory system, as well as severe damage to the kidneys, liver, and central nervous system, leading to gas poisoning. Inadequate ventilation systems result in poor air circulation. Workers performing the anti-corrosion coating tasks do not wear protective gloves and goggles with activated carbon and particle-filtering capabilities. There are too many workers carrying out these tasks, and large amounts of coating remain inside the tower. 　　Prevention: 1. Before carrying out anti-corrosion spraying, use a combustible gas detector for testing. 　　2. Use a styrene detector to conduct a thorough inspection of the area where desulfurization tower operations take place (especially dead corners and areas with poor air circulation), and carefully record the explosion-proof concentrations for flammable and explosive gases as well as toxic gases. Construction work can only proceed once all standards are met. 　　3. Strictly control the time that workers spend in areas with harmful gases, generally not exceeding 4 hours. It is necessary to gradually increase the number of construction workers while ensuring their safety. 　　4. If the concentration of harmful gases exceeds the limit, construction must be suspended, all personnel must be evacuated from the tower, and ventilation must be enhanced. 　　5. In the event of gas poisoning among personnel, immediately inform the project team leaders, who shall then report to the company’s management right away, while simultaneously activating the fire emergency plan. 　　Fire – Causes: There are a large number of scaffolding planks and mist eliminators inside the desulfurization tower, and the special coatings used have a low flash point, making them prone to combustion. Fires can easily occur during the removal of old pipe fittings and nozzles as well as during anti-corrosion coating applications. Fire blankets are not placed properly beneath areas where welding or gas cutting is being carried out; when welding and gas cutting are done simultaneously, falling slag can damage acetylene and oxygen hoses. Prolonged welding and gas cutting operations can cause the temperature of the fire blankets in those areas to become too high. The operating environment may be too hot, with temperatures exceeding 33 degrees Celsius. Workers are not wearing appropriate clothing, such as cotton or anti-static work clothes. The hooks and clamps of safety belts are not properly covered with insulating tape. Low-voltage explosion-proof lighting fixtures are not used. There are also a large amount of flammable materials such as coatings inside the desulfurization tower. 　　Prevention: 1. The safety supervisors in the project company’s safety management department, the supervision engineers in the supervision department, and the specialized engineers in the engineering department should provide construction workers with instructions on fire safety measures as well as conduct safety education and training, thereby enhancing the workers’ safety awareness and improving their skills in preventing fires. 　　2. The area where anti-corrosion gasketing is being installed must be enclosed completely; there should be one entrance and exit, and a prominent warning sign reading “Gasketing work in progress – no smoking or open flames” must be hung on the isolation barrier. 　　3. Establish a security system for the construction area, with dedicated personnel on duty; access is permitted only upon presentation of proper permits, and unauthorized persons are strictly prohibited from entering. Anyone entering the rubber lining construction area is strictly prohibited from bringing open flames or smoking. 　　4. Personnel entering the desulfurization tower must wear appropriate protective equipment; it is strictly prohibited to enter the tower wearing shoes with nails or synthetic fiber clothing. There must be dedicated personnel on standby outside the tower for supervision. 　　5. Before leaving the site, welders and other construction workers must thoroughly clean the area, checking every corner for any hot welding slag. If necessary, the areas where slag has accumulated can be sprayed with water to eliminate heat sources, and it is also essential to ensure that the power supply to the welding machine has been disconnected. 　　6. In the event of a fire hazard, the on-site safety officers must activate the manual alarm, immediately cut off the main power supply, and organize and guide people to evacuate and escape. 　　7. The personnel inside the desulfurization tower should immediately put on the masks or face shields they carry with them, and evacuate through the nearest exit using the escape guide ropes. 　　8. The firefighters opened the water valves and used fire hoses to extinguish the fire, while other safety personnel assisted by using fire extinguishers. 　　9. After the fire is extinguished, the cause must be promptly investigated; work can only resume once the necessary corrections have been made.