Before entering the container equipment, think about whether these eight things have been done

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1 It is necessary to apply for a permit and obtain approval. Chemical production is generally carried out on a continuous basis, with each piece of equipment and container playing a specific role in the production process – such as storage, reaction, transportation, processing – and they are interconnected; a problem in one part can trigger a chain reaction. Inside equipment and containers, the situation is often very complex due to changes in production conditions and inherent limitations; if maintenance workers enter there blindly, accidents can occur. Especially when the system is operating normally, inspecting or repairing one of the equipment or containers increases the likelihood of accidents. Any work performed by personnel inside various containers or equipment in violation of regulations may lead to accidents such as suffocation, poisoning, burns, or fire and explosion within the container. To effectively ensure the safety of personnel entering containers and equipment, it is essential first to obtain approval by applying for and receiving a permit for working inside containers and equipment in accordance with regulations. Its main purpose is to carry out the following tasks. 1. Determine the work plan and safety measures based on the specific details of the work, and ensure that these measures are put into practice. 2. Ensure that the containers and equipment into which personnel will enter can be disconnected from the production system, and notify the relevant personnel in a timely manner so that they can make the necessary preparations. 3. Provide necessary technical instructions and safety training to personnel entering the containers and equipment. 4. Carry out thorough safety organization work, with clear division of tasks and assigned responsibilities for each person, and designate a specific individual to oversee things. In the process of applying for and obtaining permission to enter containerized equipment, signing and filling out the work permit for entering such equipment and containers is merely a formality; what’s crucial is implementing various safety measures. Therefore, all relevant personnel should not act rashly or fill out forms carelessly, but should earnestly implement various safety measures. The approver should not sign merely as a formality; instead, they must go to the site to check the implementation of safety measures before signing the approval for the \"Work Permit to Enter Equipment Vessels\". 2 Safety isolation is necessary. Safety isolation involves strictly separating the workplace where workers will be working from various hazardous factors that could lead to accidents. This means cutting off the connections between containers, equipment, and materials, as well as water, gas, electricity, and power sources, in order to prevent flammable, explosive, or toxic substances from entering the equipment or containers while workers are inside them, due to poorly sealed valves or improper operations. It also helps avoid various types of injuries and deaths caused by unresolved electrical connections. There are quite a number of examples in this regard. In chemical production, to isolate materials, water, gas, etc. within containers and pipelines, methods such as closing valves tightly, installing blind flanges, and removing pipelines are employed depending on specific conditions such as pressure, the properties of the materials, and inspection timing. Blind plates are generally used for isolation, as they are easy to operate and safe and reliable. When hot work is performed inside a vessel or during prolonged maintenance, a section of the pipe connected to the vessel being repaired can be removed; however, the end of the pipe connected to the production system must also be blinded. It is absolutely prohibited to simply add water to seal and close the valve for isolation. For the isolation of electromechanical drive equipment, the power switch must be turned off and a “Do Not Start” tag affixed. Alternatively, the switch can be locked, the fuse removed, and then kept by the maintenance personnel or under supervision. For the power section, the transmission part must be removed; if it is driven by a belt, the belt can be taken off. For the safe isolation of hot work inside equipment containers, in addition to the aforementioned isolations, it is also necessary to ensure safe isolation from surrounding equipment containers and various flammable materials. For deeper containers, layered isolation must also be considered to prevent tools or other objects from falling from above and injuring the workers at the bottom, as well as to avoid accidents caused by sparks falling from high up. Since safety isolation in chemical production is often carried out by using blind flanges, and given that the containers within pipelines are under pressure and contain hazardous substances, plus the fact that this work is frequently performed at heights, the following points must be taken into account when performing such tasks: (1) Before starting the work, it is necessary to release all pressure and contents from the containers and pipelines, reduce the temperature to below 60°C, and be careful to prevent negative pressure from forming, ensuring that there is no residual liquid (as confirmed by chemical tests) or residual pressure inside. (II) For work at heights of more than two meters, a scaffold or platform should be set up, and a safety belt must be worn. When entering equipment containing toxic and harmful substances, workers should wear appropriate protective gear. Working hours are long; shifts must be rotated. (III) In no case shall iron tools be used for striking when removing flanges on pipelines or equipment containing hazardous materials in fire-prohibited areas; welding is strictly prohibited within the specified distance, and explosion-proof tools must be used. (IV) The removal of bolts should be carried out slowly, one or two bolts being loosened at a time; all bolts can be removed only after it is confirmed that there is no danger. A “Blind Plate” sign should be hung at the location where the blind plate is removed. Medium and low pressure blind plates should be equipped with handles, and these handles should have a hole in them for lifting purposes as well as to serve as a marker for the blind plate. (5) The installation and removal of blind flanges should be carried out in accordance with the relevant diagrams, and a record book for such operations must be maintained, indicating the time and location of installation/removal, the specifications of the blind flanges, and the names of the personnel involved. The blind plate diagram is kept by the project leader, and no one is allowed to make changes to it without permission. (VI) The thickness of the blind plates at locations where pressure may be generated shall be selected through calculation. Kerosene leakage testing is used for low and medium pressure blind flanges. For high-pressure blind flanges, the sheet material must undergo strength verification and non-destructive testing before use. (7) Strict precautions must be taken to prevent hazardous substances from suddenly escaping due to operational errors or other reasons during the removal of flanges and the installation/removal of blind flanges. (8) The **device must first be cleaned and purged. Then remove and install the blind flange. 3 The power supply must be cut off, and safety lighting must be used. 4 Replacement and ventilation are necessary; usually, some material remains inside the container after the discharge of its contents. For flammable and explosive substances, when the container is operating in a sealed state, there is little to no air inside, so no explosive mixture is formed; generally, there is no danger. After the material is discharged, the container is opened and air enters it; due to the volatilization of the remaining material, it mixes with flammable gases to reach the explosion limit. At this point, if a fire source is present, an explosion will occur. For some **, toxic substances, even a very small amount in a container can be enough to cause death. Therefore, to enter the equipment container, it must first be purged and ventilated; only after sampling and analysis confirm that it is acceptable can personnel enter. In displacement, after the contents are emptied, an inert gas (such as nitrogen, carbon dioxide, water vapor, flue gas, etc.) is introduced into the container to drive out any remaining hazardous substances. Depending on the specific conditions of the container, different cleaning solutions are used for rinsing; generally, water or hot water (especially for organic substances) is used, or steam is applied for a certain period of time. Finally, air is introduced into the container. Be careful during replacement. (1) A replacement plan must be prepared before the replacement, and a flowchart of the replacement process should be drawn to avoid omissions. (II) Special attention should be paid to elbows and dead corners during displacement flushing. When cleaning containers such as storage tanks with water, fill them completely and let the water overflow from the top openings. (III) If there are flammable, explosive, or toxic precipitates accumulated inside the equipment, it must not be completely sealed after purging; air circulation must be maintained to prevent volatile substances from exceeding permissible concentrations. Forced ventilation can be used if necessary. (IV) After replacement, sampling and analysis should be conducted; the sampling point should be located at the end point of the replacement system ； Sometimes samples must be taken from the upper, middle, and lower sections; sampling should not be done earlier than 30 minutes before the start of work ； The analysis samples must be retained until the work is completed before they can be disposed of ； The analysis results must be recorded and become valid upon signature by the analyst. Replacement and ventilation play a significant role in preventing accidents, and there are many lessons learned from accidents in this regard. 5 Safety analysis must be carried out within the specified time frame. Case: On April 14, 2000, a fertilizer plant was performing maintenance on its carbonization recovery and cleaning tower; after replacing the contents with clean water, the analysis showed satisfactory results. Multiple welding operations were carried out inside the tower without any abnormal occurrences. Finally, an explosion occurred during maintenance work involving welding on the tower’s bubble caps, killing one welder. The reason is that raw material gas accumulates inside the bubble; during maintenance, when the bubble is turned over, the raw material gas escapes. When it comes into contact with an open flame, an explosion can occur. It is necessary to wear the prescribed protective equipment when working inside containers and equipment. There are many dangerous factors involved, and although we have taken numerous measures to eliminate them, there are still some safety hazards that cannot be completely removed or that are difficult to predict. For example, when acid production companies carry out maintenance work on acid tanks, acid towers, and pipelines, the acid sludge and acid mist cannot be completely removed ； Certain harmful and toxic substances are released as a result of secondary volatilization due to the high temperatures generated by welding. In this sense, the use of prescribed protective equipment by staff is the last line of defense to protect them from harm. Therefore, it must be worn and used correctly. Protective equipment is mainly used to protect against dust, toxins, corrosion, electric shock, falls from heights, and impacts from objects. The harm caused by toxins to the human body occurs mainly in the form of smoke, dust, mist, and gases, which enter the body through the skin and respiratory tract; some substances can also cause direct damage to the eyes and skin. By wearing protective gear as required, we can prevent such injuries. There are many personal protective equipment items. Below, we will mainly introduce several of them. (1) Protective clothing: 1. Dust-proof clothing: Usually made of dense cotton or flannel, it comes with a hood, cape or headscarf, as well as shoe covers. The neckline, cuffs, and trouser legs must be tied tightly, along with a dust and sand mask. 2. Erosion-resistant clothing: Generally made of rubber or polyethylene film; woolen and silk fabrics can also be used. Rubber boots and gloves are commonly used for protecting the limbs, along with protective face masks. 3. Burn-resistant clothing: generally includes asbestos-cloth work clothes, leather work clothes, leather shoes, etc. (II) Gas masks: Gas masks are primarily used to prevent harmful gases, vapors, and aerosols from entering the body through the respiratory tract. Based on their principle, gas masks can be divided into two categories: filtering (purifying) types and isolating (air-supplying) types. Each of them has its own protection range and applicable time, and must be selected appropriately based on the specific conditions inside the container equipment. The working conditions inside the container are very complex; therefore, it is necessary to choose and wear the appropriate protective equipment depending on the specific circumstances, in order to prevent harm to the human body. Below, we will look at the importance of wearing the required protective equipment through several specific examples. 7 Someone must be stationed outside the equipment for monitoring, and those who enter the container or equipment to work must do so with caution. Apart from the risks of poisoning, suffocation, electric shock, etc., the difficulty in entering and exiting as well as poor communication make it hard to detect accidents once they occur, which can lead to an increase in the severity of the accident and result in injuries or deaths. Therefore, it is necessary to have someone monitoring from outside the equipment. Generally speaking, the main responsibilities of a supervisor include the following: 1. Checking whether the application and approval procedures have been completed, whether the safety measures specified in the work permit correspond to those in the actual site, and ensuring that these measures are properly implemented. 2. Whether the staff’s physical condition is suitable for the job requirements, and whether the safety measures and job tasks are clear. Are the safety belts and protective equipment used by staff complete and up to standard? 3. Are the shelves, ladders, and railings up to standard, and is the lighting in compliance with regulations? (II) The guardian shall be responsible for the safe guardianship of the ward. Before starting work, a contact signal must be established; otherwise, work may not begin. The guardian has the right to supervise and require the ward to implement safety measures. If any violations of regulations are found, the work must be stopped immediately. (III) For hazardous operations where safety measures have not been implemented or are still inadequate, supervisors shall urge improvements. If no improvements are made despite such requests, they should refuse to participate in the supervision duties and report the situation to the department head. (IV) Supervisors must ensure that electrical equipment such as electric trams, cranes, and winches are not used as tools for lifting workers, as this will prevent the workers from escaping from the hazardous area in the event of a power outage. (5) The guardian must choose an appropriate place for guardianship and pay attention to self-protection. At the same time, all preparations for handling accidents must be made; personnel must not leave the scene or participate in construction operations. (6) In the event of an accident involving workers, supervisors must wear protective gear and employ scientific methods to carry out effective rescue efforts. It is strictly prohibited to act blindly and irrationally without following scientific principles, thereby causing accidents to escalate. (7) Generally, two persons should serve as supervisors. For tasks that require long hours of supervision and shift work, additional personnel should be assigned and rotated accordingly. However, the handover must be clear; caregivers must have certain emergency rescue experience, and the elderly or infirm should not serve in this role. (8) It is crucial for the supervisor to ensure the safety of those entering the container; neglecting this duty will result in punishment. 8. There must be backup rescue measures. Operations involving entry into containers or equipment are complex; the slightest negligence may lead to various accidents. And the availability of emergency rescue measures is precisely to enable the timely, rapid, and proper extraction of the injured from the container, as well as the provision of first aid and handling of the accident scene, in such situations. This creates favorable conditions for saving the lives of the injured and reducing the losses from accidents. Otherwise, due to inadequate rescue efforts and lost time in providing assistance, the casualties and losses resulting from the accident will increase.