Production Technology [Weekly Topic]: Accident Analysis (10-11-15~22)

In 1992, Yin, an operator at a chemical plant in Beijing, mistakenly activated the mixing button intended for cleaning the tank as if it were the button for mixing in the production tank, causing the mixing shaft of the tank being cleaned to rotate. When the two workers inside the furnace noticed this, they immediately grabbed the rotating shaft, and thanks to prompt action, a serious injury or death accident was avoided. One person suffered minor injuries in this incident, while another was frightened. The direct cause of the accident: operator Yin made a mistake in operation. Indirect cause: The cleaning work was not carried out in accordance with the procedures. Lack of safety awareness and insufficient employee training. What violations were committed by the operators: Yin did not follow the procedures and pressed the mixing button to clean the tank without first confirming that there was no one present. Before other workers entered the vessel for cleaning, no signs were placed in front of the relevant buttons, nor was anyone assigned to monitor those buttons. How to prevent similar accidents from occurring again: 1. A procedure sheet should be prepared in advance for tank cleaning, and countermeasures and plans should be established for foreseeable potential accidents such as opening the tank for mixing while people are still inside. Operators should strictly follow the operating procedures when cleaning the tank. 2. Operators must receive thorough safety education and operational training before taking up their duties, and additional training should be provided regarding potential safety issues. 3. Where feasible, a safety lock function should be added to the stirring button for cleaning the kettle. Before entering the furnace for cleaning, labels should be placed in front of the relevant buttons or a dedicated person should be assigned to monitor those buttons, to prevent accidental operation by others. 4. It is necessary to foster employees’ awareness of communication. If Yin had communicated with the people present before carrying out the operation, he would have noticed that someone was inside and could have prevented the accident.

1. A sign must be placed on the start button of the equipment under maintenance to indicate that it shall not be started; the switch should also be turned off, with a notice stating that closing the switch is prohibited. 2. The operator on duty should be aware of the condition of the equipment and whether it is under maintenance. 3. When someone is inside the equipment for maintenance work, someone should stay outside to monitor the situation. To prevent such accidents, it is essential to follow the relevant safety procedures.

The direct cause was an operator’s mistake in operation, which led to the activation of the wrong switch. The indirect cause is: inadequate training for the operators and carelessness. During maintenance operations, it is essential to provide proper technical safety instructions and have a supervisor present to oversee the process; the equipment must be powered off. (In this company’s case, the equipment was not turned off during maintenance, which created a potential risk for accidents.) This incident shows that the company has a weak awareness of safety. To prevent similar accidents, companies should prioritize safety first, provide employees with safety training to enhance their safety awareness, and ensure that maintenance and repair operations are carried out in accordance with established plans.

Reasons: 1. First, the equipment under maintenance must be tagged as a warning； 2. The rotating equipment under maintenance must be powered off ； Indirect cause: 3. Someone must be present to supervise entry into confined spaces ； 4. The operation buttons on site should be labeled ； 5. Operators must have operation cards. Preventive measures: 6. Standardize the operating procedures for equipment maintenance, and clarify the operational checks such as power shutdown, isolation, and supervision ； 7. Improve equipment operation cards and strengthen visual management ； 8. Provide comprehensive training for all staff on equipment operation and maintenance.

Immediate cause: Mistake by the operator. Indirect causes include failure to obtain the required maintenance work permit, entry permit for working on equipment, failure to disconnect electrical equipment, and absence of a maintenance confirmation form； Violation: Failure to disconnect power from the equipment being serviced; proceeding with maintenance work without following the proper procedures or obtaining authorization to enter the equipment; starting up the equipment without confirming that all necessary procedures had been followed ； Preventive measures: Obtain the necessary work permits and access cards for equipment maintenance as required, strictly follow the procedures for working on electrical equipment, ensure that all equipment and control panels are properly labeled, and train employees in basic operating skills as well as various comprehensive competencies.

The last edit to this post was made by shmily327 on 2010-11-15 at 16:40. I think there are two aspects: first, it is necessary to improve the technical training of operators; second, safety management of the equipment must be strengthened, and someone should be present to supervise during tank cleaning

1. The operator made a mistake while cleaning the kettle. 2. Operators should receive training on safe operations.

I learned a few things by seeing everyone’s answers; thank you. By the way, is the principle behind cleaning the furnace the same as that behind maintenance? If it’s different, what’s the difference?

1. Direct cause: Operator Yin violated operating procedures by mistaking the mixing button used for cleaning the tank for the mixing button of the production tank, which caused the mixing shaft of the tank being cleaned to rotate and led to the accident. Indirect cause: The factory had chaotic safety management. 2. Violations: 2.1 Failing to cut off the power supply of the production unit during work inside the unit ； 2.2 With personnel inside the reactor, press the cleaning and stirring button ； 2.3 Inadequate safety supervision. 3. Preventive measures: 3.1 Strengthen safety and technical training for operators ； 3.2 Strict safety supervision and operation system ； 3. Carry out operations strictly in accordance with the measures