Analysis of Typical Accident Cases Involving Special Equipment

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Brief description of the “6·22” boiler accident in Hechuan, Chongqing: At 18:05 on June 22, 2018, an explosion occurred in a food factory located in Community 2, Longgu Village, Dashi Sub-district, Hechuan District, Chongqing, resulting in 2 deaths and 3 people suffering minor injuries. At the time of the incident, 6 people were working at the factory. The boiler operator left the factory to buy cigarettes about 500 meters away, and asked another person (the victim) to look after things in his absence. Around 6 p.m., the stoker heard the sound of a boiler explosion at the cigarette stand and rushed back to the scene to carry out rescues. The boiler explosion caused damage to the walls of the plant’s boiler room, led to steam leakage, and ejected the boiler itself about 15 meters outside the boiler room. It is suspected that the accident occurred because water was not added to the boiler in accordance with the procedures specified in the technical guidelines, after the boiler ran out of water. Direct cause of the accident: 1. Unsafe human behavior. The person assisting in the operation of the boiler did not have the required qualifications for operating special equipment; he operated the boiler without a license ； After discovering that the boiler was running out of water and burning dry, water was added to it in violation of regulations, which caused the boiler to explode. 2. Unsafe condition of the object. The boiler experienced a situation of dry burning due to a lack of water; adding water to the boiler in violation of the operating procedures caused all the water that entered the boiler to vaporize instantly. This led to a sudden increase in steam pressure inside the boiler, **exceeding the discharge capacity of the boiler’s safety valve designed to release excess pressure. As a result, the accumulated steam could not be released in time, and the pressure generated by the steam surpassed the stress tolerance limit of the boiler’s inner tank, leading to an explosion of the tank.