A steel company is located in the development zone, mainly producing all kinds of galvanized and tinned steel coils. The company started construction in 2002 and was completed and put into operation in June 2003. * * * has three production lines. The main production processes are: feeding → automatic welding → electrochemical degreasing → preheating → rapid heating → rapid cooling+leveling → hydraulic shearing → packaging. In order to prevent the surface oxidation of steel plate during heating annealing, nitrogen should be filled in the electric heating annealing furnace for protection. At the time of the incident, the heating annealing furnace had been electrified for preheating and filled with high-purity nitrogen.

165438+1At about 5: 30 in the morning of October 9, after several days of maintenance, night shift workers began to heat up the annealing furnace to prepare for the next shift to resume normal production. During the heating process, the radiant tube in the annealing furnace failed. Zhang, the monitor on duty, decided to enter the furnace to replace the radiation tube without the maintenance man present. Zhang, wearing a simple activated carbon mask, drilled into the manhole (about 70 cm×40 cm) of the annealing furnace, and the manhole was about 4m away from the replacement point. After Zhang entered the furnace mouth for 2 ~ 3 minutes, there was no response. Other employees came forward to check and found that Zhang fell about 2 m away from the maintenance mouth. Five other workers entered the furnace and pulled out Zhang, and fainted near the mouth of the furnace. All the above six people have a series of clinical symptoms of the central nervous system.

Two hours after the accident, the inspectors used a direct reading oxygen detector at the maintenance port of the annealing furnace, which showed that the oxygen concentration was about 15%, and the existence of hydrogen sulfide and carbon monoxide gas was excluded.

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Reference answer

The lesson of this accident is profound. In order to prevent and put an end to similar accidents, the following suggestions are put forward:

(1) According to the relevant provisions of the Law on Work Safety and the Law on the Prevention and Control of Occupational Diseases in People's Republic of China (PRC), before the completion and acceptance of the construction project, the construction unit shall conduct relevant hazard assessment and implement the relevant provisions of "three simultaneities".

(2) Before entering the closed (limited) working space such as annealing furnace, it must be fully ventilated and ventilated. According to the principle of testing before operation, the concentration of oxygen and other harmful gases in the air of the working environment must be accurately determined before operation, so as to ensure that the air in the working place meets the hygiene requirements and avoid the influence of harmful gases on the health of workers. For places where ventilation and ventilation measures cannot be taken due to explosion protection or places where ventilation and ventilation cannot be fully realized due to the limitation of working environment, operators must equip and use isolated respiratory protection devices such as air respirator, oxygen respirator or hose mask, and filter masks are strictly prohibited.

(3) Establish and improve safety production facilities and safety and health protection facilities. At the same time, strengthen the training of occupational health knowledge, improve employees' awareness and ability of self-protection, and help them correctly in case of accidents to avoid further expansion.