Metal dust explosion accidents take place frequently in China, in which the hidden danger has existed early, analyzed by the insiders

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According to the reports, the metal dust explosion accidents have taken place frequently in China since 2010, which almost occupies 30 percents of the dust explosion accidents. However, in the explosion accident which was happened in August 2nd, 2014, more than 70 people were killed and nearly 200 people were injured, which again covers a new shadow for this kind of event. To recall past pain as a warning for the future, we should know how to make up for the loss.

Journalists interviewed many factory workers in the accident site and was informed that the warning and cleaning of the dust are lack of standardization. Some Chinese automobile wheel hub practitioners revealed that the hidden danger of the accident has existed early.

Ordinary people may be hard to understand why the blast occurred in the automobile wheel hub polishing workshop. However, one of the Chinese automobile wheel hub enterprise principal said frankly that the risks of flashover and blast will accompany with the whole process of aluminum alloy wheel hub polishing if someone is truly engaged in this occupation.

Insiders in China said that a lot of dust will certainly be generated in the polishing process, among which aluminum powder is one kind of the dust that generated in the wheel, which will have huge reaction force once being ignited; the other kind of dust is generated in the grinding material. This kind of aluminum powder and sand powder are very easy to mix, in which the concentration will be accumulated to high level without cleaning regularly, thus it will be easy to cause blast even if encountering with a static.

The above plant conditions just meet some of the necessary conditions of “dust explosion”. Wu Chunping, one of the researchers from Beijing General Research Institute of Mining and Metallurgy that long engaged in the study of explosion said that all kinds of combustible dust which exist in the confined space will change to “explosive powder” when reaching a certain condition. Especially the “aluminum metal powder” that may play the lead role in this accident, will be easier to cause serious accidents with careless handling.

Mr. Wu said that the calorific value of aluminum powder is very huge, especially when it changes into dust and drifts in the air, very high heat will be released once burned and the blast will occur immediately. By this time, it is useless to put out the fire even if watered with fire hydrant as the aluminum powder will burn quicker.

Since 2010, dust explosion accidents have occurred in the metallurgy, non ferrous, building materials, machinery, light industry, textile and even the tobacco industry. In August, 2012, China State Council Safety Committee Office thoroughly carried out special governance of aluminum and magnesium products processing enterprises safety production throughout the country. Regarding the above content, insiders in China also revealed that according to the national requirements, this kind of metal plating and polishing enterprises should be equipped with various explosion-proof devices.

They said that the workers who work in this kind of factories should wear respirator when working so as to prevent pneumoconiosis. Another important thing is that all the workers’ protection suits, shoes, gloves and even the light are required to be anti-static. In addition, requirements on the ventilation and dust deduction are very strict, for example, air should be exhausted regularly and dust remover should be installed.

Besides, many industries suggest the manufacturers to install dust concentration monitoring and warning device in the workshops so as to prevent flash burn or blast risk. However, the requirements which are expressly stipulated in China, the notice issued by the competent department and the advice given by the industry all fail to control the happening of dust explosion accidents. Survey shows that the dedusting air flues that are used in ventilating in the workshop of Kunshan Zhongrong Metal Products Co., Ltd are not cleaned regularly, it can be seen that it is the omission consciousness that contributed to this accident. But the deeper reason is, being known as the supporting factories of well-known enterprises, they can only compete for the production orders by competing with low price and compressing safety production cost. The insiders also told the journalists that many foreign enterprises including GM, of which the wheel hub electroplating and polishing processing charges are not very high. Moreover, in order to ensure the profits, many enterprises do not pay any attention to safety production at all.

They also said that for this kind of factories, dust extraction, environmental protection and the employees’ safety all should be paid attention to. But all these need to be invested with a lot of money, as we know that the electric fan (air blower) and air conditioner will rotate all the day, which will cause very high operating cost. However, the factory owners compress the operating cost into a very low level, thus they are unable to improve the environment and will not pay attention to the safety production at all. This can be related to nothing but the consciousness management problems.