On 2 august, a particularly significant incident occurred in kanshan city, jiangsu province, in which a dust projector explosion in a polished workshop in kunshan city, china, resulted in 75 deaths and 185 injuries。
Yesterday, 4 august, the head of the accident investigation team and director-general of the directorate-general for security and supervision, yang zheng liang, stated that, based on the problems revealed and the initial knowledge of the accident, the long-standing unresolved business problems and risks, the concentration of dust, the explosion at the source of the fire were a major liability. He mentioned that the company “did not design a separate vacuum removal device for each position as required, and was insufficiently capable of doing so”, “did not clean up the pipes on a scheduled basis, resulting in a concentration of dust exceeding the standard; did not provide workers with safety training and did not have the required fire retardation, static power protection supplies”。
The incident-related factors identified by the accident investigation team have once again drawn the attention of society to the problem of destructive dust explosions. In an interview with the daily economic news, the director-general of the institute of industrial bombings and protection at the north-east university, zhong ki-joon, stated that there was insufficient dissemination and promotion of dust-proof explosions, that companies did not keep up with the dust-proof section, and that many people were not aware of the dangers and were therefore inadequately protected。
There have been many dust explosions in my country
In his view, the incident should have been caused by an aluminum powder explosion caused by polishing and, to be precise, by aluminium alloy. It is understood that dust explosions are dust that are within the limits of the explosion, are exposed to heat sources (open fires or temperatures), that the flames are instantaneous in the entire mixed dust space, that chemical reactions are accelerating, and that they release large amounts of heat, create high temperatures and stress and are highly destructive。
According to industry experts, dust explosions generally occur under three conditions: flammable dust suspended in air at appropriate concentrations, sufficient air and oxidizers, fire sources or strong vibration and friction。
In fact, there is a wide variety of likely explosive dusts, generally metal dust, such as aluminium, zinc, magnesium powder, coal dust, by-product dusts such as cotton, tobacco, paper powder in forest products, wood powder, plastics in synthetic materials, dyes, etc., and even common wheat flour, starch, etc。
In recent years, there have been frequent security incidents involving dust explosions, resulting in large numbers of casualties. According to rough statistics by journalists, the number of historically larger dust explosions reached four. In march 1987, 58 people were killed and 177 injured in a fire caused by a dust explosion at the hamma textile factory in harbin; in february 2010, 19 people were killed and 49 injured in an explosion of maize starch dust at the qin emperor island starch company ltd. In hebei province; in august 2012, 13 people were killed and 15 injured in an explosion of aluminium dust in a civilian house in the wai sea district of wenzhou city; and in april 2014, eight people were killed and nine injured in an explosion of hard-lipid dust at the twin horse chemical company ltd. In nantung town, changtung city, jiangsu province. If this accident were included, the number of accident deaths from five dust explosions would be over 160。
With regard to the huge human toll caused by the dust explosion, jong-joon said: “there have been many such accidents in previous years, at least 78, and i have specifically counted them, many of them in handshops and four or five people died at a time, mainly because of the absence of dust removal at all
Enterprise dust-proof blasts
In recent years, my country has entered a period of multiple dust explosion incidents, with six such incidents having occurred since this year alone, with challenges to the standard-setting and safety monitoring of dust blasts in industrial production。
There are some shortcomings in government law enforcement, but zhong has indicated that in recent years the state has taken this work very seriously and has issued many documents to regulate it. As early as 2007, the state had developed the dust and detonation safety protocol, which specified that enterprises should be aware of the existence of hazardous dust explosion sites in their enterprises and take measures to prevent and control dust explosions effectively。
According to zhong, dust standards are not fully in line with development requirements, for example, there are no separate standards for the polishing industry and the aluminium powder standards are not sufficiently detailed。
In august last year, a reply from the general directorate of national security on the application of the dust and blast safety standards for processing sites for aluminium magnesium products suggested that there were currently no national and industry standards specific to the dust and blast protection of processing sites for aluminium magnesium products. Standards such as the dust and detonation safety protocol (gb1557-2007) and the dismantling and detonation guidelines for dust and dynamite hazardous sites (gb/t17919-2008) apply to aluminium magnesium processors。
In fact, the dust explosions that china is experiencing today have also occurred in countries such as europe, the united states and japan in the last century, but the problems in these countries have been few in the last decade. Zhong saint-jun explained that the reason for the relatively small number of dust explosions in these countries in recent years was, on the one hand, increased awareness and technology of protection and, on the other hand, the transfer of related industries to china。
In the case of dust explosions in china, which involved inadequate standardization, zhong was of the view that the relevant elements of dust assessment were naturally not included in the inspection form by the government regulatory authorities。
At the same time, he suggested that “wet removal can prevent large secondary explosions. However, due to the high cost of the technology and the fact that you are not aware of the danger, you do not want to do the hysteria at all.”
On the issue of persistent dust explosions, jong-joon believes that the main reason is that there are too few people who really understand it now, mainly business owners who do business safety without treating dust and blast prevention as important。
Responsible editor: zhang dei
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