Say that flour can cause an explosion. This is true?
Flour really can provoke an explosion. Moreover, in the 1980s, 10-15 such incidents occurred on milling industries. So, in 1981 in Tver, the explosion completely destroyed the brick six-storey building of the bakery and carried away the life of two shifts. In 1982, dozens of workers became victims of the explosion on the Achinsky bakery.
There were other cases. They led to the fact that in 1990, enterprises for the storage and processing of grain attributed to the most dangerous industries and transferred under state supervision.
Imagine: The temperature in the dust explosion zone reaches 3000 ° C, and excess static pressure, that is, the power of the explosion, is 10 kg / cm². For comparison: in order to break the window glass, pressure is needed 0.07 kg / cm², to destroy the wooden structure – 0.14 kg / cm², and the medium in the thickness of the reinforced concrete plate – 0.56 kg / cm².
Explosive flour is due to its chemical composition. It contains starch, and one, in turn, – sugar, which are combustible materials. But to provoke an explosion, three factors should coincide: oxygen, open fire and a certain concentration of flour.
In 1990, the enterprises for the storage and processing of grain attributed to the most dangerous industries and transferred under state supervision
First condition – the presence of oxygen. As is known, it is a catalyst for the process of burning, and mistakenly think that oxygen is always present in the desired volume. It is no coincidence that the firefighters have an expression: "Who will open the window during the fire, will jump out of it".
Second – open fire. Any source is suitable, even a burning cigarette. Therefore, special places are allocated at the smoking production. Most often, problems arise due to violation of safety regulations, but it happens that the cause of open fire is becoming failed equipment.
Third – Silence of Flour. To explode, its concentration in the closed space should be from 35 to 50 g / m³, depending on the variety and type. If the concentration is higher, the flour will only burn. And, by the way, its flammability temperature ranges from 290 ° C to 395 ° C. At home such high numbers not to reach. Consequently, in the kitchen, the flour either explode, nor will be able to burn.
In the institutions of the catering extremely permissible concentration in the air of flour dust – 6 mg / m³. At the same time, according to sanitary and epidemiological requirements, zones and / or placed equipment, which are sources of gas, flour dust, moisture and heat, should be equipped with local exhaust systems. These restrictions are introduced in order to protect the staff.
For ten years of work, I did not hear about the explosions of flour dust in catering establishments and private houses. This is more about specialized workshops and flour. There security is regulated by building standards and regulations, order of Rostechnadzor.
Theoretically flour dust can be used as a weapon, but in practice it is practically unrealistic to achieve the necessary concentration in the air. In addition, the creation of such clouds may hinder the wind and humidity. And the point of impact will be missing. True, compared to conventional ammunition "flour" weapons would have a high power of action and a strong shock wave.
Not only flour can explode – any particles of less than 0.1 mm with a certain chemical composition have such property. For example, sugar powder, starch, tea, tobacco dust. They are easily connected with oxygen and burn with a huge speed. Only the ignition temperature and the power of the explosion will be different.