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Opinion demolition: the explosion of domestic gas in Magnitogorsk could not be
“So your humble servant, finally decided to throw his copper altyn into the people's piggy bank of comments of that terrible explosion that occurred on December 30 in the residential building of Magnitogorsk. Why? Am I competent in this matter?
First, my primary military education institution (military accounting specialty) wore number 501, which in former times meant - “commander of a sapper platoon”, and in the “military officer” was a postscript - subversive. I was engaged while serving in the SA, in particular, in this regard. Secondly, in my civilian (for some reason now, it’s customary to say “civil”) “labor activity” I had dozens (!) Times to head commissions to investigate the causes of explosions and “pops” of natural gas at various facilities, industrial and civilian, and in particular - in residential buildings. So I have enough experience in this matter. A gas “gas” (gas kick) is a weak gas explosion that did not bring serious damage.
Now, individual reports in the Russian press seem to me very doubtful. Why, then, so quickly and unconditionally, the dubious version was adopted - “there was an explosion of domestic gas”? What are the reasons for this? “What is your evidence?” Or why was it quickly stated that no trace of explosive was found on the ruins of the house? Surely the consequence analyzed all the smallest parts of the wreckage? It is at first necessary to rescue people immediately from the rubble, and not to look for traces of hexogen on pieces of concrete! The very fact that the cause of the explosion is not justified by technical reasons, but rather political.
In the past, I had to repeatedly participate in investigating the causes of the explosion of domestic natural gas in residential buildings, mainly in the territory of Bukhara region, and this was almost always quite simple, since there were almost always two reasons. First, residents of local-type houses installed handicraft gas heating devices, where from the LPG cylinder to the primitive burner, through a pressure reducer, gas flowed through rubber hoses, and when this connection was broken for random reasons, “claps” occurred. The second: to warm the dwelling, people, again in houses of the local type, left gas burners on the stove lit for the night and how often it happened in Uzbekistan - the gas supply suddenly stopped, and a little later, as a rule, at night, again, the slightest spark and blast.
But all this did not apply to apartment buildings built on standard projects. I would like to assert that the requirements for safety standards in the gas industry and the norms of the relevant SNiPs (meaning former, Soviet) are not tougher around the world. At least, I continue to count like this to this day.
According to its properties, household natural gas can explode in a certain room only if its concentration in the volume of that room, for example, of the same kitchen, reaches 5% and does not exceed 15%. This is called "explosion limits." And this means that the volume of a typical kitchen room, according to building codes, must be no less than so many cubic meters with such a number of burners on the stove and a certain amount of ventilation channels in the walls, providing a natural (!) Hood.That is - no matter how much the tap on the stove does not open, but you still practically will not get the "explosive" concentration of gas in your kitchen! Other things were also regulated, such as the distance from the electrical outlet to the burner, the direction of door opening, and much, much more.
From any rule - exceptions are possible. Therefore, at times, security rules were violated, but they did not cause explosions, but so-called “claps”. Bach-bang, the windows were knocked out, the doors opened with a bang, and the curtains flashed. As for the destruction of building structures - so, no! “Slam” happens quite often, but this happens in any case with the complete irresponsibility of homeowners.
Natural gas is supplied to consumers already odorized, that is, it has previously been given a strong odor (odorant ethyl mercaptan, for example) that cannot be detected even at its finest concentration in the air. From this it follows that a gas concentration sufficient for an explosion in a living room of a modern apartment building is practically impossible !! But they, "pops" and explosions nonetheless sometimes happen ...
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We now turn directly to the theory of the explosion. The blast wave (blast essence-energy, the resulting overpressure) always propagates along the line of least resistance. What does it mean? For example, in industrial and heating boilers operating on gas fuel, both on them and on the exhaust gas ducts (combustion products) there are so-called “explosive valves”. They are thin sheets of asbestos, embedded in various ways in the construction of boilers and flues. With the explosion of gas, these "valves" are destroyed first, and it is through these openings that the entire energy of the explosion is pulled out without producing virtually no damage to the surrounding building structures. Sometimes, for security reasons, even so-called "easily reset" roofs are arranged.
Ergo: modern residential buildings, by their very design, are practically protected from the devastating effects of an explosion of domestic natural gas that occurred “through negligence”. For the same, in order to "intentionally" blow up an entire residential building with gas in the kitchen, it is necessary to have a fairly broad knowledge of the theory of bomb technology.
And finally, I am familiar with the special scientific work of the authors V.R. Karibyants and A.V. Nadezhdin. "To the question of the method of assessing the degree of destruction of a multi-storey residential building in the explosion of natural gas in one of the rooms." (it is not difficult to find it on the web) I once had to use this technique and the corresponding calculation formulas. In accordance with our topic, I think it is worth quoting the conclusions made by the authors: “The calculation of the time dependence of the overpressure resulting from the explosion of a stoichiometric gas-air mixture in the volume of a typical kitchen of an apartment building, and the corresponding dynamic response of supporting structures (for example, a concrete floor plate), shows
IMPOSSIBLE Karl! That's it, gentlemen, Russian EMCHEESniki and "vazhnyaki" investigators! By the way, a similar “explosion” occurred in Izhevsk (November 2017), which was then also attributed to household, gas ... "
