The terrible tragedy in Magnitogorsk raises a lot of practical questions that we would like to ask the relevant public utilities, ministries, officials and even special services. But for the time being we will leave it and wait for at least the first intelligible results of the investigation. Now we have a reason to learn a little about what the explosion of the gas-air mixture is, why it is so dangerous and how to avoid it.
It should be noted that such explosions raise a lot of questions and bewilderment. The vast majority of people find it strange how the explosion of several hundred grams, and in the worst case, a few kilograms of gas can lead to such monstrous destruction. Still, you must admit that a residential panel house should not fold like a house of cards from the slightest impact. Moreover, on the example of many local conflicts, we see that such houses successfully withstand hits from tank guns, including high-explosive ammunition, and sometimes continue to stand (albeit badly destroyed) after being hit by small aerial bombs or multiple launch rocket systems, containing in some cases tens of kilograms of explosives.
And here, it would seem, a trifle: someone forgot to close the gas (although there could be more reasons, and this, alas, not only forgetfulness), and the ensuing explosion of the resulting mixture literally carries the whole span of a building designed with some reserve in case of seismic activity and all sorts of man-made disasters. Often this raises doubts among an inexperienced observer, from whom rumors of terrorist attacks, bombs of tens of kilograms of TNT, total lies of the authorities, and so on, grow.
Unfortunately, even an inquisitive and persistent Internet user is not always able to find qualified information about what constitutes an explosion of a gas-air mixture. The world wide web is literally crammed with many unqualified, and sometimes simply ignorant articles that tell you about the “blast wave flowing through all the cracks”, or the fact that the blast wave with such an explosion lasts much longer and doesn't just hit the obstacle, and literally on it "is trampled down".
In fact, this is not entirely true, and now we will try to figure out how it works and why the first bombs using the principle of undermining (more precisely, very fast burning) of the gas-air mixture were called “vacuum”. And also, how much in common between the explosion of a gas mixture at the entrance of an ordinary house and the Russian vacuum bomb, which the developers call the “father of all bombs”.
How it works
We start from afar - with a school course of physics. And first of all, we recall that the intrinsic velocity of molecules of any gas is very high. Depending on temperature, density, and atomic mass, it can range from about five hundred meters to almost two kilometers per second.
Is it a lot? Well, let's calculate. If the usual wind speed 10 m / s is converted to kilometers, we get about 36 km / h. This wind in the warm summer weather will be just manna from heaven, but in winter it will make us shiver. However, as they say, everything is within the normal range.
But the wind speed 50 m / s means already a hurricane speed 180 km / h. Moreover, the hurricane is very strong - if tropical hurricanes are stronger, then for the Russian Far Eastern limits this is almost a record mark. I myself witnessed the wind 40 m / s, and it should be noted that just walking with such gusts is a difficult and almost heroic exercise.
Tropical hurricanes, as already mentioned, sometimes reach speeds in 250 km / h, and in rare cases even 300 km / h. This is roughly 80-90 meters per second. As a rule, neither trees, nor the majority of buildings (except for capital, made of brick, cement, etc. materials) can withstand such pressure.
And here the author talks about the speed of gas molecules in 500 meters per second and above. Is this some kind of madness?
Not. This is a harsh reality. You just need to remember that usually the gas molecules randomly move, colliding with each other. In most cases, their path between collisions is calculated in fractions of a millimeter, and most importantly - they do not move in an orderly, united front, and act on any object or obstacle uniformly from all directions.
The situation changes a little when the wind arises. Due to various factors (uneven heating of the earth's surface, light / shade, large obstacles, etc.), air begins to flow relatively slowly from higher pressure zones to rarefied zones. On a global scale, we are witnessing cyclonic phenomena, high-altitude aerial transfer, and the like. As a rule, the reason for them is the same: solar activity, uneven heating of the earth's surface, only specific moments like the Coriolis force are added.
How does this relate to the explosion of a gas-air mixture? Straight! That is what we now talk.
With the explosion of any gas-air mixture (and it would be more correct to say if it burns out) the oxygen of the air is associated with the fuel (it can be both household gas and specific substances like ethylene oxide or dimethylacetylene used in vacuum bombs). Since the oxygen content in the terrestrial air (by volume, not to be confused with the content by mass) reaches approximately 21%, the corresponding air exhaustion is formed almost instantly in the gassed volume.
No, we are not talking about a complete vacuum, of course. The pressure in the burnout zone drops by less than a third. But it happens almost instantly, for hundredths of a second. And this is enough so that the surrounding air in an orderly (I will underline this word) wave rushed to the epicenter of the rarefied region. Unfortunately, I did not manage to find figures on the speed of the “collapse” of a rarefied “bubble”. But it is safe to assume that the velocity of molecules of a collapsing gas reaches hundreds of meters per second, and just for a moment, forces arise in the center of the burnt-out volume, the power of which exceeds the power of the strongest terrestrial hurricane (times corrected by volume, of course).
But that's not all. After the "collapse" the air in the epicenter becomes too dense. The most usual "return" arises, and the overclocked air masses rush back, away from the epicenter. An ordinary blast wave arises, but its power can significantly exceed the power of a blast wave during a normal explosion, since both the volume of air involved in the explosion process and the energy received literally “out of nothing” can be several times and sometimes tens of times higher than similar chemical indicators. the explosion of the same initial power output.
This is exactly how it turns out that several liters (maximum) of gas dissolved in air lead to an explosion equivalent to at least ten kilograms of TNT or other explosives.
The mass of the Russian vacuum bomb, known as the “Daddy of All Bombs”, is 7,1 tons. And far from all this weight falls on the active substance - the bomb needs a very strong hull, a parachute, expelling charges, a flammable charge, etc. Its power in TNT equivalent is approximately 44 tons. That is, we can talk about an approximately tenfold excess of the power of the explosion of the gas-air mixture relative to conventional explosives.
And if so, then, probably, one should not be surprised at such a serious destruction in place of a seemingly fairly harmless phenomenon. Well, think about it, "gas flashed." Alas, this “flash” can really lead to great trouble and destruction, and in no case should we forget about it.
How to act in case of danger?
If this happens, and you find yourself in a heavily polluted room, the best thing you can do is to leave it immediately and report it to special services. And you may not know the telephone of the gas service - call the Ministry of Emergency Situations, the fire brigade, the police, in any case they will immediately inform the necessary specialists.
Important! Do not turn on the light in any way! A spark, even a microscopic one, arising in the wiring or directly at the contacts of the bulb, can cause detonation. Even if the light is already lit in the room, still do not touch any switches - the spark most often occurs when the appliance is turned on, and the long-lit light bulb can easily burn and not cause an explosion.
Unfortunately, a situation is possible in which a person cannot immediately leave the premises. For example, if he returned to his apartment, he feels a strong smell of gas and knows that someone from his family is in the apartment. In this case, remember - your stay in the room should be as fleeting as possible! The risk of losing consciousness from suffocation is very high, and without consciousness you cannot help anyone.
In this case, open the door wide. Try to get a full chest of air outside the room (at the entrance, on the landing). Holding your breath, without closing the door (!), Go to the apartment and first of all try to open the window. Any draft in the room in just a few minutes will reduce the risk of an explosion to a minimum!
Having found the victim, do not waste time - pick up and take out of the apartment as soon as possible. If it is very cold outside, you can grab a blanket or take a warm thing in the hallway. If there are several victims, take the first one out to the street, take a deep breath, inform the police / Emergencies Ministry and only after that go after the next one.
In case the strong smell of gas is felt in the entrance, you need to open the doors and try to create the most active air flow. If you still have to go to the porch (and, generally, you should not do this), try to break the windows on the porch windows in order to create as much air as possible.
It should also be remembered that experts do not recommend using even mobile phones and electric torches in a gassed room. It is better to call for help outside a gas-filled apartment, and optimally already outside.
Domestic gas leak - an extremely dangerous incident. Still, it should be remembered that it does not always end in disaster. In Russia, there are hundreds of domestic gas incidents annually. Most often these are explosions of gas cylinders, leaks in private houses equipped with gas boilers, and there are often cases of leaks in apartment buildings. A serious problem is the victim of unhappy love, which someone said that by opening the gas in the kitchen, it is relatively easy to part with life. The life of others, endangered, such sufferers rarely interested.
And yet, in most cases, gas leak incidents end without human victims. Therefore, you should not panic and feel doomed by smelling the smell of gas in the room: as a rule, in most cases the situation is saved by a simple call for help and following the simplest recommendations.
The explosion of the gas-air mixture still relates to complex phenomena, depending on various factors, difficult to calculate. That is why, by the way, terrorists almost never use this method - a small gap in the attic hatch can make all their efforts unsuccessful with much greater efficiency than even the efforts of the all-powerful FSB.
Nevertheless, the state is simply obliged to address the issue of gas security. Now, in the era of one hundred percent coverage of cities and even large villages with the Internet, it seems not so difficult to develop appropriate devices that signal an increased gas content. Surely, you can learn to turn off a house from gas supply on the first signal of gas pollution, without waiting for a group of technical specialists to come to the place.
And then we find money for the next “pipe bypassing”, and we don’t even find it difficult. But to ensure the safety of hundreds and thousands of Russians - "expensive."
Yes, just forbid Gazprom from entering into new gas export contracts until the country has solved the problem of security of gas communications. Just ban!
And you can not even imagine how quickly this issue will be resolved.
In the meantime: Magnitogorsk against the Nord Stream 2. And we know that we will win ...
Gas explosion How does it happen and what to do in case of danger?
- Viktor Kuzovkov
Noticed oshЫbku Highlight text and press. Ctrl + Enter