Red bottle to know

2006/02/01 Kortabitarte Egiguren, Irati - Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Teknologia
• Kimika

(Photo: Boulder)

Computers, papers, oils... Everything around you can burn. Maybe you too, at a certain temperature. As explained in Ray Bradbury's book Farenheit 451, paper, for example, burns at that temperature. Imagine that the set of paper you've thrown into recycling burns and you don't have water nearby. Undoubtedly, extinguishers are the best means of extinction in the absence of water. However, despite knowing the theory about extinguishers, it is essential to know how to use them to face the situation.

If taken and reviewed in the hands, several main chapters in the extinguisher stand out. The first and obvious is the bottle. It is the container with an extinguisher that will extinguish the fire. Inside there will be dust extinguisher. The bottle always has a valve that blocks or measures the flow of this extinguisher. Outside, a label with general information for everyone. The latter is also part of the extinguisher.

The extinguisher is taken in the hand and it is verified that we know how to handle it in case of fire. Fires occur every year. 30% of the fires are caused accidentally; they occur when burning bushes, throwing cigars badly extinguished anywhere, badly extinguishing the fires that occur during leisure time, etc. They are ultimately the fruit of human irresponsibility. They are also naturally originated, for example by rays, but very few.

(Photo: R. Cardboard)

Whatever the type of one or the other, fuel (e.g. wood, plastic, gasoline, scrub...), comburent (in general, air oxygen) and activation energy or heat are the essential elements for fire production. The sum of these three components produces fire. On the contrary, if one of these elements is removed, the fire is extinguished. There are several ways to do this: reduce concentration by removing or dissolving the fuel, removing heat or reducing temperature and preventing the resulting vapors from mixing with oxygen from the air -- using a blanket, for example, or directly with the extinguisher.

Type of fire, extinguisher

The most commonly used fire extinguishers are those containing carbon dioxide, mixtures of various powders and halogenated hydrocarbons. Depending on the fire that occurs, a fire extinguisher or another will be used. Because not all fires are equal.

Carbon dioxide extinguishers have a trumpet filter. Extinguishers with chemical powder no.

I. Kortabitarte

Fire types are generally classified according to fuel: Class A fires are solid materials. In most cases, these materials are organic and usually form embers when burned. The combustion of liquids such as gasoline, paints, oils, etc., produces type B fires. When gases are burned (methane, propane, butane...) and metals (sodium, magnesium, potassium...) are of classes C and D, respectively. Finally, there are class E or electric fires. This differentiation is very important and it is essential to be clear.

Suppose, therefore, that your computer burns you. So you have a fire type E. Carbon dioxide, for example, is easily penetrable into the fire and conducts no electricity. The most suitable type E electric fire extinguisher is therefore carbon dioxide. In addition, it does not emit waste that can damage the electrical circuit. It is also very effective in case of fire of metals of electrical nature. In addition, carbon dioxide extinguishers are characterized by having a trumpet shaped filter. Even with flexible tubes, at the end of these flexible tubes there is a special filter, the trumpet. In fact, CO ₂ goes below zero to 70ºC and can cause skin burns by contact. Cold also burns often. The strong output expansion cools the gas.

Formula 1 vehicles, when set on fire, immediately turn off fire with fire extinguishers.

MEC

Similar to the previous ones but without trumpet are extinguishers with mixture of several powders. They are very efficient but produce great damage, especially in electrical appliances. In addition, they have a small obstacle: these powders are somewhat suffocating.

The following, fire extinguishers containing halogenated hydrocarbons, have many uses. In general, except for type A and D fires, everyone else is able to turn them off. However, these compounds in the chlorofluorocarbons group damage the ozone layer, so experts seek new solutions to prevent environmental damage. Who would say that these compounds exist in fire extinguishers... The use of these extinguishers is currently prohibited. However, they are still used in older installations.

We also have fire hydrants. Fire mouths must be equipped with water. They are very simple. They have flexible tube, pressure control pressure gauge and spear. There are two types: Rigid and flexible. The main advantage of the first is that it can be used without completely releasing the rigid tube. It seems silly, but in an emergency it is not so easy to completely release the tube. The second, completely soft and flexible, requires a total release for use.

Water, universal extinguisher

Rigid mouths can be used without completely releasing the flexible tube.

G. Roa

Water can also turn off B-type fires or liquids. But not all. If the burning liquid is polar (like alcohol), there will be no problem turning it off. However, if it is an apolar liquid, such as oil, the flames may expand.

Moreover, the water pressure at the outlet of the flexible tube is high and in some cases this pressure can disperse the burning liquid and increase the fire instead of turning it off. That is why, often, when the fire is very localized, for example when it is in a paint boat, the ideal is to drown it with a blanket.

And don't say when the fire occurs around plugs, cables, etc., just in case you don't use it. Because you risk getting an electric shock.

First extinguisher XIX. dependent. Then they have changed a lot.

G. Roa

Do not forget the foam used by firefighters in general, product of the mixture of special powders with water. Foam is mainly used in firefighting liquids. Although to a lesser extent, it can also be used when solids are burned.

Imagine that you are a company employee and that an oil tank burns at high temperatures. To turn this off, not all the extinguishers around you will be enough. That's why it's best to call firefighters. Its foam, in addition to cooling the medium, will produce a top layer that will prevent physical contact between oil and oxygen. Thus, in the short term the fire will be completely extinguished.

All these extinguishers are manual. But there are also stable extinguishers. Automatic fire detectors are currently installed in different areas, both above a temperature and if flames are observed.

As important as having a fire extinguisher. You also have to be cautious and relaxed. Try to extinguish the fire from a distance at first and, as it goes out, go slowly, without endangering yourself. If you ever have to resist the fire, be careful.

Benefits of Fire

We see the images of the fires and we think that the forests are going to go bankrupt and, in addition, the assessments after the fires make us think that the assumptions are absolutely correct. However, fire, despite not being so cited, also has its benefits, as long as it occurs in some ecosystems and with a certain periodicity.

If you eat each year, nature does not leave enough time to regenerate, so gradually it will become impoverished both the soil and the ecosystem itself. On the contrary, the managers of singular ecosystems occasionally set fire to some areas in order to create new vegetation, and have seen that a good domain of the fire benefits the ecosystem. According to a report by the FAO (Food and Agriculture Organization of the United Nations), fire has been for many years one of the main agents of deforestation, so they wanted to put it out as soon as possible. However, it has been proven that fire plays an important role in ecosystem health and that, at present, some areas are intentionally burned. However, it should be noted that not all plants respond in the same way to fire and that the influence of fire is very different from forest to forest.

(Photo: archive)

For example, a pine forest will burn much faster and easier than a oak tree. In fact, conifers - pines, sequoias, etc. - retain little water and, in addition, being resinous, burn like matches. In conifers there are curious cases, such as Pinus banksiana. For this type of pine, fire, besides beneficial, is an indispensable element for reproduction. The seeds of this pine, like the rest of the pines, are found in the pineapple. What happens is that to open the pineapples and drop the seed to the ground is essential a very high temperature. Surprisingly, this temperature is only achieved with fires. On the contrary, leafy plants have much more water and, although dry, can contain enough water to cope with the fire.

In addition to plants, raptors can take advantage of fires. These birds, just after the fire, explore the burnt corners to find snakes, rabbits and similar animals that have died but are not calcined. Thus, without any difficulty, they earn copious meals.

It is therefore evident that fires cause obvious damage, but they can also be beneficial for some species of plants and animals. However, it's not why start calcining.

One of the biggest fires in history

If we look back, throughout history there have been numerous fires of great magnitude, from which in the year 64 BC destroyed Rome to the present day. But there are other examples closer.

For example, what happened in London in September 1666. Fortunately, no one died in that fire. The fire began in a bakery and firefighters had to put it out in days. In the capital dominated wooden buildings. Brick and stone were mainly used in the reconstruction.

Perhaps one of the best known of the last hundred and fifty years is the one that occurred in Chicago on October 8, 1871. In the city of Chicago, in general, wooden buildings predominate. So, as you imagine, the city was completely damaged, destroying more than 17,000 buildings. More than 300 people died. The cause of the fire has not yet been clarified.

(Photo: archive)

In San Francisco, the fire came after the earthquake of April 18, 1906. Little earthquake and fire. The fire began with the kitchens and lamps moved by the earthquake. In addition, the earthquake totally damaged water sources, so for firefighters it was practically impossible to extinguish them. It lasted three days and finally several buildings were destroyed with dynamite to disrupt the spread of fire. This caused approximately 3,000 deaths and the destruction of 300,000 buildings.

One of the last and most recent is the one in England on Sunday, December 11, 2005. It was a sunny day for many inhabitants of the London capital. Not precisely because it rains, but because it was black smoke that dominated. At six in the morning, a large fuel tank was set on fire about 40 km north of the capital. Firefighters took hours and hours to turn it off due to repeated flames.

But what caught fire? It is said that fuel is stored in the tank for both planes and houses, well separated. According to sources, the fuel used for planes can be responsible for this massacre. This December was one of the biggest fires in an oil plant in England from 1974 to the present.