Is it better to use hot or cold water to fight a fire?

It's not very clear.

It is said that it is hot water. Because hot water evaporates easily into water vapor, a layer of air is formed above the fire to isolate oxygen and extinguish the fire.

However, the teacher said that the main function of water is to cool down when using water to extinguish fires, and it is better to use cold water from this point of view, because cold water has a better cooling effect than hot water.

I think it's better to use cold water, because it can also evaporate due to the high temperature from the fire while cooling down, forming a layer of water vapor, which plays a role in isolating oxygen.

There is no opportunity to use hot water when fighting fires, if it is good, it is better to use cold water, and while cooling down, the water is also vaporizing, which can still isolate the air.

Vaporization and exothermic ??? Solid melt exothermic ??? Take a second look.

Anyway, when extinguishing the fire, the cold water should be turned into hot water, what does it matter......Besides, when fighting fires, do you still go to boil hot water first?? It's ......haha

Water can extinguish fires, 1 is to cool down, 2 is to isolate the air It is mainly the function of isolation

Because no matter how hot the water is, it's 100 degrees, right?

So I think, it's not interesting, if I choose, or choose cold water, what if I scald people with hot water? Ha ha.

Hot water is good and evaporates easily.

Big brother, if you have water, use it !! If you're really going to quantify it, you also need the temperature of the fire and what kind of material is burning.

If the fire extinguishing effect is good, it is better to use hot water.

In daily life, if there is a fire at home, we generally use water to extinguish the fire, and the general small fire, as long as it is not an electrical fire, can basically be extinguished with water. So if you had a bucket of cold water and hot water in front of you, which one would you pick to extinguish the fire?

I believe that many people will pick cold water to extinguish. This is a matter of common sense, because the greater the temperature between cold water and fire, the more heat will be absorbed when it rises to the same temperature. This understanding is also correct, so why is the fire extinguishing effect of hot water better?

Let's take a look at the three conditions under which an object burns:

1) reach the ignition point;

2) ignition source; 3) There is plenty of oxygen.

And all the fire extinguishing principles that people think of are based on these three conditions. Cold water does reduce the ignition point, but two other conditions can't stop it. On the other hand, if you use hot water to extinguish a fire, the hot water can quickly vaporize in a short period of time, produce water vapor, and cover the fire source, so that the fire source cannot be burned without sufficient oxygen, so hot water can suppress the development of fire from two aspects.

So since the effect of hot water fire extinguishing is good, what about ordinary water used to extinguish fires?

In fact, this point is very easy to explain, the same volume of cold water and hot water, it must be that the way to get cold water is much easier, because there are fire hydrants in many places, and hot water to boil, it is very troublesome, sometimes even impossible.

01 Hot water.

Extinguishing a fire with hot water, which can quickly vaporize in a short period of time, produce water vapor, cover the fire source, and make the fire source unable to burn without sufficient oxygen.

According to the general knowledge we know, it is better to extinguish a fire with cold water, as cold water can quickly reduce the temperature of the fire. It is true that cold water is good for extinguishing fires, but for more effective extinguishing of fires, it is better to use hot water. For an object to think of fire, three conditions must be met:

One is to reach the ignition point; the second is the source of fire; Third, there is plenty of air. Therefore, if we want to put out the fire, we must contain it from these three aspects. Cold water can reduce the ignition point, but two other conditions can't stop it.

The use of hot water to extinguish the fire, the hot water can quickly vaporize in a short time, produce water vapor, cover the fire source, so that the fire source can not get enough oxygen and cannot burn, so hot water can curb the development of the fire from two aspects.

However, it is still important to note that you must be careful with fire in your life. Although hot water is effective in extinguishing fires, it is very difficult to get a large amount of hot water to extinguish fires in a critical moment. Why firefighters don't use hot water to extinguish fires, the time is tight, the task is heavy, and the difference is small, so it is not applicable (hot water is relatively hot and easy to hurt people).