Dry powder fire extinguishers are suitable for all kinds of flammable, flammable liquid and flammable, flammable gas fires, as well as electrical equipment fires
Carbon dioxide fire extinguishers have high fire extinguishing performance, low toxicity, low corrosiveness, no traces after fire extinguishing, and are more convenient to use. It is suitable for all kinds of flammable, flammable liquid and flammable gas fires, and can also put out the initial fire of instruments, books, archives and low-voltage electrical equipment and electrical appliances below 600 volts.
Foam fire extinguishers are suitable for fighting all kinds of oil fires and fires of solid combustibles such as wood, fiber, and rubber. But foam carries water and cannot put out electrical equipment.
What are the biggest advantages of the three fire extinguishers?
Carbon dioxide has a molecular weight of 44 and air has a molecular weight of 29, so carbon dioxide flows downward in the air. In confined spaces, carbon dioxide can build up like water, and once it gets past the fire, the flame goes out quickly.
However! However! However! Once in an open area or in a large space, carbon dioxide can easily flow like water, but it does not have the ability to infiltrate water. Therefore, it is easy to spread around, and it cannot accumulate enough to cover the fire source, so it will not be able to extinguish the fire.
In addition, carbon dioxide is expensive, and the temperature of minus 30 degrees can easily freeze people (including the metal parts of fire extinguishers), so the use is limited. The dry powder is relatively cheap and has little harm to people. The ABC dry powder using phosphate is also easy to adhere to the surface of the object and isolate the air.
Foam fire extinguishers are used a lot in petrochemical facilities, mainly because they are cheap. A little solid agent mixed with water can produce a lot of bubbles (even 200 times its own volume of foam), covering a large area or spraying for a long time. Usually, it is enough to store the fire extinguishing agent in a can. When it is used, open the water inlet pipe and mix it into a liquid medicine and send it out.
Once an oil tank with a height of several floors or even a dozen floors catches fire, the fire extinguishing agent can be pressurized to the top of the tank and filled with pressure. The foam liquid will fill all the pores and form a foam protection layer nearly 1 meter thick, which not only cools the temperature but also blocks oxygen.
Dry powder fire extinguishing agents are difficult to do. The biggest advantage of carbon dioxide is that it has less side effects and leaves no traces after volatilization. Libraries and server rooms sprayed with water or powder are disastrous, and they are confined spaces that are ideal for carbon dioxide. The biggest advantage of dry powder is that it has no obvious shortcomings, is cheap, has relatively few side effects, is widely used, and has good overall performance.
Therefore, the most common dry powder in life is dry powder. ABC dry powder is mainly composed of hydrogen phosphate and has a wide range of uses; BC dry powder is mainly composed of bicarbonate, which is not suitable for Class A fires.
The advantage of foam is that the liquid is easy to transport, it can be sprayed far and high, or it can be sent to a high place for spraying; the amount of water used is enough. Therefore, fire trucks and factories love to use them.