Watch the video again. Decide if the following statements are true or false. Correct the false ones.

 

1. The fire in the video is a planned one.

2. It is possible to survive flashover.

3. The house has neither a smoke alarm nor a fire sprinklers system.

4. The fire started in the living room.

 

5. If you discover a fire you should call the fire department first and then leave the house.

 

7. Home fires are typically reported some time after the fire starts.

8. Firefighters usually arrive ten minutes after the fire has been reported

9. There is a fire sprinkler on the wall in the room on the left.

10. The fire didn’t do much damage in the left room.

 

11. The room on the right combusts in flashover in twenty seconds.

 

12. The purpose of the video is to show lifesaving effectiveness of fire sprinklers.

 

16

UNIT 2

 

CLASSES OF FIRES

 

VOCABULARY

 

Study the active vocabulary.

 

1. to denote                                    – обозначать, означать

2. liquefiable                                  – сжижаемый

 

3. to reach                                        – достигать

4. suitable                                         – подходящий, годный

5. extinction                                    – тушение пожара

6. compound                                – соединение, смесь; составной, сложный

7. to take place                           – происходить

8. jet                                                        – компактная струя

9. spray                                               – водяная пыль (распыленная струя)

 

10. to choose                               – выбирать

11. to cool                                        – охлаждать

cooling                                       – охлаждающий; охлаждение

12. quantity                                     – количество

13. sand                                             – песок

14. foam                                             – пена

 

15. vaporizing                              – парообразующий

16. blanketing                              – покрытие, покров

 

17. dry powder                           – сухой порошок

 

18. live                                                  – находящийся под напряжением

19. exception                               – исключение

20. nozzle                                         – насадок, ствол

21. electrically dead             – обесточенный

22. to apply                                     – применять, употреблять, обращаться

 

23. available                                  – имеющийся в распоряжении

24. flexible                                       – гибкий, податливый

25. to decompose                  – разлагаться,

 

26. to liberate                               – освобождать

 

27. to aggravate                       – ухудшать

 

 

17

TEXT A

 

Discuss the questions with your partner.

 

1. Do you know any classification of fires? According to what principles are fires classified?

 

2. Look at the table. What can you say about each class of fire?

 

Class A      Class B      Class C           Class D               Class K

 

3. What is the fuel?

4. Could you give examples for each class of fire?

 

Read the text using a dictionary if necessary. Check your answers for Ex. 2.

 

CLASSIFICATION OF FIRES

 

In firefighting, fires are identified according to one or more fire classes. Each class designates the fuel involved in the fire, and thus the most appropriate extinguishing agent. Multiple classification systems exist in different countries.

 

The United States uses the NFPA (National Fire Protection Organisation) system. The NFPA defines five classifications of fire, including classes A, B, C, D and K according to the nature of the combustible materials, the size and intensity of the fire and the substances which are the most suitable for their extinction.

 

Class A is the most common type of fire involving ordinary combustible materials such as wood, cloth, paper, rubber, and many plastics. This type of fire leaves an ash behind after burning and has an ember flame. The most common and the most effective extinguishing agent for them is generally water in the form of a jet or a spray. Water is used in a cooling or quenching effect to reduce the temperature of the burning material below its ignition temperature.

 

Class B fires are the ones involving liquids or liquefiable solids. A flammable liquid must be burning at room temperature in order to be a Class B fire, and a combustible liquid must be heated to its flammable point to be classified as Class B. Some flammable and combustible liquids included in this classification are petroleum, tars, oil-based paints, oil, alcohols, lacquers,

 

18

solvents and flammable gases. For the purpose of choosing effective extinguishing agents, flammable liquids may be divided into two groups:

– those that are extinguished with water;

– those that are not extinguished with water.

 

Depending on a liquid, the extinguishing agents include water spray, foam, vaporizing liquids, carbon dioxide and dry powder. Blanketing is the most suitable method of extinguishment of this class of fires.

 

A Class C fire is a fire that can be classified as an A or B fire, but that involves electrical equipment as well. Extinguishing agents should not be conductors of electricity. Water and foam are both conductors of electricity and should not be used on live electrical equipment, but in some circumstances an exception may be made in favour of a spray from specially designed nozzles. It is not always possible to extinguish a fire without using the cooling effect of a large quantity of water. In such cases equipment must be made electrically dead before jets of water are applied in order to avoid the danger of shock.

Class D fires are ones involving combustible metals such as magnesium, titanium, lithium, zirconium, sodium, and potassium. Extinguishing agents containing water are ineffective and even dangerous. A Class D fire burns at an exceptionally high temperature, and when water is used on these types of fires it can decompose into hydrogen and oxygen aggravating the fire. Special extinguishing agents such as sodium chloride, carbon dioxide, dry sand or salt are available for the fire control specifically for each metal.

Class K is the newest NFPA classification of fire. This classification includes cooking appliances that involve a combustible medium such as cooking oil, other fats and alcohols. Though such fires are technically a subclass of class B, the special characteristics of these types of fires are considered important enough to recognize separately. Saponification can be used to extinguish such fires.