Decide if the following statements true or false or there is no information in the text. Correct the false statements.

 

1. A half of all electrical fires occur during the Christmas holidays in the USA.

2. Overloaded outlets are the only cause of electrical fires.

3. Electrical devices built to put out heat use more power than other devices.

 

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4. Only counterfeit products cause overload.

5. Loose wiring may produce an electric arc and thus ignite the house.

6. Electrical fires occur in summer less often.

7. It is easy to notice an electrical fire immediately.

8. It is enough to switch off the device from a burning socket to stop the fire.

 

9. The use of chemical powders may cause electrocution.

 

10. In case of electric fire you should immediately go out of the house and call the fire brigade.

 

TEXT C

 

Translate the following text in writing.

 

METAL FIRES

 

Potassium, sodium and calcium decompose water readily, liberating hydrogen. These metals are all used in industry but not as widely as the “light metals” which are widely used in aircraft and motor vehicles industries and in the trades where lightness is desirable attribute. Magnesium, some of its alloys and titanium are easily ignited when in the forms of wire, powder, turnings of swarf: aluminum in similar forms is capable of burning.

 

The dusts may form inflammable and explosives mixture with air. Water applied to any of these fires is decomposed, giving off hydrogen, which aggravates the fire and may give rise to explosions which would scatter the burning metal. Other metals too, e.g. zinc, in finely – divided form are combustible.

 

Water, foam, carbon tetrachloride, methyl bromide, chlorobromomethane or carbon dioxide, in fact, none of the usual extinguishers may be used on metal fires. They are all ineffective and most of them are dangerous, because they are liable either to cause the explosion or to do more harm than good by scattering the burning metal.

 

Gas-expelled dry powder extinguishers are unsuitable for the latter reason, but there is one specially-constructed model which discharges through a long tube in a cone-shaped nozzle by which powder is delivered lightly onto the fire. The solid extinguishing agents that find little application in firefighting generally, are of value in dealing with metal fires. They must be applied gently in order to cover the burning metal without disturbing it, and care is necessary, as some scattering may, nevertheless, occur. Dry sand, talc, mixture of asbestos dust and graphite may be used. Asbestos hand-clothes or blankets are useful where small quantities of metal are involved, not so much to extinguish the fire as to prevent its spread.

 

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LISTENING

 

You are going to watch a video. Before watching discuss the questions with your partner.

 

1. What is flammability?

2. What flammable or explosives substances do you know?

 

Watch the video “FLAMMABLES & EXPLOSIVES” at http://www.youtube.com/watch?v=6693BvJoKQI

 

Watch the video again and complete the notes:

 

Part 1

 

A flammable can be simply described as a (1) ___ that will readily catch fire and (2) ___. Silane is a commonly used flammable substance. There can be two identical amounts sitting side by side in identical dishes, yet one will (3)

 

___, the other one won’t. The reason is the silane that (4)___ was (5) ___ by dry ice, the other one was (6) ___ to just over 81° F, the flashpoint of silane.

 

Flashpoint is the lowest temperature at which a substance (7) ___ __ a vapour that will burn. One of the first things you need to(8) ___ when you’re dealing with (9) ___ and (10) ___ is that it’s the vapour that the substance gives off that burns not the substance itself.

 

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Flammables and explosives are two classes of materials that can always be (11) ___: well, flammables can ignite and burn, explosives are a subject of a very rapid (12) ___ reaction or (13) ____ and can (14) ___ gas and heat with potentially violent results. Flammables and explosives are both (15) ___ that you ought to be very careful with.

 

Part 2

 

Let’s look at another (1) ___ flammable material – gasoline. Its (2) ___ ignite easily at temperatures as low as negative 45° F and even when it’s at its (3) ____ and a (4) ___ is created gasoline may not (5) ____ (6) ____. Whether it does, will depend on a gasoline’s fuel – air mixture and limits of flammability. Materials have both lower and upper limits of flammability. A substances’ (7) ___ flammability limit is the minimum percentage of vapour to air that required for ignition to (8) ____ ___. The (9) ____

 

flammable limit is the percentage of the vapour to air beyond which ignition is no longer (10) _____.

 

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UNIT 3

 

FIRE EXTINGUISHMENT

 

VOCABULARY