Exercise 28. Write if these statements are true or false. Exercise 27. Answer the questions

Exercise 27. Answer the questions.

Exercise 26. Complete the sentences.

LISTENING COMPREHENSION EXERCISES

Exercise 24. Find and correct 10 mistakes.

Each material have its own fire characteristics.

Wood is combustible. Fire spreads rapidly over wooden surfaces, particularly when the wood is thin. To reduce the fire spread wood is treat with salts that retard ignition. They is applied strictly in accordance with directions and, in the case of wood paneling, are ineffective if the hidden back surface is untreated. Wood treated to resist decay and insects emit toxic smoke. When the wood carries part of the load of the building, the loss of material can to cause collapse.

Concrete is non-combustible but not necessarily fire resistive. Concrete made fire resistive by specified improvements in the mix. Different types of concrete structures have different fire problems. Fire in concrete buildings may be very hazardous to firefighters. Even a total collapse of all floor can happen.

Plastics describes a wide range of materials. In general, they are easily ignited, produce greater amounts of heat than other materials and emit combustion products that are more toxic than ordinary smoke. Some plastics may melt or deform.

Steel is non-combustible. She is very strong. But steel has negative fire characteristics. At relatively low fire temperatures steel elongates significantly. Cooling brings it back to its original dimensions. But it do not cause failure of the steel. The best use of water is to cool the steel constantly, to prevent the structure from failing and thus reduce the hazard to firefighters and the loss.

Exercise 25. Listen to the text “Fire hose couplings”.

1. Earlier hose couplings were made of ….

a) metal; b) leather; c) wood.

2. Alloys of brass, aluminum and magnesium ….

a) do not corrode easily; b) corrode easily; c) do not corrode at all.

3. It is necessary to examine couplings ….

a) every day; b) after every use; c) when hose is washed and dried.

4. Connected couplings … receive injury from being dropped or dragged.

a) never; b) often; c) seldom.

5. Today you can couple and uncouple hose couplings ….

a) without any effort; b) with much effort; c) with little effort.

1. What are fire hose couplings of today made of?

2. What does the efficiency of fire hose operation depend upon?

3. What were fire hose couplings used for?

4. What are the main rules for the care of fire hose couplings?

5. How are fire hose couplings of today designed?

1. Connected couplings require the most protection.

2. You must clean the couplings of tar, oil, dirt.

3. You should avoid dropping or dragging couplings.

4. Connected couplings can be bent or crushed when they are run over by heavy vehicles.

5. When the couplings are connected there is more danger of damage during common usage.

Дата добавления: 2014-12-29