Unit 2. Water extinguishment (a close-up)
Useful vocabulary
to displace – перемещать, убирать
sufficient/insufficient – достаточный/недостаточный
a combustive agent – горючее вещество
smoke – дым
to prevent – предотвращать
means – (зд.) средства
a fire seat – очаг пожара
a source – источник
to reduce – уменьшать
consequences - последствия
a flashover – круговой огонь, искровое перекрытие
an urban fire – пожар в городских условиях
a fire hose – пожарный шланг
a droplet – капля
Task I. Read the text
Often, the main way to extinguish a fire is to spray with water. The water has two roles:
in contact with the fire, it vaporizes, and this vapor displaces the oxygen leaving the fire with insufficient combustive agent to continue, and it dies out.
the vaporization of water absorbs the heat; it cools the smoke, air, walls, objects in the room, etc., that could act as further fuel, and thus prevents one of the means that fires grow, which is by "jumping" to nearby heat/fuel sources to start new fires, which then combine.
For fires in the open, the seat of the fire is sprayed with a straight spray: the cooling effect immediately follows the "asphyxia" by vapor and reduces the amount of water required. A straight spray is used so the water arrives massively to the seat without being vaporized before. A strong spray may also have a mechanical effect: it can disperse the combustible product and thus prevent the fire from starting again. Spray is aimed at a surface, or object: the strategy is sometimes called two-dimensional attack or 2D attack.
When we consider a closed volume fire we should remember that spraying of the seat of the fire directly can have unfortunate and dramatic consequences: the water pushes air in front of it, so the fire is supplied with extra oxygen before the water reaches it. This activation of the fire, and the mixing of the gases produced by the water flow, can create a flashover.
The modern methods for an urban fire dictate the use of a massive initial water flow, e.g. 500 L/min for each fire hose. When the flow is too small, the cooling is not sufficient, and the steam that is produced can burn firefighters (the drop of pressure is too small and the vapor is pushed back). Although it may seem paradoxical, the use of a strong flow with an efficient fire hose and an efficient strategy (diffused, sprayed, small droplets) requires a smaller amount of water: once the temperature is lowered, only a limited amount of water is necessary to suppress the fire seat with a straight spray.
Task II. Say if the statements are
Firemen shouldn’t direct water towards the seat of the closed volume fire
a. true b. false c. no such information in the text
Fuel removal is helpful in firefighting
a. true b. false c. no such information in the text
Task III. Which passage contains the following information: Water’s vapor prevents fire growth.
1 b. 2 c. 3 d. 4
Task IV. Answer the following questions
What is the main way to extinguish a fire?
What are the functions of water in extinguishing a fire?
What type of sprays is used for fires in the open?
Why mustn’t firefighters use direct sprays for closed volume fires?
What is a standard initial flow for urban fires? What are the reasons for such standards?
What dangers can firefighters face when working?
Task V. Match the beginning with the end
Objects in the room can act as a. for open fires.
Displacement of oxygen leaves the fire b. a flashover.
A straight spray is used for c.with insufficient combustive agent.
In some cases direct spraying d. further fuel.
Fire activation can cause e. leads to bad results.
Task VI. Give Russian/English equivalents to the following words and phrases
to suppress the seat of the fire, a combustive agent, the source of heat, to be aimed at a surface, to vaporize, a strong spray, dramatic consequences;
основной способ, охлаждающий эффект, смешение газов, падение давления, необходимый, пожар в городских условиях, дым.
Task VII. Make up 3 sentences using the words and phrases from Useful vocabulary and Task VI
Task IX. Grammar focus. Participles I, II revision: find their examples in the text and translate them
Task X. Translate the following sentences into Russian. Find Participles I, II and name their functions. Be attentive: some sentences don’t contain examples of participles I, II
Extinguishing a fire takes time and efforts.
Extinguishing a fire one firefighter got serious burns.
Water required for fire extinguishment is provided through fire hoses.
Reducing oxygen supply slows down the spreading of the fire.
The means taken by the residents of the house stopped flaming.
A small fire burning in the bushes can cause a big fire devastating a century-old forest.
The source of smoke was quickly identified.
The operation was very quick and successful due to the combining of two teams’ efforts and experience.
Working out an efficient strategy makes at least 50% of success.
After exploding the car started burning.
Some people going along the street saw flames of fire and called 01.
Water being sprayed directly may also provide a mechanical effect.
Task XI. Translate the given phrases and make up your own sentences with them
… дым, выходящий из окна …
… вода, подаваемая через шланги, …
… методы, используемые для/в …
… работая пожарным, …
… закончив работу, …
… ограниченное время …
… удаление тепла/топлива …