Match  the verbs with the nouns

Verb	Noun
1. trigger	a) metallic parts
2. cut	b) vapor
3. cause	c) current transfers
4. turn	d) protective clothing
5. grease	e) victims
6. wear	f) an accident
7. rescue	g) pipes
8. retrieve	h) an explosion
9. inhale	i) a star grip
10. avoid	j) bodies (of victims)

Complete the text with necessary words or word combinations.

rescue operations, stabilized, to rescue, star grip, airbag cartridges, detrimental, protective clothing, blade arms, retrieve, "dead-man’s" function

1. Jaws of life devices have been specially designed 1) ______ to rescue people or retrieve the bodies of victims of road, rail or aircraft accidents.

2. They are used during 3) ______ from buildings.

3. Using hydraulic shears wear 4) ______, a safety helmet with visor, protective goggles, protective footwear and gloves.

4. To open the device turn the 5) ______ in the direction of the corresponding symbol (open) and hold it in this position.

5. 6) ______ guarantees load retention.

6. The object must be 7) ______ in its current position to ensure that there is no risk of sliding or shifting.

7. 8) ______ of the device should be closed until after the work.

8. Hydraulic fluid can be 9) ______ to health if it is swallowed or its vapor is inhaled.

9. Don’t cut live cables, springs, pipes under pressure, steel, concrete and explosive bodies like 10) ______.

 

6. Work in groups. Use words and word combination from the text “How to use jaws of life” and questions to the text.

Role I. You are a rescue worker. Answer the new-comers’ questions and explain them how to use jaws of life.

Role II/III... You are a new-comer of a rescue unit. Ask the rescue worker how to use jaws of life.

 

Explain how to use Jaws of life.

Firstly / The first step is / To begin with …

Secondly / Thirdly / The next step is …

After that /Then …

Following that …

Finally / Lastly / The last step is …

 

 

                                          Раздел 3.

AUTHENTICAL TEXTS

DEFINITIONS

There are some basic terms that a fire extinguisher or pre-engineered systems technician should be familiar with.

Apparatus: fire service vehicle.

Apparatus, aerial: vehicle that carries a fixed extendable ladder and portable ladders.

Apparatus, pumper: vehicle that carries hose, a pump, and a water tank.

Auto ignition: ignition of a material without the presence of an extraneous source of ignition.

Backdraft (Backdraught): the explosive or rapid burning of heated gases (unburnt pyrolysis products) that occurs when oxygen has been introduced into a compartment or building that has a depleted supply of oxygen due to an existing fire.

Code Official: a person legally designated to enforce a building code, a fire code, or a life safety code in a particular jurisdiction.

Combustible: likely to catch fire.

Competent: in respect of a function, task or duty, possessing the knowledge, experience and training to perform the function, task or duty.

Contain: to restrain within limits, enclose or cease spreading.

Control: to exercise restraining or direct influence over.

Designer: a person involved in one or more facets of creating the built environment, including architects, engineers, planners, and design technicians.

Disperse: to break up or scatter (as in - to disperse a flammable gas or vapor cloud).

Emergency responder: a person designated to respond to mitigate structural fires or similar emergencies, including firefighters and rescue technicians.

Employer: every partnership, group of persons, corporation, owner, agent, principal contractor, subcontractor, manager or other authorized person having charge of an establishment in which one or more workers are engaged in work.

Engine company: pumper apparatus and personnel.

Equipment: any mechanical or non-mechanical article or device, such as a machine, tool, appliance, apparatus, implement, service or utility, other than personal property owned by a person, unless that property is used in the carrying on of any work.

Explosion range: applies generally to vapors and gases and is defined as the concentration range in which a flammable substance can produce an explosion or fire when an ignition source (such as a spark or open flame) is present. The concentration is generally expressed as percent fuel by volume.

Extinguish: to put out (as in fire) to bring to an end the process of combustion.

Firefighter: a worker who fights fires full-time, part-time or as a volunteer member of a fire department and does not exclusively fight forest fires.

Fire Chief: highest-ranking officer in the fire department and is directly responsible for the operation and control of all personnel and activities.

First due unit: engine company or truck company designated to respond first to an incident at a given location.

Fire phases: one can characterize most fires by one, or a combination of three unique phases related to the fire’s rate of heat release. These are the Growth Phase, Steady State Phase and Decay Phase.

Flammable: easily ignited.

Flash Point: The lowest temperature at which enough vapor is generated from a flammable liquid to form a mixture in the air capable of being ignited.

Flashover: the term is used in general by firefighters to describe an element of rapid fire progress although scientists are somewhat at conflict as to any specific meaning.

Foam Solution: mixture of foam concentrate and water at proper proportions.

Foam: foam solution that has been air-aspirated to form expanded foam.

Frothing: bubbles formed in or on high flash point combustible liquids.

Fuel: a substance used to produce heat or combustion.

Gas: the physical state of a substance composed of molecules in constant motion that has no shape or volume, but will assume the shape and volume of an enclosure. A fluid that tends to expand indefinitely.

Hazard: any situation, thing, or condition that may expose a person to risk of injury or occupational disease.

Hazard Assessment: the process followed to identify, assess, and eliminate or manage workplace e hazards and risks to worker health and safety.

HAZMAT: Hazardous materials.

Heat: a form of energy that causes a body to rise in temperature, to fuse and to evaporate.

High-rise building: qualitatively used in this manual as a building with one or more floors above the reach of fire service ladders. Many codes and standards use a more quantitative definition.

Hose line, pre-connected: a hose of fixed length with a nozzle attached and connected to a discharge outlet on a pumper.

Incident: an occurrence arising in the course of work that could result in an injury or illness.

Incident Commander: the supervisor responsible for overseeing and managing incident objectives, personnel, and resources at an emergency response.

Inhibit: to hold in check, restrain or repress.

Miscible: capable of being mixed.

Nozzle: a device used to direct the flow, change velocity of the flow, change the pattern of the flow, or change the volume of the flow of any agent.

Nozzle Reaction: the rearward thrust caused by the flow of water or other agent through the nozzle.

Organization: a company, operation, undertaking, establishment, enterprise, institution, association, or a combination thereof that has its own management. An organization may be incorporated or unincorporated, public or private.

Oxidize: to be chemically combined with Oxygen.

Oxygen: a colorless, odorless, gaseous chemical element that is found in the air and is essential to life, and when combined with fuel vapors will produce heat and light when ignited.

Personal Protective Equipment (PPE): any clothing, device, or other article intended for use by a worker to prevent injury or to facilitate rescue.

Pre-incident plan: a compilation of information and diagrams on a specific facility to facilitate emergency operations.

Quenching: the application of water spray to cool the fuel down below its flash point.

Rapid Fire Progress - An NFPA definition of all types of rapid fire escalation that may occur and be linked to the above described phenomena as flashover, backdraft and their associates.

Saponification: the formation of a soapy foam on burning cooking fats or oils through the application of an alkaline based fire extinguishing agent such as wet chemical, sodium bicarbonate or potassium bicarbonate based dry chemical. The foam is a reaction of the alkaline with the free fatty acids in the cooking medium.

Vapor: a substance in the gaseous state.

Viscous: the property of resistance to flow in a fluid or semifluid, for example, glue is thick and resists flow.

Volatile: readily becoming a vapor at low temperatures; easily erupting into violent action.

Water Mist: water dispersed in a finely divided form using droplet sizes of 200 micron or less.

Wet Chemical: a solution of water and potassium acetate, potassium carbonate, potassium citrate or combinations thereof.

THE BASICS OF FIRE FIGHTING

Fire explained

Several factors need to be present before combustion can occur. The first requirements are fuel and oxygen. Fuel can range from a forest to home furniture or from crude oil to gasoline. A fuel can present itself in any physical form i.e. gases, liquids or solids can burn.

The oxygen required usually originates from the surrounding air. The oxygen concentration in normal air varies around 21%. If the oxygen concentration is lowered the combustion will be hindered and eventually stop. If, however the oxygen concentration is raised the combustion reaction will be more vigorous. An object can become saturated with oxygen and suddenly ignite when an ignition source is presented. Such a situation can occur in hospitals or other environments where oxygen is used. Another source of oxygen is the one contained in the molecule. In organic or inorganic peroxides the oxygen present in the molecule can sustain the combustion. This effect is used in gunpowder or in fireworks.

In scientific terms one can describe a fire as being an exotherm reation between fuel and oxygen. This means that the reaction produces energy, e.g. heat. Next to heat a fire generally produces light, combustion gases and soot.

To initiate a fire a certain amount of energy is needed. One can visualise this parameter by referring to a simple test with gasoline and diesel fuel, a match has enough energy to light the gasoline but in the diesel fuel the match extinguishes. In chemistry the energy needed to start a reaction is called the activation energy. Chemical reactions need to surmount this activation energy before the reaction can take place (enthalpy, thermodynamics). In a fire, the initial energy sources that cause the fire can be multiple e.g. a spark, an open flame, electricity, sunlight…Once the reaction is started however it generates more than enough energy to be self-sustaining, a chain reaction occurs. The energy given off in excess can be seen as light and heat generated by the fire.

The energy liberated in the combustion process causes the pyrolysis and the evaporation of the fuel. In the pyrolysis process the chemical composition of the fuel is broken down into small molecules. These molecules evaporate and react with the oxygen in the air. Stochiometric or complete combustion means that just enough oxygen molecules are present, to oxidise the fuel molecules. When hydrocarbons undergo complete combustion only water and carbon dioxide would be formed. Such conditions are however rare, therefore we need to note that other combustion products will also be formed. In the case of hydrocarbons the formation of carbon monoxide and soot increases with the oxygen defiency. If other types of fuel are burned other toxic products are formed based on their moleculair composition e.g. hydrogen chloride, hydrogen cyanide, hydrogen bromide, sulfur dioxide, isocyantes.

Combining the factors that we already mentioned above one can create the fire triangle, which symbolizes all the factors needed for combustion.

However next to fuel, oxygen and energy one should also note the mixing ratio between oxygen and fuel. A log of wood will not sustain a fire if it’s lit with a match, an amount of wood shavings however will. There is a better mixture between the fuel and the air, which favorises the combustion. A much larger surface of the fuel is in contact with the air thus a greater reaction surface is offered.

A further factor in the combustion process should be added which is called the inhibitor. In a combustion process a chemical chain reaction occurs, radicals of fuel react with radicals of oxygen heat and combustion products are formed. If one adds a chemical molecule (inhibitor), which reacts with those radicals without sustaining the combustion process one can stop the fire. This principle is used in dry chemical extinguishers which contain e.g. potassium or sodium bicarbonate or in the now banned halon extinguishers. A catalyst has the opposite effect of an inhibitor, a catalyst is a substance, which promotes the reaction (without being altered or used in the reaction) e.g. adding metal shavings to oil rags aids their combustion.

The ignition temperature of a substance (solid, liquid or gaseous) is the minimum temperature to which the substance exposed to air must be heated in order to cause combustion. The lowest temperature of a liquid at which it gives off vapour to cause a flammable mixture with the air near the surface of the liquid or within the vessel used, that can be ignited by a spark or energy source is called the flashpoint. Some solids such as camphor and naphthalene already change from solid to vapour at room temperature. Their flaspoint can be reached while they are still in solid state. The lowest temperature at which a substance continues to burn is usually a few degrees above its flashpoint and is called fire point. A specific ignition temperature for solids is difficult to determine because this depends upon multiple aspects such as humidity (wet wood versus dry wood), composition (treated or non-treated wood) and physical form (dust or shavings or a log of wood).

The auto-ignition temperature is the lowest temperature at which point a solid, liquid or gas will self-ignite without an ignition source. Such conditions can occur due to external heating - a frying pan that overheats causing the oil to autoignite, an exhaust-pipe from a car driving over dry grass or straw can cause it to auto-ignite- or they can occur due to chemical or biological processes - a silo fire can occur because of the biological processes in humid organic material. The autoignition temperature of substances exceeds its flashpoint.

When considering vapour or gas explosions or fires it is important to look at their vapour or gas density relative to air. In this way air has a coefficient of 1. A substance having a relative vapour of 1.5 will be one and a half times as heavy as air, while a substance with a relative vapour density of 0.5 is half as heavy as air. Heavier than air gases or vapours stay low to the ground or enter lower-lying structures such as sewers or cellars. Via this downward spread a localised incident can cause effects at greater distances. To illustrate the effect of vapour density a test with a gasoline soaked cloth, a candle and a trough (as channel) can be performed. When you place the burning candle at the lower end of the tilted trough and you place the cloth at the upper end, gasoline vapours will flow downward through the trough, where they will ignite and flash back to the top of the trough.

Next to vapour pressure when handling liquids their “volatility” is also important. Volatility refers to how readily a liquid will evaporate. The volatility of a product is closely linked to its boiling point. The higher the boiling point of a liquid the harder it will be for the liquid to evaporate. An amount of higly volatile fluid spilled will be of greater concern than the same amount of low volatile liquid, because of its ease to find an ignition source or because of the toxicity of the vapours. A more scientific term for volatility is the saturated vapour pressure of a liquid at a certain temperature, this is the pressure exerted by the vapour of at that temperature. The larger the vapour pressure of a liquid the more vapour is produced. The vapour pressure has an impact on the extent and area of the gas/air release. The vapour pressure of a liquid rises with the rise in temperature. The boiling point of a liquid is defined as the temperature at which the vapour pressure reaches 1 atmosphere. The lower the boiling point, the greater the vapour pressure at normal ambient temperatures and consequently the greater the fire risk.

Text 2

Fire classes

Fires are divided in classes depending on the materials that burn. Commonly the classes A, B, C and D are recognized.

Class A fires are fires in ordinary solid combustible materials such as bedding, matresses, paper, wood. Class A fires must be dealt with by cooling the fire below its ignition temperature. Most class A fires leave embers, which are likely to rekindle if air comes in contact with them. A class A fire should therefore not be considered extinguished until the entire mass has been cooled thoroughly. Smothering a class A fire may not completely extinguish the fire because it doesn’t reduce the temperature of the embers below the surface.

A class B fire are those that involve flammable liquids such as gasoline, kerosene, oils, paints, tar and other substances, which do not leave embers or ashes. Class B fires are best extinguished by providing a barrier between the burning substance and the oxygen. Most applied are chemical or mechanical foam. Depending on the type of substance, apolar (e.g. hydrocarbon) or polar, water soluble (e.g. alcohol), an adapted type of foam concentrate should be used. Extinguishing a small liquid fire with a water mist is also possible. This cools the liquid below its fire point or even flash point and puts out the flames; if however the heat source is not removed the fire can reignite.

Class C fires involve gases like natural gas, propane, butane etc. Extinguishing such a fire equals shutting of the source of the gas. Putting out the flames without being able to reach the valve creates a dangerous situation where a spark can cause an explosion.

Class D fires involving burning metals are less common. Combustible metals include sodium, potassium, lithium, titanium, zirconium, magnesium, aluminium and some of their alloys. Most of the lightweight metal parts in cars contain such alloys. The greatest hazard exists when they are present as shavings or when molten. Fighting such fires with water can cause a chemical reaction or it can generate explosive hydrogen gas. Special extinguishing powder based on sodium chloride or other salts are available. Extinguishment by covering with clean sand is another option.

Class E fires concern electric fires aren’t really considered a true fire class. Electricity doesn’t burn but e.g. a short circuit can cause a fire of the insulating material around the wires, which can propagate the fire. Extinguishing electrical fires is best done by using carbon dioxide or by using a powder extinguisher. The use of water is not advised, certainly not as a direct jet on apparatus remaining live. Water spray or mist might be used but with great caution. Due to the air between the water droplets a much larger resistance exists than when using a direct jet. Where possible the electrical supply should be isolated prior to applying water in any form.

Class F fires are sometimes added for educational purposes. This is also not a true class but is used to emphasise the dangers when combating fires of molten fats or tars. The class F or Fat fires are particulary dangerous when tackled with water. The molten fat is lighter than the water, which sinks, heats up and vaporises, expanding enormously. As a result the molten fat is pushed out in very tiny droplets, which allows easy contact with the oxygen and causes the fire to produce a flame ball up to several meters high.

Text 3

Fire growth

Now back to regular fires. The energy liberated during combustion can radiate back on the fuel substance, where it causes pyrolysis and evaporation of the fuel. It can also aid further pyrolysis of the products in the gasphase. The heat liberated by the fire also causes the surrounding materials to warm up. The heat transfer is accomplished by three means, usually simultaneously: conduction, radiation and convection.

Conduction is direct thermal energy transfer due to contact. The heat on molecular level means that the kinetic energy of molecules, their movement increases. This energy is than passed on from one molecule to the next. Materials conduct heat at varying rates. Metals are very good conductors while concrete and plastics are very poor conductors, hence good insulators. Nevertheless, a fire in one sidewall of a compartment will result in the transfer of heat to the other side of the wall by conduction. If a metal beam passes through the wall this effect will be even larger. In ship fires, where most the walls are of metal, removing materials from the wall close to the burning compartment is necessary to limit the fire spread.

Radiation is electromagnetic wave transfer of heat to an object. Waves travel in all directions from the fire and may be reflected or absorbed by a surface. Absorbed heat raises the temperature of the material causing pyrolysis or augmenting the materials temperature beyond its ignition point causing it to ignite. Radiation from a fire plume is one of the major concerns when limiting a fire in an oil tank field, cooling of the tank on fire and the surrounding tanks is necessary to gain the time needed to mount an adequate foam attack.

Convection is heat transfer through a liquid or gaseous medium. This transfer is caused by density difference of the hot molecules compared to the cold ones. Hot air, gases expand and rise. Convection normally determines the general direction of the firespread. Convection causes fires to rise as heat rises.

Radiation, convection and conduction next to flame contact consist of normal fire growth. Burning embers carried by the wind, debris falling, breakdown of recipients containing flammable liquids or gases or the melting of lead pipes or plastics can cause firegrowth in an unforeseen direction.

Normal fire spread, once it breaches the compartment, is known as the cube model. If all the compartment walls are equal, the first one breached will be the ceiling due to the exposure to the rising heat. A less likely fire spread will be the horizontal one, breaching the walls. And an even less probable fire spread will be the downward spread through the floor. All depending of course on the materials the compartment boundaries are made of.

Three different fire phases can be distinguished namely the growth phase, the steady state phase and the decay phase. The early stage of a fire during which fuel and oxygen are virtually unlimited is the Growth Phase. This phase is characterized by an exponentially increasing heat release rate. The middle stage of a fire is the Steady State Phase. This phase is characterized by a heat release rate, which is relatively unchanging. Transition from the Growth Phase to the Steady State Phase can occur when fuel or oxygen supply begins to be limited. The final stage of a fire is the Decay Phase, which is characterized by a continuous deceleration in the heat release rate leading to fire extinguishment due to fuel or oxygen depletion.

Flashover normally is the culmination of the fire growth phase and occurs when the ceiling temperature reaches around 500-600°C, depending on the materials present in the compartment and the geometric arrangement. After flashover, room temperature rapidly increases to reach up to 1000°C.

The same diagram can be redrawn more schematically to visualize fire growth in relation to time. In the first phase of the fire, shortly after the fire’s ignition, the fire growth is limited to the object on fire and it’s immediate surroundings. The fire heats up the room slowly. Once however the fire gets a grip on its surroundings the fire shows a steep progress rate. All the objects in the room suffer from the intense heat radiating from the fire but mostly from the combustion gases and smoke produced, causing them to initiate pyrolisation, to evaporate or to heat up beyond their ignition point. At a certain point this effect causes flashover, to engulf the whole room in flames and thereby rapidly spread the fire until it reaches a ventilation-controlled state. At this point the fire growth slows, limited by the oxygen defiency. If however the fire breaches the compartment walls, the new source of fuel and oxygen again allows a steep rate of fire growth.

Using this data to harness fire prevention concepts, one can easily deduct safeguards, which can be taken at different levels of fire growth. Preventing ignition can be done by eliminating energy or ignition sources (e.g. a smoking ban) or by removing/treating any easily ignitable materials (e.g. the use of flammable materials in upholstery etc). The fire growth phase can be slowed by installing automatic fire suppression; an automated fire detection system followed by an in house first response; by using materials which limit fire spread; by installing automated smoke and heat extractors or by the storage of flammable liquids in fire safe closets etc. The breach of the fire compartment can be slowed by using special fireproof doors or by using building materials with high fire resistance. Normally the breach of a compartment can also be hindered by the intervening fire department, which at this point should have arrived on the scene in time.

Depending on the inflow or the amount of oxygen present in a compartment a beginning fire can evolve to flashover as described above but it may also slowly die out as a result of the lack of oxygen. This lack of oxygen inflow in a compartment is mostly due to modern heat saving construction utilising double or even triple glazing, which often maintains its structure so well during a fire. Furthermore, modern energy efficient doors and windows do not allow any air-drafts. Consequently, in modern buildings a fire can smoulder due to the lack of oxygen producing large amounts of carbon monoxide and pyrolysis gases. Due to the high thermal insulation of modern buildings a major heat build-up may occur, even from a small fire. Due to the sudden opening of a door or a window the sudden intake of oxygen enriched air can cause the combustible gases to explode in what is called a backdraft. This is not only a dangerous situation for intervening fire crews but it can be even more dangerous to an untrained occupant of the premises.