Fire

Fire is a very good servant, but, a very bad master. As long as fire is under our control, it serves a lot of useful purposes for us, but, once it goes out of our control, it can create a lot of destruction. However, despite the presence of fire safety measures, the occurrence of accidents is oftentimes inevitable.

It is this combination (of good servant and bad master), which is dangerous.

Because of the useful purposes that it serves, people keep sources of fire in/around their houses/workplace. And, these sources could sometimes result in "undesired" fire. Had fire been something, which serves no useful purpose – the number of incidents of fire would have been very less – as people wont keep sources of fire around them.

Thus, the occurrence of fire-related accidents is oftentimes inevitable - inspite of all the safety precautions. For this reason, an insurance policy should always be taken.

• Causes Of Fire

• Uneven Distribution Of Incidents

• Conditions Needed For A Fire

• Classes Of Fire

• Types Of Fire Extinguishers

• Fire Fighting Strategies

• Using An Extinguisher

• Precautions While Fighting A Fire

• Deciding Whether To Fight The Fire Or Leave The Site

• During The Fire

• When On Road

• If You Want To Help

• Finally

Causes Of Fire

The most common causes of fire are:

• Electrical

• Pantry Area

• Smoking

Electrical

Incidents of Fire mainly caused due to overloading, short circuit etc.

As people start staying in a new apartment, or, a new office, they start making modifications to the wall socket outlets – in order to be able to plug in additional apparatus etc. Then, there reaches a time, when the total amount of current drawn from all the sockets together could exceed the rated capacity of the internal wiring.

A simple solution to this is - not to make too many changes to the electrical circuitry inside your apartment/work-place. And, any alterations etc. if done, should keep in mind the capacity of the wires used.

As time progresses, due to various minor repairs etc. wires might be changed, jumbled up etc., or, the insulation among wires might break down. This might cause some wires to come in contact with each other, and, thus, create a short circuit. This short-circuit can cause a very high current flow through the wires – and, thus causing fires.

A simple solution to this is: periodic inspection of the conditions of the wiring, and, taking preventive action, whenever needed. And, install MCBs (Miniature Circuit Breakers), so that any short-circuit would result in immediate disconnection of the current flow.

Pantry Area

Incidents involving cooking gas, cooking oil etc.

Leakage of cooking gas, accompanied by a spark around the leakage could cause fire. These are typically very dangerous. Sources of sparks could be anything: - a burning item, turning on/off of electrical gadgets/switches etc.

The leak itself can be in the gas cylinder itself, the pipeline carrying the gas, the regulator, joints etc. Some simple precautions to be taken for this include:

• Regular inspection of gas pipes, and, timely replacement.

• No sparks etc. in case there is any trace of LPG smell. LPG itself does not have any odour. A trace odour is put in the LPG – only so that any leakage might be detected.

• Just like electrical points, turn off gases at multiple points, when not in use, rather than just at the point of usage.

While cooking, sometimes, the cooking medium could get overheated, resulting in fire. These are more frequent, but, fortunately - relatively easy to manage (if attended to immediately).

A simple precaution to be taken for this is - never let cooking oil etc. unattended, when its being heated, nor, do keep bottles of oil etc. in contact with very hot object, like, hot utensils etc.

Smoking

Smoking in/around combustible materials could cause fire, due to hot ashes falling from the cigarette.

Some simple precautions to be taken include:

• Don’t smoke in/around bed, sofa etc.

• When you throw away the cigarette etc. always stub it out

• Always try to dispose off the cigarette-ash at proper places

Uneven Distribution Of Incidents

Incidents of fires are usually not evenly distributed. There are higher number of fires during:

• Summer season: Due to higher ambient temperature; as well as leaves etc. being dry - catch fire easily. This is the time, when many forest-fires start.

• Some specific festive events – due to use/availability of fire-crackers, and/or lights etc. Fire based lights could pose a direct fire-risk, while, electricity based lighting could cause the risk due to overloading.

Hence, its more important to be specially careful during these periods. Not only are the chances of incidents higher, but, the chances of your local fire department being overloaded is also very high. This might have an impact on their ability to respond swiftly to your call – in case there is a need – as they could be busy fighting fire elsewhere.

Conditions Needed For A Fire

For a fire to take shape (as well as continue), the following three conditions should be met:

1. A combustible material

2. A specific temperature at which the above material would burn

3. Some fuel (mostly oxygen) to aid the burning

When petrol/gasoline is burning, the petrol/gasoline is the combustible material, and, the atmosphere provides the fuel (oxygen). The presence of the above 3 elements together is called the “fire triangle”. Each of these 3 elements have to be present to start a fire, and for the fire to continue.

Sometime, one element may aid in producing the other element.

Lets consider an example of how one element aids in the production of another element. Lets say, we want to burn a piece of cloth. The cloth is lying there in front of us. There is enough oxygen in the atmosphere. But, the cloth does not burn. So, we now douse the cloth in gasoline. Still, there is no fire. Now, we burn a matchstick – by rubbing a matchstick against the matchbox/matchbook. This rubbing causes a minor increase in temperature. At this temperature, the matchstick lights up. The lighted matchstick creates still higher temperature. Now, when the matchstick is touched to the doused (with petrol/gasoline) piece of cloth, the petrol/gasoline also starts burning. This further increases the temperature, which causes the cloth to start burning, which can now produce still higher temperature. So, here, friction caused an increase in temperature. This increase in temperature converted the matchstick into a combustible element. This in turn raised the temperature further, and so on.

Now, that we know that for a fire to be sustained, we need all 3 arms of the fire-triangle. This forms the fundamental principle behind all fire-fighting techniques.

If we have to control a fire, the way to extinguish it is to remove atleast one arm of the fire-triangle. Sometimes, we might want to simultaneously attack 2 arms also. That is because, we know that one arm could aid the other arm. So, by trying to simultaneously fight two arms, we might achieve the results faster.

It’s a matter of experience and the situation which decides which arm to fight. Usually, you try to remove that arm, which is the easiest to remove.

Classes Of Fire

Let us also understand the classes of fires.

Class A

These are fires that involve some solid material like, clothers, paper, junk-heap, wood etc.

Class B

These are fires that involve liquid materials like: petrol, gasoline, diesel, oil etc.

Class C

These are fires that involve electrical elements

Class D

These are fires are those involve metals

Its important to know about the classes of fires because fire-extinguishers are classified and marked based on the type of fire on which they would be effective.

So, in case of a fire, you first want to know the Class of fire, so that you can use the right extinguishers.

If you use the wrong extinguisher(s), the result could be fatal also in some cases. In best case situation, there would be no injury etc. but, you could still loose precious time - in performing an activity which is useless.

Types Of Fire Extinguishers

• Water Based

• Foam Based

• CO2 Based

• CFC Based

• Dry Chemical Based

Water Based

These are most effective on Class A fires.

On Class B fires, these are mostly ineffective. This is because, oil/petrol/gasoline etc. being lighter than water continues to float over water, and, thus, it continues to burn. In some cases, use of water based extinguishers on Class B fires could turn out to be injurious also. That is because, as water is thrown over burning fuel, the force due to water-stream could cause burning petrol etc. to be sputtered, and, this hot fuel could cause injury, if it falls on somebody.

On Class C fires, these should never be used. Use of water based extinguishers on Class C fires would surely be fatal. That is because, water is a good conductor of electricity, and, the electric current flows through the water-jet directly into the hands of the person who is holding the water-hose, resulting in immediate electrocution.

The way, these extinguishers work is: As water reaches the burning material – because of the high temperature, it vaporizes. While vaporizing, it extracts the latent heat from the burning element, thereby reducing the temperature. Besides, as it vaporizes, it expands. Usually, the expansion is in the order of 100 times (by volume). The need for higher volume of steam (vaporized water) displaces oxygen from the immediate vicinity of the burning material, thus, cutting off the oxygen supply.

Also, water being non-combustible material also tries to form a coating between the atmosphere (which is supplying the oxygen) and the combustible material.

Thus, it tries to reduce temperature, as well as displace oxygen, thus, attacking two arms of the fire-triangle, while, making a very feeble attack on the third arm also.

Foam Based

These are used mostly on Class B fires.

It can also be used on Class A fires.

These should never be used on Class C fires. The main constituent of foam being water – it can easily prove to be fatal on a Class C fire.

Foam being lighter engulfs the burning liquid. By covering the burning liquid, it cuts off the supply of oxygen to the burning material. Besides, the vaporization of water also helps in reduction of temperature – due to extraction of latent heat.

The basic principle is thus, similar to Water Based Extinguisher. The only difference is, foam stays above burning oil, thus, trying to engulf it - something that water could not do.

CO₂ Based

These are mostly used on Class C fires.

It can also be used on Class A and Class B fires.

These kind of extinguishers might also be used to extinguish fires in computers, costly electronic equipments etc. where, usage of water etc. could cause damage to the equipment.

The biggest advantage of these kinds of extinguishers are that it does not leave any residue, smell or mess.

However, usage of these kinds of extinguishers in confined space could result in poisoning. Because, under lack of oxygen, carbon-di-oxide could act as a fuel, and, the resulting gas produced could be carbon-monoxide – which is highly poisonous.

The way these extinguishers work is: A stream of dry-ice (trade name for solidified carbon-di-oxide) is directed towards fire. Dry ice being very cold helps to reduce the temperature. Being heavy, carbon-di-oxide gas settles on the burning equipments, thus blowing away the oxygen – thereby cutting out the availability of oxygen.

Sometimes, the printed circuit boards (PCBs) of these electrical equipments could develop a crack, because the burning material which was hot is suddenly subjected to a very cold temperature (of dry ice). However, having a few cracks on a few boards might be a better choice than using water/foam, which will cause total short-circuit within the electrical circuit.

Carbon-di-oxide based extinguishers have an additional advantage. Being primarily gaseous in nature, the extinguishing agent can easily percolate inside machinery through fine slots (usually provided for ventilation/heat dissipation) on the outer casing of the equipments. So, it can be much more effective in fires which are inside the casing of electronic equipments.

CFC Based

These are mostly used on Class C fires.

It can also be used on Class A and Class B fires. The main difference between CO₂ Based Extinguisher and CFC based extinguishers is that instead of carbon-di-oxide, it uses some inert gases, like: CFCs. These extinguishers also do not leave any residue, smell or mess. However, these are highly damaging to the environment (because of the tendency of CFCs to deplete the ozone layer). Many variants of CFCs are already banned. Some newer (and, cleaner) variants are already under consideration.

These extinguishers are very costly (both in terms of money as well as impact on environment), and hence, should be used only on very costly, specialty equipments.

The working of these equipments is very simple. They simply displace the oxygen at the burning site. And, these being highly inert gases – would not take part in any chemical reaction (including the process of burning), nor would let the burning material take part in the burning process – thereby extinguishing the fire.

These kind of extinguishers can also be used on metallic fires (Class D). Other extinguishers mentioned earlier could have mixed results on Class D fire, depending on which metal is burning.

Dry Chemical Based

These are most commonly used type of extinguishers.

It can be used on Class A, B and C fire. Hence, its popularly also called as ABC type extinguisher. Its impact on Class D fire could be varied, depending on the type of metal being burnt.

It works in the following way:

It stores dry yellowish chemical powder (mono-ammonium phosphate) under pressure of nitrogen gas (or, any other inert gas). When turned on, the dry powder is sprayed with pressure onto the burning material, along with the inert gas. Nitrogen displaces oxygen. The powder itself sits on the burning material – thus removing contact between burning material and its other two arms of fire.

The powder is a non-conductor of electricity – hence, its equally effective on Class C fire.

Fire Fighting Strategies

Now we know all the constituents of a fire and various kinds of fire-extinguishers. If you have to fight a fire, depending on the circumstances, you have to decide as to what method/strategy (i.e. which arm to fight) you would like to use. Accordingly, you might want to choose an appropriate extinguisher.

Lets look at some different fire-situations and the corresponding strategies:

Smothering a fire

Say: A person’s clothing catches a fire. You could simply wrap the person in blankets (or, any other thick piece of clothing layer), and, roll the person on the ground. The fire gets extinguished – due to lack of oxygen supply.

Letting it die

Sometimes, you might just isolate the burning material from other combustible material. The fire would simply die down, once it has burnt the burning material – as it finds nothing else to burn.

Fire in pantry area – say oil/ghee on fire

Simply cover the utensil which contains the burning oil etc. Lack of oxygen supply will simply extinguish the fire. Meanwhile, don’t forget to turn off the stove. This will help bring down the temperature – thus, cutting off another arm.

Class C Fire

Use of incorrect extinguishing agent (water or foam based) on a class C fire would simply be fatal. Hence, first thing to do would be to convert it into a Class A fire. This can be done by turning off the electric supply. However, if you are suspecting gas-leak also, don’t flip the switch.

Even after you have turned off the switch, one needs to exercise caution. If the main and neutral connections are reversed, while the switch might be turned off – the wires would still be energized. This would provide a false sense of security, while, the fire is still Class C. Hence, its very important that at the time of construction/renovation, electrical wirings are done/supervised by appropriately qualified electricians.

Thus, do not ever pour/direct water jet/stream on a Class C fire (or, even where electrical involvement is suspected). It will be fatal.

If you have to use water (only as a last resort), throw mugful of water from a safe distance, such that the last drop of water has left the mug, before the first drop of water touches the electrical line. This way, the continuity of the water stream is broken, and, electricity can not reach your body. This method is to be used only in case no other alternative is visible, and, also, extreme caution is to be used. This method should never be used with more than one person simultaneously trying this method. Because, water leaving from different mugs could together form a continuity, thereby turning FATAL for somebody.

LPG Cylinder related fire

First and foremost, keep the cylinder standing upright. An upright cylinder, with a fire at its mouth is not necessarily that dangerous (though, it might appear to be really scary). Its simply equivalent to a refinery-chimney flaring excess gases. Cylinder on fire in a rolled-down position/upward-down is an explosive. Stay away from it. The regulator of LPG cylinders are not designed to handle rolled-down cylinder. The fire can enter the cylinder causing the pressure in its neck area – thus causing an explosion. Fire around the base of the cylinder is also dangerous. It can cause explosion. In order to put out a fire at the mouth of a cylinder, pour approximately 60 litres of water in one go at the base of the fire. In very high probability, the fire would be extinguished. Even if the fire is out, a gas-leak could still be involved – which is equally dangerous. Do not confuse a LPG fire and LPG leak. These are two different things, and, both need to be tacked individually.

Using An Extinguisher

So, now that you have decided how to fight a fire, and, what kind of extinguishers to use, lets see, how to use an extinguisher. Most extinguishers are based on PASS System.

1. “P” -> Pull the Pin on the extinguisher. This pin is kept to prevent accidental discharge while carrying/transporting the extinguishers.

2. “A” -> Aim the nozzle of the extinguisher at the base of the fire. Its very important that the discharge from the extinguisher is directed towards the base of the fire. Most people make the mistake of directing the extinguishing agent on the fire itself. That’s ineffective. The extinguishing agent should be directed at the base of the fire – where the burning material is located. That is the point, where the fire-triangle is established, which needs to be broken.

3. “S” -> Squeeze the trigger, so that the extinguishing agent starts flowing out of the cylinder, and, onto the burning material – at the base of the fire.

4. “S” -> Swipe the nozzle sideways to coat the entire burning material, with the extinguishing agent.

“PASS” is an acronym to remember the steps involved – Pull (the pin), Aim (the nozzle), Squeeze (the trigger), Swipe (sideways).

Precautions While Fighting A Fire

When fighting a fire:

1. Always stay upwind: It protects you from heat, smoke etc. It allows you to go closer to fire – thus, being able to better direct your extinguishing agent. It protects you from inhalation of poisonous gases, which might be given out during the fire.

2. Keep under observation, even when the fire is extinguished. Smoldering particles can easily rekindle, thus, catching you off-guard.

3. Pour extinguishing agent in adequate quantity, rather than small quantities. Doing it in installments does not help. One discharge of 60 liters of water is not the same as two discharges of 30 liters each. E.g. If you have to pour 4 buckets of water, have the 4 buckets ready, and, pour all 4 buckets in one go. Instead, if you pour two buckets of water, refill them, and, pour again – its not the same.




Deciding Whether To Fight The Fire Or Leave The Site




So, now that you are well equipped in fighting a fire – you just need to decide, whether you want to fight a fire, or, flee away from it. Remember, in general, timely action helps a lot in containing the damage. Besides, more often than not, general fires (specially Class A fires) don’t spread suddenly – unless, chemical reactions are involved. This means that if you can nip a fire in the bud, you should try to fight and extinguish it.




Still, no material is worth more than human life. So, don’t fight, if any of the following conditions are involved:

1. You don’t have sufficient/right material to fight the fire. The time spent in fighting could impact your ability to evacuate

2. You don’t have backup. You should be able to get help, in case, there is a need

3. Fire seems to be blocking your exit path

4. You have no idea what is burning For example - Class D fire would need specialized knowledge of the metal under fire, and, how will that metal react with different extinguishing agents – at high temperature

5. Fire seems to be spreading too fast

6. There are explosives around

7. You don’t feel comfortable and confident




During The Fire




So, there could be a possibility that many people are not going to take part in fighting against a fire. These people need to evacuate. Hence, there needs to be an evacuation plan in place. This evacuation plan should be in place - before the incident of fire.




The evacuation plan should have the following items identified, and, well communicated to everybody: - A command and control structure, which should be effective and operational as soon as a fire is reported - Assembly area - Mechanism and responsibility for head-count etc.




In case of a fire, one should never use escalators (irrespective of the height of building which is being evacuated). Escalators could be unreliable – due to failure of electrical circuits which operate it, or, it could have mechanical failure – due to snapping of wires/ropes – causing it to go into a free-fall. At the minimum, there is a high risk of smoke inhalation, as, smoke has a tendency to go up, and, hence, will always try to enter escalator pits – from where, it can go all the way up to the top, without any hindrance.




If there is lot of smoke, crawl on the floor. Because of smoke’s tendency to go up, even during very dense smoke conditions, the lower few inches of the ground are expected to be relatively free of smoke.




To reduce smoke inhalation, put a wet handkerchief to cover your nose. If there is no water available, use your own saliva to wet a small portion of the handkerchief, and, use that portion to cover your nostrils.




If you can go to an open-area (for example uncovered terrace, open ground etc.), there will be no risk of smoke-inhalation. However, use your own judgment if you decide to go to the terrace of a high-rise building. While there will be no risk of smoke-inhalation, rescue efforts could become difficult and is dependent on the level of sophistication that the local fire department has (e.g. access to snorkel, very long ladders-capable of reaching high-rise buildings, rescue-helicopters etc.).




Always evacuate in an orderly manner. A building housing 200 or so people (normal, healthy adults) across 3-4 floors with a single exit can easily be evacuated in less than 2-3 minutes if done in an orderly manner. If people push and shove, stampede can occur, causing much more injury, and, it might take much longer to evacuate. Worse: Backing up might be impossible. Say, while, people are evacuating towards an exit, and, its found that – the specific exit is blocked, there might be a need to backup. If the evacuation is not proceeding in an orderly manner, it might not be possible to back-up; as people towards the end of the evacuation queue (who are not aware of the blockage at the exit) will try to push forward, while, those at the front of the queue (who are aware of the blockage) want to back-up.




Since, panic might set in, during a fire – thereby clouding people’s thought process and ability to think reasonably, its highly likely that during a fire, people forget these simple tenets, and, in their attempt to rush out, actually create chaos and disorderliness. Thus, its important that regular mock evacuation-drills are carried out. That will cause people to behave in a much more orderly manner – during an actual fire.




While evacuating, do a quick survey to see, if there is somebody around you, who might need some assistance, e.g. somebody who is old, too weak, injured, child, any disability etc. If possible, provide assistance to such a person. Even if you yourself are not in a position to provide assistance, at least request for help on this person’s behalf.




If an area is already clear, while, evacuating, close the door behind you. It will serve several purposes:

1. Will isolate the area, thereby, causing an impediment to the spread of the fire.

2. Will save time for others, who might want to recede the area.




While, you should close the door, lock it only if you are absolutely sure that there is nobody inside. Because, if there was even a single person inside it, and, you have locked it, the chances of that person being rescued is diminished by a huge factor.




If you are inside a closed door – with fire outside:




Feel the inside of the door with your hand. If the door feels hot, many a times, it might be safer to stay inside. At this time, whether your should stay inside, or, still venture out could be a judgment call, depending on: how long do you expect a rescue team to arrive and/or alternative avenues (e.g. possibility of jumping from the window). If you are on the high floor of room, with windows having strong grills and the local fire-department is not well-equipped/staffed, then, the time that you spend inside the room is actually going against you – as the fire outside becomes more vigorous. If you do decide to stay inside the room, wet towels, bed sheets etc. and put below the doors to prevent smoke etc. from coming inside your room.




When On Road




When on road:

1. Always give way to fire-engines.

2. Even if you are not coming directly in the way of fire-engines, goto the extreme side of the road, and, stop your vehicle – to let the fire-engine pass.

3. Do not rubber-neck/crowd the site of a fire incident: as you could hamper movement of rescue teams/material




If You Want To Help




If you want to help in case of a fire-incident, you could help in one of the following ways:

1. direct help in fighting the fire (if you are able, and, are knowledgeable in fire-fighting)

2. provide background logistics support

3. inform the local fire station

4. help in crowd-control, and, keeping the curious onlookers at bay

5. help in directing fire engines and rescue vehicles (particularly in the internal lanes/bylanes etc.)

6. clearing the way for fire-fighting crew




Do not put yourself and others at risk Do not question the established chain of command. There are multiple ways of fighting a fire. This is not the time to argue and convince each other on the best method.




Finally




Finally: In case of a fire:

1. DO NOT PANIC

2. Decide your strategy.

3. If you want to fight:

   1. With What

   2. How

   3. Which arm (of the fire triangle) to fight

4. Or, you might want to flee (evacuate)




Remember, all the conditions might not be met, e.g. to stay upwind, you might have to get away from the exit. Depending on the circumstances, you would have to choose which conditions to meet, and, which one to compromise.




You should know the local Fire-Station Number. Most countries have a uniform number (valid across the whole country) to reach the local fire-station. Do not ever make test/prank calls. Besides, being illegal (in most countries), you might have to live with guilt for the rest of your life – if your prank call – caused delayed response to a real fire-emergency somewhere else.