19 November 2024 02:34 am Views - 25
Damage caused by bush fire to highly sensitive environmental zone rich in bio diversity would be an irreparable loss
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Fire prevention is a major issue that concerns the disaster management process in any country The intensity of a fire depends on the continual emission of heat A through study of the causes of fire, how it breaks out and spread is required to minimise the consequences to the barest minimum |
However, in the modern era, fire can be the cause and contribution to catastrophic disasters; due to its uncontrollable nature. The reason is everything has changed due to the evolving human lifestyle; thanks to all-round development.
Improper storage and reckless handling of chemicals, fuel and inflammable material, mishandling of electrical appliances, defective electrical circuits, inflammatory weather conditions and human activities are the major causes of fire.
The main factor that results in the spark off of a fire is the contact of combustible matter with oxygen and sufficient thermal energy or ignition source. However, a fire that sparked off would subside in a short while or develop into a roaring inferno claiming human lives and ruining property. The intensity of a fire depends on the continual emission of heat. A through study of the causes of fire, how it breaks out and spread is required to minimise the consequences to the barest minimum.
Any combustible material in a solid state even in liquid state should be disintegrated into smaller volatile molecules or minute particles by heat to put down their structure before burning. That process is known as pyrolysis and after pyrolysis, these disintegrated particles ignite when mixed with oxygen. For example, thin paper and firewood cut into small pieces quickly burn out while logs of wood burn slowly. When heat is applied, the thermal degradation is very fast in thin paper and therefore instantly ignites.
With regard to using domestic LP gas, minute hydrocarbon particles are turned into liquid and packed in an iron cylinder. As such LP gas need not break into particles within the cooker. The gaseous particles released from the cylinder that mix with oxygen in the air, instantly ignites. Petrol is another highly inflammable kind of fuel and consists of volatile minute hydrocarbon particles.
In the case of arson attacks, criminals use petroleum fuel including petrol, kerosene and thinner that are highly inflammable. When Arson attacks are caused by petroleum fuel, the preventing of the spread of the fire is hard.
The fire that broke out at one location could spread through a vast area of a building or a vehicle causing extensive damage; depending on the nature of combustible material and the strength of oxygen flow.
In fact, fire accidents in environments are abundant when there are plastic goods because such products cause much havoc within a short time when exposed to heat.
It is imperative that we have to study the impact of heat emitted by convection, conduction and radiation when dealing with fire. During a fire in the room, the smoke produced by the flame increases and accumulates at the ceiling level horizontally making a uniform layer. Eventually the layer of smoke grows downward and some of it can escape from the room through an opening. However, we should understand that this layer of smoke is very hot and is transferring energy to its surroundings; including to the items in the room. All combustible goods made of wood, plastic and fibre etc. on the floor level get heated due to the radiation caused by the hot smoke layer. When the heat reaches 650 centigrade, the surface of all goods is vulnerable to catch fire at once, completely rendering it impossible to save them. This is called ‘flashover’. Although it would be observed as an arson attack caused by the use of petroleum fuel, subsequent scientific investigations would reveal that it was a fire that developed into a state of ‘flashover’ and depending on the evidence that also reveal its origin.
Firefighter must premeditate situation
It is imperative that the firefighters should premeditate if the fire had reached the flashover. Or else their lives would be at risk when entrying to enter the building. When the flashover is about to occur, this hot dark smoke layer behaves like rolling clouds that twist upward. If the room is tightly closed, the amount of oxygen will not be sufficient to sustain the burning fire; hence the fire eventually dies after a few moments, even though fuel/smoke is present. However, if more oxygen or ventilation is introduced through the opening of a door, an explosion is possible.
It is quite obvious how a fire that sparks off with a minute flame, in case of an arson, or due to some lapse, develops into a raging inferno.
However, it is the duty of everyone to focus particular attention on fire safety measures and take precautions to prevent a minute spark into a raging fire. A thorough awareness of the causes leading to fire disasters and the factors that contribute to a fire outbreak are mentioned above.
To detect fires at an early stage, fire alarms can be installed so that people can be safely evacuated. This will also facilitate steps that can be taken to prevent the fire from spreading.
An effective firefighting and suppression considerations mainly include firefighting agents, fixed water systems and fire brigade’s actions on the fire scenes.
Firefighting agents like water, water additives and foam, gases (carbon dioxide) and dry powders are used in combatting a fire. These are available in the form of hand held extinguishers and therefore the firefighting operation is swift and easy.
Likewise, foams are used to control flammable liquid fires.
Further, it is important to keep in mind not to use water extinguishers to control fires involving electricity because it may cause electrocution.
If a fire cannot be controlled, the fire fighters should come immediately to the scene. Since not having quick responses many of the fires may cause to lose our valuable properties and lives.
(The writer is a Senior Asst. Govt. Analyst and possesses a B.Sc. Chemistry (Hons), M.Sc Fire Investigation (UK) and an M.Sc. Industrial and Environmental Chemistry (Sri Lanka)