•Sources of ignition (heat) – a heat or ignition source is essential to start the combustion process. Once combustion has started it generates its own heat which is usually sufficient to keep the fire burning (in other words once the fire starts the heat source can be removed and the fire stays alight). Some examples will be described later in this element.
Once a fire has started it will produce heat, a flame (the zone where oxygen and flammable vapours are chemically combining in the combustion process) and smoke. The exact composition of the smoke will vary but typically smoke is made up of hot combustion gases such as carbon monoxide (CO) and carbon dioxide (CO2 ) and small particles (soot).
CLASSIFICATION OF FIRES:-
Fires are classified into five categories according to fuel type. The classification is useful as the basis for identifying which type of fire extinguisher to use.
UK Based Classification of Fire:
Class A – solid materials, usually organic, such as paper, wood, coal and textiles.
Class B - flammable liquids, such as petrol, oil and solvents.
Class C – gases, such as methane, propane and acetylene.
Class D – metals, such as aluminium or magnesium.
Class F – high-temperature fats and oils, such as cooking fat.
Note that there is no Class E fire. This classification was avoided because of potential confusion between Class E and electricity. Electricity is not a fuel (though it can be an ignition source).
US Based Classification of Fire:-
Class A – Solid fire
Class B – Liquefiable solid (waxes, plastics etc.), Liquid and Gas fire
Class C – Electrical fire
Class D – Metal fire
Class K – Kitchen fire.
CAUSES OF FIRE IN THE INDUSTRIES:-
Fires in workplaces start for many different reasons. Some of the most common causes of workplace fires are:
•Electrical equipment – faulty wiring, overloaded conductors, misused equipment and the incorrect use of electrical equipment in inappropriate environments
•Deliberate ignition – many workplace fires are started deliberately. In some cases, the workplace has been targeted, e.g. by a disgruntled employee or an unhappy customer. In other cases, it has not, e.g. youths playing with matches on an industrial estate.
•Hot work – any work involving the use of naked flames (e.g. a propane torch or oxy-acetylene cutting equipment), or which creates a significant ignition source (e.g. arc-welding and grinding).
•Smoking – in particular, carelessly discarded smoking materials, such as cigarette butts and matches.
•Cooking appliances, e.g. fat pans left unattended.
•Heating appliances, e.g. electric fan heaters and space heaters, especially when left unattended. Unsafe use and storage of flammable liquids and gases, e.g. petrol, acetone and liquefied petroleum gas (LPG). Static sparks can be generated, which could ignite a flammable vapour.
•Mechanical heat – generated by friction between moving parts, such as a motor and its bearings, or cold work generating sparks.
•Chemical reactions - can also generate heat, e.g. oxidisers (rags soaked in oil and solvents are a fire hazard, because as the oil or solvents oxidise, heat is replaced and there is a risk of spontaneous combustion).
{Blue Fire Or Blue Whirls}

~Blue whirls evolve from traditional yellow fire whirls. The yellow color is due to radiating soot particles, which form when there is not enough oxygen to burn the fuel completely.
~Blue in the whirl indicates there is enough oxygen for complete combustion, which means less or no soot, and is therefore a cleaner burn.
~Fire whirls are more efficient than other forms of combustion because they produce drastically increased heating to the surface of fuels, allowing them to burn faster and more completely.
~A fire whirl is usually turbulent, but this blue whirl is very quiet and stable without visible or audible signs of turbulence.
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Briefing about the blue whirl:-(https://youtu.be/uApSQxIpM1o)
How does a fire tornado occurs? (in hindi)
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