Here I will discuss the basics of fire. This topic was the same topic I discuss during the Emergency Preparedness Seminar/Traing on Portable Fire Extinguisher held last November 8, 2008 at Capitol University. To access photos during the event go to the Gallery section. To download the powerpoint presentation, go to the Downloads section.
FIRE – it is a chemical reaction that takes place between fuel, heat and oxygen
in form of light and noticeable heat.
HOW FIRE BURNS?
Fire occurs whenever a given material is heated on the presence of oxygen to a temperature corresponding to the ignition point of the material.
FUEL – any substance that will burn when heated or hot enough in the presence of sufficient oxygen.
OXYGEN – atmosphere consists of 21% of oxygen, 78% nitrogen and 1% of other elements.
HEAT
Three Stages:
1. Flash point – lowest temperature at which a flammable substance will give off vapor that will ignite when a flame or spark is introduced in the presence of sufficient oxygen.
2. Fire point – a temperature which is a few degrees higher than a flash point in which a flammable substance will continue to burn after it has been ignited.
3. Ignition point – a temperature which is higher than a fire point at which a substance is heated to give off vapor that will burn without the application of spark or a flame in the presence of sufficient oxygen.
Breaking the Fire Triangle
Removal of Fuel:
• Shut off fuel supply
• Jettisoning or relocation
Reduction of Heat:
• Use something that will absorb heat
• Water is the best cooling agent
Control of Oxygen:
• Closing ventilation
• Displace or dilute oxygen by means of CO2
• Blanketing
CLASSES OF FIRE
Class “A” – combustible materials
• Characteristics – deep seated, leave ash and embers.
• Extinguishing method – cooling
Class “B” – flammable liquid, gases, greases and similar products.
• Characteristic – surface burning.
• Extinguishing method – cut off oxygen supply or prevent flammable vapor from being given off.
Class “C” – electrical fires
• Characteristic – electrical shock
• Extinguishing method – use non-conducting extinguishing agent.
Class “D” – combustible metal fires
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