FIRE SAFETY

Fire TriangleThe old diagram of a fire comprised three components: Fuel, oxygen, and heat. Remove any one of the three, and the fire would die. However, research has lead to the addition of an equally important forth component: a self-sustaining chemical chain reaction.FUELHEATOXYGEN

Fire TetrahedronEach component of the tetrahedron must be in place for combustion to occur. Remove one of the four components and combustion will not occur. If ignition has already occurred, the fire is extinguished when one of the components is removed or consumed from the reaction.

The 4 components of fire:Oxidizing Agent ( Any of the various gases that supports combustions)Represents one of the necessary components of fire an oxidizing agent (typically oxygen).

Reducing Agent ( Any material that is reducible to combustible materials, becoming fuels)The material is reduce able through heat action (pyrolysis) into component parts such as carbon monoxide, hydrogen, alcohol, etc. These are the fuels of fire.

Heat, from with-in or without the materialHeat, which could be from any source ( electrical, chemical, nuclear, or mechanical, in form of friction).

Self-sustaining chemical chain-reaction The interaction of the other three ingredients. The reaction will continue until one of the components is no longer present either because it has consumed to the reaction or removed to stop the fire.

Transmission of Heat

Conduction: the point-to-point transmission of heat energy.Convection: The transfer of heat energy by the movement of heated liquid or gases.Radiation : The transmission of energy as an electromagnetic wave ( such as light waves, radio waves, or X rays) without an intervening medium.

Methods of Fire Extinguishment

Temperature ReductionExtinguish a fire by reducing its temperature, enough water must be applied to the burning fuel to absorb the heat being generated by combustion.

Fuel RemovalThe fuel source maybe removed by stopping the flow of liquid or gaseous fuel of by removing solid fuel in the path of a fire. Another method of fuel removal is to allow a fire to burn until all fuel is consumed.

Oxygen ExclusionReducing the oxygen available to the combustion process reduces a fire growth and may totally extinguish it over time.

Chemical Flame InhibitionExtinguishing agents such as some dry chemical and halogenated agents ( Halons) interrupt the combustion reaction and stop flaming.

Fire Classification

Class A fires involve ordinary combustibles materials such as wood, cloth, paper, rubber, and many plastic. Water is used to cool or quench the burning material below its ignition temperature.

Class B fires involve flammable and combustible liquids and gases such as gasoline, oil, lacquer, paint, mineral spirits and alcohol. The smothering or blanking effect of oxygen exclusion is most effective for extinguishment and also helps reduce the production of additional vapors.

Fires involving energized electrical equipment are Class C fires. Household appliances, computers, transformers, and overhead transmission lines are examples. These fires can sometimes be controlled by no conducting extinguishing agent such as halon, dry chemical, or carbon dioxide.

Class D fires involves combustible metals such as aluminum, magnesium, titanium, zirconium, sodium, and potassium. These materials are particularly hazardous in their powdered form. The extremely high temperature of some burning metals makes water and other common extinguishing agents ineffective.

CLASS KIs a new classification of fire as of 1998 and involves fires in combustible cooking fuels such as vegetable or animal oils and fats.Its fuels are similar to Class B fuels but involves high temperature cooking oils and therefore have special characteristics.Class K agents are usually wet chemicals.

CLASS EFires involving high voltage electrical installation and bulk LPG.

This class of fire needs special fire fighting operation by trained personnel.

TWO TYPES OF FIRE EXTINGUISHERS:Cartridge type

Stored pressure type

PORTABLE FIRE EXTINGUISHERS

Water Fire Extinguisher Air-Pressurized Water (APW) are useful for all types of small Class A Fires.

CO2 Fire ExtinguisherCarbon dioxide (CO2) extinguishers are found as both handheld units and wheeled units. CO2 extinguishers are effective in extinguishing Class B and Class C fires.

Dry Chemical (ABC) Fire ExtinguishersDry chemical extinguishers are among the most common portable fire extinguishers in use today (Sodium bicarbonate, potassium bicarbonate, Urea- potassium bicarbonate, Potassium chloride or Mono ammonium phosphate)

AFFF Fire ExtinguisherAqueous film forming foam (AFFF) extinguishers suitable for Class A and Class B fires. They are useful in combating fires or suppressing vapors on small liquid fuel spills.

Combustible Metal Fire ExtinguisherClass D fire extinguishers also uses dry powder depending on metal fuel fire but the active agent commonly used is sodium chloride plus flow enhancers.

P.A.S.S Method