INTRODUCTION OF FIRE

 

1.0    INTRODUCTION OF FIRE

 

1.1       When one thinks of fire, the famous proverb “To Dig a Well After the Fire breaks out’ comes to one’s mind.

 

Fire can strike anywhere at any time, and once it gets hold can spread with frightening speed putting lives and property at risk. It can put your business out of operation for years together and can even cause long term liabilities on you.

 

1.2       What is fire and when it occurs?

 

                Fire is a chemical reaction and normally occurs when following three elements are present:

 

a) Heat

b) Fuel

c) Oxygen

 

Fire is traditionally represented as a triangle.

 

Hence removal of one of the elements of the triangle causes the combustion process to collapse and thus extinguish the fire.

                                                                                         

1.3       How can Fire be extinguished?

 

            The process of extinguishing can be as follows:

 

a) REMOVAL OF HEAT: Cooling by applying heat absorbing Agent e.g. water.

 

            b) REMOVAL of FUEL: Closing the valve in leaking hydro-carbon of gas pipeline.

 

            c) REMOVAL OF OXYGEN: Blanketing by using suitable agent E.g. foam or CO2.

 

In addition to above inhibition of the combustion reaction by the extinguish ant will also cause the fire to cease.

 

d) STOP THE REACTION: By using Dry Chemical or Halogenated Gases

 

1.4       Classification of Hazard

 

                        Fuel                                        Classification

            Carbonaceous                                                A

            Hydrocarbon                                                  B

            Gas                                                                 C

            Metal                                                              D

            Electrical                                                        E

 

1.5       Classification of fire

 

            a)         Surface fire

 

Fire generally occurs to the solid materials in which flaming takes place on the surface of the fuel.  E.g. loose paper, wood etc.

 

            b)         Deep Seated

 

Fire involving ‘A’ materials in which smouldering combustion has taken place long before flaming e.g. computer panel card and data print out.

 

            c)         Spill of Pool fire

 

                  Fire occurs class ‘B’ liquids spill, usually on the ground and to form a pool.

 

d)          Pressure Jet fire

 

Fire involving either class ‘B’ liquids or class ‘C’ gases comes out under pressure from a split flange, faulty gland of a valve shaft seal.

           

e)           Impinging Pressure Jet Fire

 

Pressure jet fires which is impinging on adjacent plant or structural members.

 

1.6            Type of Agent to be used on classified Hazard

 

Following fire extinguishers are most commonly used to extinguish the fires of one or more classes:

 

Agent                                      Class of fire

 

                        Water                                      A limited class ‘B’

                        Foam                                       B

                        Dry Chemical                         A, B, C, D, E

                        CO₂                                         B, C, D, E

 

1.7       Principal causes of fires

 

Although there can be number of causes of fire but most of the fires are caused because of the following causes:

            a)         Arson

b)               Electric sparks / Short circuits

c)               Overheating of electric equipment

d)               Gas cutting and welding etc.

e)               Smoking

f)                Naked Lights

g)               Rubbish burning

h)               Mechanical heat and spark

i)                Overheating of oil equipment

j)                Spontaneous combustion

k)               Carelessness and ignorance