Basic of fire fighting

Introduction to Fire

Educational fire safety infographic showing fire triangle, fire tetrahedron, classes of fire, types of fire extinguishers, PASS method, sprinkler systems, fire alarm system, emergency evacuation, fire hydrant system, and sprinkler head types for industrial and workplace safety training.

Fire is a process of combustion or burning in which substances combine chemically with oxygen in the air and produce heat, smoke, and light.

Fire consists of four essential components:

  1. Fuel
  2. Oxygen
  3. Heat
  4. Chemical Chain Reaction

These four components together form the Fire Tetrahedron.
If any one of these components is removed, the fire will extinguish.

Fire extinguishers are designed based on this principle.

Fire triangle:

The Fire Triangle explains the three main factors required for a fire to occur:

  1. Sufficient Oxygen to support combustion
  2. Enough Heat to reach ignition temperature
  3. Fuel or combustible material

When these three combine, a chemical reaction occurs, resulting in fire.

Classes of fire:

Fire are classified according to the type of fuel that is burning. There are five classes of fire.

Class A fire: wood, paper, cloth, rubber, some plastic (ordinary Combustible)

Class B fire: Gasoline, Kerosene, Paint, Paint thinner, Propane ( Flammable liquids and gases)

Class C fire : Electrical equipment such as electrical panels, switches, motors, appliances, and wiring.

Class D fire: Combustible metals such as Magnesium, titanium, Potassium, Sodium.

Class K fire:  Cooking oil, Grease, animal fats, Vegetable fats.

How to Prevent Fire?

  • Keep storage and work areas clean and free from waste materials.
  • Do not refuel gasoline-powered equipment while it is hot or running.
  • Store flammable liquids in approved tightly closed containers.
  • Inspect electrical equipment that emits unusual smells, smoke, or sparks.
  • Avoid overloading electrical circuits.
  • Maintain proper housekeeping in the workplace.
  • Understand the properties of combustible metals and chemicals.
  • Keep fire exits and escape routes clear at all times.

Types of Fire Extinguishers

1. Water Type Extinguisher

Used for Class A fires.

2. Mechanical Foam Type (AFFF)

Used for Class A and B fires

3. Carbon Dioxide (CO₂)

Used for electrical and flammable liquid fires.

4. Dry Chemical Powder (DCP)

Types include:
  • ABC Type
  • BC Type
  • DC Type

5. Clean Agent Extinguisher

Used for sensitive electronic equipment and server rooms.

How to Use a Fire Extinguisher (PASS Method)

P – Pull

Pull the safety pin.

A – Aim

Aim at the base of the fire.

S – Squeeze

Squeeze the operating handle.

S – Sweep

Sweep the nozzle from side to side.

Fire Alarm System

A fire alarm system is used to detect fire and warn people during an emergency.

Components of Fire Alarm System:

Smoke Detector

Detects smoke particles in the air.

Heat Detector

Detects abnormal rise in temperature.

Manual Call Point (MCP)

Used to manually activate the fire alarm.

Hooter / Alarm Bell

Provides audible warning during fire emergency.

Fire Control Panel

Controls and monitors the complete fire alarm system.


Types of Smoke Detectors

Ionization Smoke Detector

Best for detecting fast-flaming fires.

Photoelectric Smoke Detector

Best for detecting slow smoldering fires.

Emergency Response During Fire

  • Raise the fire alarm immediately.
  • Inform the emergency response team.
  • Shut down electrical power if safe to do so.
  • Use the correct type of fire extinguisher.
  • Evacuate through the nearest emergency exit.
  • Never use elevators during fire emergencies.
  • Move to the designated assembly point.
  • Do not panic.

Emergency Evacuation

Important Points
  • Follow evacuation routes.
  • Use emergency exits only.
  • Assist injured persons if possible.
  • Assemble at the designated assembly point.
  • Wait for further instructions from safety personnel.

Fire Hydrant System

A fire hydrant system provides a continuous water supply for firefighting operations.

Main Components:

Hydrant Valve

Connection point for firefighting hose.

Hose Reel

Provides quick firefighting response.

Landing Valve

Used in multi-story buildings.

Fire Hose

Carries water to the fire area.

Fire Pump

Maintains required water pressure.

Sprinkler System:

A sprinkler system is an automatic fire protection system in which water is released through sprinkler heads when temperature rises above a certain level.

The sprinkler system was developed by Henry S. Parmalee in 1874 to protect his piano factory.


Types of Sprinkler Systems:

  1. Wet sprinkler system 
  2. Dry sprinkler system 
  3. Deluge sprinkler system 
  4. Pre action sprinkler system 


Wet Sprinkler System:

  • Water is always present in the branch lines and sprinkler heads.
  • Cannot be used in freezing areas.
  • Water pressure must be maintained continuously.
  • Requires less maintenance.


Dry Sprinkler System:

  • Air pressure is maintained instead of water in the branch lines.
  • Air pressure prevents water from entering the system until activation.
  • Suitable for freezing areas.
  • An air compressor maintains constant pressure.
  • When the sprinkler head activates, air escapes and water enters the piping system.
  • Maintenance cost is higher due to pipe corrosion and air system maintenance.

Deluge Sprinkler System:

  • Used in special and high-hazard areas.
  • Sprinkler heads remain open at all times.
  • Deluge valve opens automatically during smoke or heat detection.
  • Large amounts of water are discharged rapidly.

Pre-Action Sprinkler System: 

Similar to the deluge system, but water is controlled by an electrically operated valve.

Two conditions are required:

  1. Detection system must detect smoke, heat, or flame.
  2. Sprinkler head must activate before water is discharged.
Used in:
  • Data centers
  • Server rooms
  • Museums
  • Libraries

Types of sprinkler Heads : 

  1. Pendent Sprinkler
  2. Upright Sprinkler
  3. Sidewall Sprinkler
  4. Concealed Sprinkler
  5. Special Coverage Sprinkler
  6. ESFR Sprinkler 


Sprinkler Temperature Color Coding : 

Temperature Rating            Color Code

135°F -170°F                              RED

175°F - 225°F                             GREEN 

250°F - 300°F                             BLUE

325°F - 375°F                             PURPLE 

400°F - 650°F                             BLACK

Importance of Fire Safety

Fire safety helps to:

  • Protect human life
  • Prevent property damage
  • Reduce financial loss
  • Improve workplace safety
  • Ensure emergency preparedness

Proper fire safety knowledge and training can save lives and property during emergencies.



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