The document discusses different types of fires and fire extinguishers. It describes Class A, B, C, D, and K fires and notes that dry chemical systems are used on flammable and combustible liquid fires. The document then discusses dry chemical powder extinguishers, noting they use sodium bicarbonate and work by insulating and cutting off oxygen to Class B and C fires. Prevention methods like training, maintenance, and fire suppression systems are also summarized.

1. Wahab [D-18-CH-52]
Student of final year of Chemical Engineering

2. Introduction
 Fire is an exothermic chemical reaction between oxygen
and fuel at certain temperature
 Class A -Ordinary materials such aspaper, wood, cloth
 Class B - Flammable liquids or Combustible liquids such as
gasoline, paint, propane, kerosene
 Class C -Electrical equipment fires, appliances, switches,
panels
 Class D -Certain metals such as magnesium, sodium,
potassium, titanium, and aluminium.
 Class K-Fires involving commercial cooking appliances
with vegetableoils, animal oils or fats at high
temperatures.

3. Introduction
 Fire extinguisher is a device which can used to
control fire and help to remove the fire and
stop burning
 Wet and dry chemical used when water would
have no effect or make worse

4.  Dry chemical systems extinguish flammable and
combustible liquid fires
• Flammable liquid : ex: nitro phenol, ammonium
nitrate, potassium chlorate, paint & oil soaked rags,
cotton or cellulose soaked with sulphuric acid etc.
 The system uses gas to expel the agent and have a
finite amount of agent available
• Dry Chemical powder extinguishers utilize a
specially siliconized Sodium Bicarbonate.
• It insulates class B , C fires by forming a cloud and
cutting off the oxygen supply

5. • Dry chemical powder Used in- Homes / Offices,
Buildings, Warehouses, Pump Room and Refinery
• Color band- Blue
• Capacity- 4kg-9kg.
• Other fire extinguisher Includes sand bucket.

6. PREVENTION OF FIRE HAZARDS
 Well planned design and layout
 Proper ventilated systems
 Chemical data sheets
 Proper training of personnel
 Proper maintenance of surroundings
 Uses of fire extinguishers, alarms ,sensors, detectors
 Fire fighting equipment
 Sprinkler systems

7.  A “Dry” standpipe is NOT filled withwater.
 The intakes of dry standpipes are usually located
near a road or driveway so that a fire engine can
supply water to the system.
 This system can be used only by firefighters.
 Regulations in many countries require that
standpipe systems be charged by hoses from two
 different pump trucks, which can be accomplished
by using both sides of a Siamese connection.

8. Dry Chemicals
 Small solid particles propelled by pressurized gas
 When discharged, chemical covers and smothers the burning
material
 Three categories: sodium bicarbonate-based, potassium-based,
multipurpose
 Sodium bicarbonate and potassium-based work well on Class B and C fires
 Ammonium phosphate works well on Class A, B and C fires
 Main component of dry chemical systems are agent storage tank, expelling gas,
piping and fitting, nozzles and system alarms and indicators.

9. Applications of dry chemicals
 Protects a specific area
 Use dry extinguishing agents Discharge the agent directly onto
the hazard and Smother, cool, extinguish the fire
 Protect enclosed hazards and areas within a structure
 When discharged, the agent fills entire protected area to
disrupt the fire’s chain reaction
 Amount of agent and nozzles needed depend on total volume
of area
 When supplementing dry chemical system, hand hose line
must have separate chemical supply
 Minimum 30-second dry chemical supply
 Must be accessible and reach the hazard

10.  Anautomaticsprinkler systemisthe sprinkler,which
dischargewater in specificpattern for extinguishing
or controlling afire.
 Three major component of sprinkler are nozzle,
detector and water spray pattern detector.

11. Dry chemical powder extinguishers
Advantages Disadvantages
 Versatile - can be used on many
different types of fire
 Powerful - extinguish fires
quickly
 Compact - Effectiveness
 Economical - low prices and
good performance ratio
 Coverage - can provide fire
protection for large areas
 Variety - come in may differing
sizes and ratings
 Safe - due to their versatility they
are safe for use on electrical fires
 Cleanup - due to the powder
cleanup can be extensive after
use
 Dust - The dust can affect
sensitive equipment such as
computers
 Visibility - When used in
enclosed spaces visibility can be
reduced to almost zero. Always
know where the exit is before
use.
 Respiratory
 Single shot
 Compacted powder