This document discusses fire and explosions, including:
1. The fire triangle requires three elements - fuel, oxygen, and an ignition source. Different types of combustion exist depending on the combustion rate.
2. Factors that influence fire include minimum ignition temperature, auto-ignition temperature, flammable ranges, gas densities, and catalysts.
3. Fires are classified A-F based on their fuel. Proper extinguishing agents must be selected depending on the fire type to safely put it out.
2. CHARACTERISTICS OF FIRE
Fire can cause large losses (human & materials)
Chemical reaction requiring three components: fuel, oxygen and an
ignition source (fire triangle).If any one of these three components is
missing, a fire cannot start! The ratio has to be right.
Ignition can be caused by convention, conduction and radiation.
Several types of combustion process depending on the combustion
rate: Slow combustion (no flames and temperatures very low),
normal combustion (controlled combustion process), explosion (very
quickly), detonation (very quickly and propagates very quickly).
3. INFLUENCING FACTORS
Minimum ignition temperature: flash point.
The temperature at which the substance catches fire spontaneously:
auto-ignition temperature.
The range between the upper and lower explosion limit is called the
flammable range, indicating the range for which the ratio of gas to
air is dangerous.
The alarm phase is reached as soon as the concentration of a gas
or vapor exceeds 10 percent of the lower explosion limit.
4. INFLUENCING FACTORS II
The density of a gas is an important factor in determining whether
the risk of explosion exists and to eliminate that danger.
Catalysts: substance which makes another substance flammable.
Oxidizing substances: When heated, these substances give off
additional oxygen, which causes the fire to intensify.
5. CLASSIFICATION OF FIRES
A (fuelled by solids, no metal. Extinguished with water or foam),
B (fuelled by a liquid or a solid that melts because of the heat.
Extinguished with powder, CO2 or foam but NEVER with water!),
C (fuelled by a gas, extinguished with powder)
D (fuelled by combustible metals, extinguished with special powders
or dry sand).
E (caused by electrical installations, put out with CO2).
F (cooking fires, caused by oils/ fats.
6. EXTINGUISHING AGENTS
Several types of extinguishing agents can be used to put out a fire
depending on the nature and the size of the blaze:
A wrong extinguishing method may have catastrophic consequences!
• Water: most frequently. It is very efficient to extinguish fires involving
solids. Disadvantages: conducts electricity and few chemicals that
react violently, freeze.
• Sand: isolates the fire from the oxygen it requires. Disadvantage:
lumps and hardens easily.
7. EXTINGUISHING AGENTS II
• Powder: suited to nearly every type of fire. Not all powders have the
same characteristics, label. Disadvantage: damage, mess, reduce
visibility in small spaces.
• Foam: dry fires, Disadvantage: conducts electricity and is
susceptible to freezing. damaging to the environment.
• CO2 ideal for electrical fires. Disadvantage: suffocating effect.
8. FIRE EXTINGUISHERS
Fire Extinguishers: portable, red in color, can be filled with different
extinguishing agents. label indicates the type of agent the
extinguisher contains.
Fire Blanket: non-flammable fabric, smothers the fire by cutting off
its oxygen supply.
Fire Hydrant: valve installed above or below ground, connected to
the water mains.
Fire Hose Reel : drum supporting a rolled-up fire hose that´s
connected to the water mains. Only suited for extinguishing solid
fuel fires. Only used for trained personnel.
9. FACING THE FIRE
Steps to follow in case of fire:
• Act quickly. Do not panic. Start by saving yourself.
• Alert the emergency services or the person in charge or push the
alarm button.
• Fire marshals: personnel assisting co-workers in case of fire. Easy
recognizable. Trained. Ensuring evacuation (specially disabled)
• Follow the directions of the fire brigade and those in charge of the
evacuation.
• NEVER use the elevator, take the stairs instead. Use the handrails.
10. FACING THE FIRE II
Take in mind in case of fire:
• Only try to extinguish after reporting it, clearing exit and if you know
how and what extinguisher has to be used.
• Fire Extinguishers: PASS CODE (pull the pin, aim at the base of
flames, squeeze the trigger and sweep from side to side)
• In case of fumes: stoop and crawl. Check the doors before opening.
If hot, try another door.
• If clothes get fired: get clear, drop to the ground and roll.
11. PREVENTING FIRES
Important aspects to prevent fires:
• Fire risk assesment: identifying hazard, assestment, controlling the
hazards, training personnel, visible fire procedures.
• Extinguishers must be clearly identified and regularly tested
• No liquids (drinks) near electrical equipment.
• Empty waste periodically.
• Checking the label and safety data sheets of chemicals substances
present at work: important information to avoid fires.
12. FIRST AID
How to help in case someone is burned:
• Water first, everything else can wait!
• Cool the burned body part under cold running water for at least 15
minutes.
• Clothing that is stuck to the burn should be left in place until the
emergency services arrive.