Classes of fire and how to extinguish them
Download as PPTX, PDF2 likes1,489 views
This document provides an overview of fire, its classes, and how to extinguish various types of fires. It describes the fire triangle, the characteristics of different fire classes (A, B, C, D, and K), and the appropriate fire extinguishers for each class. Additionally, it outlines safety precautions for using fire extinguishers.
Classes of fire and how to extinguish them
- 1. CLASSES OF FIRE AND HOW TO EXTINGHUISH THEM By Gian Gabriel Ibo BSMT Student
- 2. WHAT IS FIRE? • Fire is the rapid oxidation of a material in the exothermic chemical process of combustion, releasing heat, light, and various reaction products.
- 3. FIRE TRAINGLE • The fire triangle or combustion triangle is a simple model for understanding the necessary ingredients for most fires. The triangle illustrates the three elements a fire needs to ignite: heat, fuel, and an oxidizing agent
- 4. What are the Classes of Fire?
- 5. CLASS A FIRE • Class A fires are fires in ordinary combustibles such as wood, paper, cloth, rubber, and many plastics.
- 6. CLASS B FIRE • Class B fires are fires in flammable liquids such as gasoline, petroleum greases, tars, oils, oil-based paints, solvents, alcohols. Class B fires also include flammable gases such as propane and butane. Class B fires do not include fires involving cooking oils and grease.
- 7. CLASS C FIRE • Class C fires are fires involving energized electical equipment such as computers, servers, motors, transformers, and appliances. Remove the power and the Class C fire becomes one of the other classes of fire.
- 8. CLASS D FIRE • Class D fires are fires in combustible metals such as magnesium, titanium, zirconium, sodium, lithium, and potassium.
- 9. CLASS K FIRE • Class K fires are fires in cooking oils and greases such as animal and vegetable fats.
- 10. WHAT ARE THE TYPES OF FIRE EXTINGUISHERS?
- 11. WATER AND FOAM • Water and Foam fire extinguishers extinguish the fire by taking away the heat element of the fire triangle. Foam agents also separate the oxygen element from the other elements. • Water extinguishers are for Class A fires only - they should not be used on Class B or C fires. The discharge stream could spread the flammable liquid in a Class B fire or could create a shock hazard on a Class C fire.
- 12. CARBON DIOXIDE • Carbon Dioxide fire extinguishers extinguish fire by taking away the oxygen element of the fire triangle and also be removing the heat with a very cold discharge. • Carbon dioxide can be used on Class B & C fires. They are usually ineffective on Class A fires.
- 13. DRY CHEMICAL • Dry Chemical fire extinguishers extinguish the fire primarily by interrupting the chemical reaction of the fire triangle. • Today's most widely used type of fire extinguisher is the multipurpose dry chemical that is effective on Class A, B, and C fires. This agent also works by creating a barrier between the oxygen element and the fuel element on Class A fires. • Ordinary dry chemical is for Class B & C fires only. It is important to use the correct extinguisher for the type of fuel! Using the incorrect agent can allow the fire to re-ignite after apparently being extinguished succesfully.
- 14. WET CHEMICAL • Wet Chemical is a new agent that extinguishes the fire by removing the heat of the fire triangle and prevents re- ignition by creating a barrier between the oxygen and fuel elements. • Wet chemical of Class K extinguishers were developed for modern, high efficiency deep fat fryers in commercial cooking operations. Some may also be used on Class A fires in commercial kitchens.
- 15. CLEAN AGENT • Halogenated or Clean Agent extinguishers include the halon agents as well as the newer and less ozone depleting halocarbon agents. They extinguish the fire by interrupting the chemical reaction and/or removing heat from the fire triangle. • Clean agent extinguishers are effective on Class A, B and C fires. Smaller sized handheld extinguishers are not large enough to obtain a 1A rating and may carry only a Class B and C rating.
- 16. DRY POWDER • Dry Powder extinguishers are similar to dry chemical except that they extinguish the fire by separating the fuel from the oxygen element or by removing the heat element of the fire triangle. • However, dry powder extinguishers are for Class D or combustible metal fires, only. They are ineffective on all other classes of fires.
- 17. WATER MIST • Water Mist extinguishers are a recent development that extinguish the fire by taking away the heat element of the fire triangle. They are an alternative to the clean agent extinguishers where contamination is a concern. • Water mist extinguishers are primarily for Class A fires, although they are safe for use on Class C fires as well.
- 18. CARTRIDGE OPERATED DRY CHEMICAL • Cartridge Operated Dry Chemical fire extinguishers extinguish the fire primarily by interrupting the chemical reaction of the fire triangle. • Like the stored pressure dry chemical extinguishers, the multipurpose dry chemical is effective on Class A, B, and C fires. This agent also works by creating a barrier between the oxygen element and the fuel element on Class A fires. • Ordinary dry chemical is for Class B & C fires only. It is important to use the correct extinguisher for the type of fuel! Using the incorrect agent can allow the fire to re-ignite after apparently being extinguished successfully.
- 19. HOW TO USE A FIRE EXTINGUISHER
- 20. ONLY FIGHT A FIRE IF: • The fire is small and contained • You are safe from toxic smoke • You have a means of escape • Your instincts tell you it's OK