Chapter 6: Portable Fire Extinguishers Questions and Answers Rated A+

Chapter 6: Portable Fire Extinguishers Questions and Answers Rated A+ Five classes of portable fire extinguishers A, B, C, D, and K Class A Ordinary combustibles (wood, paper, plastic, rubber, cloth) Class B Flammable/Combustible Liquids and Gases (hydrocarbon/alcohol based liquids/gases) Class C Electrical (fires involving energized electrical equipment) Class D Combustible metals (magnesium, potassium, titanium, zirconium) Class K Cooking oils Dry chemicals Any powdery extinguishing agents used to extinguish fires Extinguishing agents Any substance used for the purpose of controlling or extinguishing a fire Two ways portable fire extinguishers are identified 1. Geometric shapes of specific colors 2. Pictographs Class A portable fire extinguishers rating 1-A through 40-A Based on amount of water and duration and range of the discharge used in extinguishing fires Class B portable fire extinguisher rating 1-B through 640-B Based on approximate square foot area of a flammable liquid fire that a non expert operator can extinguish using one full extinguisher Why is a Class C extinguisher different than class A/B Class C fires involve energized electrical equipment and water/water-based agents conduct electrical current. Once the electricity is completely shut off, then treat it as a Class A/B fire Dry Powder Extinguishing agent suitable for use on combustible metal fires (Class D) Wet Chemical System Extinguishing system that uses a wet chemical solution as the primary extinguishing agent; usually installed in range hoods and/or where grease may be accumulated Saponification extinguishing method Takes place in a Class K fire. Oils in the flammable liquids turn into foam All extinguishing agents use at least one of the following methods to extinguish fire 1. Smothering 2. Cooling 3. Chemical flame inhibition 4. Saponification Smothering extinguishing method Excluding oxygen from fuel Cooling extinguishing method Reducing burning material below its ignition temperature Chemical flame inhibiton Interrupting the chemical chain reaction in the burning process