WEEK 7 DRRR

FIRE HAZARDS

• Conditions that favor fire development or growth

• Oxygen, fuel, and heat

• usually involve the mishandling of fuel or heat

• Source of ignition= Spark, flame and high temperature are needed

Fire

combustion is a chemical reaction between oxygen and a combustible fuel

Fire Triangle

• illustrates the three elements a fire needs to ignite: heat, fuel, and an oxygen

• The fire extinguishes by removing any one of the elements in the fire triangle

Types of Fires

Class A, B, C, D, K Fires

Class A Fires

solid materials such as wood or paper, fabric, and some plastics.

Class B Fires

Class C Fires

electrical failure from appliances, electronic equipment, and wiring

Class D Fires

metallic substances such as sodium, titanium, zirconium, or magnesium

Class K Fires

grease or oil fires specifically from cooking

Fuels

Solid

Liquid

Gases

fire extinguisher

1. nozzle

2. hose

3. pin and seal

4. gauge

5. inspection tag

PASS

pull, aim, squeeze. sweep

Class A fire extinguisher

contain water for use against fires involving ordinary combustibles like paper, wood, cloth, and most plastics

Class B fire extinguisher

use dry chemicals to put out fires caused by gasoline, oil, and solvents

Class C fire extinguisher

contain carbon dioxide for use against electrical fires

Class D fire extinguisher

spray dry powder on combustible metals like magnesium, titanium, aluminum, sodium, and potassium

Class K fire extinguisher

use a wet, potassium acetate-based, low pH urgent to put out “cooking” fires in which there are animal and vegetable oils and fats

Fire Detection Devices

smoke, heat, and flame detectors

Smoke detectors

• require a flow of air in order to work well

Heat detectors

• detect fires where there is no smoke activated by the significant increase of temperature associated with fire

Flame detectors

• react to the movement of flames.

WATER (EXTINGUISHER)

• CLASS A ONLY

• DO NOT USE ON LIQUID OR ELECTRIC FIRES

FOAM (EXTINGUISHER)

• CLASS A & B ONLY

• not suited to domestic use

DRY POWDER (EXTINGUISHER)

• EXCEPT CLASS F

• can be used safely to 1000 volts

CO2 (EXTINGUISHER)

• CLASS B AND ELECTRICAL ONLY

• safe on both high and low voltage

WET CHEMICAL

• CLASS A AND F ONLY

• use on extremely high temperature