FIRE EXTINGUISHER

THERE ARE 5 TYPES OF FIRE EXTINGUISHERS .

• Class A
• Class B
• Class C
• Class D
• And ABC combined

Class A (green label)

Class A fire extinguishers take out Wood,Paper,Cloth, and trash fires.

CLASS B (red label)

Class B fire extinguishers take out Gasoline,solvents,vapors, and gas leak fires.

CLASS C (blue label)

For electrical fires only

CLASS D (yellow label)

For fires involving combustible metals such as Magnesium , Sodium Potassium, and sodium potassium alloys.

A,B,C combined

For combination fires .

Hand held fire extinguishers, which are commonly sold at hardware stores for use in the kitchen or garage, are pressurized with nitrogen or carbon dioxide (co2) to propel stream of fire-squelching agent to the fire.

The active material may be a powder such as potassium bicarbonate (KHCO3) ,liquid water,an evaporating fluorocarbon, or the propelling agent itself.

The most effective and common fluorocarbon used until recently had been bromochlorodifluoromethane.
(CF2ClBr), referred to as halon 1211.

Halon 1211

Halon 1221 is a liquidefied,compressed gas that stops the spread of fire by chemically disrupting combustion.

By international agreement, however, production of all types of halons was stopped in 1994 because the bromine and chlorine atoms in the chemical were found in migrate over time to the stratosphere.

When the fire extinguisher is sprayed on the fire, the chemicals in the fire extinguisher stop the oxygen from entering the fire, and that's how the fire goes out.

The average response time for the fire department is 10 minuets, so by the time they arrive, many valuable things could be gone, or some one could even die from inhaling the smoke or burning to death.

WORK CITED

• Www.ScientificAmerican.com
• Www.fire-extinguisher101.com