Overview
What is a fire extinguisher? Classes of extinguishers Closer look at the extinguishers we
use at CFD Extinguisher Maintenance
What is a fire extinguisher?
A portable container, usually filled with special chemicals for putting out a fire.
Classes of Extinguishers
Fire extinguishers are divided into five classes, based on different types of fires. (A,B,C,D,K)
Each fire extinguisher also has a numerical rating that serves as a guide for the amount of fire the extinguisher can handle.
The higher the number, the more fire-fighting power.
Class A: Ordinary combustibles (paper, wood…)
Class B: Flammable liquids (gasoline, oil…)
Class C: Electrical equipment (wiring, circuit breakers…)
Class D: Combustible metals (magnesium, titanium…)
Class K: Organic oils (peanut oil, vegetable oil)
We’ll be focusing on class “A, D, ABC” because that’s what we carry on our engines.
Class A “Water Extinguisher”
Water extinguishers or APW extinguishers (air-pressurized water) are suitable for class A fires only.
Filled with water and pressurized with oxygen.
Our water extinguishers are 1.75gal/2.5 gal
How to Use a Class A Extinguisher When using ANY extinguisher,
remember the simple pneumonic “PASS”.
Pull the locking ring Aim at the base of the fire from
about 20ft away Squeeze the lever on the hose Sweep side to side along base of fire
Reminder
Never use a water extinguisher on grease fires, electrical fires or class D fires - the flames will spread and make the fire bigger!
Only fight the fire if you're certain it contains ordinary combustible materials only.
Class ABC “Multipurpose Dry Chem Extinguisher” filled with
monoammonium phosphate,
a yellow powder that leaves a sticky residue that may be damaging to electrical appliances such as a computer
uses a compressed, non-flammable gas as a propellant.
Class ABC Uses
These extinguishers can be used on:
Class A: Ordinary Combustibles
Class B: Flammable Liquids
Class C: Electrical Fires
How To Use an ABC Extinguisher Compress Plunger button Stand about 12 ft back from fire Aim at base of fire Squeeze lever on the hose Sweep back and fourth
Class D “Combustible Metals Extinguisher” The extinguishing
agent is Sodium Chloride.
Effective at controlling magnesium, sodium, potassium, sodium potassium alloys, uranium, and powdered aluminum metal fires.
How to Use Class D Extinguisher Compress Plunger button Stand about 12 ft back from fire Aim at base of fire Squeeze lever on the hose Sweep back and fourth
Extinguisher Maintenance
The pressure is at the recommended level. That means the needle should be in the green zone - not too high and not too low.
The nozzle or other parts are not obstructed. The pin and tamper seal (if it has one) are intact. There are no dents, leaks, rust, chemical deposits and other
signs of abuse/wear. Wipe off any corrosive chemicals, oil, gunk etc. that may have landed on the extinguisher.
Shake up the dry chemical extinguishers once a month to prevent the powder from settling/packing.
Fire extinguishers should be pressure tested (a process called hydrostatic testing) after a number of years to ensure that the cylinder is safe to use.
If the extinguisher is damaged or needs recharging, get it replaced immediately!