The Ontario Fire Code requires commercial buildings to have the appropriate type and quantity of fully-charged fire extinguishers on site for life safety. While most people are accustomed to seeing them, very few understand the mechanics of fire extinguisher operation. This short article attempts to give the reader a simple fire extinguisher tutorial.
Before understanding how a fire extinguisher operates, you must first comprehend the mechanics of fire itself. Fire results from chemical combustion between oxygen and a fuel source, such as wood, paper, or gasoline. Of course, oxygen is always surrounding these fuel sources without causing a fire, so combustion also requires that the fuel heats up to its ignition temperature.
Wood requires a temperature above 260 celsius to decompose the wood’s cellulose and release its volatile gases: a compound of hydrogen, carbon, and oxygen. At this temperature, the compound molecules break down, and the atoms reconstitute with oxygen to form water, carbon dioxide, and other debris.
The remaining gases rise upwards to form the flame, and the flame’s carbon atoms generate its characteristic light. The flame generates its own heat, which continues to ignite the fuel and oxygen as long as both are present. To sum it up, fire requires:
- Heat above 260 celsius
- Fuel source
Fire Extinguisher Operation
Modern fire extinguishers are designed to eliminate one of these three elements from the equation to put out a fire. There are three fundamental methods of accomplishing this task:
- Remove heat. The simplest way to put out a fire is to cool it down by dousing it with water. Once the heat subsides, there’s no possibility of ignition. However, if the heat is from an electrical or chemical source, you must not use water.
- Remove oxygen. Smothering a fire with something like a blanket can deprive it of oxygen. Nonflammable materials, such as baking soda and sand can accomplish the same and is also effective.
- Remove fuel. This is both a difficult and dangerous method of firefighting. Fuel removal involves depriving the fire of its fuel source. Think of removing logs from a fire pit.
Fire extinguishers are pressurized metal canisters full of water or a non-conductive chemical. Squeezing a lever at the top of the extinguisher allows the extinguishing agent to escape.
These extinguishers have a tube that stretches from the bottom of the tank to the nozzle. This tube contains a spring-activated valve that prevents the extinguishing agent from discharging. A small canister of liquid carbon dioxide is located at the top of the extinguisher.
When you’re ready to use the extinguisher, you must first pull the safety pin and then squeeze the lever. This lever simultaneously opens the valve to expel the extinguishing agent and also pierces the canister of liquid co2 with a sharp point.
The CO2 gas then expands and creates the pressure necessary to propel the extinguishing agent forcefully toward the fire. Once the extinguishing agent is flowing from the canister, aim it toward the fuel of the fire rather than the flames.
Depending on your building’s environment, you need to have the proper extinguisher on hand to extinguish the type of fire you’re likely to encounter. Please see this article to get a detailed explanation of the different types available.
Learning the operation of today’s modern extinguishers is not only interesting, it can also help you better operate and maintain them over time. All Protect System Inc has been servicing Ontario area businesses’ fire extinguishers and the rest of their fire protection needs. They also install and service gas protection, fire alarms, emergency exit signs and lighting, and design fire safety plans. Call them today to find out what they can do for you!