The combination of factors that go into contracting often produce hazards which can lead to flammability or even explosive conditions. Understanding how fires start and work, and how fire extinguishers factor into snuffing the flames can make the difference between saving lives and job sites and creating additional hazards that can lead to disastrous conditions and increased liability for contractors.
The Fire Triangle
The fire triangle refers to the three elements that must be present for a fire to ignite and burn. These three elements are:
- Heat: enough heat has to be present to raise the temperature of a material to its combustion point. Paper, for example, ignites at 451 degrees Fahrenheit.
- Fuel: Fuel is needed to get a fire going. This fuel is generally the combustible material.
- Oxygen: Just like people need oxygen to survive, so does fire. Oxygen is what feeds the flame and keeps it going.
When these three elements are present, an exothermic chemical reaction occurs that results in fire.
Extinguishing a Fire
Removing any of these three elements will stop the chemical reaction and will extinguish or prevent a fire from occurring in the first place. This is how fire extinguishers work: they remove one of the elements required to create a fire.
Every extinguisher is not right for every fire, however. There are five classifications of fire, and your extinguisher must be rated for the fire you are trying to put out. These classifications are as follows:
- Class A: Includes wood, paper, trash, cloth and solid, nonmetal combustibles such as plastic.
- Class B: Includes flammable liquids such as oil, gas and acetone as well as any nonmetal that exists in a liquid state and is burning.
- Class C: Electrical fires from electrical equipment that is plugged in and energized.
- Class D: Burning metals such as magnesium, sodium, potassium or aluminum.
- Class K: Sometimes combined with class B, this is a fire started from cooking materials, such as grease.
Knowing What to Use
Most fire extinguishers are rated for one or more classes of fire and the rating will be clearly indicated on the canister. Class D fires require specialized firefighting equipment, so if your job site may involve one or more combustible metals, you will want to be sure you are protected against that possibility.
Never try to use an extinguisher on a fire for which it is not rated. Not only will it likely fail to extinguish the flames, it could in fact make the blaze worse and create a disaster.
Preventing the Triangle
The best way to fight fires is to avoid conditions where they can start in the first place. This means keeping the three elements of the triangle separate as much as possible. It is often difficult to remove oxygen, since it is all around us.
As such, it is best to avoid conditions where heat will raise a combustible material to its ignition point. Post safety procedures and hazard signs anywhere fire is a possibility and be sure that your staff are thoroughly trained and follow all OSHA safety standards.
Always be sure you have the best safety policies and procedures, and that you are insured against any hazards on the job site. Check out our website for more information, and give us a call for a free quote and evaluation of your policy today.