Fire is a chemical reaction that requires three elements to be present for the reaction to take place and continue. The three elements are:
- Heat, or an ignition source
- Fuel
- Oxygen
These three elements typically are referred to as the “fire triangle.” Fire is the result of the reaction between the fuel and oxygen in the air. Scientists developed the concept of a fire triangle to aid in understanding of the cause of fires and how they can be prevented and extinguished. Heat, fuel, and oxygen must combine in a precise way for a fire to start and continue to burn. If one element of the fire triangle is not present or removed, fire will not start or, if already burning, will extinguish.
Ignition sources can include any material, equipment, or operation that emits a spark or flame—including obvious items, such as torches, as well as less obvious items, such as static electricity and grinding operations. Equipment or components that radiate heat, such as kettles, catalytic converters and mufflers, also can be ignition sources.
Fuel sources include combustible materials, such as wood, paper, trash and clothing; flammable liquids, such as gasoline or solvents; and flammable gases, such as propane or natural gas.
Oxygen in the fire triangle comes from the air in the atmosphere. Air contains approximately 79 percent nitrogen and 21 percent oxygen. OSHA describes a hazardous atmosphere as one which is oxygen-deficient because it has less than 19.5 percent oxygen, or oxygen enriched because it has greater than 23.5 percent oxygen. Either instance is regarded by OSHA as an atmosphere immediately dangerous to life and health (IDLH) for reasons unrelated to the presence of fire. Depending on the type of fuel involved, fires can occur with much lower volume of oxygen present than needed to support human respiration.
Every roofing project has all three of the fire triangle elements present in abundance. The key to preventing fires is to keep heat and ignition sources away from materials, equipment and structures that could act as fuel to complete the fire triangle.
Fire Classifications Fires are classified as A, B, C, D or K based on the type of substance that is the fuel for the fire, as follows:
- Class A—fires involving ordinary combustibles, such as paper, trash, some plastics, wood and cloth. A rule of thumb is if it leaves an ash behind, it is a Class A fire.
- Class B—fires involving flammable gases or liquids, such as propane, oil and gasoline.
- Class C—fires involving energized electrical components.
- Class D—fires involving metal. A rule of thumb is if the name of the metal ends with the letters “um,” it is a Class D fire. Examples of this are aluminum, magnesium, beryllium and sodium. Class D fires rarely occur in the roofing industry.
- Class K—fires involving vegetable or animal cooking oils or fats; common in commercial cooking operations using deep fat fryers.
All workers should have a clear understanding of the organization’s fire safety plan. Guidance to employees should include when it might be appropriate and helpful to fight a small fire with a portable fire extinguisher and when it is the right decision to evacuate immediately.
Using a fire extinguisher may seem easy, but it is best for every employee to have some basic knowledge of fire safety including an understanding of the different types of fires and fire extinguishers, how to decide to attempt to fight a fire or evacuate, and how to use a fire extinguisher in the event of a fire emergency. All employees should be familiar with the location and types of extinguishers available.
Personnel who are trained and authorized to use portable fire extinguishers must know how to conduct a risk assessment to determine whether it is safe to fight a fire or if the best course of action is to evacuate. Before attempting to extinguish any fire, these questions should be considered first.
- How big is the fire? Only attempt to put out a fire if it is contained to a small area, is in the early stages of developing, and has not started to spread quickly, also known as an incipient stage fire.
- Is the atmosphere safe? If there is a lot of smoke, hot temperatures, limited visibility, or hazardous materials in the area, then no one should attempt to stay and fight the fire.
- Where is the escape route? If anyone attempts to fight a fire, an escape route should be behind them. No one should use a fire extinguisher if their means of evacuation is not clear or is compromised.
- Is the correct fire extinguisher available? Make sure the fire extinguisher on hand matches the type of fuel that is burning.
- Are you calm and in control? If you feel panicked, overwhelmed, or unsure of the situation, do not attempt to fight the fire.
When the decision has been made to attempt to put out a fire, take these actions first, before pulling the pin on the fire extinguisher.
- Activate the fire alarm system and notify emergency services or delegate someone to do this.
- Ensure that personnel evacuation has started, and all other workers are safely exiting the area.
- Identify a safe evacuation route.
If no person on site attempts to extinguish the fire, then all personnel should evacuate the area immediately. If indoors, everyone should exit the building, no matter how far away from the fire they are located. Report any fire extinguishers that have been used. Even if the extinguisher was used for a short time, it should be reported as used.
All firefighting equipment, including fire extinguishers, must be periodically inspected and receive routine maintenance on a regular basis to ensure they are operating properly and ready, if needed. Portable fire extinguishers should be inspected by a trained professional once a year with a visual inspection conducted monthly.
Visual inspections are quick checks to ensure that the fire extinguisher is fully charged, in good operating condition and ready for use, should it be needed. During monthly inspections, also check the surrounding area to ensure the fire extinguisher remains easily accessible in the event of an emergency.
Working in a shop, on a construction site, at a distribution center, in an office… regardless of the work environment, fire prevention as well as fire protection are both great safety meeting topics to cover at least once a year with all employees.
Employees should be instructed that if a fire cannot be extinguished using one full extinguisher, they should evacuate the site and let the fire department handle the situation.
Spencer-SHE has been providing Safety, Health, and Environmental Compliance Guidance since 1980. Let our team evaluate your fire protection plan, suggest improvements, and train your employees. We will document your fire protection efforts and provide updates when required.
Contact us here to help you to develop and maintain a safe and healthy workforce.
Sources:
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https://www.osha.gov/sites/default/files/2019-03/fireprotection.pdf