Generally speaking, fire safety involves two elements: fire prevention and fire fighting.
The best way to provide fire safety is to prevent a fire from starting in the first place. There are several measures that personnel can take to help prevent fires.
Work should always be done in a well-ventilated area, especially when flammable materials such as shellac, lacquer, paint stripper, or construction adhesives are used.
Personnel who are working with flammable materials must never smoke or light matches.
Combustible materials should be stored only in approved containers, and oily rags should be kept in approved metal containers.
It is also important for personnel to know how to use fire extinguishers. This includes knowing where fire extinguishers are located and what types of extinguisher to use for different types of fires.
Of course, accidents can happen, and fires can start. For a fire to start, fuel, heat, and oxygen are needed in the same place at the same time. In addition to fuel, oxygen, and heat, one more thing is needed for a fire: a chemical reaction between all three elements that allows combustion to occur and to continue. If any of the three elements is missing, there cannot be a chemical reaction, and a fire cannot start. If a fire has started, removing any one or more of these elements will extinguish the fire.
Fuel can be defined as anything that will combine with oxygen when heat is present. Heat can be considered as anything that will raise a fuel’s temperature to what is called the flash point. The flash point is the temperature at which a fuel gives off enough gases to burn. The flash point temperature of many substances is quite low – room temperature or less. When burning gases raise the temperature of a fuel to its ignition temperature, the fuel itself will burn, and keep burning even though the original source of heat is removed.
The best way to prevent a fire is to make sure that the three elements for a fire to start are never present in the same place at the same time. This can be done for different types of fuel by recognizing and removing at least one of the elements.
Fires involving a flammable liquid or a combustible liquid can be prevented by removing heat, fuel, or oxygen, or by stopping the chemical reaction despite the presence of heat, fuel, and oxygen.
Flammable liquids are liquids with a flash point below 140 degrees Fahrenheit. Combustible liquids are liquids with a flash point at or above 140 degrees Fahrenheit. Flammable liquids and combustible liquids do not burn. The gases or vapors given off as the liquid evaporates (turns to vapor) burn. If there is no evaporation, the fuel will not burn.
Oxygen can be removed by keeping safety containers tightly sealed to prevent oxygen from coming into contact with the fuel. The vapors from these liquids will not burn if oxygen is not present.
Heat can be removed by storing the liquids away from sources of heat so that there will not be sufficient heat to ignite the evaporating gases.
The chemical reaction producing a fire can be stopped, despite the presence of heat, fuel, and oxygen, by using special extinguishing agents such as Halon.
Many other materials at work sites are referred to as ordinary combustibles, and they can become fuel for a fire. The term “ordinary combustibles” refers to wood, paper, cloth and similar materials. The easiest way to prevent fire involving ordinary combustibles is to remove the fuel by keeping a neat and clean work area.
If a fire does start, workers are not expected to be expert firefighters. However, workers may have to deal with a fire to protect themselves, others and property. It is important for everyone to know the location of fire fighting equipment at the job site. It is equally important for everyone to know which equipment to use on different types of fires. Workers should also know the procedure for reporting fires. If a company fire brigade has been formed, workers should know how to contact them in case of a fire.
Fires are divided into four classes, and each class of fire has a different method of fire fighting, and a different type of extinguisher. The different classes of fires are identified with the letters “A” through “D.” Fire extinguishers have labels that clearly identify the class or classes of fire on which they can be used.
- Class A fires involve ordinary combustibles such as wood or paper. A Class A fire is commonly fought by cooling the fuel. Water is the fire fighting substance contained in a Class A extinguisher. Using a Class A extinguisher on any other type of fire can be dangerous.
- Class B fires involve grease, liquids, and gases. Class B extinguishers put out these types of fires by cooling them and smothering them.
- Class C fires are any fires near or involving energized electrical equipment. Class C fires extinguishers are designed to protect firefighters from electrical shock. These extinguishers fight fires by smothering them.
- Class D fires involve metals that burn. Class D extinguishers contain a powder that either forms a crust around the burning metal or gives off gases that prevent oxygen from reaching the fire.
An extinguisher with the an ABC code may be used to fight fires in any of these three categories. A single-code fire extinguisher should not be used on any other class of fire. For example, water sprayed on a grease fire will actually serve to spread the fire and will not extinguish it.
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