Fire Control: An Introduction
Fire prevention measures are a key component in fire safety management. This involves the identification and elimination of potential fire hazards both inside and outside of doors of the building, and also the establishment of fine housework practices, periodic inspections, and also the diligent application of safety rules. The ways to manage fire and its prevention is a crucial topic to be mentioned.
Classes of Fire
A fire occurs when the elements, i.e., heat, fuel, oxygen, and chemical chain reaction are present and combined within the right mixture. A fire may be prevented or extinguished by removing any one of the elements within the fire triangle. Primarily all four components should be present for fire to occur: heat, fuel oxygen, and a chain reaction.
While fire can look like one massive threatening force, it’s vital to understand that there are actually many categories of fires. A fire’s class will determine how quickly it burns, and how dangerous it is.
The main categories of fire are as follows:
Class A: Fires involving solid materials like wood, paper, or textiles.
Class B: Fires involving combustible liquids and gases like petrol, diesel, or oils, gases like propane and alkane series, etc.
Class C: Fires involving electrical fires.
Class D: Metallic fires. Metallic fires involve ignitable materials like magnesium and potassium.
Class F: Fires involving cooking oils like deep-fat fryers.
Forest Fires
Forest fires may be outlined as any uncontrolled and non-prescribed combustion or burning of plants in a natural way like a forest, grassland, brushland, or tundra that consumes the natural fuels and spreads according to the environmental conditions (e.g., wind topography).
Forest Fire
Forest fires occur in 3 principal forms, the distinctions relying essentially on their mode of spread and their position in relation to the ground surface.
Types of Forest Fires
There are three types of forest fires.
Surface Fires
Ground fires
Crown fires
Surface Fires
They burn only surface litter like dried leaves, twigs, and grasses.
These are the simplest fires to place out and cause the least harm to the forest.
Parched grass or fallen leaves usually fuel surface fires.
Ground Fires
These are generally referred to as underground or subsurface fires.
They occur in deep accumulations of humus, peat, and similar dead vegetation that become dry enough to burn.
These fires move very slowly however can become tough to completely put out or suppress.
Ground fires will smoulder for a long time, even a whole season, till conditions are right for them to grow to a surface or crown fire.
Underground fires spread slowly and are hard to notice, thus they may burn for months destroying the vegetative part of the soil.
Crown Fires
This type burns trees up their entire length to the highest.
They burn through the canopy, spreading from treetop to treetop.
These are the most intense and dangerous forest fires as they're terribly tough to contain.
It needs strong winds, steep slopes, and a significant fuel load to continue burning.
Causes of Forest Fires
The forest fire causes and effects are listed below:
The reason for forest fire includes lightning which is the natural cause of forest fire and may end up in fires on trees which can be spread by wind. Sometimes, high atmospheric temperatures and dry conditions (low humidity) provide favourable circumstances for a fire to start out.
Man-made causes are the ones that are more dangerous. Fire is caused because of the sources like naked flame, cigarette, electrical spark, or any source of ignition that comes into contact with combustible material.
Other human-led causes are land clearing and different agricultural activities, maintenance of grasslands for livestock management, extraction of non-wood forest products, industrial development, transportation, hunting, negligence, and arson.
Effects of Forest Fires
Forest fires emit billions of tonnes of greenhouse gas into the atmosphere which causes damage to climate and living organisms.
This can also have an effect on the carbon cycle because of excess carbon dioxide and loss of vegetation.
High-intensity forest fires can destroy flora and fauna.
Forest fires can impact the economy as several lives and communities rely upon the forest for food, fodder, and fuel.
It burns down the small shrubs and grasses, resulting in landslides and soil erosion.
Excessive forest fires can even boost the ozone depletion process.
Ways to Control Fire
A fire can occur at any time. Thus, numerous measures are to be adopted prior to managing a fire. How do we control fire? Fire may be controlled or extinguished by removing the fuel and heat and by isolating the air supply from the burning substance. Fire management plays a vital role in controlling fire.
Remove the Fuel
When a fire starts in an area, all the flammable substances need to be removed quickly in order to control the fire. If possible, the cooking gas cylinder should be removed and the electricity must be switched off.
Remove the Heat
Water is used to get rid of heat from a burning substance. When water is thrown on a burning substance, it gets cooled below its ignition temperature and also stops burning.
Cut off the Air Supply
The air supply to a burning substance may be cut off in a number of ways like covering the burning substance with CO2, sand, a blanket, or moist material. The electrical fires are extinguished by using CO2 gas fire extinguishers. Such precautions for forest fire must be taken into consideration.
Forest Fire Prevention
The majority of forest fires or wildfires are human-caused. The few precautions of a forest fire or a few ways to prevent forest fires are listed below:
Obey local laws relating to open fires, as well as campfires.
Have fire fighting tools nearby and handy.
Keep all ignitible objects far from the fire. Scrape away leaves, twigs, and grass within a 10-foot diameter circle from fire. Never leave a fire unattended.
Carefully extinguish smoking materials.
Careful disposal of hot charcoal.
Conclusion
When a fire breaks out in a house, office, factory, oil tanker, or petrol pump, then the fire is harmful. It will cause loss of life or property. Fire can be extinguished in three ways and it may be prevented by following some basic rules. Forest fires are dangerous and it adversely affects the flora and fauna.
FAQs on How to Prevent and Control Fire
1. What are the different classes of fire based on the type of fuel involved?
Fires are classified into different categories based on the fuel they burn. The main classes, as per safety standards, are:
- Class A: Involves solid combustible materials like wood, paper, and textiles.
- Class B: Involves flammable liquids and gases such as petrol, diesel, oils, and propane.
- Class C: Involves energised electrical equipment, where using a non-conductive extinguishing agent is crucial.
- Class D: Involves combustible metals like magnesium, titanium, and potassium, which require special extinguishing agents.
2. What are the three essential requirements for a fire to start, often called the fire triangle?
The three essential requirements for combustion, known as the fire triangle, must be present simultaneously for a fire to start and continue burning. They are:
- Fuel: Any combustible material that can burn, such as wood, gas, or oil.
- Heat: An ignition source sufficient to raise the fuel to its ignition temperature.
- Oxygen: The oxidising agent, usually from the air, that sustains the chemical reaction.
The principle of fire control is based on removing at least one of these elements.
3. How does water help extinguish common fires, and what are its limitations?
Water is effective on most common fires (Class A) because it attacks two sides of the fire triangle. Firstly, it cools the combustible material below its ignition temperature. Secondly, the steam it produces can help displace oxygen from the fire. However, water should never be used on electrical fires (Class C) because it conducts electricity and can cause electrocution. It is also highly dangerous for oil or petrol fires (Class B) as oil floats on water, which can spread the flames.
4. How does a carbon dioxide (CO₂) fire extinguisher work to put out a fire?
A carbon dioxide (CO₂) fire extinguisher is highly effective, especially for electrical (Class C) and flammable liquid (Class B) fires. It works by:
- Displacing Oxygen: Being heavier than air, CO₂ gas forms a blanket around the fire, cutting off its oxygen supply and smothering it.
- Cooling Effect: The CO₂ is released as an extremely cold discharge, which helps to cool the fuel.
A key advantage of a CO₂ extinguisher is that it leaves no residue, making it safe for use on sensitive electrical equipment.
5. What are some key safety measures to prevent fires at home?
To prevent fires at home, several important precautions should be taken, particularly in areas like the kitchen. Key measures include:
- Regularly checking electrical wiring and appliances for signs of wear or damage.
- Never leaving cooking unattended and keeping flammable items like cloth or paper away from the stove.
- Storing flammable liquids like kerosene in safe, well-ventilated areas away from ignition sources.
- Ensuring all smoking materials are completely extinguished before disposal.
- Having a fire extinguisher and smoke alarms installed and functional.
6. Why is it extremely dangerous to use water on electrical or oil fires?
Using water on certain fires is dangerous due to its physical and chemical properties. Here’s why:
- On Electrical Fires: Water is a good conductor of electricity. Throwing water on a fire involving live electrical equipment can create a path for the current, leading to severe electric shocks or electrocution for the person holding the hose.
- On Oil Fires: Oil is less dense than water and does not mix with it. When water is thrown on an oil fire, it sinks to the bottom, rapidly boils into steam, and causes an explosive effect that throws the burning oil, spreading the fire dramatically.
7. What is the difference between controlling a fire by cooling versus by cutting off its oxygen supply?
Both methods work by removing a side of the fire triangle, but they operate on different principles:
- Controlling by Cooling: This involves reducing the temperature of the fuel below its ignition point. The most common example is using water on a wood fire. Once the fuel is no longer hot enough, the chemical reaction of burning cannot continue.
- Controlling by Cutting Off Oxygen: This method, also known as smothering, involves preventing air from reaching the fire. Examples include covering a small pan fire with a lid, using a fire blanket, or using a CO₂ extinguisher that displaces oxygen. Without sufficient oxygen, the fire suffocates.
8. In the context of a forest fire, why is a 'crown fire' considered more dangerous than a 'surface fire'?
A crown fire is significantly more dangerous and harder to control than a surface fire due to its intensity and how it spreads:
- A surface fire burns along the forest floor, consuming litter like dry leaves and twigs. It moves relatively slowly and is generally easier for firefighters to manage and extinguish.
- A crown fire, however, burns through the top layer of trees or canopy. It can spread rapidly from treetop to treetop, often driven by strong winds. Its intense heat and speed make it the most destructive and dangerous type of forest fire, capable of overwhelming standard firefighting efforts.
