In the world of fire safety, knowledge is power. Understanding the various classes of fires is essential for effective prevention and response strategies. Among these classifications, Class C fires can involve highly explosive materials and must be managed appropriately to minimise the risks. Hence, learning all you can about how to prevent and manage a Class C fire is vital. Join us as we identify the common sources of ignition and the recommended interventions for Class C fires.
- What is a Class C Fire?
- Preventing a Class C Fire
- Class C Fire Examples
- Identifying a Class C Fire
- How to Tackle a Class C Fire
- Gas Fire Hazards FAQs
What is a Class C Fire?
A Class C fire is identified as the burning of flammable gases, which can be highly explosive and dangerous if ignited. Combustible gases such as butane, propane and methane form the fuel aspect of the fire triangle, which is essential for a fire to start, spread and continue to burn.
Causes & Risks of Class C Fires
Class C fires occur most frequently in environments that store and use significant combustible gases, such as industrial warehouses and chemical plants. Natural gas fires, which you use to heat your home and cook food, are also flammable, meaning homes, hospitals, and schools can also be at risk.
Flammable gases must be maintained, installed and stored correctly to avoid unforeseen fire outbreaks. Similarly to Class B, these fires are rarely used as a controlled fire method; instead, they are involved in accidental or arson-related fire attacks.
As flammable gases are heavier than air, they can travel significantly to an ignition source, meaning a fire can spread rapidly and uncontrollably. The speed at which this fire spreads can cause explosions, leading to devastating effects.
Class C Fire Examples
Below are a handful of examples of Class C gas fires that can occur in residential, commercial and industrial settings:
- Propane Tank Leak: Propane is widely used in heating and cooking in residential and commercial settings. A leak in a propane tank can lead to a fire if the gas is ignited by a spark or open flame.
- Natural Gas Leaks: Natural gas is used in many homes for cooking, heating and as a source of hot water. Leaks can occur randomly in gas lines or applications. A kitchen stove with a loose connection may leak gas, which ignites when someone turns on the cooker.
- Industrial Gas Cylinders: Industrial workplaces often store various flammable gases in cylinders for welding, cutting, and other applications. Mishandling or faulty equipment can lead to leaks and fires. For example, if a cylinder develops a leak, a welding torch may ignite the escaping gas, leading to a fire.
Identifying a Class C Fire
It is crucial to identify the type of fire you are faced with so that you can use the appropriate extinguishing method.
Initial Signs of a Class C Gas Fire
- Smell of Gas: Many flammable gases, such as natural gas and propane, have a distinct odour (often described as rotten eggs or sulphur). Detecting this smell can indicate a gas leak, which is a precursor to a potential Class C gas fire.
- Hissing or Whistling Sounds: Escaping gas can create a hissing or whistling sound near gas lines, connections, or appliances. This sound indicates a leak that could lead to a fire if ignited.
- Visible Gas Flames: Flames or flickers of light around gas appliances, pipelines, or connections where there should be none indicate that the gas is already igniting, which can rapidly escalate into a fire.
- Smoke: Particularly near gas lines or appliances, smoke can be an early sign of a Class C fire starting due to a gas leak.
- Changes in Flame Characteristics: Gas appliances typically have a stable blue flame. Any change to a yellow or orange flame can indicate incomplete combustion or a leak, which could result in a fire.
How to Distinguish Class C Fires from Other Fires
- Source of Ignition: Class C fires originate from flammable gases such as propane, natural gas, butane, or methane. Look for fires starting near gas lines, appliances, or storage tanks. On the other hand, Class A fires originate from solids and Class B from flammable materials.
- Behaviour of the Fire: Gas fires can quickly become intense due to the rapid combustion of gas. They may be accompanied by a hissing sound from escaping gas. Other fires have varying behaviours, such as Class A fires spreading more slowly, whereas Class B fires can have explosive bursts.
Class C fires require unique firefighting methods. Therefore, it is crucial to successfully identify a Class C fire and use the correct method of extinguishing.
Preventing a Class C Fire
Class C fires are often one of the most difficult to extinguish, as a fire extinguisher is unlikely to put out all the flames of a gas fire. Therefore, trying to prevent a Class C fire from starting in the first place is crucial.
Appropriate Storage
Class C fires can be prevented by storing flammable gases in compliant containers, such as gas bottle storage cages. These clearly labelled storage units are the best way to store flammable gases. It is vital to store only a few combustible gases in a unit, as storing many gas canisters in one location can result in a highly explosive fire outbreak. Gas canisters must also be kept away from possible ignition sources, and flames, sparks, or burning embers should not be located near the equipment.
Inspect Gas Canisters
If your gas supply is stored in gas canisters, it is crucial to conduct regular checks for any signs of wear and tear. If there are any signs of rust or dent, your canister may be at risk of leaking, so it is essential to dispose of it appropriately.
To check if your canister is leaking, avoid using an open flame. This type of ignition will trigger a more significant and dangerous fire. Instead, use soap mixed with water and place it near the area you suspect is leaking. If bubbles start to appear, this indicates you have a gas leak, and it becomes essential to switch off your gas supply.
Fire Risk Assessment
Each building must legally appoint a responsible person per the Regulatory Reform (Fire Safety) Order 2005. This responsible person has the legal duty to protect occupants and property from the fire threat.
The order highlights the responsibility of conducting and regularly updating fire risk assessments, reducing fire risk, and installing fire safety equipment such as fire alarms, doors, and extinguishers.
Most commercial and residential properties should receive a fire risk assessment every six months to ensure that the fire safety equipment is appropriately installed and in good working condition. This will protect the occupants and the building from the detrimental effects a Class C fire can cause.
How to Tackle a Class C Fire
If a fire outbreak occurs, you should turn off the gas supply if possible to reduce the risk of explosions. Only dry powder fire extinguishers can safely extinguish Class C fires. Using a different type of extinguisher, such as carbon dioxide or wet chemical extinguishers, is hazardous for flammable gas fires.
Dry powder fire extinguishers cool the flames until there is no longer enough heat to keep them burning. The dry powder within the extinguisher acts as a suppressing agent, smothering the oxygen within the fire and stopping embers from spreading.
Gas Fire Hazards FAQs
What category of fire does flammable gas come under?
Fires involving flammable gases are classified as Class C fires. Flammable gases form an explosive mixture when mixed with air, leading to a fire hazard.
What is the difference between a Class B and Class C fire?
Both Class B and C fires are hazardous, but they originate from different sources. Class B fires burn flammable liquids such as alcohol, oil, and petrol. These liquids have lower ignition temperatures than others, meaning once they are heated to extreme temperatures, you are at risk of a fire outbreak. On the other hand, Class C fires burn flammable gases, including propane, butane, and methane. If ignited, these gases are extremely dangerous and highly explosive.
Can I use water to extinguish a Class C gas fire?
Avoid using water on a Class C gas fire, as it will simply cause the fire to spread further. Use a Class C-rated fire extinguisher, known as a dry powder extinguisher.
Manage Class C Fire Hazards with Fire & Safety Centre
Class C fires can be easily prevented with the correct handling and storage procedures. With adequate storage and handling training, the risk of a Class C fire outbreak can be significantly reduced. At Fire and Safety Centre, fire prevention is at the heart of our business. We are dedicated to helping you store and appropriately manage your flammable gases securely.
Dive into our product range, which includes dry powder extinguishers and gas storage cabinets. It enables you to safely manage and handle Class C fire hazards. Contact our team today to discuss your fire safety requirements.