Table of Contents
Key Takeaways
Aspect | Description |
---|---|
Functionality | Foam fire extinguishers work by creating a foam blanket that cools the fire and smothers it by blocking oxygen. |
Suitable Fires | Effective for Class A (solid combustibles like wood, paper) and Class B (flammable liquids like petrol) fires. |
Unsuitable Fires | Not suitable for Class F fires (cooking oils) or fires involving electrical equipment unless certified. |
Components | Includes a canister with foam solution, hose, nozzle, and pressure gauge. |
Usage Process | Remove the safety pin, aim at the base of flames, squeeze the handle, and sweep side to side. |
Advantages | Non-toxic, versatile, and creates a barrier to prevent re-ignition. |
Limitations | Not effective on flammable gases or electrical fires (unless certified); more involved cleanup compared to other extinguishers. |
Applications | Suitable for offices, warehouses, factories, garages, and hotels, particularly where Class A and B fire risks are present. |
Foam fire extinguishers are essential safety tools, specifically designed to tackle a range of fires, primarily involving flammable liquids and solids.
Typically distinguishable by their cream label, these extinguishers are versatile and form a critical part of fire safety in various environments such as offices, schools, and hospitals.
When a fire breaks out, the foam produced by these extinguishers blankets the flames, excluding oxygen and effectively preventing the fire from spreading further.
The composition of the foam in these extinguishers allows for a dual-action approach in fire suppression. It not only smothers the fire but also creates a cooling effect on the fuel.
It’s important to recognize when and how to use a foam fire extinguisher to ensure that it is deployed effectively.
Familiarising yourself with the operational procedures, regular maintenance routines and the correct application can greatly influence the outcome of a fire-related emergency.
Understanding Foam Fire Extinguishers
Foam fire extinguishers are an essential tool for tackling certain types of fires, providing a safety solution that is both effective and versatile. Here, you’ll gain an understanding of the components that make up these extinguishers and the specific fire classes they’re suited to combat.
Composition and Types
Foam extinguishers, also known as aqueous film forming foam (AFFF) extinguishers, utilise a foaming agent that expands when expelled from the extinguisher. This creates a blanket that cools the fire and coats the fuel, effectively separating it from the oxygen it needs to continue burning.
There are primarily two types you might encounter:
- AFFF (Aqueous Film Forming Foam): Creates a film that seals the surface of the liquid to prevent flammable vapours from reaching the air.
- FFFP (Film-Forming Fluoroprotein): Contains naturally occurring proteins that provide a thicker foam blanket with a higher resistance to heat.
Classes of Fires and Suitability
Understanding the classifications of fires is crucial when selecting a foam fire extinguisher. Here are the classes of fires foam extinguishers are designed to address:
- Class A: Suitable for fires involving solid combustibles such as paper, wood, and textiles.
- Class B: These extinguishers are also effective against fires involving flammable liquids like petrol and paints.
However, foam extinguishers should not be used on Class F fires (cooking oils and fats) or fires involving electrical equipment unless they have passed a 35kV conductivity test. It is essential to check the specific product information to ensure safety and effectiveness for the intended use.
Working Principle of Foam Extinguishers
Foam fire extinguishers are an effective solution for tackling certain types of fires, primarily because of their ability to create a smothering and cooling effect that can quickly suppress flames. They work by forming a barrier that helps to prevent re-ignition.
Smothering and Cooling Effects
When you deploy a foam fire extinguisher, it releases a foam solution that expands upon contact with air. This foam is primarily water-based, which allows it to have a cooling effect on the fire.
The water in the foam cools the fuel, reducing its temperature below the ignition point. Moreover, the smothering aspect of the foam suffocates the fire by blocking oxygen, further inhibiting the chemical reaction that sustains the fire.
Creating a Barrier Against Re-Ignition
Upon application, the foam forms a blanket over the burning material. This barrier is crucial in sealing off the fuel from the surrounding oxygen, effectively cutting off the fire’s air supply.
Additionally, the foam layer acts as a deterrent against re-ignition, as it prevents flammable vapours from escaping and creating new points of flame, ensuring you have a better chance at completely extinguishing the fire.
Steps for Using a Foam Fire Extinguisher
This section provides a structured approach to safely and effectively operate a foam fire extinguisher in an emergency.
Safety Precautions
Before attempting to tackle a fire, ensure that the area is safe to enter, and you have a clear escape route. Always stand with the wind at your back to avoid inhaling fumes or having the fire spread towards you.
- Inspect the Extinguisher: Verify that it is fully charged, the safety pin is intact, and the tamper seal is unbroken.
- Secure the Area: Make sure bystanders are at a safe distance and there is a clear path for evacuation if needed.
Operation Procedure
Acting swiftly and efficiently during a fire breakout is critical. Follow these steps to use a foam fire extinguisher:
- Position the Extinguisher: Place the extinguisher on the ground a safe distance from the fire.
- Remove the Safety Pin: Withdraw the safety pin to unlock the mechanism, breaking the tamper seal.
- Aim the Hose: Direct the hose toward the base of the fire, not the flames, to target the fuel source.
- Squeeze the Handle: Discharge the foam by squeezing the handle, which will release the extinguishing agent.
- Sweep Side to Side: Use a sweeping motion across the area of the fire until it is fully extinguished.
Remember, if the fire does not begin to die down immediately, evacuate the area and call the fire brigade. Your safety is the number one priority.
Applications of Foam Extinguishers
Foam fire extinguishers are versatile and effective for tackling various types of fires, particularly where quick suppression is essential. They’re suited to environments with a mix of fire hazards.
Suitable Locations
Warehouses and Factories: Your workspace might be varied, with risks from both combustible materials and flammable liquids. Foam extinguishers are ideal here due to their effectiveness on Class A (solid combustibles) and Class B(flammable liquids) fires.
Garages and Hotels: In areas like garages, where petrol or diesel might spill, or in hotels, where a fire could rapidly escalate, having foam extinguishers is prudent. They create a barrier against oxygen, helping to prevent re-ignition.
Office Buildings: Given that offices often contain a large amount of flammable material like paper and electrical equipment, foam extinguishers can cover both bases – they can safely extinguish fires with a reduced risk of harm to electrical appliances (Note: always ensure the extinguisher is certified for electrical fire safety and has passed the 35kV conductivity test).
Inappropriate Use Cases
Electrical Equipment and Electrical Fires: While foam extinguishers can be safe to use on electrical fires under certain conditions, it’s crucial that your extinguisher is specifically rated for this purpose. Not all foam extinguishers are designed to handle electrical risks, and using an uncertified extinguisher on electrical fires can be dangerous.
Deep Fat Fryers: Kitchens, especially those with deep fat fryers, are not suitable for foam extinguishers. The discharge could spread the fire or hot oil, creating a serious hazard. You would require a wet chemical extinguisher for these environments instead.
Advantages and Limitations
When considering the use of a foam fire extinguisher, it’s essential to understand both the benefits it provides and the limitations you may encounter. Here’s a breakdown to help guide your choices.
Benefits
Foam fire extinguishers are known for their versatility and effectiveness, especially when tackling fires involving flammable liquids and solids. They provide a barrier between the fuel and the oxygen, suppressing the fire:
- Non-toxic: Generally safe for use in varied situations without the risk of toxic repercussions.
- Versatile: Can be employed on diverse types of fires including Class A (flammable solids) and Class B (flammable liquids).
Relying on foam extinguishers means you benefit from a tool that is less destructive than powder extinguishers, which can leave behind a residue that could damage sensitive equipment. They are often compared favourably to water extinguishers due to their improved cooling properties, which can swiftly lower temperatures and prevent re-ignition. Their adaptability makes them an asset in environments where multiple types of fire risks are present.
Considerations
However, foam extinguishers are not without their limitations and might not always be the most suitable choice:
- Flammable gases: Not effective on fires involving flammable gases (Class C) such as propane or butane.
- Electrical fires: Their use on electrical fires is limited; CO2 fire extinguishers might be better suited for electrical risks.
- Cleanup: Cleanup can be more involved compared to CO2 or powder extinguishers.
- Freezing temperatures: The water content can freeze, so they’re not recommended for use in environments susceptible to freezing conditions.
Maintenance and Inspection
Regular maintenance and inspection are essential to ensure that your foam fire extinguisher is operational and effective when needed. Pay attention to components like the tamper seal and pressure gauge to help safeguard against fire risks.
Routine Checks
You should perform routine checks on your foam fire extinguisher monthly. Ensure that the tamper seal is intact and that the safety pin is not missing or damaged.
The pressure gauge should point to the green zone, indicating the extinguisher is properly pressurised.
You are responsible for regularly verifying the extinguisher’s accessibility, ensuring it’s not obstructed, and checking for any signs of wear or corrosion.
- Checking the Tamper Seal: Look for any signs of tampering or damage.
- Inspecting the Safety Pin: Confirm it is securely in place and not bent or broken.
- Gauge Inspection: The needle should be within the operational range, often marked in green.
- Physical Inspection: Examine the extinguisher for any visible defects or signs of leakage.
Professional Assessments
At least annually, your foam fire extinguisher needs a professional assessment by a certified engineer.
During this comprehensive assessment, engineers carry out physical inspections and more detailed checks. They may perform a discharge test to ensure that the extinguisher functions correctly and recharge it if necessary.
An engineer will also:
- Verify the correct operation of the lever.
- Replace any parts, including the tamper seal or safety pin, if required.
- Confirm that the device is compliant with fire safety regulations.
Regulatory Standards and Compliance
When you select a foam fire extinguisher, it’s crucial to comply with regulatory standards and manufacturer’s guidelines to ensure safety and effectiveness.
UK Regulations
In the UK, foam fire extinguishers are subject to specific regulatory requirements that dictate their use, servicing, and maintenance.
A 35kv conductivity test must be passed to guarantee their safety when tackling fires in the presence of live electrical equipment.
Fire extinguisher sizes are governed by British Standards, and you need to have a minimum of two ‘Class A’ foam extinguishers on every storey of your building. These extinguishers come with a cream-coloured label, making them easily identifiable.
Manufacturer’s Guidelines
Following the manufacturer’s guidelines is imperative to ensure that your range of foam fire extinguishers is used correctly and maintained to the highest standards.
Guidelines typically include advice on:
- Installation: Where and how extinguishers should be installed.
- Maintenance: Frequency and methods for checks and servicing.
- Operation: Instructions on how to use the extinguisher properly in case of a fire.
Frequently Asked Questions
When considering the use of a foam fire extinguisher, pertinent questions about its applications, operation, limitations, contents, and environmental impact often arise. Below you’ll find targeted information addressing these common inquiries.
What types of fires is a foam fire extinguisher suitable for?
Foam fire extinguishers are adept at tackling class A fires involving solid combustibles like wood, paper, and textiles, as well as class B fires caused by flammable liquids such as petrol, diesel, and paint.
How is a foam fire extinguisher operated effectively?
To use a foam fire extinguisher properly, ensure you remove the safety pin, aim the nozzle at the base of the fire, squeeze the handle to release the foam, and sweep the nozzle side to side over the fire area. The technique optimises the extinguishing agent’s effectiveness by covering the fire comprehensively.
What are the limitations of using a foam fire extinguisher?
Foam extinguishers are not suitable for kitchen fires involving cooking oils, electrical fires, or fires involving reactive metals. Misuse on these types of fires can worsen the situation or pose safety risks to the operator.
What substances are contained within a foam fire extinguisher?
Foam extinguishers typically consist of water and a foaming agent. This mixture, once deployed, expands to form a film that smothers the fire and prevents re-ignition.
Why might a foam fire extinguisher be unsuitable for electrical fires?
Foam extinguishers conduct electricity due to their water content and should therefore not be used on electrical fires or equipment. Doing so poses a high risk of electric shock to the user.
What are the environmental implications of using foam fire extinguishers?
Environmental considerations include the potential for foam extinguishers to contain substances harmful to the ecosystem.
Current guidelines restrict chemicals like PFOS due to their persistence in the environment and toxicity.