Using a Foam Fire Extinguisher

Using a Foam Fire Extinguisher

There are six unique types of fire extinguishers to suit various fire incidents. Each class and fire extinguisher are covered in detail as per Australian standards in a previous post. However, this guide touches on the workings of a foam fire extinguisher. 

Fires are highly unpredictable and can get out of control very quickly. Therefore, a portable fire extinguisher and other fire fighting safety equipment [i.e. fire hose reels, fire sprinklers & emergency lighting] are vital to take immediate action and keep it from spreading. 

Read on to learn more about a foam-type fire extinguisher, when to use it specifically,  how to manage a fire emergency with it effectively and ensure its fire safety maintenance.  

What Colour is a Foam Fire Extinguisher?

All fire extinguishers in Australia, no matter what type you find, are painted an easily identifiable ‘Signal Red’ colour. However, the foam fire extinguisher colour also includes a bright blue coloured band to distinguish their unique type for specific use. This prominent blue band is visible on the top half of the cylinder. 

In addition to the colour band, foam fire extinguishers have their type labelled in large font, with the cylinder size, usage instructions, and situations when they are suitable and effective. 

Foam fire extinguishers in Australia are available in two sizes including:

  • 9-litre portable fire extinguisher
  • 30-litre mobile fire extinguisher

9-Litre Portable Fire Extinguisher

These portable foam extinguisher models are hand-held cylinders made of stainless steel and weigh approximately 12 KG. They have a discharge time of around 30 seconds, making them ideal for small spaces.  

30-Litre Mobile Fire Extinguisher

Although the 30-litre foam extinguishers also consist of stainless steel, they are too large to handle, weighing approximately 78 KG, and come mounted on a trolley with solid rubber wheels for portability. These models also include a discharge hose to disperse foam at the desired area. 

What is a Foam Fire Extinguisher Used For?

Unfortunately, you cannot control all fires using a foam fire extinguisher. Knowing what circumstances they can handle will ensure you have the best safety equipment on-hand for each possible situation. 

The most common types of fires that call for foam extinguishers include ones in Class A and B. Class A fires will typically be from flammable carbon solid materials, such as plastic, paper, and wood items. Class B fires consist of flammable liquid materials, including paint and fuels.. 

In addition, there are a few select Class F fires where foam fire extinguishers are suitable and adequate to control flammable liquid fires and combustible solids.  

Typically, this type of extinguisher is common in locations like fuel stations, storage facilities, commercial buildings, and warehouses. Although a water fire extinguisher can also control fires in these areas, they are limited in the fires they can handle effectively. Alternatively,  ABE Dry Powder fire extinguishers can also tackle Class A and B fires.  

When NOT to use a Foam Fire Extinguisher?

You must not use a foam fire extinguisher on some sources, as the wrong type can have disastrous effects instead of controlling a fire. Therefore, Class C, D, E, and most Class F situations require an alternative extinguisher. 

Foam extinguisher types are ineffective for Class C fires, including flammable gases like butane, methane, and propane. Instead, a C rated chemical dry powder fire extinguisher is most effective in these combustible situations. 

Class D fires that include flammable metals are not suitable for foam extinguishers. These situations include materials such as magnesium, potassium, sodium, and titanium. Therefore, rather than a foam type, it is better to use a D rated powder fire extinguisher. 

Class E flammable situations involve electrical equipment, which foam fire extinguishers cannot control because of the water contents of the foaming agents. Instead, carbon dioxide extinguishers are best to tackle electrical fires. 

Although there are minimal Class F fires where a foam fire extinguisher will be suitable, you should generally avoid using them. It is especially crucial when involved with flammable liquids like cooking oils and fats. Instead, a wet chemical fire extinguisher is the best model to use in these situations. 

What Are the Different Foam Types of Extinguishers?

Foam extinguishers fall into two categories: synthetic and protein-based foam. Each type has its pros and cons, making them ideal for different situations. Australia offers seven various foam extinguishers within these two categories for complete coverage. 

Alcohol-Resistant Film-Forming Fluoroprotein (AR-FFFP)

This foam extinguisher model works well for Class A and B fire sources. It includes an alcohol-resistant solvent specific for fighting fires with alcohols, hydrocarbons, and polar solvents. It also offers a film to prevent volatile vapours from escaping. 

Fluoroprotein Foam (FP)

This protein-based foam is for Class B fire sources, including hydrocarbon substances like crude oils, gasoline, diesel, and aviation fuels. This extinguisher type is not for use on water-soluble sources. 

Alcohol-Resistant Fluoroprotein Foam (AR-FP)

Like other alcohol-resistant foam models, the AR-FP extinguishers are for Class B fires. However, they aren't suitable for ethanol-based solvent fires containing more than 10% ethanol. 

Regular Protein Foam (RP)

Regular Protein Foam extinguishers (RP) are only ideal for Class A fire sources. This model offers excellent burn-back resistance, is tolerant of heat and has great drainage properties. 

Film-Forming Fluoroprotein (FFFP)

These extinguishers combine protein foam with fluorochemical surfactants as an effective way to fight Class A and B fires. Its aqueous film helps blanket the source to prevent volatile vapours from escaping. 

Alcohol-Resistant Aqueous Film-Forming Foams (AR-AFFF) [Synthetic]

AFFF models use synthetic materials to fight Class B fires that contain combustible fuel sources. Its film-forming foam is a quick solution for large-scale hydrocarbon fires. 

Aqueous Film Forming Foam (AFFF) [Synthetic]

AFFF is a popular foam type of extinguisher. Its synthetic foam suppresses a Class B fire at its source, smothering it and blocking its fuel. However, it contains traces of water, making this type ineffective for grease and oil fires.

How Does a Foam Fire Extinguisher Work?

For a fire to exist and grow, it needs fuel, oxygen, and heat. All fire extinguisher models work on eliminating one or more of these elements to control and eliminate a fire. 

Therefore, foam fire extinguishers dispense foaming agents that remove oxygen from the fire and aid in preventing it from spreading. The thick foam coating covers the source of the fire, blocking the oxygen supply. 

With flammable liquid fires, a foam extinguisher not only takes away the oxygen but also drains the liquid and forms an aqueous film over the source. This thin film covers the fire and prevents fuel vapours from escaping and spreading further. 

In addition, the water content in foam extinguishants helps combat the heat that fires need to grow. It provides a cooling effect to manage and eliminate fires effectively.

Foam extinguishers also work on the basis of expansion. Aqueous foam fire extinguishers can be ideal for large areas due to their low expansion properties. In contrast, high-expansion foam extinguishers are better suited for enclosed spaces when you need to cover a fire quickly. Finding the best foam extinguisher for your situation will provide the safest fire control method. 

Cleaning Up After a Foam Fire Extinguisher

After using a foam fire extinguisher, proper clean-up is vital. Newer fluoride-free foam extinguisher models are safer than older generations with fluoride foam which can harm the environment when you discharge them. Older models, including fluorinated ones, can be carcinogenic, so personal protective equipment (PPE), like airtight goggles, gloves, and other gear, is critical to keep yourself safe. 

The best method of cleaning up foam residue is using paper towels to soak it up, then dispose of them in a plastic bag and a waste bin. Next, thoroughly wash away the residue, careful not to inhale any fumes, as they can cause throat irritation. 

Maintenance of Foam Fire Extinguishers

Following a proper 6-month maintenance schedule according to current regulations is critical to keep all fire extinguisher types in optimal condition. There should be a visible maintenance tag attached, and list the most recent inspection date on it. 

Discharge & Recharge: Foam extinguishers should go through discharge and recharge every 12 months, while hydrostatic testing should occur every five years. 

Storage: Always store a foam fire extinguisher in a location that allows easy access, is not subjected to freezing temperatures [as foam extinguishant may freeze in negative temperatures], or is in an area where fire risk is high. 

Disposal: Old extinguishers need to go through proper recycling disposal according to Australian regulations. Therefore, these items are not to be discarded as regular waste materials. 

Prioritise Fire Safety

Understanding fire safety procedures will help you use foam fire extinguishers correctly and efficiently in emergencies. These models are for Class A and B fire situations, with some limited Class F circumstances so knowing the type of fire is critical before using a foam fire extinguisher. 

Regular fire extinguisher testing, inspection and maintenance will keep all types of fire extinguishers operational and ready to use. In addition, having the proper fire safety and protection services in place is vital for the safety of people and property.