Unveiling the Chemistry: What is Fire fighting Foam Made Of?

Firefighting foam, also known as fire foam or fire suppression foam, is a specialized substance designed to control, suppress, and extinguish flammable liquid fires. But what is fire fighting foam made of? This article will explain the composition of firefighting foam, highlighting the key components that contribute to its effectiveness in tackling various types of fires.

Firefighting foam is typically composed of water, foam concentrate, and air. The foam concentrate is a crucial component and contains various chemicals that contribute to the foam’s ability to suppress fires involving flammable liquids. 

The main types of firefighting foam are classified as AFFF (Aqueous Film-Forming Foam), AR-AFFF (Alcohol-Resistant Aqueous Film-Forming Foam), and Class B foams. 

What Is Fire Fighting Foam Made Of? 7 Major Ingredients

What Is Fire Fighting Foam Made Of

The specific formulation may vary, but common ingredients include water, surfactants, hydrocarbon-based solvents, stabilizers, and other additives.

  1. Water: The base of firefighting foam is water, which is a primary fire-suppressant. Water helps cool the fire and prevent re-ignition.
  2. Foam Concentrate: This is the key ingredient that gives the foam its firefighting properties. Foam concentrates contain surfactants that reduce the surface tension of water, allowing it to spread more easily over the burning liquid. They also contain stabilizers to improve the foam’s longevity and other additives to enhance performance.
  3. Surfactants: These are surface-active agents that help in the formation of a stable foam blanket on the surface of flammable liquids. Surfactants reduce the water’s surface tension, allowing it to form a protective film that smothers the fire.
  4. Hydrocarbon-Based Solvents: Some foams include hydrocarbon-based solvents to improve their effectiveness on fires involving hydrophobic (water-repellent) fuels, such as oil and gasoline.
  5. Stabilizers: Stabilizers are added to increase the foam’s resistance to environmental factors, such as temperature changes and wind.
  6. Additives: Depending on the specific requirements, firefighting foams may contain additional additives to enhance performance, such as corrosion inhibitors or antifreeze agents in cold climates.

It’s important to note that the composition of firefighting foam can vary based on the type of foam and its intended application. 

Environmental considerations and regulations have led to the development of more environmentally friendly foams that aim to minimize the impact on ecosystems while maintaining effective fire suppression capabilities.

Basics of Firefighting Foam

Firefighting foam is a specialized substance used to suppress and extinguish fires involving flammable liquids. It is formulated to create a stable blanket on the surface of the burning liquid, preventing the release of flammable vapors and cooling the fire. The primary purpose of firefighting foam is to smother the flames and prevent re-ignition.

The main purposes of using firefighting foam include:

  1. Suppression of Flammable Liquid Fires: Foam is particularly effective in tackling fires fueled by hydrocarbons like oil, gasoline, and other combustible liquids.
  2. Vapor Suppression: Foam helps to suppress the release of flammable vapors from the liquid surface, reducing the risk of explosive ignition.
  3. 3. Cooling: The water content in the foam aids in cooling the fire, lowering the temperature and mitigating the risk of reignition.
  4. Prevention of Fire Spread: The foam forms a protective barrier, preventing the spread of the fire to adjacent areas.
  5. Enhanced Penetration: Foam can penetrate and reach concealed fires in materials that may be difficult for water to penetrate alone.

Types of Firefighting Foam

Types of Firefighting Foam

  1. Aqueous Film-Forming Foam (AFFF):
  • AFFF is a commonly used foam that contains water, fluorosurfactants, and hydrocarbon-based solvents.
  • It forms a thin, protective film on the liquid surface, suppressing vapors and smothering the fire.
  1. Alcohol-Resistant Aqueous Film-Forming Foam (AR-AFFF):
  • AR-AFFF is designed to combat fires involving polar solvents, such as alcohols and ketones.
  • It contains additives that resist the disruptive effects of polar solvents on the foam’s stability.
  1. Protein Foam:
  • Protein-based foams are derived from animal proteins and are effective on hydrocarbon-based fires.
  • They create a stable foam blanket that covers the burning liquid and prevents reignition.
  1. Synthetic Foam:
  • Synthetic foams are formulated using synthetic surfactants and are versatile in their application.
  • They can be used on both hydrocarbon and polar solvent fires.
  1. 5. High-Expansion Foam:
  • High-expansion foams are used in confined spaces, generating large volumes of foam to fill areas and displace oxygen, suppressing the fire.
  1. Film-Forming Fluoroprotein (FFFP):
  • FFFP foam combines fluorosurfactants with protein foam, offering a balance between hydrocarbon and polar solvent fire suppression capabilities.

Knowingthe different types of firefighting foam allows emergency responders to select the most appropriate foam based on the specific characteristics of the fire and the type of flammable liquid involved.

Chemical Components

A. Surfactants:

Surfactants, or surface-active agents, play a critical role in firefighting foam by reducing the surface tension of water. Surface tension is the force that tends to minimize the surface area of a liquid, causing it to bead up. 

In the context of firefighting, high surface tension can prevent water from spreading across the surface of flammable liquids effectively. Surfactants break down this tension, allowing the foam to form a cohesive and stable blanket on the burning liquid. This film helps to suppress vapors and smother the fire.

Examples of surfactants used in firefighting foam include fluorosurfactants in Aqueous Film-Forming Foam (AFFF). These fluorinated compounds are effective at reducing surface tension and enhancing the foam’s ability to cover the liquid surface. 

Variations of surfactants exist to address specific applications, such as those designed for alcohol-resistant foams (AR-AFFF) to combat fires involving polar solvents.

B. Solvents:

Solvents are essential components of firefighting foam, especially in the context of flammable liquid fires. Hydrocarbon-based solvents are commonly used to improve the foam’s effectiveness on hydrophobic fuels, like oil and gasoline. 

These solvents help the foam to spread more evenly over the liquid surface, ensuring efficient coverage and extinguishing the fire by creating a barrier that blocks oxygen and suppresses vapor release.

Commonly used solvents in firefighting foam include hydrocarbon-based compounds such as heptane or isooctane. These solvents are chosen for their ability to mix with water and foam concentrate, facilitating the formation of a stable foam blanket on the burning liquid.

C. Additives:

  1. Stabilizers:

Stabilizers are additives included in firefighting foam formulations to enhance the foam’s resistance to environmental factors. 

These factors can include temperature changes, wind, and other conditions that may affect the foam’s stability over time. Stabilizers contribute to the longevity of the foam, ensuring its effectiveness in suppressing fires for an extended duration.

  1. Thickening Agents:

Thickening agents may be added to firefighting foam to increase its viscosity and improve adherence to vertical surfaces. This can be particularly useful in situations where the foam needs to cling to surfaces for an extended period, such as when dealing with storage tank fires. 

The thickening agents contribute to the overall effectiveness of the foam in creating a durable and persistent barrier on the burning liquid.

Class A Foam Composition

Class A Foam Composition

1. Water as the Primary Component:

Class A firefighting foam is specifically designed for combating fires involving ordinary combustibles, such as wood, paper, and vegetation. The primary component of Class A foam is water. Unlike foams designed for flammable liquid fires, Class A foam does not rely on the creation of a stable foam blanket.

 Instead, it enhances the water’s firefighting capabilities. The water in Class A foam serves to cool the burning material, reduce the fire’s intensity, and prevent re-ignition.

2. Humectants and Wetting Agents:

To improve the water’s effectiveness in penetrating and wetting Class A materials, humectants and wetting agents are often added to the foam formulation. These substances enhance the water’s ability to soak into porous materials like wood and help break down the surface tension of water, allowing it to spread more easily. 

Humectants retain moisture in the treated materials, prolonging the firefighting effect and reducing the chances of rekindling. Wetting agents, on the other hand, facilitate better water penetration into the fuel, making it more effective in extinguishing the fire.

3. Corrosion Inhibitors:

Corrosion inhibitors may be included in Class A foam formulations to protect firefighting equipment, especially metal components in pumps and hoses, from corrosive effects. These inhibitors help prevent the formation of rust and corrosion that could compromise the functionality of firefighting apparatus over time. 

It contribute to the longevity and reliability of firefighting equipment, ensuring it remains in good working condition for future firefighting operations.

Generally,  Class A foam is tailored for fires involving ordinary combustibles, and its composition focuses on optimizing water’s firefighting properties. Humectants and wetting agents enhance water penetration and wetting, while corrosion inhibitors help protect firefighting equipment during and after firefighting operations.

Class B Foam Composition

Class B Foam Composition

Hydrocarbon-Based Components:

Class B firefighting foam is specifically formulated to combat fires involving flammable liquids, such as oil, gasoline, and petroleum-based substances. The foam concentrate for Class B foam contains hydrocarbon-based components, often in the form of solvents. 

These hydrocarbons serve several crucial purposes in the foam formulation. They aid in the creation of a stable foam blanket on the liquid surface, preventing the release of flammable vapors and smothering the fire. 

The hydrocarbon-based components also facilitate the mixing of the foam concentrate with water to form an effective firefighting foam.

 Fluorosurfactants and Fluoropolymers:

Class B foam formulations commonly include fluorosurfactants and fluoropolymers. These specialized chemicals contribute to the foam’s ability to spread rapidly across the surface of flammable liquids. Fluorosurfactants reduce the surface tension of water, enabling it to form a thin, uniform film on the liquid. 

This film suppresses vapors, prevents re-ignition, and enhances the foam’s overall effectiveness in extinguishing the fire. Fluoropolymers, which are long-chain molecules, further stabilize the foam, providing durability and maintaining its integrity on the liquid surface.

Vapor Suppression Agents:

In addition to fluorosurfactants, Class B foam formulations may include vapor suppression agents. These agents work to minimize the release of flammable vapors from the liquid fuel, reducing the risk of explosive ignition. 

Vapor suppression is a critical aspect of Class B foam’s functionality, as it helps create a safer environment for firefighting personnel and prevents the escalation of the fire.

So, Class B foam is designed for flammable liquid fires and its composition includes hydrocarbon-based components for foam stability, fluorosurfactants and fluoropolymers for rapid spreading and stability, and vapor suppression agents to minimize the release of flammable vapors. 

This combination of ingredients makes Class B foam an effective tool in suppressing fires involving a wide range of flammable liquids.

Environmental Considerations

The biodegradability of firefighting foam is a crucial factor in assessing its environmental impact. Traditional firefighting foams, especially those containing fluorinated compounds, have raised concerns due to their persistence in the environment and potential adverse effects on ecosystems.

 Biodegradability refers to the ability of a substance to be broken down by natural processes into harmless components. In the context of firefighting foam, biodegradability is desirable to minimize the long-term environmental impact.

Some newer formulations of firefighting foam are designed with improved biodegradability. Manufacturers are developing foams that break down more readily in the environment, reducing the risk of long-term contamination of soil and water sources. 

These environmentally conscious formulations aim to strike a balance between effective firefighting capabilities and reduced ecological impact.

 Eco-Friendly Alternatives:

In response to environmental concerns, efforts are underway to develop and adopt eco-friendly alternatives to traditional firefighting foam. 

These alternatives focus on using ingredients that are less harmful to the environment without compromising firefighting effectiveness. Some key developments include:

  1. Fluorine-Free Foams: These foams are formulated without the use of fluorinated compounds, addressing concerns about the persistence and potential toxicity of these substances in the environment. Fluorine-free foams aim to provide effective firefighting capabilities while minimizing environmental impact.
  2. Protein-Based Foams: Protein-based foams, derived from natural sources such as animal proteins, are considered more environmentally friendly than some synthetic counterparts. They offer effective fire suppression for certain applications while having a reduced ecological footprint.
  3. Bio-Based Surfactants: The use of bio-based surfactants in foam formulations is another approach to enhance environmental compatibility. These surfactants are derived from renewable resources and can contribute to the biodegradability of the foam.
  4. Water Additives: Some firefighting strategies focus on using water alone or water with additives like wetting agents for certain fire scenarios. While not a foam per se, these approaches minimize the introduction of synthetic chemicals into the environment.

As environmental awareness grows, there is increasing emphasis on developing and adopting firefighting foam alternatives that align with sustainability goals. Firefighting agencies and industries are working to transition towards more eco-friendly practices to mitigate the environmental impact of firefighting activities.

Real-world Applications

Firefighting Foam Usage in Various Industries:

  1. Aviation Industry:
  • Airports and aviation facilities use firefighting foam to respond to aircraft emergencies. Foam is applied to suppress fires involving aviation fuel and to create a protective barrier during rescue operations.
  1. Oil and Petrochemical Industry:
  • Refineries, oil storage facilities, and petrochemical plants often face the risk of flammable liquid fires. Firefighting foam is extensively used to combat fires involving crude oil, gasoline, and other hydrocarbons.
  1. Marine and Shipping Industry:
  • Shipboard firefighting involves the use of foam to control fires in engine rooms, fuel storage areas, and cargo spaces. The maritime industry relies on foam to address fires fueled by diesel, oil, or other flammable liquids.
  1. Industrial Manufacturing Facilities:
  • Various manufacturing industries, such as chemical and pharmaceutical, use firefighting foam to address the risk of fires associated with the production and storage of flammable materials.
  1. Warehousing and Storage Facilities:
  • Large storage facilities, including warehouses and distribution centers, employ firefighting foam systems to protect valuable inventory from fire. Foam is effective in suppressing fires involving stored goods and materials.
  1. Military and Defense:
  • Military installations utilize firefighting foam for aircraft crash response, fuel depot protection, and other scenarios involving flammable liquids. The military often employs specialized foams tailored to their unique requirements.

Success Stories and Case Studies

  1. Buncefield Oil Depot Fire (2005):
  • The Buncefield oil depot fire in the UK is an example of a large-scale incident where firefighting foam played a crucial role. The fire, caused by a massive fuel tank explosion, was successfully controlled using foam to prevent the spread of the fire and mitigate environmental impact.
  1. Singapore Chemical Plant Fire (2012):
  • In 2012, a major fire broke out at a petrochemical plant in Singapore. Firefighting foam was instrumental in containing the fire, preventing it from spreading to nearby facilities and minimizing the impact on the surrounding environment.
  1. Aviation Incidents:
  • Numerous aviation incidents, both civilian and military, highlight the successful use of firefighting foam. Foam has been employed to manage emergencies ranging from aircraft crashes to fuel leaks, protecting lives and minimizing property damage.
  1. Industrial Plant Fires:
  • Various industrial plant fires worldwide have been successfully managed using firefighting foam. These cases underscore the importance of foam in preventing the escalation of fires in facilities dealing with flammable materials.

Success stories and case studies demonstrate the effectiveness of firefighting foam in diverse scenarios. 

These incidents highlight the importance of proper foam application, training, and equipment in ensuring successful fire suppression and mitigating the impact of emergencies in different industries.

Regulations and Compliance

Firefighting foam and its usage are subject to various international standards that provide guidelines for formulation, testing, and application. Some of the key international standards related to firefighting foam include:

NFPA 11 (National Fire Protection Association):

  • NFPA 11 provides standards for low-, medium-, and high-expansion foam systems. It covers the design, installation, operation, testing, and maintenance of foam systems used for fire protection in various industries.

NFPA 16:

  • NFPA 16 addresses the installation of foam-water sprinkler and spray systems, outlining the requirements for system components, water supplies, and acceptance testing.

EN 1568 (European Standard):

  • EN 1568 specifies requirements and test methods for foam concentrates used in firefighting. It includes classifications based on performance in different applications and fuel types.

ICAO (International Civil Aviation Organization):

  • ICAO provides guidelines for aircraft rescue and firefighting (ARFF), including the use of firefighting foam at airports. It sets standards for foam application rates and response times during aircraft emergencies.

IMO (International Maritime Organization):

  • The IMO regulates the use of firefighting foam on ships and in port facilities. Guidelines include requirements for foam systems on vessels and recommendations for dealing with flammable liquid fires.

Compliance with Environmental Regulations

Compliance with Environmental Regulations

The environmental impact of firefighting foam, particularly those containing fluorinated compounds, has led to increased scrutiny and the development of regulations to mitigate potential harm. Key considerations include:

  1. REACH (Registration, Evaluation, Authorization, and Restriction of Chemicals):
  • REACH is a European Union regulation that addresses the production and use of chemical substances. Manufacturers and importers must comply with REACH requirements, including the registration of substances, to ensure their safe use.
  1. EPA (Environmental Protection Agency) Regulations (U.S.):
  • The EPA regulates the use of firefighting foam through various programs, including the Clean Water Act and the Resource Conservation and Recovery Act. Efforts are underway to restrict or phase out certain types of fluorinated foam due to environmental concerns.
  1. Local Environmental Regulations:
  • Many countries and regions have enacted or are considering regulations specific to firefighting foam to address environmental issues. These regulations may restrict the use of certain foam formulations or mandate the use of environmentally friendly alternatives.
  1. Montreal Protocol:
  • The Montreal Protocol aims to protect the ozone layer by phasing out the production and consumption of ozone-depleting substances. Some older formulations of firefighting foam containing ozone-depleting chemicals have been subject to restrictions under this protocol.

Compliance with these regulations is essential for industries and firefighting agencies to minimize environmental impact and ensure the safe and responsible use of firefighting foam. 

The development of environmentally friendly alternatives and the ongoing review and adaptation of regulations contribute to sustainable firefighting practices.

Frequently Asked Questions

What chemical is in firefighting foam?

Firefighting foams contain a variety of chemicals depending on their type. Common components include water, surfactants, solvents, stabilizers, and additives. Class B foams may contain hydrocarbon-based components, fluorosurfactants, and other specialized agents.

What are firefighting foams made of?

Firefighting foams are typically composed of water, foam concentrate (containing surfactants and other chemicals), and air. The specific formulation varies based on the type of foam and its intended application.

What is the mixture of firefighting foam?

The mixture of firefighting foam involves combining water with a foam concentrate. The foam concentrate contains various chemical components, such as surfactants and solvents, to enhance the foam’s fire-suppressing properties.

How do you make firefighting foam?

Firefighting foam is typically made by mixing water and a foam concentrate in specific proportions. The foam concentrate contains the necessary chemical components, such as surfactants and stabilizers, to create a stable and effective foam when mixed with water.

What is the main purpose of firefighting foam?

The main purpose of firefighting foam is to suppress and extinguish fires, especially those involving flammable liquids. Foam forms a blanket on the liquid surface, preventing the release of vapors, cooling the fire, and preventing re-ignition.

How does foam combat different types of fires?

A: Foam combats fires by forming a stable blanket on the liquid surface. For Class A fires, the foam enhances water’s firefighting capabilities. For Class B fires, the foam suppresses vapors, prevents ignition, and creates a barrier to smother the fire.

Are there different types of firefighting foam?

Yes, there are different types of firefighting foam designed for specific applications. Examples include Aqueous Film-Forming Foam (AFFF), Alcohol-Resistant Aqueous Film-Forming Foam (AR-AFFF), protein foam, synthetic foam, and high-expansion foam.

What are the key ingredients in Class A foam?

Class A foam primarily consists of water. Humectants and wetting agents are often added to improve water penetration into combustible materials, aiding in fire suppression.

Why are fluorosurfactants used in Class B foam?

Fluorosurfactants are used in Class B foam, such as AFFF, to reduce the surface tension of water. This allows the foam to spread more effectively on the liquid surface, forming a stable film that suppresses vapors and prevents re-ignition.

Is firefighting foam environmentally friendly?

Traditional firefighting foams, especially those with fluorinated compounds, have raised environmental concerns. Efforts are underway to develop environmentally friendly alternatives, and regulations are evolving to minimize the ecological impact of firefighting foam.

Are there any health concerns associated with firefighting foam exposure?

Some firefighting foams contain substances that, in high concentrations, may raise health concerns. Long-term exposure to certain chemicals, such as per- and polyfluoroalkyl substances (PFAS), has been associated with potential health risks. Proper training and adherence to safety guidelines are essential for minimizing exposure risks.

Conclusion

Firefighting foam is a specialized substance designed to combat fires involving flammable liquids. But what is fire fighting foam made of? The composition of firefighting foam varies based on its intended application and the type of fire it is meant to address. 

Common components include water, foam concentrate containing surfactants, solvents, stabilizers, and other additives. Class A foam primarily utilizes water with the addition of humectants and wetting agents, while Class B foam incorporates hydrocarbon-based components and fluorosurfactants for combating flammable liquid fires.