Difference Between AFFF and FFFP Foam

Aqueous Film-Forming Foam (AFFF) and Film-Forming Fluoroprotein Foam (FFFP) are two specialized Class B firefighting foams designed to combat flammable liquid fires, such as those involving hydrocarbons like gasoline, diesel, and jet fuel. While both share the ability to form a protective film on fuel surfaces, their chemical compositions, performance characteristics, and applications differ significantly.

1. Chemical Composition

AFFF is a synthetic foam concentrate formulated with a blend of fluorinated surfactants, hydrocarbon surfactants, solvents, and stabilizers. The fluorinated surfactants, historically derived from perfluorooctanesulfonic acid (PFOS) or perfluorooctanoic acid (PFOA), are the key to AFFF's effectiveness. These compounds reduce the surface tension of water to as low as 15–20 mN/m, enabling the foam solution to spread rapidly across hydrocarbon surfaces and form a thin, continuous aqueous film. Modern AFFF formulations increasingly use short-chain fluorotelomers or fluorine-free alternatives to mitigate environmental concerns.

FFFP, on the other hand, is a hybrid foam that combines the properties of fluoroprotein foam with advanced fluorochemical surfactants similar to those in AFFF. Fluoroprotein foam is derived from hydrolyzed protein material (e.g., animal hooves and horns), with stabilizers and inhibitors added to prevent corrosion and bacterial decomposition. FFFP enhances this base by incorporating fluorinated surfactants, which improve its fluidity and extinguishing power while retaining the burnback resistance of traditional fluoroprotein foam.

2. Performance Characteristics

Knockdown Power:
AFFF excels in rapid fire suppression due to its low surface tension, which allows it to spread quickly and form an aqueous film that cuts off oxygen supply. This makes it ideal for spills of jet fuels or other low-viscosity hydrocarbons. FFFP, while also effective, has a slightly slower knockdown speed compared to AFFF but offers better performance on burning fuels that form deeper pools, such as crude oil or heavy hydrocarbons.

Burnback Resistance:
FFFP demonstrates superior burnback resistance, meaning it can withstand direct flame exposure for longer periods without breaking down. This is attributed to the protein-based structure of its base foam, which provides greater thermal stability. AFFF, while effective at initial suppression, is more susceptible to burnback due to its thinner aqueous film and lower heat resistance.

Foam Stability and Drainage Time:
FFFP generally exhibits longer foam stability and drainage times compared to AFFF. The protein component in FFFP creates a more resilient foam blanket that resists premature collapse, making it suitable for prolonged firefighting operations. AFFF, while effective for short-term suppression, may require reapplication in scenarios where the fire persists or reignites.

3. Applications and Suitability

AFFF is widely used in industries and settings where rapid fire suppression is critical, such as:

Aviation: Protecting aircraft hangars and fuel storage areas from jet fuel fires.
Petrochemical Plants: Controlling spills and fires involving gasoline, diesel, and other volatile hydrocarbons.
Military Installations: Extinguishing high-hazard flammable liquid fires in training facilities and operational zones.

FFFP is preferred in scenarios where burnback resistance and foam stability are paramount, such as:

Oil Refineries: Managing fires involving crude oil or heavy hydrocarbons that form deep pools.
Marine Applications: Combating fires on ships or offshore platforms where prolonged foam application is necessary.
Industrial Storage Facilities: Protecting large fuel storage tanks where the risk of re-ignition is high.