Key Recommendations for Choosing the Right Fluorine-Free Firefighting Foam

Always prioritize the most concentrated version possible (e.g., 0.5% or 1% instead of higher use percentages).

Key advantages:

• Significant reductions in logistics, storage, and packaging costs.
• Lower discharges and reduced environmental impact — anticorrosive or antifreeze additives remain the same regardless of concentration.

Success factor: Ensure precise proportioning at all times, regardless of the system (venturi eductors, electronic proportioners, hydraulic systems, bladder tanks, etc.).

Select fluorine-free foams with a broad effective range for maximum versatility and safety.

• Below nominal concentration (e.g., 0.7% in a 1% product): Reduces expansion and effective application rate (less surfactant). May delay fire control and complicate extinguishment on hydrocarbon fires.
• Above nominal (e.g., 1.4% in a 1% product): Accelerates initial knockdown but introduces excess hydrocarbon surfactant, increasing foam contamination and potentially delaying or preventing complete extinguishment.

A correctly proportioned PFAS-free foam extinguishes fires only when applied above the critical rate for each fuel (e.g., 3 L/min·m² for gasoline). Below this threshold, extinguishment fails regardless of foam quality.

Recommendation: Choose the fluorine-free concentrate with the lowest minimum application rate on your target fuels. For SFFF foams, specific fire tests with each fuel type are essential — performance variations can be significant even between seemingly similar fuels.

Do not confuse freezing point with minimum operating temperature. The decisive factor is the concentrate’s viscosity at low temperatures: it must allow correct, fluid proportioning.

Two critical aspects:

• Aspirated vs. non-aspirated: In fluorine-free foams, foam quality is paramount (no aqueous film-forming or vapor suppression). Aspirated systems demand high-quality foam blankets.
• Expansion ratio: Low, medium, or high, depending on equipment (nozzles, monitors, sprinklers).

In fluorine-free concentrates:

• Expansion and drainage time vary significantly between fresh water and seawater.
• Hydrocarbon contamination is typically more pronounced with seawater.

In addition to the above, polymers provide specific benefits for polar solvent fires (alcohols, ketones, etc.). They form a polymeric barrier that shields the foam blanket from the fuel, enabling coverage and extinguishment.

Key considerations:

• Gel formation speed, alcohol impermeability, and reignition resistance.
• These vary by fuel type and, in some cases, water quality.
• Higher polymer content = higher viscosity → greater proportioning challenges.

We differentiate two types:

1. Fully Hydrated Polymers:
   • Any water dilution reduces viscosity (never gels).
   • Maximum pseudoplastic coefficient: very low viscosity at working shear rates.
   • Safer, more stable, and easier to use.
2. Partially Hydrated or Semi-Hydrated Polymers:
   • Water addition dramatically increases viscosity and gel risk → potential blockages in pipes (backflow in venturi or condensation in foam tank).
   • Used to extend drainage or add more polymer, but with higher operational risk.

For hydrocarbon fires: Water retention is not the key factor. True effectiveness comes from foam oleophobicity, achieved through precise ingredient selection and formulation.