What types of fire is this foam for?

It is for Class B fires, effective on both non-polar hydrocarbon fuels (e.g., diesel, petrol) and polar solvents (e.g., ethanol, acetone).

What are the standard concentration percentages?

The standard covers concentrates designed for use at 3% or 6% concentration with either fresh or sea water (Clause 1.2).

What are the fire performance requirements?

The foam must extinguish a standard fire in a maximum time and resist burnback for a minimum time, as specified for both hydrocarbon (n-heptane) and polar solvent (acetone) fuels (Table 2).

What is the shelf life requirement?

The concentrate must meet all performance requirements after an accelerated ageing test (24 hours at 65°C) to simulate long-term storage stability (Clause 4.6).

IS 4989

: 2000

multipurpose aqueous film forming foam liquid concentrate for extinguishing hydrocarbon and polar solvent fires

CurrentSpecializedSpecificationFire Safety · Fire Fighting

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This standard specifies the requirements for multipurpose aqueous film-forming foam (AFFF) concentrate, also known as alcohol-resistant AFFF (AR-AFFF). It covers the chemical, physical, and fire performance criteria for foam intended to extinguish fires involving both hydrocarbons (like petrol) and water-miscible polar solvents (like alcohol). The standard details test methods to verify performance, ensuring the foam is effective and stable upon storage.

multipurpose aqueous film forming foam liquid concentrate for extinguishing hydrocarbon and polar solvent fires

Quick Reference Values

pH range of concentrate6.0 to 8.5

Maximum sediment content0.25 % by volume

Minimum spreading coefficient on cyclohexane3.0 mN/m

Foam expansion ratio range5 to 10

Minimum 25% drainage time for solution3.0 min

Viscosity for pseudoplastic concentrate at 375 s⁻¹< 200 cP

Practical Notes

This foam is typically pseudoplastic (viscosity changes with shear), which is critical for proportioning equipment design. Standard venturi-type inductors may not be suitable.

Gentle application (Type II) is essential for polar solvent fires to allow the protective polymer membrane to form on the fuel surface.

Always verify compatibility with system components, especially seals and gaskets, as the solvents in the concentrate can be aggressive.