The IS 4989 Part 4:2003 standard outlines specifications for multipurpose aqueous film-forming foam (AFFF) liquid concentrates designed to combat fires involving hydrocarbon fuels and polar solvents like alcohols. It details performance benchmarks, testing methodologies, and storage conditions to ensure effective suppression of both water-insoluble and water-miscible flammable liquid fires. This code is vital for manufacturers, fire safety professionals, and emergency responders requiring dependable foam agents compatible with potable and seawater.
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The IS 4989 Part 4:2003 standard outlines specifications for multipurpose aqueous film-forming foam (AFFF) liquid concentrates designed to combat fires involving hydrocarbon fuels and polar solvents like alcohols. It details performance benchmarks, testing methodologies, and storage conditions to ensure effective suppression of both water-insoluble and water-miscible flammable liquid fires. This code is vital for manufacturers, fire safety professionals, and emergency responders requiring dependable foam agents compatible with potable and seawater.
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As per IS 4989 Part 4 (2003), hydrocarbon fuel fires (water-insoluble) require a foam concentrate proportion of 3% in water, whereas fires involving polar solvents (water-miscible, such as alcohols and ketones) need a 6% foam concentrate mixture. The 3% solution forms a foam blanket that excludes oxygen for hydrocarbon fires, while the 6% solution forms a polymer membrane atop the fuel surface to support the foam blanket and inhibit vapor release, ensuring effective suppression.
IS 4989 Part 4 specifies that fire extinction time is measured by igniting a defined volume of fuel (e.g., 125 ± 5 liters of iso propyl alcohol), allowing it to burn briefly, then applying foam at a pressure of 7 kgf/cm² via a foam nozzle. The timing starts with foam application; fire control time (time to 90% fire suppression) and fire extinction time (complete fire elimination) are recorded through visual observation. This standardizes evaluating the foam's effectiveness under controlled conditions.
According to IS 4989 Part 4, foam concentrate should be stored in a dry, well-ventilated area protected from direct sunlight, maintaining temperatures typically between 0°C and 50°C. Under such tropical storage conditions, the concentrate retains its integrity for a minimum of five years. Containers must be clearly marked and kept sealed to preserve foam quality and ensure reliable fire suppression performance.
The standard mandates that manufacturers declare if their foam concentrate is compatible with sea water. Compatibility testing involves preparing foam solutions using 6% concentrate mixed with sea water (conforming to IS 4989 Part 1 composition) and potable water, conducting fire performance and foam characteristic evaluations under controlled temperature and wind conditions. Successful compatibility is confirmed when no significant differences occur between sea water and potable water results, ensuring dependable foam performance in marine environments.
IS 4989 Part 4 requires a foam generation setup comprising a 100-liter stainless steel pressure vessel rated for 25 kgf/cm², equipped with a foam-making nozzle capable of discharging 7.5 liters per minute at 7 kgf/cm² inlet pressure. The system includes an air compressor, pressure gauges calibrated every six months, high-pressure rubber tubing, mild steel pipes, and an adjustable stand arranged as per the standard's schematic. This configuration ensures consistent foam quality for accurate performance assessment.
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