The IS 4308:2003 standard outlines the specifications for dry chemical powders specifically formulated to extinguish Class B (flammable liquids) and Class C (flammable gases) fires. It details the chemical makeup, physical attributes, packaging, and performance benchmarks required for these powders to ensure reliable fire suppression. This standard is vital for producers, distributors, and users of dry chemical powders in various firefighting applications.
Overview
The IS 4308:2003 standard outlines the specifications for dry chemical powders specifically formulated to extinguish Class B (flammable liquids) and Class C (flammable gases) fires. It details the chemical makeup, physical attributes, packaging, and performance benchmarks required for these powders to ensure reliable fire suppression. This standard is vital for producers, distributors, and users of dry chemical powders in various firefighting applications.
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Frequently Asked
The dry chemical powders primarily consist of sodium bicarbonate, potassium bicarbonate, and potassium chloride along with additives that enhance water repellency, flow characteristics, and safety. According to Clause 4.3.1 (as amended), the declared chemical composition must account for at least 90% by mass of the powder, excluding constituents below 10% by mass. These powders are white in color and designed for effective extinguishment of Class B and C fires, while being non-toxic, non-corrosive, and compatible with firefighting foams specified in IS 4989.
Particle size distribution is regulated through sampling representative powder portions and conducting sieving tests as specified by IS 1607. The sieve sizes and retention percentages are defined in Table 1 of Clause 4.4.1, with hand sieving performed for 30 minutes or machine sieving for 10 minutes. Thermal stability tests involve drying a 150 ±2 g sample at 60 ±2°C for one week, after which the powder must remain friable and comply with particle size limits. These controls ensure the powder maintains efficacy and stability under operational conditions.
Packaging must use containers capable of withstanding a 10 kg load without deformation and endure a drop test from 1 meter onto concrete without damage. Each package should be clearly marked with the manufacturer's name or trademark, net quantity in kilograms, powder type (ordinary or foam compatible), manufacture date or batch number, and the percentage of base material present. These requirements facilitate safe handling, traceability, and compliance with BIS regulations as outlined in Clause 8.1.
IS 4308 ensures powder effectiveness by mandating compliance with Class B fire tests, which also validate suitability for Class C fires. The powder's chemical composition balances fine and coarse particles to optimize fire knockdown and projection. It must demonstrate thermal stability by resisting caking when exposed to 60 ±2°C for one week. Additionally, powders are required to be non-corrosive, non-conductive, and compatible with firefighting foams. Rigorous testing including fire knockdown, foam compatibility, and particle size distribution confirm the powder’s operational reliability.
Resistance to moisture and caking is assessed through humidity exposure, penetrometer testing, and thermal stability evaluations. Powder samples are stored at 92% relative humidity and 27 ±2°C for 6 hours, then placed in a desiccator with concentrated sulfuric acid for 24 hours to observe caking. Friability is tested by dropping lumps from specified heights. Penetrometer tests involve vibrating powder samples under controlled humidity and temperature conditions and measuring penetration distances to quantify caking resistance. Thermal stability tests heat samples at 60 ±2°C for one week to ensure lumps remain friable and meet particle size standards.
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