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IS 4308:2003 is the Indian Standard (BIS) for dry chemical powder for fighting b and c class fires. This standard specifies the physical, chemical, and performance requirements for dry chemical powder (based on sodium bicarbonate or potassium bicarbonate) used as an extinguishing agent for Class B and Class C fires.
Specification for Dry Chemical Powder for Fighting B and C Class Fires
dry chemical powdersodium bicarbonatepotassium bicarbonatefire extinguishing agent
International Equivalents
Similar International Standards
EN 615:2009CEN - European Committee for Standardization, Europe
HighCurrent
Fire protection - Fire extinguishing media - Specifications for powders (other than class D powders)
Specifies requirements for ABC, BC, and D powders, with the BC powder section being a direct counterpart.
ISO 7202:1987ISO - International Organization for Standardization, International
MediumWithdrawn
Fire protection — Fire extinguishing media — Powder
Provided specifications for ABC and BC powders, forming the basis for many national standards.
UL 299Underwriters Laboratories, USA
MediumCurrent
Standard for Safety for Dry Chemical Fire Extinguishers
Covers the entire extinguisher assembly; powder requirements are part of the overall performance-based certification, not a standalone specification.
Key Differences
≠IS 4308 mandates a prescriptive chemical composition, requiring a minimum of 90% sodium bicarbonate, whereas EN 615 is performance-based and does not specify a minimum purity for the base extinguishing agent.
≠The method for specifying particle size differs significantly. IS 4308 uses traditional sieve analysis (percentage retained on sieves), while EN 615 uses a more modern approach specifying a maximum particle size (125 µm) and a mass median diameter (d50).
≠Fire test requirements are not directly comparable. IS 4308 specifies a test on a 21B class fire, while EN 615 requires powders to be rated according to EN 3-7, which has different fire sizes and test protocols (e.g., 34B, 55B, 144B).
Key Similarities
≈Both standards specify an identical maximum moisture content of 0.25% by mass, a critical parameter for preventing caking and ensuring powder flowability during discharge.
≈The core application is the same: specifying requirements for dry chemical powders primarily based on sodium bicarbonate intended for extinguishing Class B (flammable liquids) and Class C (flammable gases) fires.
≈Both standards include mandatory tests for key physical properties such as apparent density, water repellency, and resistance to caking (hygroscopicity) to ensure long-term stability and performance.
≈Both require that the powder and its combustion by-products are not significantly toxic, ensuring the safety of personnel during and after firefighting operations.
Parameter Comparison
Parameter
IS Value
International
Source
Principal Agent Content (Sodium Bicarbonate)
Minimum 90% by mass
Not specified; performance-based
EN 615:2009
Moisture Content (Max)
0.25% by mass
0.25% by mass
EN 615:2009
Apparent Density
0.85 to 1.10 g/ml
0.80 to 1.10 g/ml (if declared)
EN 615:2009
Particle Size (Largest)
Max 5% retained on 150 micron sieve
No particles > 125 micron
EN 615:2009
Particle Size (Median)
Defined by % retained on 75 & 45 micron sieves
Mass median diameter (d50) must be 20 to 45 micron
EN 615:2009
Resistance to Caking (Hygroscopicity)
Max 1.5% moisture absorption after 48h at 40°C & 80% RH
No caking/lumping after 48h at 60°C & 80% RH (different test)
EN 615:2009
Water Repellency
Min 90% must pass through a 150 micron sieve after test
Powder shall be free-flowing (no quantitative value)
EN 615:2009
⚠ Verify details from original standards before use
Key Values4
Quick Reference Values
Maximum Moisture Content0.25 % by mass
Apparent Density0.75 to 1.15 g/ml
Water Repellency Test Moisture AbsorptionMaximum 1.5 % by mass