Dry Chemical Powder for Fighting A, B, C, Class Fires -Specification
1999 Edition

Overview of Scope and Sampling (Clause 1.2 & Annex B)

• Sampling conducted for each lot to confirm compliance.
• Sample size varies with lot size as per Table 1:

Particle Size Distribution Requirements (Clause 4.4)

Additional points:

• BIS certification and marking regulated under Clause 8.1.1.1.
• Base material percentage must be declared (Clause 8.1f).
• Refer IS 1607 for test sieving procedures.

This section establishes the sampling strategy and particle size conformity to assure quality.

Summary of Sampling Procedures (Clause B-1.2 & B-2.1)

• Random selection of containers from lots according to IS 4905.
• From each selected container, multiple portions are taken from various locations.
• Portions are blended per container to form a representative sample.
• Sample quantity must suffice for all required tests (density, particle size, moisture repellency, flowability).
• Each container is tested individually; the entire lot meets standards only if all samples comply.

Reference standards:

• IS 4905 for random sampling techniques.
• IS 1607 for sieving methods.
• Other relevant IS codes as listed in Annex A.

This ensures representative and statistically valid sampling for conformity evaluation.

Chemical Composition Criteria (Clause 4.3)

• Declared chemical constituents exclude those below 10% by weight.
• The powder must contain over 50% mono-ammonium phosphate or polyammonium phosphate.
• A tolerance of ±3% applies to declared constituents.
• Moisture content should not exceed 0.25% by mass (Clause 4.8).
• Absorption is limited to a maximum of 2.5% (Clause 4.5.1).

Typical Composition

• Predominantly mono-ammonium phosphate or ammonium polyphosphate with ammonium sulfate additives.
• Additives ensure water repellency, free flow, non-toxicity, non-corrosiveness, and electrical insulation.

Summary Table

The composition balance is vital for effective fire suppression and foam compatibility.

Key Physical and Chemical Parameters

• Moisture absorption must not exceed 2.5% (Clause 2.5).
• Particle size distribution as per Clause 4.4 and IS 1607:

• Apparent density should be within ±10% of the declared value (g/ml).
• Color of the powder is pale yellow (Clause 4.13).
• Composition must be non-toxic, non-corrosive, non-abrasive, electrically non-conductive.
• Compatibility with foam concentrates per IS 4989.

Avoid use on fires involving reactive metals or sensitive electronics.

Essential Equipment (Clause 4.3.2)

Sample Preparation (Clause 4.6.2.1)

• Use 100 g powder placed in nickel crucible-shaped vessel.
• Vessel dimensions updated to 26 mm diameter and 1000 cc volume.
• Tray height specified at 200 mm.

Density Measurement

• Apparent density must fall within ±10% of declared values.

This ensures precise and standardized testing per the standard's requirements.

Sampling (Annex B, Clause 1.2)

• Random container selection per IS 4905.
• Sample size depends on lot size (Table 1):

Compliance Evaluation (Clause 6)

• All samples must pass the specified tests.

Additional Information

• Powders must be non-toxic and safe for use on energized electrical equipment.
• Exposure to humidity above 50% or temperatures above 121°C may induce corrosion or conductivity.
• Immediate cleaning of spills is advised to prevent damage.

This framework ensures reliable quality verification of dry chemical powders.

Container Strength Requirements (Clause 7.1.1)

• Containers must not deform or fail when subjected to a 10 kg load on any face.
• Containers must withstand a 1-meter drop onto a concrete surface without rupturing.

Sampling for Container Testing

• Random container selection as per IS 4905.
• Samples are drawn from multiple container locations and mixed for testing.

Testing Includes

• Apparent density
• Particle size distribution
• Water repellency
• Flow characteristics

Packaging Specifications

• Powders are packed in hermetically sealed, moisture-resistant plastic bags or lined containers.
• Available pack sizes include 1, 2, 5, 10, and 25 kg.

These measures ensure packaging integrity and powder quality preservation.

Labeling Essentials (Clause 8.1)

Each package must display:

• Manufacturer’s name or trademark
• Quantity of powder (in kilograms)
• Indication of foam compatibility
• Manufacturing date or batch number
• Applicable fire classes: A, B, C
• Base material type and percentage

BIS Certification Mark (Clause 8.1.1)

• Use of the Standard Mark is subject to BIS licensing rules under the BIS Act, 1986.
• Licensed products may bear the Standard Mark.

Referenced IS Standards (Annex A)

This ensures product traceability, safety, and regulatory compliance.

Fire Extinguishing Powder Test (Clause 1.6)

• Powder must successfully extinguish fires in four consecutive tests; a fifth test is optional upon success.
• Testing performed in still air conditions.
• Fire extinguishers such as Halon 1211, CO2, DCP, or AFFF foam are available as backups.
• Cooling intervals must be observed between tests.
• Puffer chamber constructed from 1.6 mm thick stainless steel, operated at 276 kN/m² (40 psi).

Foam Compatibility & Fire Tray Test (Clause 6.35)

• Uses 3 liters of n-heptane over water in a tray.
• Protein foam concentrate per IS 4989 (Part 1), at 4% concentration.
• Procedure includes ignition, foam application, LPG bubbling ignition, and timing flame involvement.
• 60 g dry powder applied using puffer chamber at specified pressure.
• Compatibility confirmed if post-foam burn time is at least half the initial foam burn time.

Fire Knockdown Test (Clause 4.12.1.2)

• Wood crib with 13 layers, each having 6 sticks arranged orthogonally.
• Supported on steel angles atop concrete blocks, elevated 405 mm from the floor.
• Outer sticks secured with staples or nails.

These tests validate the powder’s effectiveness on various fire classes.

Essential Equipment (Clauses 4.12.2.1, 4.3.2, etc.)

• Air compressor with pressure regulator and moisture trap mounted on a stand.
• Precision weighing scales, including analytical balances accurate to 0.1 mg.
• Standard weights for calibration.
• Plastic or stainless-steel spoons for sampling.
• 1-liter graduated glass measuring cylinders.
• Stopwatch and lighting devices (torch, matchbox).
• Stainless steel fire pan and asbestos sheet cover.
• Stainless steel puffer chamber.
• Centrifuge tubes (100 ml, preferably conical) and centrifuge.
• Steam bath maintained near 80°C.
• pH meter or titrimeter apparatus.
• Alkali-resistant burette (5 ml, 0.1 ml gradations).
• Vacuum oven operating around 60°C.

This equipment supports accurate, repeatable testing under controlled conditions.

Test Setup (Clause 4.9)

• Sample size: 150 ± 2 grams.
• Container: Tinned steel cup, 75 mm diameter, 50 mm depth, with flanged lid.
• Oven temperature: 60 ± 2°C for 7 days.
• Upon completion, samples cooled and examined for caking.
• Lumps must be friable when dropped from 100 mm onto a smooth hard surface.
• Particle size distribution must still conform to Clause 4.4.

Purpose

• Verifies thermal stability of powder and additives.
• Confirms powder performance in high-temperature environments like boiler rooms.

This test ensures powder integrity under prolonged heat exposure.

Procedure (Clause 4.6)

• Place 100 g of powder in a 250 ml beaker.
• Condition at 90% relative humidity and 27 ± 2°C for 6 hours.
• Transfer to a desiccator containing 98% sulfuric acid for 24 hours.
• Inspect for lump formation.
• Drop lumps from 200 mm onto a hard, smooth surface; lumps must break easily.

Sampling

• Composite samples from equal portions of each container.
• Single test per composite; lot passes if criteria met.

This test confirms powder stability against moisture-induced caking, essential for storage and handling.

Testing Method (Clause 4.10.3)

• Use two 500 cc Erlenmeyer flasks connected neck-to-neck.
• Rotate 180° to transfer powder from upper to lower flask, then back.
• Repeat this aeration process 10 times consecutively.
• After the 10th rotation, measure the time (t) for powder to flow completely.
• Calculate fluidity rate as 500 g divided by time in seconds.
• Passing fluidity requires a flow rate of at least 50 g/s.

Equipment Needed

• Two 500 cc Erlenmeyer flasks.
• A leveling stand with a screw adjustment.

This test ensures the powder maintains free-flowing properties critical for extinguisher performance.

Class A Fire Setup (Clause 4.12.1)

• Wood crib consisting of 13 layers, each layer having 6 wood sticks.
• Wood sticks dimensioned approximately 63 × 38 mm.
• Elevated on concrete blocks 405 mm high with steel angle supports.
• Test conducted indoors, protected from wind to allow natural fire development.
• Powder must effectively extinguish this wood fire.

Class B Fire Setup (Clause 4.12.2)

• Flammable liquid pool fire established in a pan or tray.
• Powder must suppress this liquid fire effectively.

Class C Fire Setup (Clause 4.12.3)

• Simulated energized electrical equipment fire.
• Powder must be non-conductive and suitable for electrical fires.

This section describes test fire setups to evaluate powder effectiveness.

Overview

• Use of the Standard Mark is regulated under the Bureau of Indian Standards Act, 1986.
• Manufacturers apply for licenses to mark products with the Standard Mark.
• Sampling and testing protocols are outlined in Annex B.

Testing Requirements

• For Class B fires: Minimum of 3 samples tested; 2 must pass.
• For Class A fires: At least 1 test required.
• Foam compatibility requires 2 samples tested, both must pass.

Licensing Workflow

• Application followed by BIS evaluation.
• License granted if criteria are satisfied.
• Market surveillance and ongoing conformity testing maintain license validity.

Certification ensures adherence to quality, safety, and regulatory standards.