Specification for Dry Chemical Powder for Fighting B and C Class Fires

IS 4308: Scope - Key Specifications & Tables

• Scope: Covers dry chemical powders for firefighting (Class B & C fires), detailing particle size, sampling, and marking requirements.

1. Particle Size Distribution (Clause 4.4.1, Table 1)

Tested as per IS 1607, particle size limits (% retained):

• Sieving Duration: 30 min (hand), 10 min (machine).

2. Sampling Procedure (Clause B-1.2, Table 2)

Sample size based on lot size:

3. Fire Pan Dimensions (Clause 2.24, Fig. 7)

• Stainless steel sheet thickness: 2.24 mm
• Vertical cylindrical portion diameter:
  • Inner: 51.4 mm
  • Outer: 57.6 mm

4. Marking (Clause 8.1.1.1)

Use of Standard Mark per BIS Act, 1986; license conditions available from BIS.

Summary Diagram: Sampling & Particle Size Flow

flowchart TD
    A[Lot Size] --> B{Sample Size}
    B -->|Up to 50| C[3 samples]
    B -->|51-100| D[4 samples]
    B -->|101-150| E[5 samples]
    B -->|151-300| F[6 samples]
    B -->|301+| G[7 samples]
    
    H[Dry Chemical

IS 4308 - Key References, Formulas, and Tables

1. Dimensions (Clause 2.24)

• Fire pan thickness: 2.24 mm stainless steel sheet
• Vertical cylindrical portion diameter:
  • Inner dia: 51.4 mm
  • Outer dia: 57.6 mm

2. Particle Size Distribution (Clause 4.4.1, Table 1)

• Sieving duration: 30 min (hand), 10 min (machine)

3. Load Specification (Clause 2.8)

• Substitute load: 2.8 kN/m² (replaces 0.276 kN/m²)

4. List of Referenced Indian Standards (Clause 8.1.1.1)

Summary Diagram: Particle Size Distribution

graph LR
A[0.425 mm (40 mesh)] -->|0% retained| B[0.150 mm (100 mesh)]
B -->|0-2% retained| C[0.075 mm (200 mesh)]
C -->|0-10% retained| D[0.045 mm (325 mesh)]
D -->|10-35% retained| E[Bottom pan]

**Use these tables and specs for quality control and design compliance in fire-fighting powder materials and

IS 4308 — Terminology & Key Specifications

The standard defines key terms and dimensions relevant to fire fighting foam concentrates and equipment.

Key Dimensions (Clause 2.24)

• Fire Pan Thickness: Stainless steel sheet, 2.24 mm
• Vertical Cylinder Diameter (mounted on puffer chamber):
  • Inner diameter = 51.4 mm
  • Outer diameter = 57.6 mm

Particle Size Distribution for Foam Concentrate (Clause 4.4.1, Table 1)

• Sieving Duration: 30 min (hand), 10 min (machine)

Sampling & Marking

• Sampling follows IS 4905 (random sampling)
• Marking governed by BIS Act 1986 (Clause 8.1.1.1)

Summary Diagram of Foam Particle Size Distribution

barChart
    title Particle Size Distribution (% Retained)
    x-axis Sieve Mesh Size
    y-axis % Retained
    40 mesh: 0 to 0
    100 mesh: 0 to 2
    200 mesh: 0 to 10
    325 mesh: 10 to 35
    Bottom pan: 53 to 90

Use these definitions and tables to ensure compliance with IS 4308 for foam concentrate particle size and equipment dimensions.

IS 4308: Qualitative Requirements - Key Points & Tables

1. Sampling (Clause 1.2 & Table 2)

• Sample containers selected depend on lot size:

2. Particle Size Distribution (Clause 4.4.1 & Table 1)

• Sieving duration: 30 min (hand), 10 min (machine).

3. Chemical Composition - % KHCO3 (Clause 322.8)

[ \text{Percentage KHCO}_3 = \frac{a}{b} \times 100 ]

• a = loss of mass (g) after heating at 250°C
• b = dry sample mass (g)

4. Testing Requirements (Clause 2.1)

• Sample from each container must be mixed and tested for:
  • Apparent density
  • Particle size distribution
  • Water repellency
  • Free flowing nature

All samples must meet requirements for the lot to conform.

This ensures quality control and performance of dry chemical powders for Class B & C fire extinguishing.

Sampling as per IS 4308

1. Scale of Sampling (Clause B-1.2, Table 2):

• Samples must be drawn from different containers in the lot.

2. Sampling Procedure (Clause B-2.1):

• Use an appropriate sampling instrument.
• Draw small portions from different parts of each selected container.
• Thoroughly mix portions from the same container.
• Quantity must suffice for all required tests (apparent density, particle size distribution, water repellency, free flowing).
• The lot conforms only if all samples meet the requirements.

3. Particle Size Distribution (Clause 4.4.1, Table 1):

• Sieving duration: 30 min (hand), 10 min (machine).

Summary Diagram: Sampling Flow

flowchart TD
    A[Select Lot] --> B[Determine Sample Size (Table 2)]
    B --> C[Draw Samples from Containers]
    C --> D[Mix Portions per Container]
    D --> E[Conduct Tests]
    E --> F{All Samples Conform?}
    F -- Yes --> G[Lot Accepted]
    F -- No --> H[Lot Rejected]

References:

• IS 1607 for test sieving methods.
• Sampling ensures representativeness and quality control compliance.

IS 4308: Key Test Methods & Specifications

1. Sampling (Clause B-1.2 & Table 2)

• Sampling depends on lot size:

• Samples are taken from each lot to verify conformity.

2. Particle Size Distribution (Clause 4.4.1 & Table 1)

Test as per IS 1607 with sieving durations:

• Hand sieving: 30 min
• Machine sieving: 10 min

3. Equipment for Testing (Clause 4.10.2)

• Two 1000 ml Erlenmeyer flasks joined mouth-to-mouth with a rubber collar.
• A 1 mm thick stainless steel disc with 26 mm aperture fits into the neck.
• Used to hold and test 500 g powder samples.

4. Referenced IS Standards

• IS 1607: Methods for test sieving
• IS 4905: Methods for random sampling
• IS 4989: Foam concentrate for fire fighting
• IS 7406: Jute bags for packing fertilizers

flowchart LR
    A[Lot Size] --> B[Sample Size per Table 2]
    B --> C[Sample Testing]
    C --> D[Particle Size Distribution]
    D --> E[Sieving per IS 1607]
    E --> F[Confirm Material Conformity]

Summary: Sampling size is based on

IS 4308: Packing and Marking Key Points

Packing Specifications (Clause 7.1.1)

• Container strength: Must withstand a 10 kg load on any side/end without distortion.
• Drop test: No disintegration when dropped from 1 m height on concrete after packing.

Marking Requirements (Clause 8.1)

Each pack of dry chemical powder must be labelled with:

• Manufacturer's name or trademark
• Quantity of powder (in kg)
• Type: Ordinary or foam compatible
• Date of manufacture / Batch number
• Percentage of base material

Standard Mark (Clause 8.1.1)

• Packing may carry the BIS Standard Mark as per BIS Act 1986.
• License conditions for Standard Mark use are governed by BIS rules.

Related IS Standards (for packing materials and testing)

Summary Table: Packing Strength Test

flowchart TD
    A[Packing Container] --> B{Load Test}
    B -->|Apply 10 kg| C[No distortion/failure]
    A --> D{Drop Test}
    D -->|Drop 1 m height| E[No disintegration]
    A --> F[Marking]
    F --> G[Manufacturer's name]
    F --> H[Quantity (kg)]
    F --> I[Type]
    F --> J[Date/Batch No.]
    F --> K[Base material %]

This ensures safe handling and traceability of dry chemical powder packs per IS 4308.

IS 4308: Fire Knockdown Properties - Key Points & Formulas

Fire Knockdown Testing (Clause 4.12)

• Conduct tests in wind-free enclosures to avoid disturbance.
• Keep suitable extinguishers (Halon 1211, CO2, dry chemical powder, or AFFF foam) ready for safety.
• Allow the fire pan to cool before repeating tests for consistency.

Composition & Fire Knockdown Efficiency

• Dry chemical powder mainly contains sodium bicarbonate, potassium bicarbonate, potassium chloride.
• Particle size balance is critical:
  • Fine particles: Better knockdown but poor projection.
  • Coarse particles: Better projection but less effective knockdown.
• Powders must be non-toxic, non-corrosive, non-abrasive, and electrically non-conductive.

Important Formula (Clause 322.8) - Potassium Bicarbonate (KHCO3) Percentage:

[ \text{Percentage KHCO}_3 = \frac{a}{b} \times 100 ]

• (a) = loss of mass (g) after heating at 25°C
• (b) = dry sample mass (g)

Fire Pan Dimensions (Clause 1.6 & Fig. 8)

• Puffer chamber made of stainless steel sheet, thickness 1.6 mm.
• Fire tray: 60 cm (L) x 25 cm (B) x 20 cm (H) on a 68 cm high stand.

Fire Knockdown Test Procedure (Summary from Clause 4.11.2)

• Fill tray with 8 L potable water.
• Add 3 L n-heptane fuel.
• Ignite and burn for 10 seconds.
• Apply foam or powder to extinguish.

Notes:

• Not suitable for fires with chemicals having their own oxygen supply, radioactive or reactive metals.
• Powder must be foam compatible per IS 4989.

flowchart TD
    A[Prepare Fire Tray] --> B[Add Water (8L)]
    B --> C[Add Fuel (3L n-heptane)]
    C --> D[Ignite Fuel]
    D --> E[Burn for 10 sec]
    E --> F[Apply Extinguishing Agent]
    F --> G[Observe Fire Knockdown]

This summary aligns with IS 4308

Foam Compatibility as per IS 4308:2003

Clause 4.11 & 4.11.2: Test Procedure

• Fire Tray Dimensions:

  • Length = 600 mm
  • Breadth = 250 mm
  • Height = 200 mm
  • Stand Height = 680 mm

• Test Setup:

  1. Pour 8 L potable water into tray to submerge sparge pipe.
  2. Add 3 L n-heptane fuel on water layer.
  3. Ignite fuel, burn freely for 10 s.
  4. Apply foam (protein foam concentrate IS 4989 Part 1, 4% v/v) using goose neck nozzle for 10 s.
  5. After foam application, connect LPG gas line to sparge pipe, ignite gas bubbling through foam after 30 s.
  6. Measure time T (seconds) for complete tray area to catch fire.
  7. Extinguish and cool tray.
  8. Apply 60 g dry chemical powder at 276 kN/m² (40 psi) on burning tray surface.
  9. Immediately apply foam again for 10 s, repeat ignition and timing for complete flame spread, record time T₁.

• Compatibility Criterion:
  Dry powder is compatible with foam if:
  [ T_1 \geq \frac{T}{2} ]

Key Points:

Summary Diagram (Test Setup):

flowchart LR
    A[Fire Tray: 600x250x200 mm] --> B[8 L Water]
    B --> C[3 L n-Heptane Fuel Layer]
    C --> D[Ignite Fuel for 10 s]

IS 4308: Heat Resistance Test - Key Specifications & Procedure

1. Heat Resistance Test (Clause 4.9 & 4.9.1)

• Sample: 150 ± 2 g dry powder in a tinned steel cup (Ø 75 mm, depth 50 mm) with a flanged lid.
• Condition: Oven at 60 ± 2℃ for 1 week.
• Post-Test: Cool and check for caking/lumps.
• Acceptance: Lumps must be friable when dropped from 100 mm on a hard surface, meeting particle size distribution of Clause 4.4.
• Purpose: Ensures thermal stability; no melting/decomposition at 60℃.

2. Fire Extinguishing Test Setup (Clause 4.12.1.3)

3. Test Procedure Summary

• Setup fire pan with water and fuel as per dimensions.
• Ignite fuel; burn for 10s.
• Open butterfly valve and release powder puff via compressed air.
• Powder cloud should extinguish fire.
• Repeat 5 times; at least 4 successful extinctions required.

Diagram: Fire Extinguishing Test Setup

flowchart LR
    A[Compressed Air Reservoir] -->|Pressure 276 kN/m²| B[Pressure Reducer & Moisture Trap]
    B --> C[Puffer Chamber with Butterfly Valve]
    C --> D[Dry Powder Sample]
    D --> E[Powder Cloud over Fire]
    F[Fire Pan] -->|Inner Area: Water + Fuel| E
    F -->|Outer Area: Water| G[Water Reservoir]

Note: Conduct test in a draught-free room with fire

IS 4308 — Free Flowing Characteristics (Clause 4.10)

Key Procedure (Clause 4.10.3)

• Aeration: Hold the two-flask assembly vertically by necks, rotate 180°, let powder flow to lower flask.
• Repeat rotation 10 times quickly to aerate the powder.
• Immediately after the 10th aeration, measure flow time t (seconds) for powder to flow completely.
• Perform 10 such measurements; calculate arithmetic mean time t.

Fluidity Calculation

[ \text{Fluidity (rate of flow)} = \frac{500 \text{ g}}{t \text{ (s)}} ]

• Pass criteria: Fluidity ≥ 50 g/s

Particle Size Distribution (Clause 4.4.1, Table 1)

• Sieving time: 30 min (hand), 10 min (machine)

Summary

• Aerate powder by 10 quick 180° rotations.
• Measure flow time, calculate fluidity as 500g divided by mean flow time.
• Fluidity ≥ 50 g/s confirms free-flowing quality.
• Particle size distribution must conform to Table 1 limits.

flowchart TD
    A[Start: Powder in upper flask] --> B[Rotate 180°]
    B --> C[Powder flows to lower flask]
    C --> D[Rotate back 180°]
    D --> E{Repeat 10 times?}
    E -- No --> B
    E -- Yes --> F[Measure flow time t]
    F --> G[Calculate Fluidity = 500/t g/s]
    G --> H{Fluidity ≥ 50 g/s?}
    H --

IS 4308: Hygroscopicity & Moisture Content

1. Hygroscopicity (Clause 4.5 & 4.5.2)

• Procedure:

  • Weigh 10 g dry powder in a 250 ml beaker.
  • Place in a desiccator at 80% RH (using glycerin-water mixture).
  • After 48 hours, weigh again.

• Formula:

  [ \text{Percent Hygroscopicity} = \frac{\text{Increase in weight of sample}}{\text{Original weight of sample}} \times 100 ]

2. Moisture Content (Clause 4.8 & 4.8.2)

• Procedure:

  • Place ~50 g sample in a tared aluminium dish (65 mm dia, 15 mm depth).
  • Condition at 50 ± 5% RH, 27 ± 5°C for 6 hours.
  • Weigh sample (W1).
  • Dry in desiccator with 95-98% reagent grade sulphuric acid at 21 ± 5°C for 24 hours.
  • Weigh dried sample (W2).

• Formula:

  [ M = \frac{W_1 - W_2}{W_1 - W} \times 100 ]

  where:

  • ( M ) = Moisture content (%)
  • ( W ) = Mass of empty aluminium dish
  • ( W_1 ) = Mass of dish + powder before drying
  • ( W_2 ) = Mass of dish + powder after drying

This ensures standardization of moisture and hygroscopicity measurements per IS 4308.

IS 4308: Particle Size Distribution (Clause 4.4.1)

When tested per IS 1607, the particle size distribution of dry chemical powders shall conform to:

• Sieving duration:
  • Hand sieving: 30 minutes
  • Machine sieving: 10 minutes

Additional Relevant Formula (Clause 4.2.1): Apparent Density

[ \text{Apparent Density} = \frac{100 \text{ g}}{\text{Volume of powder in ml}} ]

• Use 100 ± 1 g sample in a 250 ml graduated cylinder (40 mm dia, 320 mm height).
• Rotate cylinder 10 revolutions (1 rev/2s), then settle for 180 s before reading volume.

Sampling (Clause 2.1):

• Take small portions from different parts of each container.
• Mix thoroughly.
• Test samples for particle size, apparent density, water repellency, and flowability.
• Lot conforms if all samples meet requirements.

flowchart TD
    A[Sampling from Containers] --> B[Mix Samples]
    B --> C[Particle Size Distribution Test (IS 1607)]
    B --> D[Apparent Density Test]
    B --> E[Water Repellency Test]
    B --> F[Flowability Test]
    C & D & E & F --> G[Lot Conformance Decision]

This ensures consistent quality of dry chemical powders per IS 4308.

IS 4308: Chemical Content Determination for Dry Chemical Powder

Key Specifications (Clause 4.3.1)

• Declared chemical content excludes constituents < 10% by mass.
• Declared content must cover > 90% of total powder composition.
• Tolerance on declared values: ±3%.

Calculation Formula (Annex D-2)

[ \text{Percentage of chemical} = \frac{V \times N \times 100}{M} ]

Where:

• V = volume of sulphuric acid (ml) used in titration,
• N = normality of sulphuric acid,
• M = mass of sample (g).

Procedure Highlights (Annex D-1)

• Use sulphuric acid titration to quantify chemical content.
• Record titration volume accurately (Clause 1.5 D-1.5).
• Follow standard titration steps for dry powder samples.

flowchart TD
    A[Sample Preparation] --> B[Titration with H2SO4]
    B --> C[Measure Volume V (ml)]
    C --> D[Calculate % Chemical Content]
    D --> E[Compare with Declared Value ±3%]

This ensures compliance with IS 4308 for fire-fighting dry powders B & C class.

IS 4308: Key Annexes Summary

1. Sampling (Clause B-1.2 & Table 2)

• Sample size depends on lot size:

• Samples are tested from each lot to verify conformity.

2. Test Procedures (Clause B-2.3 & Annex D)

• Fire Test (Class B): Test 3 samples; at least 2 must extinguish fire.

• Foam Compatibility: Test 2 samples; both must pass.

• Chemical Content Determination (Annex D):
  Use loss of mass after heating to calculate % KHCO₃:

  [ \text{Percentage KHCO}_3 = \frac{a}{b} \times 100 ]

  • a = mass loss after heating (g)
  • b = dry sample mass (g)

• Heating temperature for tests: 250°C (Amendment No. 4).

3. Committee Composition (Annex C)

• Multi-organization committee including:
  • Ministry of Home Affairs (Chairman: Shri Om Prakash)
  • Airport Authority of India
  • Bhabha Atomic Research Centre
  • Defence Research and Development Organization
  • Fire Brigades, Fire Services, Industry Experts, BIS representatives.

Summary Diagram (Sampling & Testing Flow)

flowchart TD
    A[Lot Received] --> B[Select Sample Size (Table 2)]
    B --> C[Test Samples for Chemical Content]
    C --> D{Fire Test (3 samples)}
    D -->|≥2 Pass| E[Conforms to Fire Test]
    D -->|<2 Pass| F[Reject Lot]
    C --> G{Foam Compatibility (2 samples)}
    G -->|2 Pass| H[Conforms to Foam Compatibility]
    G -->|<2 Pass| F

Note: Dry chemical powder must be non-toxic, non-corrosive, free