Specification for portable fire extinguishers for aircraft, Part 1: Halon 1211 Type

IS 4862 Part 1 - Scope & Key Specifications

Scope Summary (Clause 4.1 & Table 1)

• Specifies materials of construction for various fire extinguisher components.
• Materials must conform to relevant IS standards.

Key Materials & Relevant IS Codes:

Rounding Off (Clause 0.3)

• Final test/analysis values must be rounded per IS 2:1960.
• Number of significant digits retained should match the specified value.

Summary Table for Materials (Excerpt):

IS 4862 Part 1 — Key Formulas & Specifications for Capacity and Pressure Ratings

1. Material Specifications (Clause 4.1, Table 1)

• Body: Steel Grade D or DD (IS 513) or any grade of IS 6240.
• Valve Body: Leaded Tin Bronze Grade LTB-2 (IS 318).
• Spring: Steel Grade I (IS 4454 Part 1).
• Sealing Disc: Copper (IS 1972).
• Other components: Brass, Rubber, Stainless Steel as per relevant IS codes.

2. Wall Thickness Calculation (Clause 7.1.1)

For cylindrical shell:

[ t = \frac{200 \times 0.8}{Re} \times (ph \times D_i) + ph ]

For tori-spherical end:

[ t = \frac{200 \times 0.8}{Re} \times (ph \times D_o) ]

For semi-ellipsoidal end:

[ t = \frac{200 \times 0.8}{Re} \times (ph \times D_o) \times K (0.65 + 0.1K) ]

Where:

• ( t ) = minimum thickness (mm)
• ( ph ) = test pressure above atmosphere (kgf/cm²)
• ( D_i, D_o ) = inner and outer diameters (mm)
• ( Re ) = yield strength (kgf/mm²)
• ( K = \frac{D_o}{H} ) (ratio of outer diameter to depth of dishing)
• Weld joint factor ( \phi = 0.9 )

3. Pressure Ratings & Testing (Clauses 2.5b & 10.1)

IS 4862 Part 1 — Design and Operation Key Points

Materials of Construction (Clause 4.1, Table 1)

Design & Operation Requirements (Clause 10.5)

• Extinguishers filled to specified mass must discharge ≥ 75% liquid content.
• Discharge time: ≥ 10 seconds.
• Test conditions: Stored for 24 h at -40°C, 24 h at +70°C, then 24 h at test temperature.
• Discharge tested at -26 ± 2°C and +55 ± 2°C, held at 60° from vertical.
• Discharge must be continuous.

Summary Formula for Discharge Efficiency:

[ \text{Discharge Efficiency} = \frac{\text{Mass discharged}}{\text{Initial charged mass}} \times 100 \geq 75% ]

Notes:

• Materials must conform to specified IS standards for durability and safety.
• Temperature conditioning ensures reliability under extreme climates.
• Angle and discharge time simulate real operational use.

flowchart LR
    A[Fill Extinguisher] --> B[Condition:

IS 4862 Part 1 - Materials for Fire Extinguisher Components

Key Notes:

• Steel grades (e.g., Grade D, DD) conform to cold-rolled or hot-rolled specifications.
• Leaded tin bronze (LTB-2) is used for corrosion resistance in valve bodies.
• Brass sections are used for nozzles and fittings for machinability and strength.
• Springs use cold-drawn steel wire for elasticity and durability.
• Rubber washers meet water fitting standards for sealing.

Example: Steel Grade Reference (IS: 513-1973)

Material Selection Flow (Mermaid

IS 4862 Part 1: Construction Requirements - Key Specifications

Materials of Construction (Clause 4.1, Table 1)

Notes:

• Materials conform to specified IS standards ensuring quality and compatibility.
• Steel grades and bronze/brass types are selected for strength, corrosion resistance, and machinability.
• Rubber washers comply with IS:937 for fire fighting water fittings.

Summary Diagram of Components and Materials

graph TD
    A[Body] -->|Steel| B(IS:513 / IS:6240)
    C[Neck ring] -->|Steel| D(IS:226 / IS:1875 / IS:7283 / IS:9550)
    E[Valve body] -->|Leaded tin bronze| F(IS:318)
    G[Nozzle] -->|Extruded brass| H(IS:291 / IS:319)
    I[Spring] -->|Steel plated| J(IS:4454)
    K

IS 4862 Part 1 - Anti-Corrosive Treatment (Clause 8.1)

• Types of Coatings & Minimum Thickness:

• Thickness Measurement:
  Use any method from IS 3203-1982 for local thickness testing of electroplated coatings.

Key Points:

• Anti-corrosive treatment is mandatory on all internal and external surfaces of the extinguisher body.
• Lead-tin alloy coating ensures corrosion resistance with tin content ≥10%.
• Copper coating provides additional protection with a thinner layer.
• Testing methods ensure coating uniformity and adherence.

Summary Diagram:

flowchart TD
    A[Extinguisher Body] --> B[Anti-Corrosive Treatment]
    B --> C{Type of Coating}
    C --> D[Lead-Tin Alloy (≥10% Sn)]
    C --> E[Copper Coating]
    D --> F[Thickness ≥ 0.012 mm]
    E --> G[Thickness ≥ 0.005 mm]
    F & G --> H[Thickness Measured by IS 3203-1982 Methods]

Reference Standards:

• IS 3203-1982: Methods for testing local thickness of electroplated coatings
• IS 4862 (Part 1): Fire extinguisher specifications including materials and coatings

Key Specifications & Formulas for Mounting and Valve Mechanism (IS 4862 Part 1)

Materials of Construction (Clause 4.1, Table 1)

Mounting & Threading (Clause 7.2 & 7.3)

• Thread standard: Class A threads per IS: 2643 (Part 1)-1975.
• Valve fixing: Minimum 12 mm effective length of parallel threads.
• Neck ring attachment: Welding or pressing; welding minimum 20 mm away from cylinder wall.

Valve Mechanism (Clause 7.4)

• Type: Spring-loaded, pressure-sealed sliding spindle.
• Operation: Manual depression via cantilever hinged grip lever.
• Safety: Safety pin fitted through valve body on grip lever to prevent accidental operation.
• Regulation: Pressing/releasing squeeze grip lever controls extinguisher discharge.

Summary Diagram: Valve Mechanism Operation

flowchart LR
    A[Manual Press on Grip Lever] --> B[Spindle Depresses]
    B --> C[Valve Opens]
    C --> D[Extinguis

IS 4862 Part 1 – Marking and Identification of Halon 1211 Aircraft Extinguishers

Key Marking Requirements (Clause 9.3 & 12.1):

• Fire Class Letters:

  • Letters B and C indicate suitability for fire classes per IS 2190-1979.
  • Letter B: Black, 2.5 cm size, inside a green square (4 cm side).
  • Letter C: Black, 2.5 cm size, inside a green circle (2 cm radius).
  • Green color: Shade No. 284 as per IS 5-1978.
  • Paint: Must conform to IS 2932-1974.

• Mandatory Markings on Extinguisher (Clause 12.1):

  • Manufacturer’s name and trademark.
  • Method of operation (prominent letters).
  • Words: "Halon 1211 Aircraft Extinguisher".
  • Capacity and charged pressure; radiography status.
  • Warning: "Send for re-charging immediately after use".
  • Year of manufacture.
  • Test pressure and capacity (kg).
  • Tare weight, full weight (gas + liquid).
  • Warning: "WARNING: Ventilate the area after use".

• Optional:

  • Standard Mark as per BIS licensing (Clause 12.1.2).

Summary Table of Marking Dimensions:

flowchart LR
    A[Extinguisher Body] --> B{Marking}
    B --> C[Letter B: Black, 2.5 cm]
    B --> D[Square: Green, 

IS 4862 Part 1: Performance Tests Key Points

1. Performance Test Clause: See Clause 10.5 (not provided in excerpt) for detailed procedure.

2. Sampling:

   • One sample is tested for performance (Clause 1.2.5).
   • If no manufacturer certificate, individual components and charge quality are tested (Clause 1.2.7).

3. Material Specifications: Refer Table 1 (Clause 4.1) for material requirements of components.

4. Rounding Off: Test results should be rounded per IS 2-1960 (Clause 0.3).

Typical Performance Test Checks (General Engineering Knowledge)

• Discharge Time: Measure time for complete discharge under standard conditions.
• Discharge Range: Minimum throw distance as per extinguisher type.
• Pressure Test: Ensure pressure retention within limits during operation.
• Leakage Test: No leakage under specified pressure for a set duration.

Example: Performance Test Parameters (Typical Values)

Summary Diagram of Performance Test Flow

flowchart TD
    A[Sample Selection] --> B[Component Inspection]
    B --> C[Charge Quality Check]
    C --> D[Discharge Test]
    D --> E[Pressure & Leakage Test]
    E --> F{Pass/Fail}
    F -->|Pass| G[Certification]
    F -->|Fail| H[Rejection/Retest]

For exact formulas and detailed test procedures, refer to Clause 10.5 of IS 4862 Part 1 and related annexures.

IS 4862 Part 1: Sampling and Criteria for Conformity (Appendix A)

Key Points:

• Purpose: Ensures high reliability of fire extinguishers by controlling quality through sampling.
• Sampling: Random samples are taken from each lot for testing.

Sampling Table (Clause A-1.2.2):

Criteria for Conformity:

• Samples must meet all specified test requirements.
• Failure in any sample may lead to rejection of the entire lot.
• Emphasizes high reliability due to critical safety function.

Summary:

• Select random samples per the table.
• Test all samples rigorously.
• Ensure zero tolerance for failure due to safety risk.

flowchart TD
    A[Lot of Fire Extinguishers] --> B{Lot Size}
    B -->|Up to 25| C[Select 3 Samples]
    B -->|26 to 50| D[Select 5 Samples]
    B -->|51 to 100| E[Select 8 Samples]
    B -->|101 to 200| F[Select 8% Samples]
    C & D & E & F --> G[Test Samples]
    G --> H{All Samples Pass?}
    H -->|Yes| I[Lot Accepted]
    H -->|No| J[Lot Rejected]

This approach ensures quality control and safety compliance in manufacturing fire extinguishers.

IS 4862 Part 1 - Test Methods: Key Points & Specifications

1. Rounding Off (Clause 0.3):

• Final test or analysis values must be rounded as per IS 2-1960.
• Retain the same significant figures as specified in the standard.

2. Sample Testing (Clause 1.2.7 & 1.2.5):

• If no manufacturer certificate is available, test one sample of each component and charge for conformity.
• Tests include:
  • Vibration test (Clause 7.7)
  • Drop test (Clause 10.3)
  • Performance test (Clause 10.5)

3. Material Specifications (Clause 4.1):

• Materials for components are listed in Table 1 (not provided here).

4. Units and Symbols:

• SI units as per the standard:

  Quantity	Unit	Symbol
  Length	metre	m
  Mass	kilogram	kg
  Time	second	s
  Force	newton	N (1 N = 1 kg·m/s²)
  Pressure/Stress	pascal	Pa (1 Pa = 1 N/m²)

Summary Table: Key Tests

If you need formulas or detailed procedures for these tests, please specify the test type.

IS 4862 Part 1: Standard Mark and Licensing Key Points

Standard Mark Usage (Clause 12.1.2):

• The Standard Mark on fire extinguishers certifies compliance with IS 4862 Part 1 under BIS supervision.
• It assures quality via inspection, testing, and continuous surveillance by BIS.
• Licensing for Standard Mark use is governed by the Bureau of Indian Standards Act, 1986.

Licensing Details:

• Manufacturers must follow BIS rules for licensing.
• License grants permission to use the Standard Mark on compliant products.
• Continuous product conformity checks by BIS ensure ongoing compliance.

Quality Assurance (Clause 1.2.7):

• In absence of manufacturer test certificates, sample components and charge quality must be individually tested per IS 4862 requirements.

Summary Table: Standard Mark Licensing

Additional Notes:

• Contact BIS for detailed licensing conditions.
• Standard Mark use is a legal and quality assurance requirement for fire extinguishers under IS 4862 Part 1.

flowchart LR
    A[Manufacturer] --> B[Apply for BIS License]
    B --> C[Compliance Testing & Inspection]
    C --> D{Meets IS 4862 Requirements?}
    D -->|Yes| E[License Granted + Standard Mark Use]
    D -->|No| F[Rejection / Corrective Action]
    E --> G[Continuous Surveillance by BIS]
    G -->|Non-compliance| F

This ensures only quality fire extinguishers carry the Standard Mark, safeguarding users.