Specification for Non-Metal Helmets for Firemen and Civil Defense Personnel

IS 2745 - Scope: Key Points & Specifications

Scope Summary:

• IS 2745 covers specifications for protective helmets, including materials, dimensions, and performance requirements.
• Definitions and sampling methods conform to IS 9695-1980.
• Performance tests include burner flame test with specific parameters.

Key Specifications from Clauses:

Important Notes:

• Burner operation and flame test ensure helmet material's heat resistance.
• Brim shape and size are critical for helmet integrity (see Fig.1 in IS 2745).
• Holes for visor fixing are optional, made only if visor is provided.

Typical Brim Shape (Fig. 1) - Conceptual:

graph TD
    A[Helmet Shell] --> B[Brim: Continuous, Integral]
    B --> C[Width as per Fig. 1]
    A --> D[Optional Visor Fixing Holes]

For detailed dimensional tables and test procedures, refer directly to IS 2745 clauses and IS 9695-1980 for sampling.

IS 2745 - Definitions (Clause 2.0)

This standard defines terms related to helmets for firemen and civil defence personnel, focusing on:

• Materials: Specifications for helmet materials ensuring durability and safety.
• Construction & Workmanship: Guidelines for manufacturing quality.
• Finish & Weight: Requirements for helmet surface and acceptable weight limits.
• Performance: Criteria helmets must meet under test conditions.

Key Specifications from IS 2745:

Notes:

• Sampling and conformity criteria refer to IS 9695-1980.
• Helmets must withstand flame exposure without failure.
• Rounding off numerical values follows the revised rules (not detailed here).

Summary Diagram: Helmet Testing Setup

flowchart LR
    Burner[Burner with fuel level 760 ± 75 mm]
    Flame[Flame height 150 mm]
    Wire[Copper wire at 50 mm above burner]
    TestPiece[Helmet lower edge at wire position]

    Burner --> Flame --> Wire --> TestPiece
    Wire -- Melts within 6 sec --> TestPiece

For detailed definitions, materials, and performance requirements, refer to IS 2745 Clause 2.0 and related clauses.

IS 2745: Key Specifications for Materials (Helmets)

• Material Requirements: The helmet materials must comply with IS 9695-1980 for sampling and conformity criteria (Clause 8.1).
• Performance: Materials should ensure adequate protection, durability, and flame resistance for firemen and civil defence personnel (Clause 1.1).
• Burner Test (Clause 2.4):
  • Flame height: 150 mm.
  • Fuel level: 760 ± 75 mm above burner base.
  • Copper wire test: A bare copper wire placed 50 mm above burner should melt within 6 seconds to confirm flame intensity.

Summary Table: Burner Test Parameters

Additional Notes:

• Materials must ensure workmanship, finish, and weight as per the standard.
• Sampling and testing follow IS 9695-1980 procedures.

This ensures helmets meet safety and performance standards for fire and civil defence use.

flowchart LR
    A[Fuel Level 760 ± 75 mm] --> B[Burner]
    B --> C[Flame Height 150 mm]
    C --> D[Copper Wire 50 mm above burner]
    D --> E[Wire melts ≤ 6 sec]

IS 2745: Dimensions and Construction Key Points

1. Concrete Block for Support (Clause 1.4)

• Dimensions:
  • Height: 1 m
  • Length: 1 m
  • Width: 0.6 m
• Mass: 1 tonne
• Bedding: On dry sand over a solid floor

2. Helmet Sizes (Clause 4.1)

• Inside Headband Circumferences (mm):
  530, 540, 550, 560, 570, 580, 590, 600, 610, 620
• Tolerance: ±3 mm
• Measurement: Using fixed plug gauge or expanding metal gauge

3. Burner Setup for Testing (Clause 2.4)

• Flame Height: 150 mm
• Fuel Level: 760 ± 75 mm above burner base
• Test Wire: Copper wire placed 50 mm above burner, melts within 6 seconds

4. Brim Specifications (Clause 5.2.1)

• Brim: Integral and continuous around dome
• Width: As per Fig. 1 (typical shell shape, not provided here)
• Visor Fixing Holes: Provided if visor is included

Summary Table: Helmet Sizes

flowchart TD
    A[Concrete Block] --> B[Dimensions: 1m x 1m x 0.6m]
    B --> C[Mass: 1 tonne]
    A --> D[Bedding: Dry sand on solid floor]
    E[Helmet Sizes] --> F[530 to 620 mm circumference]
    F --> G[±3 mm tolerance]
    H[Burner Setup] --> I[Flame height: 150 mm]
    I --> J[Fuel level: 760 ± 75 mm]
    J --> K[Copper wire melts <6 sec]
    L[Brim]

IS 2745: Components of Helmet - Key Specifications & Formulas

1. Shell (Clause 5.2)

• Smoothly finished surface, no sharp edges.
• Shape as per Fig. 1 (not provided here).
• No metallic parts through shell except visor fixing.
• Protective padding:
  • Thickness ≥ 8 mm.
  • Covers entire inner surface except 15–25 mm near retention anchorage.
  • No gaps > 5 mm.
  • Padding must not be readily detachable.

2. Headform & Chin Strap (Clause 1.1)

• Headform simulates bony jaw structure.
• Chin strap fastened over two metal rollers:
  • Diameter: 12.5 ± 0.5 mm.
  • Centers apart: 76 ± 0.5 mm.
• Ensures realistic load transfer to shell.

3. Helmet Size (Clause 4.1)

• Inside headband circumference sizes:
  530, 540, 550, 560, 570, 580, 590, 600, 610, 620 mm
• Tolerance: ± 3 mm.
• Measurement tools: fixed plug gauge or expanding metal gauge.

4. Shock Absorption Test (Clause 9.1)

• Test after conditioning:
  • 65 ± 2°C for 4 hrs (oven),
  • 10 ± 2°C for 4 hrs (refrigerator),
  • Water flow at 1 L/min for 4 hrs at room temp.
• Test method: Appendix A (details not included here).

Summary Table: Helmet Padding & Size

flowchart TD
    A[Helmet Shell] --> B[Protective Padding (≥8mm)]
    B --> C[Retention Anchorage (15-25

IS 2745: Workmanship and Finish - Key Points

• Workmanship & Finish Requirements:
  As per Clause 8.1, the method of sampling and conformity criteria follow IS 9695-1980. This ensures helmets meet quality standards in materials, construction, and finish.

• Visor Specifications:
  From Clause 5.3.5, visor holes for fixing must be ≥ 5 mm diameter and conform to IS 9995-1981.

• Performance Testing (Burner Test):
  Clause 2.4 details burner operation for flame testing:

  • Flame height = 150 mm
  • Fuel level = 760 ± 75 mm above burner base
  • Copper wire placed 50 mm above burner, melts within 6 seconds to confirm heat resistance.

Summary Table: Workmanship & Finish Checks

Notes:

• Workmanship includes smooth finishing, no sharp edges, and secure fixing of parts.
• Finish quality affects helmet durability and wearer safety.
• Refer to IS 9695 for detailed sampling plans and acceptance criteria.

flowchart LR
    A[Helmet Production] --> B[Workmanship Inspection]
    B --> C{Sampling as per IS 9695}
    C -->|Pass| D[Visor Hole Check (≥5mm)]
    D --> E[Flame Test per Clause 2.4]
    E --> F{Wire melts ≤6s?}
    F -->|Yes| G[Helmet Approved]
    F -->|No| H[Reject / Rework]

This ensures helmets meet IS 2745 standards for safety and quality.

IS 2745 - Marking Specifications for Helmets

Per Clause 10.1 of IS 2745:

Each helmet shall be clearly and indelibly marked with:

• Manufacturer's name or trade-mark
• Size with colour
• Year of manufacture
• Presence or absence of visor (With or without visor)

Standard Mark Usage (Clause 10.1.1 & 10.2):

• The helmet may bear the Standard Mark as per BIS Act 1986.
• Use of the Standard Mark is subject to licensing conditions from the Bureau of Indian Standards.

Summary Table for Marking Details

No specific formulas apply to marking, but clarity and durability of markings are essential for compliance and traceability.

flowchart TD
    A[Helmet] --> B[Mark Manufacturer Name]
    A --> C[Mark Size with Colour]
    A --> D[Mark Year of Manufacture]
    A --> E[Mark Visor Status]
    A --> F[Optional: Standard Mark]

Note: For licensing and Standard Mark details, contact BIS regional offices listed in the standard.

IS 2745: Sampling and Criteria for Conformity

• Reference Standard: Sampling and conformity criteria follow IS 9695-1980 (Helmet sampling methods).

• Sampling:

  • Samples must be selected as per Clause 8.1 referencing IS 9695.
  • Typically involves random sampling from production batches.

• Performance Testing (Clause 9.1): Shock absorption tests on helmets after conditioning:

  • Conditioning:
    • (a) 65±2°C for 4 hours (oven)
    • (b) 10±2°C for 4 hours (refrigerator)
    • (c) Water flow over helmet at 1 L/min for 4 hours (room temp)
  • Test to be done within 1 minute after conditioning.

• Mass Specification (Clause 7.1):

  • Maximum mass (excluding visor): 800 g
  • If >800 g, mark mass rounded to nearest 30 g.

• Additional Specifications:

  • Wooden headforms for testing helmets.
  • Visor specs for non-metal police/fire helmets.

Summary Table: Conditioning & Testing

For detailed sampling procedures, refer to IS 9695-1980.

flowchart LR
    A[Batch of Helmets] --> B[Sampling as per IS 9695]
    B --> C[Conditioning]
    C -->|a) Oven 65±2°C 4h| D[Shock Absorption Test]
    C -->|b) Fridge 10±2°C 4h| D
    C -->|c) Water flow 1L/min 4h| D
    D --> E[Conformity Decision]

This ensures helmets meet safety and quality requirements under various environmental conditions.

IS 2745: Performance Requirements (Clause 9)

IS 2745 covers helmets for firemen and civil defence personnel, emphasizing strength and durability.

Key Points on Performance Requirements (Clause 9):

• Clause 9.3 & Appendix C:
  Specifies the Test for Strength of Retention System (helmet straps and attachments) to ensure helmets remain securely fastened during use.

• Sampling & Conformity (Clause 8.1):
  Sampling methods and acceptance criteria follow IS 9695-1980, ensuring consistent quality.

Typical Performance Criteria for Helmets:

Important Notes:

• Helmets must maintain structural integrity under impact and retention load tests.
• Rounding off rules apply to numerical values for consistency (as per IS guidelines).

flowchart LR
    A[Helmet] --> B[Retention System]
    B --> C[Test for Strength]
    C --> D{Pass/Fail}
    D -->|Pass| E[Conforms to IS 2745]
    D -->|Fail| F[Reject/Retest]

For detailed test procedures and load values, refer to Appendix C of IS 2745 and IS 9695-1980.

IS 2745 — Marking and Use of Standard Mark

Clause 10.1.1

• The product may be marked with the Standard Mark as per BIS guidelines.

Clause 10.1 — Mandatory Marking on Helmets:
Each helmet shall be clearly and indelibly marked with:

• Manufacturer's name or trade-mark
• Size with colour
• Year of manufacture
• With or without visor

Clause 10.2 — Use of Standard Mark:

• Governed by the Bureau of Indian Standards Act, 1986.
• License for use of the Standard Mark is granted under BIS rules.
• Details and conditions for licensing are available from BIS.

Summary Table for Marking Requirements

Additional Notes

• The Standard Mark certifies compliance with IS 2745.
• For licensing and detailed use conditions, contact BIS regional offices.

flowchart TD
    A[Helmet] --> B[Mark Manufacturer's Name]
    A --> C[Mark Size & Colour]
    A --> D[Mark Year of Manufacture]
    A --> E[Mark Visor Presence]
    A --> F[Optional: Standard Mark (BIS License)]

For licensing details, refer to BIS offices listed in the standard.

IS 2745: Shock Absorption Test Summary

Shock Absorption Test (Clause 9.1 & Appendix A)

• Preconditioning: Helmets are conditioned for 4 hours at:

  • (a) 65 ± 2°C (oven)
  • (b) 10 ± 2°C (refrigerator)
  • (c) Water flow at 1 L/min over the shell at room temperature

• Test Setup:

  • Helmet mounted on a wooden headform (specification per IS 2745).
  • A striker is dropped freely from a height of 2.5 m ± 5 mm onto the helmet.
  • Impact force is recorded via photographic or high-speed instrumentation.

Key Specifications:

Procedure:

1. Condition helmet as per (a), (b), or (c).
2. Within 1 minute, perform shock absorption test.
3. Record transmitted force to evaluate energy absorption.

Penetration Resistance (Clause 9.2 & Appendix B)

• After shock absorption test, perform:
  • Plate Test: No shell failure or contact with headform.
  • Plumb Bob Test: Max penetration/dent ≤ 10 mm.

flowchart TD
    A[Condition Helmet] --> B{Conditioning Type}
    B -->|65±2°C Oven| C[4 hrs]
    B -->|10±2°C Refrigerator| C
    B -->|Water Flow 1L/min| C
    C --> D[Mount on Wooden Headform]
    D --> E[Drop Striker from 2.5m]
    E --> F[Record Impact Force]
    F --> G{Pass Shock Absorption?}
    G -->|Yes| H[Perform Penetration Test]
    G -->|No| I[Reject Helmet]

Note: This test ensures helmets maintain protective performance after environmental exposure.

IS 2745: Penetration Resistance Test Key Points

1. Test Conditions (Clause 9.2 & 2.1)

• Test performed within 1 minute after shock absorption test (worst result).
• Helmet placed on wooden headform.
• Striker dropped from 2.5 m ± 5 mm height onto helmet.
• Force recorded via high-speed photography or instrumentation.

2. Penetration Resistance Tests (Appendix B)

3. Summary of Penetration Limits

Visual Summary (Mermaid Diagram)

flowchart TD
    A[Helmet on Headform] --> B[Striker Raised to 2.5 m]
    B --> C[Striker Falls Freely]
    C --> D{Test Type}
    D --> E[Plate Test]
    D --> F[Plumb Bob Test]
    E --> G[No failure/stretch; no dent/piercing]
    F --> H[No failure/stretch; dent ≤ 10 mm]

Note: Refer to Appendix B for detailed test setup and procedure.

IS 2745: Strength of Retention System Test (Clause 9.3 & Appendix C)

Key Specifications:

• Maximum Load: 0.5 kN (50 kgf)
• Preload: 0.25 kN (25 kgf) applied for at least 30 seconds
• Extension Limit: ≤ 25 mm between preload and max load

Test Procedure (Appendix C):

1. Apply preload of 0.25 kN for 30 seconds.
2. Increase load by 0.25 kN at a uniform rate of 1 kN/min until reaching 0.5 kN.
3. Maintain maximum load (0.5 kN) for 2 minutes.
4. Measure elongation as the vertical extension between:
   • Reference point on the device retained by the chin strap
   • Top of the helmet shell
5. Calculate extension difference between preload and maximum load conditions.

Acceptance Criteria:

• No failure of retention system under 0.5 kN load.
• Total elongation ≤ 25 mm.

Definition:

• Retention System: Complete assembly including headband, chin strap, and cradle (Clause 2.8).

Summary Table:

flowchart TD
    A[Start Test] --> B[Apply Preload 0.25 kN for 30s]
    B --> C[Increase Load to 0.5 kN at 1 kN/min]
    C --> D[Hold 0.5 kN Load for 2 min]
    D --> E[Measure Elongation]
    E --> F{Elongation ≤ 25 mm?}
    F -- Yes --> G[Pass]
    F -- No --> H[Fail]

This test ensures the retention system reliably holds the helmet on the head without excessive stretch or failure.

IS 2745 - Electrical Resistance Test for Helmets (Clause 9.4, Appendix D)

Test Setup:

• Helmet inverted on wire frame inside a container.
• Filled with 6 g/L sodium chloride solution up to 12 mm below brim/dome junction or 12 mm below crown holes.
• Soak for 18-24 hours at 27±2°C.

Test Procedure:

• Apply 2000 V RMS, 50-60 Hz sine wave AC for 1 minute between electrodes inside and outside helmet.
• If no breakdown, disconnect high voltage.
• Connect milliammeter on earth side.
• Slowly raise voltage to 2000 V and observe leakage current.

Acceptance Criteria:

• Leakage current ≤ 3 mA at 2000 V.

Summary Table:

flowchart LR
    A[Helmet inverted on wire frame] --> B[Fill container with 6 g/L NaCl solution]
    B --> C[Soak 18-24 hrs at 27±2°C]
    C --> D[Apply 2000 V AC for 1 min]
    D --> E{Breakdown?}
    E -- No --> F[Disconnect HV, connect milliammeter]
    F --> G[Raise voltage to 2000 V, measure leakage current]
    G --> H{Leakage ≤ 3 mA?}
    H -- Yes --> I[Pass]
    H -- No --> J[Fail]

This ensures helmet insulation integrity per IS 2745 standards.

IS 2745: Water Absorption Test for Helmets

Key Specifications:

• Maximum water absorption: 5% of helmet mass (Clause 9.5)
• Test temperature: 27 ± 2℃ (Clause 2.1, Appendix E)
• Immersion duration: 24 hours (Appendix E-2.1)

Test Procedure (Appendix E):

1. Weigh dry helmet sample (used previously for shock absorption test).
2. Immerse sample in water at 27 ± 2℃ for 24 hours.
3. Remove sample, wipe surface dry, and weigh again.
4. Calculate water absorption %:

[ \text{Water Absorption (%)} = \frac{W_{wet} - W_{dry}}{W_{dry}} \times 100 ]

Where:

• ( W_{dry} ) = initial dry weight
• ( W_{wet} ) = weight after immersion

Summary Table:

flowchart TD
    A[Weigh Dry Helmet] --> B[Immerse in Water (27±2℃) for 24h]
    B --> C[Remove & Wipe Dry]
    C --> D[Weigh Wet Helmet]
    D --> E[Calculate Water Absorption %]

This test ensures helmet materials resist water uptake, maintaining safety and durability.

IS 2745: Flammability Resistance Test Summary

Key Specifications (Clause 9.6 & Appendix F)

• Requirement: No flaming or visible flame penetration inside the helmet during test.
• Test Setup: Use a Barthel burner per IS 4355-1967 (A-1).
• Fuel: Absolute alcohol in reservoir and tube; remove air bubbles before ignition.
• Ignition: Cotton waste soaked in spirit placed on burner cup, lit to preheat burner.
• Test Procedure: After preheating, adjust regulator to allow spirit vapor flow for flame exposure.

Important Notes:

• Wooden headform and fire-resistant brattice cloth are specified for mounting and flame containment.
• The helmet is exposed to flame; observe for any flame penetration inside.

Related Clause (Water Absorption Test - Clause 2.1):

• Weigh sample before and after 24 hr immersion in water at 27±2°C.
• Calculate average mass gain %:

[ \text{Mass gain %} = \frac{\text{Weight after immersion} - \text{Initial weight}}{\text{Initial weight}} \times 100 ]

Diagram: Flame Exposure Setup

flowchart LR
    A[Absolute Alcohol Reservoir] --> B[Barthel Burner Tube]
    B --> C[Cotton Waste soaked in Spirit]
    C --> D[Burner Flame]
    D --> E[Helmet on Wooden Headform]
    E --> F[Observation for Flame Penetration]

This test ensures helmet material resists flame penetration, critical for safety compliance per IS 2745.