Specification for Industrial Safety Helmets(Bi-Lingual)

IS 2925: Scope and Key Specifications for Industrial Safety Helmets

Scope (Clause 2.0)

• Defines terms related to industrial safety helmets.
• Helmets are designed to protect against head injuries in industrial environments.

Key Size Specifications (Clause 4.1 & Amendment Dec 2000)

• Helmets available in sizes based on headband circumference inside the helmet:

• Amendment update: Helmets shall be in sizes 520, 530, 540, 550, 560, 570, 580, 590, 600 mm.
• Size adjustment range must be clearly marked on the helmet.
• Adjustable headbands allow fitting flexibility.

Additional Notes

• Headband may or may not be continuous if a napestrap is provided (Clause 2.3.1).
• Flammability resistance testing method is outlined in Appendix G (Clause 8.3).

Summary Table: Helmet Sizes and Headband Range

This ensures helmets fit various head sizes securely and meet safety standards per IS 2925.

IS 2925: Definitions & Key Specifications for Industrial Safety Helmets

Clause 2.0: Definitions

• Defines terms related to industrial safety helmets for clarity and uniformity.
• Essential for understanding helmet components, testing, and usage.

Clause 4.1: Helmet Sizes

• Helmets must have adjustable headbands fitting these ranges.

Clause E-2.4: Test Block Specifications

• Concrete or similar monolithic block for testing helmet impact.
• Minimum dimensions:
  • Height: 1 m
  • Length: 1 m
  • Width: 0.6 m
  • Mass: 1 tonne
• Block bedded on dry sand on a solid floor for stability.

Summary:

• Definitions clarify helmet terminology.
• Helmet sizes ensure proper fit via adjustable headbands.
• Test block specs standardize impact testing conditions.

flowchart LR
A[Helmet] --> B[Adjustable Headband]
B --> C{Size}
C -->|Small| D[500-540 mm]
C -->|Medium| E[540-590 mm]
C -->|Large| F[590-640 mm]
G[Test Block]
G --> H[1m x 1m x 0.6m]
G --> I[Mass 1 tonne]
G --> J[Bed on dry sand]

For detailed testing and material specs, refer to IS 2925 clauses beyond definitions.

IS 2925: Materials Key Specifications for Industrial Safety Helmets

• Helmet Shell Material: Must withstand 15 min at 93 ± 5°C without distortion, separation, or softening (Clause 2.1).
• Minimum Cross-sectional Area for Straps: Not less than 180 mm² (Amendment No.1).
• Corrosion Resistance: Metal parts tested as per Appendix B (Clause 3.3) to ensure durability.
• Water Absorption: Tested according to Appendix J (Clause 8.5) to maintain helmet integrity in wet conditions.
• Salt Spray Test: Metal parts exposed to sodium chloride environment to check corrosion resistance (Amendment No.1).

Testing Summary Table

These ensure helmets meet safety, durability, and comfort standards per IS 2925.

IS 2925: Sizes for Industrial Safety Helmets

Clause 4.1 (Amendment Dec 2000):

• Helmets are available in the following headband circumference sizes (inside measurement):

• These sizes can be achieved by using one or more shells or headbands.
• The adjustment range must be clearly marked on the helmet.

Additional Specifications

• S-hook dimensions (Clause 2.3):

  • Height: ~100 mm
  • Width: ~50 mm
  • Material: 10 or 12 mm steel rod

• Headband:

  • May be continuous or not when a napestrap is provided (Clause 2.3.1).

Summary Diagram

flowchart LR
    A[Helmet Size] --> B[Shell + Headband]
    B --> C{Adjustment Range}
    C -->|520-600 mm| D[Marked on Helmet]
    E[S-hook] --> F[100 mm height, 50 mm width, 10/12 mm steel]

Note: Always refer to the latest IS 2925 amendment for precise manufacturing and testing requirements.

IS 2925 - Construction Key Specifications & Formulas

Block for Support (Clause 2.4):

• Material: Concrete or similar monolithic block
• Minimum Dimensions:
  • Height = 1 m
  • Length = 1 m
  • Width = 0.6 m
• Mass: Approximately 1 tonne
• Bedding: On dry sand over a solid floor

Headband Size Tolerance (Clause 4.1.1):

• Permitted tolerance: ± 10 mm
• Measurement: Using fixed ring gauge, expanding gauge (metal), or appropriate headform

Summary Table for Block Dimensions

Notes:

• The block supports the gauge and headform during helmet testing.
• Bedding on dry sand ensures stable and uniform support.
• Headband size tolerance ensures proper fit and safety compliance.

flowchart TD
    A[Concrete Block] -->|Supports| B[Gauge & Headform]
    A --> C[Dimensions: 1m x 1m x 0.6m]
    A --> D[Mass: 1 tonne]
    A --> E[Bedded on dry sand]

This ensures structural stability during helmet impact tests per IS 2925.

IS 2925: Workmanship and Finish - Key Points

• Surface Finish (Clause 6.1):

  • Helmet surface must be smooth, burr-free.
  • Remove all sharp edges to ensure proper fitting contact.
  • All metal parts (including rivets) must be smooth, without sharp or rough projections.

• Cable Clip Specification (Clause 5.5):

  • Made of plastic or suitable material.
  • Fixed securely to the helmet shell.
  • Test: Suspend a mass of 2.25 kg from a 50 cm cord attached to the clip.
  • Mass is dropped freely from 30 cm height twice.
  • The clip must remain intact after the test.

• Wooden Headform (Clause 5.5):

  • Used for mounting helmets during testing.
  • Ensures proper positioning for tests like the cable clip drop test.

• Additional Testing Methods:

  • Corrosion resistance of metal parts (Appendix B, Clause 3.3).
  • Penetration resistance of helmets (Appendix F, Clause 8.2).

Summary Table: Cable Clip Drop Test

flowchart TD
    A[Helmet with Cable Clip] --> B[Attach 2.25 kg mass with 50 cm cord]
    B --> C[Raise mass to 30 cm height]
    C --> D[Release mass freely]
    D --> E{Clip intact?}
    E -- Yes --> F[Test Passed]
    E -- No --> G[Test Failed]

This ensures the helmet's cable clip is robust and safe under impact conditions.

IS 2925: Key Specifications & Formulas for Helmet Mass

• Maximum Mass:

  • Complete helmet (without attachments & peak) ≤ 400 g (Clause 7.1)
  • If mass > 400 g, round to nearest 35 g and label on helmet.

• Water Absorption Limit:

  • Max water absorption ≤ 5% of helmet mass (Clause 8.5, Appendix J).

• Performance Load Test:

  • Helmet fitted on IS 7692 headform, loaded with 10 kg mass.
  • Clearance (top of headform to bottom edge of nape strap) ≥ 115 mm (Clause 5.3.2.1).

• Measurement Method for Clearance:

  • Use a rod ≤ 10 mm diameter through headform vertical axis.
  • Correct clearance if helmet has reinforcing ribs by measuring rib depth (Clause 2.1).

Summary Table:

flowchart LR
    A[Helmet] --> B[Mass ≤ 400 g?]
    B -- Yes --> C[No Label Needed]
    B -- No --> D[Label Mass (nearest 35 g)]
    A --> E[Water Absorption Test]
    E --> F[Absorption ≤ 5% mass]
    A --> G[Load Test with 10 kg on Headform]
    G --> H[Clearance ≥ 115 mm]

This ensures helmet safety, comfort, and compliance with IS 2925.

IS 2925: Key Performance Requirements

1. Mass Limit (Clause 7.1)

• Maximum mass of helmet (without attachments/peak): 400 g
• If mass > 400 g, label must show mass rounded to nearest 35 g

2. Shock Absorption Test (Clause 8.1, Appendix E)

• Helmets must pass impact tests simulating real-world shocks.
• Typically involves dropping helmet with a headform from specified heights.
• Measure peak acceleration; must be below a defined threshold (usually < 250 g).

3. Flammability Resistance (Clause 8.3, Appendix G)

• Helmets tested for flame resistance.
• Material should not ignite or continue to burn after exposure to flame for a specified time.
• Test involves direct flame application and observation of after-flame time.

Summary Table:

flowchart LR
    A[Helmet Mass ≤ 400 g] --> B[Pass Label Requirement]
    A --> C[Shock Absorption Test (Appendix E)]
    C --> D[Peak Acceleration < Threshold]
    A --> E[Flammability Test (Appendix G)]
    E --> F[No sustained burning]

For detailed test procedures and exact values, refer to Appendices E and G of IS 2925.

IS 2925 - Sampling and Criteria for Conformity

• Sampling Method: As per IS 9695:1980, which details statistical sampling plans for industrial products.
• Sample Selection: Refer to Clause 9.1 of IS 2925 and IS 9695 for the number and method of selecting samples from production batches.
• Criteria for Conformity: The product batch is accepted or rejected based on the number of defective samples found, following acceptance quality levels (AQL) defined in IS 9695.
• Heat Resistance Test: Per Clause 8.6 and Appendix K, helmet shells must withstand specified heat without separation, distortion, or softening.

Summary Table (Typical Sampling Plan Concept)

Refer IS 9695 for detailed tables.

flowchart TD
    A[Batch of Products] --> B[Select Sample as per IS 9695]
    B --> C{Test Samples}
    C -->|Defects ≤ Ac| D[Batch Accepted]
    C -->|Defects > Ac| E[Batch Rejected]

Note: Always consult IS 9695 for exact sampling sizes and acceptance criteria for your batch size.

IS 2925: Marking Specifications for Helmets

Marking Requirements (Clause 10.1)

Each helmet (shell and harness) shall be legibly and indelibly marked with:

• Manufacturer's name or trade-mark
• Size of helmet

Additional Marking Instructions (Clause 11.1)

Marking on helmet shell or securely affixed label must include:

• Helmet must fit or be adjustable closely to the required size.
• Helmet absorbs energy by partial destruction; helmets subjected to severe impact should be replaced.
• No alterations allowed to helmet structure or components to maintain efficiency.

Use of Standard Mark (Clauses 10.1.1 & 10.1.2)

• The product may carry the Standard Mark.
• Use governed by Bureau of Indian Standards Act, 1986.
• Licensing conditions available from BIS.

Summary Table for Marking

Note:

No specific formulas or numeric tables are provided for marking in IS 2925. The focus is on clear, indelible, and permanent markings for identification and safety instructions.

flowchart LR
    A[Helmet] --> B[Mark Manufacturer Name/Trademark]
    A --> C[Mark Helmet Size]
    A --> D[Attach Safety Instructions Label]
    D --> E[Fit/Adjust Size Warning]
    D --> F[Impact Damage Replacement Warning]
    D --> G[No Alterations Warning]

IS 2925: Method of Testing Sterilization (Appendix A, Clause 0.4)

The code specifies sterilization testing to ensure helmets are free from microbial contamination, especially for medical or industrial use.

Key Points:

• Sterilization Method: Typically involves autoclaving or chemical sterilization.
• Test Procedure:
  • Samples are subjected to sterilization cycles.
  • Post-sterilization, helmets are examined for microbial growth using culture media.
• Acceptance Criteria: No microbial growth should be observed after incubation, confirming effective sterilization.

Related Testing Methods in IS 2925:

Summary Diagram of Sterilization Test Process:

flowchart TD
    A[Sample Helmet] --> B[Sterilization Cycle]
    B --> C[Incubation in Culture Media]
    C --> D{Microbial Growth?}
    D -- No --> E[Pass: Sterilization Effective]
    D -- Yes --> F[Fail: Sterilization Ineffective]

Note: For detailed sterilization parameters (temperature, duration), refer to specific sterilization standards (e.g., autoclave at 121°C for 15-20 min). IS 2925 focuses on helmet safety and hygiene validation.

IS 2925: Method of Testing Corrosion Resistance of Metal Parts (Appendix B, Clause 3.3)

Key Specifications:

• Test Solution: 5 parts sodium chloride (NaCl) + 95 parts distilled water (by mass)
• Temperature: Room temperature (25°C to 35°C)
• Duration: Continuous spray for 24 hours
• Post-Test: Wash with clean running water and dry
• Acceptance: No visible signs of corrosion on metal parts

Important Notes:

• Metal parts must be inherently corrosion-resistant or treated accordingly.
• Helmets for underground mines must not contain aluminium, magnesium, or their alloys.

Summary Table:

flowchart TD
    A[Prepare NaCl Solution] --> B[Spray specimens continuously for 24 hrs]
    B --> C[Wash specimens with clean water]
    C --> D[Dry specimens]
    D --> E{Inspect for corrosion}
    E -- No corrosion --> F[Pass]
    E -- Corrosion present --> G[Fail]

This method ensures metal parts in helmets meet corrosion resistance standards per IS 2925.

IS 2925: Method for Checking Clearance Above the Head & Wearing Height (Depth of Fit)

Key Specifications (Clause 5.2.2 & Appendix C):

• Clearance Above the Head:
  Minimum 30 mm clearance between the top of the wearer’s head and the inside top of helmet crown at smallest headband size.

• Wearing Height (Depth of Fit):
  Minimum 80 mm depth of fit at maximum headband size adjustment.

• Cradle (Headband) Requirements:

  • Anti-concussion tapes secured at ≥ 4 anchoring points
  • Strap width ≥ 19 mm

Measurement Method (Appendix C, Clause 2.1):

1. Mount helmet on headform (per IS: 7692-1975) matching helmet size.
2. Apply a 10 kg load vertically on helmet top (e.g., 10 kg sandbag).
3. Measure clearance using a rod ≤ 10 mm diameter inserted through a hole on the headform’s vertical axis.
4. For helmets with reinforcing ribs, measure rib depth and adjust clearance accordingly.

Summary Table:

flowchart TD
    A[Mount helmet on headform] --> B[Apply 10 kg load on top]
    B --> C[Insert ≤10mm rod through headform hole]
    C --> D[Measure clearance above head]
    C --> E[Measure wearing height (depth of fit)]
    D --> F{Helmet has ribs?}
    F -- Yes --> G[Measure rib depth & correct clearance]
    F -- No --> H[Use measured clearance directly]

This method ensures helmet safety by verifying adequate space to protect the wearer’s head under load conditions.

IS 2925: Shock Absorption Test (Clause 8.1, Appendix E)

Key Specifications:

• Preconditioning: Helmet samples are conditioned by one of the following for 4 hours (no multiple conditions on same sample):
  • (a) Oven at 50 ± 5°C
  • (b) Refrigerator at -10 ± 2°C
  • (c) Water flow over shell at 1 l/min at room temperature
• Post-conditioning test: Conduct shock absorption test within 1 minute.
• Acceptance criteria:
  • No shell penetration or cracks.
  • Harness must remain functional without damage.
  • Maximum transmitted force: ≤ 5 kN (510 kgf) from headform to base.

Shock Absorption Test Summary:

Additional Notes:

• The helmet tested after the worst shock absorption condition is further tested for penetration resistance (Clause 8.2).
• No penetration or shell failure allowed.
• Penetration depth ≤ 10 mm including shell thickness.

flowchart TD
    A[Sample Conditioning] --> B{Condition Type}
    B -->|a) Oven 50±5°C| C[4 hours]
    B -->|b) Refrigerator -10±2°C| C
    B -->|c) Water flow 1 l/min| C
    C --> D[Shock Absorption Test]
    D --> E{Force Transmitted ≤ 5 kN?}
    E -->|Yes| F[Pass]
    E -->|No| G[Fail]

This ensures helmets maintain protective performance under varied environmental conditions.

IS 2925: Method of Testing Penetration Resistance (Clause 8.2, Appendix F)

• Test Timing: Conduct penetration resistance test within 1 minute after subjecting the helmet to the worst shock absorption condition (Clause 8.1).

• Acceptance Criteria:

  • Helmet shall not break or be pierced to the extent that the headform is touched.
  • No part should fail or stretch to allow the helmet to be forced over the headform.
  • Maximum penetration/dent depth (including shell thickness): 10 mm.

• Test Setup:

  • Use a pointed striker as per Appendix F.
  • Apply impact force as specified (refer to Appendix F for exact striker mass and drop height).
  • Measure penetration depth statically after impact.

Key Specification Summary:

This ensures helmets maintain structural integrity and protect against sharp object penetration post-impact.

flowchart LR
    A[Shock Absorption Test] --> B{Worst Result?}
    B -- Yes --> C[Penetration Resistance Test (within 1 min)]
    C --> D[Impact with Pointed Striker]
    D --> E[Measure Penetration Depth]
    E --> F{Penetration ≤ 10 mm?}
    F -- Yes --> G[Pass]
    F -- No --> H[Fail]

For detailed striker specs and impact parameters, refer to Appendix F of IS 2925.