Specification for head forms for testing of helmets

IS 7692 - Scope Key Specifications and Tables

IS 7692 covers detailed dimensional specifications for structural components, focusing on precise geometric data using polar coordinates relative to a reference plane.

Key Highlights:

• Scope: Defines dimensions of structural elements at various heights/depths and angular positions around a reference plane.
• Dimensions: All in millimeters (mm).
• Measurement Around Head: Typically 560 mm to 610 mm depending on clause/table.

Important Tables:

Example Table Snippet (Height Above Reference Plane):

Usage:

• These tables guide the precise shaping and sizing of structural parts.
• Used for fabrication and quality control to ensure compliance with IS 7692.

Summary Diagram (Polar Coordinate Concept)

polarArea
    title Polar Coordinates of Structural Section
    0: 108.5
    15: 107.5
    30: 103.5
    45: 96.0
    60: 90.5
    75: 87.0
    90: 87.0
    105: 90.0
    120: 94.5
    135: 100.0
    150: 105.0

IS 7692: Dimensions of Headforms

Key Specifications (from Clauses 2.1, 2.2, 2.4)

• Circumference: Internal helmet circumference at headband level (Plane AA' in Fig.1).
• For intermediate circumference values, use the next lower headform.
• Tolerance on dimensions (except circumference): ±0.25 mm.

Reference Planes & Axes

• Reference Plane: Base for vertical measurements.
• Central Vertical Axis and Inclined Axis of Testing are used to locate dimensions on the headform.

Depth Below Reference Plane (Selected from Table 3)

(All dimensions in mm)

Summary:

• Use Table 1 for basic headform dimensions (H, V, circumference).
• Use Table 3 for detailed shape profile below reference plane.
• All dimensions are in millimeters.
• Reference planes and axes ensure consistent positioning during testing.

graph TD
    A[Reference Plane] --> B[Vertical Axis (V)]
    A --> C[Horizontal Axis (H)]
    B --> D[Headform Height (V)]
   

IS 7692: Construction of Headforms - Key Data & Specifications

1. Headform Dimensions (Table 1)

• H and V are key dimensional heights (see Fig.1).
• Circumference refers to internal helmet circumference at headband level (Plane AA').
• For intermediate circumference values, use the next lower headform size.
• Dimensional tolerance (except circumference): ±0.25 mm.

2. Markings & Mounting (Clause 2.5)

• Each headform must be marked with:
  • Reference line (datum plane)
  • Circumference value (on both sides)
  • Code letter (from Table 1)
• Designed for mounting in vertical or inclined positions during shock absorption testing.

3. Reference Planes & Axes

• Reference Plane (Datum Level): Base for dimensional measurement.
• Central Vertical Axis and Inclined Axis used for mounting and testing orientation.

Summary Diagram (Conceptual)

graph TD
  A[Reference Plane (Datum)] --> B[Headform Dimensions H & V]
  B --> C[Inside Circumference at Plane AA']
  C --> D[Markings: Code Letter & Circumference]
  D --> E[Mounting: Vertical or Inclined]

Use these dimensions and markings strictly for helmet fitting and testing compliance as per IS 7692.

IS 7692 - Materials: Key Specifications & Tables

1. Headform Dimensions (Clause 2.4 & Table 1)

• Headforms simulate the internal helmet size.
• Inside Circumference Codes:

• Use next lower size for intermediate circumference values.
• Tolerance: ±0.25 mm (except circumference).

2. Polar Coordinates of Headform Surfaces (Clause 2.2, Table 2 & Clause 12.3, Table 3-J)

• Defines helmet surface shape in mm at various angles and heights above/below reference plane.
• Example excerpt (Height 0 mm, angles 0° to 180°):

• Depth below reference plane also tabulated for detailed fitting.

3. Application

• These dimensions and tolerances ensure helmet material fits and protects correctly.
• Material selection must accommodate these dimensional constraints.

graph LR
A[Headform Circumference] --> B[Select Size Code 0-3]
B --> C[Apply Dimensional Tolerances ±0.25mm]
C --> D[Use Polar Coordinates for Helmet Shape]
D --> E[Material & Construction Specification]

Summary: Use Tables 1, 2, and 3 for precise helmet internal geometry. Material specs must ensure compliance with these dimensions for safety and comfort.

IS 7692: Reference Planes and Measurement Points

Key Specifications:

• Reference Plane (H): Defined height above a datum for head measurements.
• Typical H values:
  • Clause 108.7: 108.7 mm (Head circumference ~610 mm)
  • Clause 111.8: 111.8 mm (Head circumference ~630 mm)
  • Clause 89.7: 89.7 mm (Head circumference ~500 mm)

Measurement Points:

• Defined by polar coordinates (angles and heights) around the head.
• Angles from 0° (front) to 180° (back) in 15° increments.
• Heights above reference plane vary (0, 20, 40... up to 110 mm).

Table Format (Excerpt):

(Values in mm represent radial distances from the reference plane at given angles and heights.)

Usage:

• These coordinates define helmet sizing and fit.
• Measurement points ensure consistent anthropometric data for design.

Summary Diagram (Polar Measurement Points):

polarChart
  title Head Measurement Points (Example)
  0: 108.5
  15: 107.5
  30: 103.5
  45: 96.0
  60: 90.5
  75: 87.5
  90: 87.0
  105: 90.0
  120: 94.5
  135: 100.0
  150: 105.0
  165: 108.0
  180: 108.5

Note: Refer to IS 7692 Table 2 for full detailed

IS 7692: Sizes and Shapes of Headforms

Key Specifications (Clause 2.4 & Table 1)

• H and V are key headform dimensions (height and vertical extent).
• Circumference is measured at the headband level (Plane AA', Fig. 1).
• For intermediate circumference values, use the next lower headform size.
• Tolerance on dimensions (other than circumference): ±0.25 mm.

Additional Notes:

• Headforms are marked with reference line and circumference on both sides.
• Designed for mounting in vertical or inclined positions during shock absorption testing.
• Reference planes and axes are defined for consistent testing orientation (see Fig. 1).

flowchart LR
    A[Headform Size Code] --> B{Circumference (mm)}
    B -->|≤ 500| C[Code 0]
    B -->|501-540| D[Code 1]
    B -->|541-570| E[Code 2]
    B -->|571-600| F[Code 3]
    C --> G[Dimensions H=89.5, V=216.4]
    D --> H[Dimensions H=96.0, V=223.4]
    E --> I[Dimensions H=102.5, V=232.4]
    F --> J[Dimensions H=107.0, V=249.0]

This ensures helmet internal sizing matches the headform for accurate protective performance testing.

IS 7692 — Manufacturing Tolerances: Key Specifications & Tables

1. Dimensional Tolerances:

• Dimension H examples:
  • 105.4 mm (Clause 12.3)
  • 105.4 mm (Clause 12.7)
  • 89.7 mm (Clause 89.7)
• Measurement around the head varies (e.g., 560 mm, 570 mm, 500 mm).

2. Polar Coordinate Tables:

• Provide precise dimensional values at various angular positions (0° to 180°) and depths/heights relative to a reference plane.
• Useful for verifying shape and form tolerances of components.

3. Usage:

• These tables ensure manufacturing accuracy by comparing actual measurements against standard tolerances.
• Critical for quality control of structural steel components.

Summary:

• Dimension H and measurement around the head define nominal sizes.
• Polar coordinate tables specify allowable deviations at angular increments and depths/heights.
• Use these tables to verify manufacturing precision per IS 7692.

graph LR
A[Reference Plane] --> B[Depth/Height Levels]
B --> C[Angular Positions 0° to 180°]
C --> D[Measured Dimensions]
D --> E[Check Against Tolerances]
E --> F[Accept/Reject Component]

For detailed manufacturing tolerance checks, refer to Clauses 12.3, 12.7, 2.2, and 89.7 tables in IS 7692.

IS 7692: Use of Headforms in Helmet Testing

Key Specifications & Dimensions (Clause 2.4, Table 1)

• H and V represent key headform dimensions (height and vertical length).
• Circumference corresponds to the internal helmet circumference at the headband level (Plane AA’).
• For intermediate helmet sizes, use the next lower headform size.
• Dimensional tolerance (except circumference): ±0.25 mm.

Markings & Mounting (Clause 2.5)

• Headforms must be marked with:
  • Reference line (datum).
  • Circumference on each side.
  • Code letter as per Table 1.
• Designed for mounting in vertical or inclined positions during shock absorption tests.

Reference Planes & Axes (Fig. 1)

• Testing is done relative to:
  • Central vertical axis.
  • Inclined axis for impact.
  • Reference plane (datum for measurements).

Summary Diagram of Headform Dimensions

graph TD
    A[Reference Plane (Datum)] --> B[Height (H)]
    A --> C[Vertical length (V)]
    B --> D[Headform circumference at Plane AA']
    C --> D

This ensures standardized helmet fit and impact testing per IS 7692.

IS 7692: Quality Control and Inspection - Key Points

Quality Control System

• Products must comply with IS 7692 under a well-defined system of inspection, testing, and quality control supervised by BIS.
• Continuous surveillance by BIS ensures conformity.
• Use of Standard Mark governed by BIS Act, 1986.

Inspection & Testing

• Inspection includes dimensional checks, material tests, and performance tests as per clauses.
• Dimensional tolerances mostly ±0.25 mm except inside helmet circumference.
• Headforms (for helmet testing) have specified dimensions and size codes (Table 1):

• For intermediate sizes, use next lower headform.

Dimensional Data

• Table 2 (Clause 2.2) provides polar coordinates of horizontal half sections for headforms in mm.
• Clause 14.1 specifies key dimensions like Dimension H = 105.4 mm and helmet head measurement circumference ≈ 640 mm.

Summary Diagram of Inspection Flow

flowchart TD
    A[Raw Material Inspection] --> B[Dimensional Checks]
    B --> C[Headform Fitting & Size Verification]
    C --> D[Performance Testing]
    D --> E[Final Inspection & Marking]
    E --> F{Conforms to IS 7692?}
    F -->|Yes| G[Standard Mark Licensing]
    F -->|No| H[Rework/Reject]

Note: Always refer to IS 7692 clauses for detailed test procedures and sampling plans.

IS 7692: Marking and Licensing (Clause 14.1 & Related Clauses)

Key Dimensions for Marking:

• Dimension H (headform height): 105.4 mm
• Dimension / : 14.1 mm
• Measurement around head (circumference): 640 mm

Licensing & Standard Mark

• The Standard Mark certifies compliance with IS 7692 under BIS supervision.
• Licensing is governed by Bureau of Indian Standards Act, 1986.
• Producers must maintain inspection, testing, and quality control systems.
• BIS continuously monitors conformity post-licensing.
• Contact BIS for licensing conditions and copyright permissions.

Headform Size Codes (Clause 2.4 & Table 1)

• For intermediate circumferences, use the next lower code.
• Dimensional tolerance (except circumference): ±0.25 mm

Headform Marking Requirements (Clause 2.5 & 2.6)

• Mark reference line and circumference on both sides.
• Mark basic plane, longitudinal & transverse planes.
• Mark two points equispaced around point K on the basic plane for peripheral vision checks.
• Mark two points 33 mm each side of point K on the basic plane.

flowchart LR
    A[Helmet Manufacturer] --> B[BIS Licensing]
    B --> C[Inspection & Testing]
    C --> D[Standard Mark on Product]
    D --> E[Continuous BIS Surveillance]

Summary: IS 7692 mandates specific headform dimensions, detailed marking for testing, and strict licensing under BIS to ensure helmet safety and quality.

IS 7692: Compliance and Rounding Off Rules Summary

1. Rounding Off Tolerances:

• All dimensions (except inside circumference of helmets) have a tolerance of ±0.25 mm.
• For inside helmet circumference, use the next lower headform size if the measurement is intermediate.

2. Headform Size Codes (Clause 2.4):

• Use the next lower size for intermediate circumferences.

3. Key Dimensions from Tables (Clauses 2.2, 2.3):

• Heights and depths at various angles (0° to 180°) are tabulated in Tables 2 and 3.
• Dimensions are in millimetres.
• Example: At 0° Front and 0 mm height above reference plane, dimension is 88.0 mm (Table 2-A).

4. Measurement Around Head:

• Around the head: 610 mm (Clause 108.7).

Usage Note:

• Use these tables for precise helmet fitting and testing.
• Rounding off ensures standardized manufacturing and testing consistency.

flowchart TD
    A[Measure Helmet Circumference] --> B{Intermediate Value?}
    B -- Yes --> C[Use Next Lower Headform Size]
    B -- No --> D[Use Corresponding Headform Size]
    D --> E[Check Dimensions with Tables 2 & 3]
    C --> E
    E --> F[Apply ±0.25 mm Tolerance for Dimensions]
    F --> G[Compliance Confirmed]

This ensures compliance with IS 7692 for helmet dimensioning and testing.

IS 7692 Key Annexures & Tables Summary

Table 2: Polar Coordinates of Horizontal Half Sections (Clause 2.2)

• Provides headform dimensions in millimeters for various angles (0° to 180°) and heights (0 to 85 mm) above the reference plane.
• Used for ergonomic and safety design of headgear.
• Example excerpt:

Clause 14.1: Head Dimension Details

• Dimension H: 105.4 mm
• Measurement around the head: 640 mm
• Used for sizing and fitment of protective headgear.

Usage Notes:

• Dimensions assist in designing protective equipment conforming to IS 7692.
• Polar coordinates help model head shapes for ergonomic fit.
• Refer to Fig. 2 & 3 for graphical representation of these dimensions (above and below reference line).

graph LR
A[Reference Plane] --> B[Headform Dimensions Above]
A --> C[Headform Dimensions Below]
B --> D[Table 2: Polar Coordinates]
C --> E[Table 3: Dimensional Details]

For detailed design, use Table 2 values to map headform contours at specified angles and heights.

IS 7692 Key References - Dimensions & Tables

1. Polar Coordinates of Horizontal Half Sections (Clause 2.2, Table 2):

   • Provides horizontal dimensions (in mm) at various heights above the reference plane and angles (0° to 180°).
   • Example: At height 0 mm and 0° front, dimension = 88.0 mm.

2. Depth Below Reference Line (Clause 2.3, Table 3):

   • Gives vertical depths below reference plane for angles 0° to 180°, useful for 3D shape profiling.
   • Example: At depth 0 mm and 0° front, dimension = 88.0 mm.

3. Dimension H (Clause 108.7):

   • Standard dimension H = 108.7 mm.
   • Measurement around the head = 610 mm.

Usage Summary:

• Use Table 2 for horizontal profiling at different heights and angles.
• Use Table 3 for vertical depth profiling below reference plane.
• Dimension H is a key fixed measurement for head circumference and height.

graph LR
A[Reference Plane] --> B[Height Above Plane (Table 2)]
A --> C[Depth Below Plane (Table 3)]
B --> D[Horizontal Dimensions @ Various Angles]
C --> E[Vertical Depths @ Various Angles]
F[Dimension H = 108.7 mm] --> A

These tables enable accurate 3D modeling of the structure per IS 7692.

IS 7692 - Revision and Amendment History Key Data

The code provides detailed dimensional tables for helmet design, specifying measurements in millimeters at various angular sections and heights/depths relative to a reference plane.

Key Tables & Dimensions:

Usage:

• Use these tables to define helmet shell geometry at specified angular increments.
• Dimensions correspond to height/depth vs. angular position around the head.
• Critical for helmet design ensuring proper fit and coverage.

Example: Reading Table 2 (Height 0 mm)

This data supports helmet shape revision and amendments by providing precise dimensional references for manufacturing and design validation.