Specification for protective helmets for scooter and motorcycle riders 1993 Edition
This specification outlines the essential criteria for protective helmets intended for scooter and motorcycle users in India, detailing construction, materials, impact resistance, retention mechanisms, and testing protocols to guarantee safety and comfort. It serves as a vital reference for manufacturers, safety professionals, and certification authorities to ensure compliance with Indian safety standards.
This specification outlines the essential criteria for protective helmets intended for scooter and motorcycle users in India, detailing construction, materials, impact resistance, retention mechanisms, and testing protocols to guarantee safety and comfort. It serves as a vital reference for manufacturers, safety professionals, and certification authorities to ensure compliance with Indian safety standards.
Audience
Who Uses This Standard
Helmet producers
Safety specialists
Quality assurance inspectors
Product developers
Certification agencies
Motorcycle safety regulators
Advocates for rider protection
Contents
Key Topics Covered
✓Helmet design and material standards
✓Specifications for protective and comfort padding
✓Requirements for retention systems and chin straps
✓Methods for impact absorption testing
✓Tests for penetration resistance
✓Audibility and sound attenuation evaluation
✓Criteria for field of vision and peripheral sight
✓Helmet sizing and headform compatibility
✓Durability conditioning processes
✓Marking and labeling protocols
✓Visor material standards and testing
✓Workmanship and finishing quality
Structure
Table of Contents
1Scope and Fundamental Specifications▼
Overview of Scope (Clause 3.0)
Defines test headforms based on IS 7692:1993 for impact absorption.
Details headform sizes and masses used for helmet testing.
Key Headform Data
Headform Symbol
Size (mm)
Mass (kg)
A
500
3.1 ± 0.10
E
540
4.1 ± 0.12
J
570
4.7 ± 0.14
M
600
5.6 ± 0.16
O
620
6.1 ± 0.18
If the specified size is unavailable, the next smaller headform shall be used.
Testing Apparatus Specifications (Clause 1.2)
Parameter
Specification
Punch mass
0.3 ± 0.01 kg
Cone angle of punch head
60° ± 1°
Radius of punch head top
0.5 mm
Drop hammer mass
3 ± 0.025 kg
Drop height
1 ± 0.005 m
Tip hardness (Rockwell C)
45–50
Minimum cone height
40 mm
Synopsis
Headforms simulate human head sizes for impact tests.
Testing devices are standardized to maintain consistent impact conditions.
Refer to IS 7692:1993 for detailed headform dimensions.
2Referenced Standards and Tables▼
Primary References (Clause 2)
IS Number
Title
1884:1981
Specification for automobile electric horns
7692:1993
Wooden headforms specification for helmet testing
9695:1980
Helmet sampling methods
9779:1981
Sound level meter specifications
9844:1987
Corrosion resistance testing of coatings
9973:1981
Visor specifications for scooter helmets
Headform Details (Clause 2.1.5)
Symbol
Size (mm)
Mass (kg)
A
500
3.1 ± 0.10
E
540
4.1 ± 0.12
J
570
4.7 ± 0.14
M
600
5.6 ± 0.16
O
620
6.1 ± 0.18
Use the next smaller size if exact size is not listed.
3Terminology and Definitions▼
Device Specifications (Clause 1.2)
Parameter
Value
Punch mass
0.3 ± 0.01 kg
Cone angle of punch head
60° ± 1°
Radius of punch head top
0.5 mm
Drop hammer mass
3 ± 0.025 kg
Drop height
1 ± 0.005 m
Tip hardness (Rockwell C)
45–50
Minimum cone height
40 mm
Headform Specifications (Clause 2.1.5)
Symbol
Size (mm)
Mass (kg)
A
500
3.1 ± 0.10
E
540
4.1 ± 0.12
J
570
4.7 ± 0.14
M
600
5.6 ± 0.16
O
620
6.1 ± 0.18
Note: For sizes not listed, use the next smaller headform size.
4Material Requirements and Construction Details▼
Testing Device Parameters (Clause 1.2)
Parameter
Value
Punch mass
0.3 ± 0.01 kg
Cone angle of punch head
60° ± 1°
Radius of punch head top
0.5 mm
Drop hammer mass
3 ± 0.025 kg
Drop height
1 ± 0.005 m
Tip hardness (Rockwell C)
45–50
Minimum cone height
40 mm
Visor Materials (Clause 4.6)
Must conform to IS 9973:1981 specifications.
Headform Data (Clause 2.1.5)
Symbol
Size (mm)
Mass (kg)
A
500
3.1 ± 0.10
E
540
4.1 ± 0.12
J
570
4.7 ± 0.14
M
600
5.6 ± 0.16
O
620
6.1 ± 0.18
Use the next smaller size if exact size is unavailable.
5Helmet Sizes and Headform Compatibility▼
Essential Specifications (Clauses 2.1.5 & 5.1)
Headform shapes and dimensions conform to IS 7692:1993.
Helmets are tested on headforms with the following sizes (mm): 500, 520, 540, 560, 570, 580, 600, 620.
Symbol
Size (mm)
Mass (kg)
A
500
3.1 ± 0.10
E
540
4.1 ± 0.12
J
570
4.7 ± 0.14
M
600
5.6 ± 0.16
O
620
6.1 ± 0.18
For sizes not explicitly listed, the next smaller headform is used.
Positioning
Helmets must be fitted on the designated headform following Annex B procedures.
6Design Criteria and Performance Standards▼
Testing Device Characteristics (Clause 1.2)
Parameter
Specification
Punch mass
0.3 ± 0.01 kg
Cone angle of punch head
60° ± 1°
Radius of punch head top
0.5 mm
Drop hammer mass
3 ± 0.025 kg
Drop height
1 ± 0.005 m
Tip hardness (Rockwell C)
45–50
Minimum cone height
40 mm
Headforms (Clause 2.1.5)
Symbol
Size (mm)
Mass (kg)
A
500
3.1 ± 0.10
E
540
4.1 ± 0.12
J
570
4.7 ± 0.14
M
600
5.6 ± 0.16
O
620
6.1 ± 0.18
Use next smaller headform if size not listed.
Helmet Weight Limit (Clause 8.1)
Maximum helmet weight excluding peak, visor, and detachable face covers: 1500 g.
Impact Test Sequence (Clause 4.3)
Conditioning
Anvils
Impact Points
Ambient
Flat then hemispherical
B, B1, X, X1 (selected)
Heat
Flat then hemispherical
B, B1, X, X1 (selected)
Low Temperature
Flat then hemispherical
B, B1, X, X1
UV Radiation & Moisture
Flat then hemispherical
B, B1, X, X1 (selected)
7Workmanship and Finishing Standards▼
Testing Device Characteristics (Clause 1.2)
Parameter
Specification
Punch mass
0.3 ± 0.01 kg
Cone angle of punch head
60° ± 1°
Radius of punch head top
0.5 mm
Drop hammer mass
3 ± 0.025 kg
Drop height
1 ± 0.005 m
Tip hardness (Rockwell C)
45–50
Minimum cone height
40 mm
Impact Test Points (Clause 4.3)
Conditioning
Anvils
Points of Impact
Ambient
Flat then hemispherical
B, B1, X, X1 (selected)
Heat
Flat then hemispherical
B, B1, X, X1 (selected)
Low Temperature
Flat then hemispherical
B, B1, X, X1
UV Radiation & Moisture
Flat then hemispherical
B, B1, X, X1 (selected)
Visor Material (Clauses 4.6 & 6.6)
Must comply with IS 9973:1981.
8Helmet Mass and Comfort Considerations▼
Headform Masses (Clause 2.1.5)
Symbol
Size (mm)
Mass (kg)
A
500
3.1 ± 0.10
E
540
4.1 ± 0.12
J
570
4.7 ± 0.14
M
600
5.6 ± 0.16
O
620
6.1 ± 0.18
If size is unavailable, the next smaller size shall be used.
Helmet Weight Limit (Clause 8.1)
Maximum helmet weight (excluding peak, visor, detachable face cover) permitted is 1500 g.
Comfort Padding (Clauses 3.5 & 4.3)
Padding materials include expanded polyurethane foam, polyethylene, or equivalent to enhance comfort.
9Helmet Performance Testing Procedures▼
Testing Device Parameters (Clause 1.2)
Parameter
Specification
Punch mass
0.3 ± 0.01 kg
Cone angle of punch head
60° ± 1°
Radius of punch head top
0.5 mm
Drop hammer mass
3 ± 0.025 kg
Drop height
1 ± 0.005 m
Tip hardness (Rockwell C)
45–50
Minimum cone height
40 mm
Test Conditions and Impact Locations (Clause 4.3)
Conditioning
Anvils
Impact Points
Ambient
Flat then hemispherical
B, B1, X, X1 (selected)
Other specified conditions
Flat then hemispherical
P, P1
Heat
Flat then hemispherical
B, B1, X, X1 (selected)
Low Temperature
Flat then hemispherical
B, B1, X, X1
UV Radiation & Moisture
Flat then hemispherical
B, B1, X, X1 (selected)
Headform Specifications (Clause 2.1.5)
Symbol
Size (mm)
Mass (kg)
A
500
3.1 ± 0.10
E
540
4.1 ± 0.12
J
570
4.7 ± 0.14
M
600
5.6 ± 0.16
O
620
6.1 ± 0.18
Use next smaller headform if size unavailable.
10Marking and Labeling Protocols▼
BIS Certification Mark (Clause 12.1.1)
Helmets may bear the BIS Standard Mark as per Bureau of Indian Standards guidelines.
Impact Point Marking (Clause 1.2)
Impact locations must be marked on helmets prior to conditioning.
Refer to Figure 4 in IS 4151 for marking positions.
Headform Data (Clause 2.1.5)
Symbol
Size (mm)
Mass (kg)
A
500
3.1 ± 0.10
E
540
4.1 ± 0.12
J
570
4.7 ± 0.14
M
600
5.6 ± 0.16
O
620
6.1 ± 0.18
If the size is not listed, use the next smaller headform.
Testing Device Specs (Clause D-1.2)
Parameter
Specification
Punch mass
0.3 ± 0.01 kg
Cone angle
60° ± 1°
Punch head radius
0.5 mm
Drop hammer mass
3 ± 0.025 kg
Drop height
1 ± 0.005 m
Tip hardness (Rockwell C)
45–50
Minimum cone height
40 mm
Annex AReferenced Indian Standards▼
Indian Standards Referenced (Annex A)
IS Number
Title
1884:1981
Electric horns for automobiles (second revision)
7692:1993
Wooden headforms for helmet testing
9695:1980
Sampling methods for helmets
9779:1981
Specifications for sound level meters
9844:1987
Procedures for coating corrosion resistance testing
9973:1981
Visor specifications for scooter helmets
Headform Data (Clause 2.1.5)
Symbol
Size (mm)
Mass (kg)
A
500
3.1 ± 0.10
E
540
4.1 ± 0.12
J
570
4.7 ± 0.14
M
600
5.6 ± 0.16
O
620
6.1 ± 0.18
Use next smaller size if exact match is not available.
Additional Notes
Helmets are not intended for high-speed competitive racing (Clause 1.2).
BIS marking is recommended but optional (Clause 12.1.1).
Retention test apparatus details updated in Amendment No. 2.
Impact tests utilize wooden headforms per IS 7692:1993.
Annex BHelmet Positioning on Headform▼
Procedure for Helmet Placement (Clause 6.5.1, Annex B)
Select headform according to IS 7692:1993.
Place helmet on headform.
Apply a vertical load of 50 N on the helmet crown to seat it properly.
Align the helmet's vertical median plane with that of the headform.
Check front edge positioning against a gauge to verify upward field of vision.
After conditioning, tilt helmet 25 mm rearward along the median plane.
Adjust and tighten the chin strap fully under the chin.
Apply load at the vertical axis through headform’s center of gravity.
Measure vertical displacement at the load application point.
Annex CImpact Absorption Testing▼
Principle (Clause 9.1 & Annex C)
Helmet mounted on a test headform is dropped in a guided free fall onto a fixed steel anvil.
Impact velocity is controlled and acceleration versus time is recorded.
This evaluates the helmet's capacity to absorb impact energy.
Headform Data (Clause 2.1.5)
Symbol
Size (mm)
Mass (kg)
A
500
3.1 ± 0.10
E
540
4.1 ± 0.12
J
570
4.7 ± 0.14
M
600
5.6 ± 0.16
O
620
6.1 ± 0.18
Headforms conform to IS 7692:1993.
Use the next smaller headform if the exact size is not listed.
Annex DPenetration Resistance Test▼
Testing Device Parameters (Annex D, Table D-1)
Parameter
Value
Punch mass
0.3 ± 0.01 kg
Cone angle
60° ± 1°
Punch head radius
0.5 mm
Drop hammer mass
3 ± 0.025 kg
Drop height
1 ± 0.005 m
Tip hardness (Rockwell C)
45–50
Minimum cone height
40 mm
Test Procedure (Clause 9.2)
Conduct tests at two helmet protection points at least 75 mm apart.
Tests follow conditioning resulting in the lowest impact absorption.
The punch head must maintain a vertical clearance of at least 5 mm from the headform.
Annex GAudibility Testing▼
Objective (Clause 9.5 & Annex G)
Assess helmet sound attenuation to ensure sound transmission loss does not exceed 10 dB over 250 to 2000 Hz.
Equipment
Headform as per IS 7692:1993.
Sound level meter complying with IS 9779:1981.
Microphone positioned at ear location.
Use A-weighting filter.
Sound Source
Horn type 2A as per IS 1884:1981.
Sound pressure level between 90 and 115 dB(A).
Sound directed from the rear of the headform.
Calculation
Sound transmission loss (STL) is the difference between incident sound level without helmet and transmitted level with helmet.
STL must be ≤ 10 dB within 250–2000 Hz range.
Frequently Asked
Popular Questions About IS 4151
?What materials are permitted for the helmet shell and padding under IS 4151?▼
Under IS 4151, helmet shells must be made from non-metallic materials that meet specified shock absorption and impact resistance standards, commonly including fiberglass, polycarbonate, ABS, or composite resins. Padding materials typically consist of energy-absorbing foams such as expanded polystyrene or polyurethane to ensure adequate shock absorption. Visors, if provided, must comply with IS 9973:1981 and are generally manufactured from impact-resistant plastics like polycarbonate.
?How is the impact absorption capacity of helmets tested according to this standard?▼
Impact absorption testing under IS 4151 involves mounting the helmet on a specified headform and dropping it in a controlled guided free fall onto a fixed steel anvil at a defined velocity. The acceleration experienced by the headform is recorded over time to assess the helmet's capability to absorb impact forces. Testing includes applying a 10 N initial load, impact with a conical metal punch struck by a drop hammer, measurement of punch penetration, and compression tests under incremental loads. Helmets are conditioned under various environmental conditions prior to testing to evaluate performance reliability.
?What are the requirements for the helmet retention system and chin strap?▼
IS 4151 mandates that the helmet retention system must securely hold the helmet on the wearer’s head, fastening firmly under the chin. The chin strap, an integral part of the retention mechanism, should pass beneath the wearer’s jaws to maintain helmet position. The attachment to the helmet shell must prevent displacement. Effectiveness is verified through retention tests conducted under the least favorable conditions to ensure reliability.
?How does IS 4151 address helmet sizing and compatibility with headforms?▼
IS 4151 specifies helmet sizes corresponding to headform dimensions defined in IS 7692:1993, including sizes from 500 mm up to 620 mm with intermediate increments. Helmets are tested by fitting them onto matching headforms according to standardized procedures. If a helmet size is not explicitly listed, the next smaller headform size is utilized for testing. This ensures accurate fit and performance consistency across typical human head sizes.
?What performance tests must a helmet pass to comply with IS 4151?▼
To comply with IS 4151, helmets must successfully pass several performance tests including shock absorption based on deceleration limits, retention system strength tests ensuring chin strap reliability, chin guard protection assessments, side impact tests under varied temperature and humidity, flexibility tests for helmet peaks measuring deflection without damage, and penetration resistance tests using a conical metal punch. Testing is performed on wooden headforms as per IS 7692:1993 with sampling and conformity verified according to IS 9695:1980.
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