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IS 4151:1993 is the Indian Standard (BIS) for protective helmets for scooter and motorcycle riders. This standard specifies the requirements regarding materials, construction, workmanship, and performance tests (such as impact absorption and penetration resistance) for protective helmets used by motorcycle and scooter riders.
Specification for protective helmets for scooter and motorcycle riders
! Compliance with IS 4151 is legally mandatory under the Motor Vehicles Act for manufacturing and selling two-wheeler helmets in India.
! Visors attached to the helmet are not covered by this standard and must conform separately to IS 9973.
! The 1993 version was superseded by the 2015 revision, which updated impact testing protocols and altered weight limits to improve rider comfort and safety.
Uniform provisions concerning the approval of protective helmets and their visors for drivers and passengers of motorcycles and mopeds
Both standards specify performance requirements for protective helmets for riders of two-wheeled motor vehicles.
FMVSS No. 218DOT (US)
HighCurrent
Motorcycle Helmets
Both are mandatory government standards setting minimum safety performance for motorcycle helmets in their respective regions.
SNELL M2020Snell Memorial Foundation (US/International)
MediumCurrent
2020 Standard For Protective Headgear For Use With Motorcycles And Other Motorized Vehicles
A voluntary, often more stringent standard focused on high-performance impact management for competitive and street use.
ECE 22.05UNECE (Europe)
HighWithdrawn
Uniform provisions concerning the approval of protective helmets and their visors for drivers and passengers of motorcycles and mopeds
The direct predecessor to ECE 22.06, with a testing regime more comparable in complexity to IS 4151:1993.
Key Differences
≠IS 4151:1993 specifies impact tests at a single velocity (7.0 m/s), whereas the modern ECE 22.06 standard mandates tests at multiple velocities (low, medium, and high speed) to assess performance across a wider range of accident scenarios.
≠ECE 22.06 includes a mandatory test for rotational acceleration by using an oblique (angled) anvil, which simulates the rotational forces on the brain during an angled impact. IS 4151:1993 does not have a requirement for testing rotational forces.
≠The Indian standard includes a penetration test where a 3 kg pointed striker is dropped onto the helmet. The modern ECE 22.06 standard has eliminated this specific test in favor of more comprehensive shell rigidity and multi-impact assessments. The US DOT standard, however, retains a similar penetration test.
≠ECE 22.06 has integrated and extensive requirements for visors, including optical quality, scratch resistance, and impact resistance. IS 4151:1993 covers helmets only and references a separate standard (IS 9973) for visors, which is not as comprehensive.
Key Similarities
≈Both standards mandate a critical impact absorption (or attenuation) test, where a helmeted headform is dropped onto an anvil, and the transmitted acceleration to the headform must remain below a specified threshold.
≈Both IS 4151:1993 and its international counterparts require a retention system (chin strap) test to ensure the helmet remains securely on the rider's head during an impact. The tests verify the strap's strength and resistance to stretching.
≈All standards specify a minimum requirement for peripheral vision, ensuring the helmet design does not dangerously obstruct the rider's field of view. The required horizontal angle is very similar across standards.
≈The fundamental construction principle is similar, requiring a hard outer shell to distribute impact force and a crushable inner liner (typically EPS - Expanded Polystyrene) to absorb impact energy.
Parameter Comparison
Parameter
IS Value
International
Source
Impact Attenuation (Peak G-force limit)
300 g (for both flat and hemispherical anvils)
Peak acceleration must not exceed 275 g; Head Injury Criterion (HIC) must not exceed 2400.
ECE 22.06
Primary Impact Test Velocity (Flat Anvil)
7.0 m/s
7.5 m/s (plus additional tests at 6.0 m/s and 8.2 m/s at different points)
ECE 22.06
Penetration Resistance Test
3 kg pointed striker dropped from 2 m height; must not contact headform.
3 kg pointed striker dropped from 3 m height; must not contact headform.
FMVSS No. 218
Retention System (Chin Strap) Dynamic Test
15 kg mass dropped from 0.75 m. Max elongation 35 mm (dynamic), 25 mm (residual).
10 kg mass dropped from 0.75 m. Max dynamic displacement 35 mm.
ECE 22.06
Peripheral Vision (Horizontal)
≥ 105° on each side of the median plane.
≥ 105° on each side of the reference point.
ECE 22.06
Rotational Force Test
Not specified.
Mandatory. Performed on an angled anvil to measure rotational acceleration. Brain Injury Criterion (BrIC) must be ≤ 0.78.
ECE 22.06
⚠ Verify details from original standards before use
Key Values4
Quick Reference Values
Maximum mass of helmet1500 g
Peripheral vision clearanceNot less than 105 degrees