KASK WG11 ROTATIONAL IMPACT TEST
Kask has always been committed to creating products that provide both excellent safety and comfort, exceeding requirements set by international standards and norms.
KASK WG11 test is an internal protocol adopted by Kask to identify an objective method, based on scientific sources, for measuring the performance of its helmets against rotational impacts.
Most helmets tests use rotational impact prevention technologies with headforms that have a higher coefficient of friction than those of the human skull and therefore may not reflect what occurs in some accidents.
The "pass-fail" criterion is based on the BrIC value, an algorithm that defines the level of brain injury.This value must be lower than 0,68.
The final test protocol is:
OBLIQUE IMPACT TESTs
oblique tests @ 45°, impact speed 6 m/s, BrIC < 0,68
+ grade 80 closed-coat aluminum oxide abrasive paper
+ headform nominal coefficient of friction 0,3
+ wireless system: triaxial accelerometer + n. 3 ARS
Headform: EN960 serie
Peak of rotational acceleration, Peak of linear acceleration, HIC, BRIC (< 0,68)
All KASK helmets successfully pass this test, with values that are substantially less than 0,68 BrIC 0,390 *ROTATIONAL IMPACT WG11 TEST PASSED is a KASK registered trademark. The ROTATIONAL IMPACT TEST PASSED is a KASK internal oblique impact test that measures the performance of its helmets against rotational impacts. This Test has not been adopted by CEN or its Working Group CEN TC158/Working Group 11.
BEHIND THE KASK WG11
Angelo Gotti, CEO of KASK, is recognized as one of the world's leading helmet experts with more than 30 years of experience in various industries. At the helm of the company, he is the driving force behind KASK's position on the subject of safety.
KASK has always been committed to creating products that guarantee both maximum safety and comfort, exceeding all requirements set by international standards and norms in all industries within which KASK is present: cycling, skiing, horse riding, industrial, mountaineering, and beyond.
In the past ten years, major international regulatory bodies such as CEN, AU/NZS have been studying the subject of rotational impacts. Over this period, however, no standards on this matter have been published.
CEN TC 158 / Working Group 11 is trying to develop a method for measuring the absorption of energy from tangential impacts. Recently a new standard for motorcycle helmets has been published, ECE 22.06, and it includes an oblique impact test method of measuring rotational acceleration.
KASK, taking inspiration from CEN, from ECE 22.06 and from other scientific publications, has created its own protocol, called ROTATIONAL IMPACT WG11 TEST PASSED, in order to be able to measure the performance of its helmets against the so called rotational impacts.
Starting from 2020, every new KASK helmet that successfully passes the KASK WG 11 test will be easily identified by a dedicated "WG11 rotational and linear impacts test passed" tag.
Organizations, associations, agencies.
BrICBrIC is an algorithm that defines the level of a brain injury. To simplify, to a lower number corresponds a lower risk of concussion. Concussive (AIS2+) values of BrIC for humans varied from 0,60 when scaled directly from animal data (Ommaya, 1985) to 0.68 when obtained directly from college football players (Development of rotational Brain Injury Criterion (BrIC), Human Injury Research Division, UNECE)
AIS is the Abbreviated injury scale: The Abbreviated Injury Scale (AIS©) incorporates current medical terminology providing an internationally accepted tool for ranking injury severity. AIS is an anatomically based, consensus derived, global severity scoring system that classifies an individual injury by body region according to its relative severity on a 6 point scale (1=minor and 6=maximal). AIS is the basis for the Injury Severity Score (ISS) calculation of the multiply injured patient. (Association for the Advancement of Automotive Medicine (AAAM)).
The limits KASK has defined or this test are also based on the following studies and norms:
Development of rotational Brain Injury Criterion (BrIC), Human Injury Research Division, UNECE
Development of Brain Injury Criteria (BRIC), Stapp Car Crash Journal
MIPS related results on motorcycle helmets, Peter Halldin, Division of Neuronic Engineering Royal Institute of Technology (KHT), Stockholm, Sweden
CEN, the European Committee for Standardization, is an association that brings together the National Standardization Bodies of 34 European countries.
CEN is one of three European Standardization Organizations (together with CENELEC and ETSI) that have been officially recognized by the European Union and by the European Free Trade Association (EFTA) as being responsible for developing and defining voluntary standards at European level.
CEN provides a platform for the development of European Standards and other technical documents in relation to various kinds of products, materials, services and processes.
CEN supports standardization activities in relation to a wide range of fields and sectors including: air and space, chemicals, construction, consumer products, defense and security, energy, the environment, food and feed, health and safety, healthcare, ICT, machinery, materials, pressure equipment, services, smart living, transport and packaging.
CEN\TC 158 Working Group 11
TC 158 is the Technical Committee dedicated to the head protection inside CEN. Its goal is to prepare European standards for all types of protective helmets. Eight Working Groups are currently active under TC 158, and Working Group 11 is focused on: Shock absorption including measuring rotational kinematics from oblique or normal impact.
ASTM International, formerly known as American Society for Testing and Materials, is an international standards organization that develops and publishes voluntary consensus technical standards for a wide range of materials, products, systems, and services. Some 12,575 ASTM voluntary consensus standards operate globally. The organization's headquarters is in West Conshohocken, Pennsylvania, about 5 mi (8.0 km) northwest of Philadelphia.
The United States Consumer Product Safety Commission (USCPSC, CPSC, or commission) is an independent agency of the United States government. The CPSC seeks to promote the safety of consumer products by addressing “unreasonable risks” of injury (through coordinating recalls, evaluating products that are the subject of consumer complaints or industry reports, etc.); developing uniform safety standards (some mandatory, some through a voluntary standards process); and conducting research into product-related illness and injury. In part due to its small size, the CPSC attempts to coordinate with outside parties—including companies and consumer advocates—to leverage resources and expertise to achieve outcomes that advance consumer safety. The agency was created in 1972 through the Consumer Product Safety Act. The agency reports to Congress and the President; it is not part of any other department or agency in the federal government. The CPSC has five commissioners, who are nominated by the president and confirmed by the Senate for staggered seven-year terms. Historically, the commission was often run by three commissioners or fewer. Since 2009, however, the agency has generally been led by five commissioners, one of whom serves as chairman. The commissioners set policy for the CPSC. The CPSC is headquartered in Bethesda, Maryland.
Standards Australia is the nation’s peak standards development body. We develop standards, technical specifications, handbooks and other publications and participate in international standards development as a member of the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC).
We do not enforce, regulate or certify compliance with standards.
We form technical committees made up of stakeholders from government, business, industry, community, academia and consumers. Through a process of consensus, these committees develop standards for Australia’s net benefit. We facilitate that process.
STANDARDS NEW ZEALAND
Standards New Zealand is a business unit within the Ministry of Business, Innovation and Employment. We specialise in managing the development of standards. We also publish and sell New Zealand, joint Australia-New Zealand, and international standards.
Norms and standards
CEN European Standard Helmets for Pedal Cyclists and for Users of Skateboards and Roller Skates, EN1078, February, 1997. The standard states that the following countries are bound by EC rules to implement it in 1997: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom ("Europe")
ASTM (formerly American Society for Testing and Materials) Standard Specification for Protective Headgear Used in Bicycling, F1447-12, and F-1446-11a, Test Methods for Equipment and Procedures Used in Evaluating the Performance Characteristics of Protective Headgear (the Base Standard). ("ASTM")
Standards Australia/Standards New Zealand, Australian and New Zealand standard 2063: 1996 - Pedal Cycle Helmets. Also requires AS/NZS 2512.1:1996 "Methods of Testing Protective Helmets: Method 1: Definitions and Headforms" as well as AS/NZS 2512.9:1996 "Methods of Testing Protective Helmets: Method 9: Determination of Load Distribution" ("Aus/NZ")
US Consumer Product Safety Commission (US) Safety Standard for Bicycle Helmets. Final Rule that took effect as U.S. law on March 10, 1999. ("CPSC")
Japanese Industrial Standard, Protective Helmets for Bicycle Users. JIS T 8134-1982. Translation by Japanese Standards Association. ("Japan")
ASTM: Flat (flat circle minimum of 125 mm in diameter and at least 24 mm thick), hemispherical with 47 to 49 mm radius, and curbstone (two faces meeting at an angle of 105 degrees radiused at 14.5 to 15.5 mm, with height not less than 50 mm and length not less than 200 mm). All anvils must be steel and solid without internal cavities.
CPSC: Flat, 47 to 49 mm radius hemispherical and curbstone.
Europe: Flat with minimum impact face diameter of 127 to 133 mm. "Kerbstone" with two faces making a nominal 105 degree angle, each inclined at 50.0 to 55.0 degrees to the vertical and meeting along a striking edge with a radius of 14.5 mm to 15.5 mm, and with height at least 50 mm and length at least 125 mm.
least 50 mm and length at least 125 mm.
Buckle and Strap Durability in Use (Not strength test)
Europe: Following the strength test the buckle must still be openable with one hand.
(For buckle and strap strength see Retention System.)
Buckle and Strap Slippage in Use
Europe: No test, but helmet strap must be able to maintain tension. Further, residual slippage in retention system test specifically includes any buckle slippage. Slippage of the buckle can be measured and recorded "for information purposes" separately from other elements that contribute to total extension when tested for retention.
(For buckle and strap strength see Retention System below.)
ASTM: Ambient: 17 to 23 degrees C (F 63 to 73 degrees) with a relative humidity of 25 to 75 per cent . Cold: -13 degrees to -17 degrees C (F 8 to -1 degree). Hot: 47 degrees to 53 degrees C (F 117 to 127 degrees) with relative humidity no higher than 25 per cent . Wet: Immersed in potable water at 15 degrees to 23 degrees C (F 63 to 73 degrees). Ageing: none. Barometric pressure in all environments must be 75 to 110 kPa. Helmet is stabilized in ambient conditions for 24 hours before any further conditioning or testing. Conditioning times 4 to 24 hours for cold, hot and wet. Sample must be tested within 1 minute after removal from conditioning environment and returned within 3 minutes or if kept out longer must be reconditioned for 5 minutes for each minute over 3.
Australia/NZ Ambient: 18 degrees to 25 degrees C (F 64 to 77 degrees). Cold: -3 to -7 degrees C (F 41 degrees). Hot: 48 to 52 degrees C (F 122 degrees) in circulating hot air oven. Wet: Immersed in water at 18 to 25 degrees (F 64 to 77 degrees). Ageing: none. All conditioning for 16 to 30 hours. If during testing the time out of the conditioning environment exceeds 5 minutes, the helmet is returned to the conditioning environment for a minimum of 3 times as many minutes as it was out of the environment, or 16 hours, whichever is the lesser, before testing is resumed. (Not yet updated for 1996 version.)
CPSC: Ambient: 17 to 27 degrees C (F 63 to 81 degrees) with a relative humidity of 20 to 80 per cent. Cold: -13 to -17 degrees C (F 9 to -1 degrees). Hot: 47 to 53 degrees C (F 117 to 127 degrees). Wet: Immersed "crown down" in potable water at 17 to 27 degrees C (F 63 to 81 degrees). Ageing: none. Barometric pressure in all environments must be 75 to 110 kPa. Helmet is stabilized in ambient conditions for 24 hours before any further conditioning or testing. Conditioning times 4 to 24 hours for cold, hot and wet. Sample must be tested within 2 minutes after removal from conditioning environment and returned within 3 minutes or if kept out longer must be reconditioned for 5 minutes for each minute over 3, not to exceed 4 hours.
Europe: Ambient: Not specified. Cold: -18 to -22 degrees C (F -4 degrees) for four to six hours. Hot: 48 to 52 degrees C (F 122 degrees) for four to six hours. Wet: none. Aging: Exposed for 48 hours to a 125 watt xenon-filled quartz lamp at 250 mm followed by spraying for four to six hours with 1 l. of water per minute at ambient temp (not specified). Alternate ageing method uses a Xenon arc lamp "filtered to provide the spectral power distribution that closely approximates that of terrestrial daylight." Helmet is fixed on a cylindrical holder concentric to the lamp and rotating every 1 to 5 minutes. If helmet is to be tested for impact the area to be tested is directed toward the lamp, with the plane tangential to the outer surface normal to the radius of the cylindrical holder. Sample should receive 1 GJ/msq. over the wavelength 280 nm to 800 nm, either measured or calculated. Samples intermittently sprayed with distilled or demineralized water with a conductivity below 5 microS/cm alternating 18 minutes of spraying and 102 minutes without. During non-spray periods the relative humidity should be 45 to 55 per cent. Temperature within the test chamber to be 67 to 73 degrees C, measured with a black standard thermometer at the same distance from the lamp as the exposed test areas of the helmet. Wet: none. No specification for time out of conditioning before first impact. Second impact on each sample except UV-wet sample is specified with "no reconditioning," which may address question of maximum time out of conditioning environment.
ASTM: Guided free fall using wire, monorail or other drop rig (example illustration shows twin-wire and monorail rigs) onto a steel anvil fixed on a rigid base. Drop assembly exclusive of helmet must weigh 3.1 to 6.1 kg. Drop assembly minus weight of headform, ball clamp, ball clamp bolts and accelerometer cannot exceed 1.1 kg. Uniaxial accelerometer capable of measuring 1,000 g's with sensitive axis aligned within 5 degrees of vertical. CG of headform must be at center of mounting ball. CG of combined headform and supporting assembly must meet F.M.V.S.S. #218 (rev. 4-6- 88) S slash.1.8 with any type of guide system.
Australia/NZ Twin-wire drop rig. Weight of support arm cannot exceed 20 per cent of mass of drop assembly, which is limited to 3.5, 4.0, 5.0 and 6.0 kg for the four headform sizes ABCD. Center of mass of assembly within 10 degree vertical cone from point of impact. Sensitive axis of accelerometer within 5 degrees of vertical. Mass of anvil mount at least 130 kg. (Not yet updated for 1996 version.)
CPSC: Guided free fall using twin wire or monorail test rig onto a steel anvil fixed on a rigid base. Base must have mass at least 135 kg, with steel plate on top at least 25 mm thick. Drop assembly (headform plus support assembly without helmet) must weigh 5 kg +/- 0.1 kg. (11 lb.). Uniaxial accelerometer capable of measuring 1,000 g with sensitive axis aligned within 5 degrees of vertical. CG of headform must be at center of mounting ball and within 10 degree vertical cone from point of impact. CG of drop assembly (headform plus support assembly) must meet FMVSS 218 S7.1.8 and lie in rectangular area 28 mm by 12.8 mm. Center of anvil must be fixed in alignment with center vertical axis of the accelerometer.
Europe: Such that in guided free fall the headform attains at least 95 per cent of theoretical velocity, that it does not affect the measurement of acceleration at the cg of the headform, and that headform can be adjusted to permit any point within the protective zone to be aligned with the vertical at the center of the anvil, although the headform is never to be turned so that the vertical axis falls "below the horizontal plane." Base must be "monolithic," made of steel, concrete or a combination of the two, and have mass of at least 500 kg. No part can have a resonant frequency "liable to affect the measurements." Requires tri-axial accelerometer weighing no more than 50 grams and able to withstand 2000 g. Simplified drawing shows a twin wire guidance system with a four-bearing square "support dolly" frame holding a headform. (Many European labs use a triple wire guidance system with headform cradled on a triangular dolly with a hole in the center which would drop away below anvil upon impact. That setup would be permitted under this description.)
ASTM: ASTM F2220. Six sizes (A, C, E, J, M and O) specified, to be of magnesium K1A material. Helmets fitting two headform sizes are tested on both unless manufacturer also makes a smaller model fitting the smaller headform. The helmet fits two headforms if it is not physically difficult to mount on the larger headform and partially compresses the fitting foam on the smaller headform.
Australia/NZ AS 2512.1 Permits headforms of "hardwood, metal or other suitable material."
CPSC: ISO-DIS 6220-1983. Five sizes (A,E,J M and O) specified. Must be made of K-1A magnesium alloy. Mass of each headform together with supporting assembly must weigh 5 kg. regardless of size.
Europe headforms conforming to EN 960, Headforms for Testing Protective Helmets. There are five headforms (A, E, J, M and O) in the body of the standard and three more (C, G and K) in a table defining the test area which has 8 sizes. Size O is very large, for helmets with inside circumferences of 620 mm. Must be made of metal and have "a low resonance frequency but not below 3000 Hz." Headform mass varies with size, ranging from 3.1 to 6.1 kg. Must have housing for triaxial accelerometer "near its centre of gravity." Chin area shape is specified in headform dimensions.
Impact Energy Management
ASTM: Not to exceed 300 g. "Theoretical" drop heights of 2.0 meters (impact velocity 6.2 meters per second) for flat anvil; 1.2 meters (impact velocity of 4.8 meters per second) for hemispherical and curbstone anvils. Velocity measured in last 40 mm of free-fall must be within 3 per cent of specification.
Australia/NZ Not to exceed 300 g, or 200 g for 3.0 ms, or 150 g for 6.0 ms. Drop heights of 1.45 to 1.80 m on flat anvil. None of the protective components can become detached during impact test. Helmet must not lose any pieces representing more than 10 per cent of its mass during testing. Has separate point loading test described under Point Loading.
CPSC: Not to exceed 300 g, On flat anvil, impact velocity of 6.2 m/s +/- 3 per cent typically requiring drop height of 2.0 m plus any height adjustment for friction losses. On hemispherical and curbstone anvils impact velocity of 4.8 m/s +/- 3 per cent typically requiring drop height of 1.2 m plus friction adjustment. Velocity measured in last 40 mm of free-fall.
Europe: No impact of the 20 required in the test series can exceed 250 g peak in 1.5 meter drop on flat or kerbstone anvil.
ASTM: Four single impacts centered at least 25 mm (arc width) above any point on the test line and at least one fifth of the maximum circumference of the helmet from any prior impact center. Flat and hemispherical anvils to be used on each set of helmets, but curbstone anvil used only once on a fifth ambient sample. Impact testing after retention system tests.
Australia/NZ Four single impacts anywhere above test line, separated by not less than one-fifth of the circumference of the helmet measured at "the nominal AA' line," shown as 12.7 mm above the Reference Plane.
CPSC: Impacts centered anywhere on or above the test line, with sites selected for most severe test in attempt to fail the helmet. Two sets of four samples required for each size and model offered. First set of ambient, hot. cold and wet samples each impacted at sites separated by 120 mm (measured on surface of helmet) two times with flat anvil and two times with hemispherical anvil. Second set of ambient, hot, cold and wet samples impacted once each on curbstone anvil.
Europe: Two impacts on each of ten samples according to a test schedule which specifies the anvil and conditioning to be used. Retention system tests are done after impact tests.
ASTM: Uniaxial accelerometer capable of withstanding 1000 g (9810 meters per second squared). SAE J211 data channel and filtering, which can be satisfied by a low-pass analog or digital filter with a 4-pole Butterworth transfer function and a corner frequency of 1000 Hz. System check before and after each series of tests by dropping onto MEP a 146 mm aluminum spherical impactor weighing 4000 to 4010 g mounted on ball-arm connector of test assembly. MEP must be 152 mm in diameter and 25 mm thick, with durometer of 58 to 62 Shore A, fixed on flat 6.35 mm aluminum plate. Impactor dropped on MEP three times at intervals of 60 to 90 seconds, at impact velocity of 5.44 m/s +/- 2 per cent (drop height 1.5 m plus friction allowance). Peak acceleration should be between 381 and 397 g. If results of pretest and posttest impacts differ by more than 5 per cent equipment must be recalibrated and test results discarded.
Australia/NZ Calibration before and after test series must be within 3 per cent of theoretical drop velocity. (Not yet updated here for 1996 version.)
CPSC: Requires uniaxial accelerometer capable of measuring 1000 g., with sensitive axis aligned within 5 degrees of vertical when test headform in impact position. SAE J211-OCT88 data channel for Channel Class 1000. System check before and after each series of tests (at least a beginning and end of each test day) by dropping onto MEP a 146 mm aluminum spherical impactor mounted on ball-arm connector of test assembly with combined weight of 5 kg +/- 0.1 kg. MEP must be 152 mm in diameter and 25 mm thick, with durometer of 58 to 62 Shore A, fixed on flat 6.35 mm aluminum plate. Geometric center of MEP aligned with center vertical axis of accelerometer. Impactor dropped on MEP at impact velocity of 5.44 m/s +2 per cent (drop height 1.5 m plus friction allowance). Six impacts at intervals of 60 to 90 seconds, three as warm-ups with results ignored, second three recorded and must fall within 380 g to 425 g. and have difference between high and low values of no more than 20 g.
Europe: Requires a tri-axial accelerometer accurate up to 2,000 g and weighing no more than 50 grams. Data channel must meet ISO specification 6487.
Labels on Helmet
ASTM: Easily legible labels "likely to remain legible throughout the life of the helmet." Include model, manufacturer, month and year of manufacture, no helmet can protect against all impacts warning, impact damage may not be apparent, destroy or return to manufacturer for inspection after impact, fit instructions must be followed for maximum protection, substances which may damage, recommended cleaning agents, not for motor vehicle use.
Australia/NZ Permanent and legible letters no less than 1.5 mm high and visible without removing padding. Name and address of manufacturer, model, size, month and year of manufacture, activity helmet is designed for, not for use on motorcycles, mass in grams, shell and liner material, damaging solvents, make no modifications, fasten strap, replace after severe blow, indication of front and rear.
CPSC: Durable, legible, easily visible labels. Certification label stating compliance with CPSC standard, with name, address and telephone number of the U.S. manufacturer, private labeler or importer issuing the label, uncoded month and year of manufacture, name and address of foreign manufacturer if not made in U.S. (can be coded if private labeler's name is on certificate), production lot number or serial number. Other labels preceded by "WARNING" stating that no helmet can protect against all impacts, serious death and injury may occur, must be fitted and attached properly to wearer's head, impact damage may not be apparent, destroy or return to manufacturer for inspection after impact, substances which may damage, recommended cleaning agents, refer to manual for details.
Europe: Easily legible markings throughout life of helmet Standard number, name or trademark of manufacturer, model, pedal cyclists' helmet, size in cm, weight, year and quarter of manufacturer, and "an appropriate warning" if shell adversely affected by solvents and such. Must be in language of the country of sale.
Positional Stability Test
ASTM: Defined in base standard but not yet required by bicycle helmet specification. (A requirement similar to CPSC below has been approved but not yet published.)
Australia/NZ Remove visor if present, place helmet on modified ISO headform, tighten strap with spacer under chin, remove spacer, put hook under edge with strap running over top of shell, pull strap in direction parallel with helmet edge with force of 50 N. After 15 to 30 seconds, helmet should not deflect enough to obscure or entirely expose a test band drawn around head between basic plane (eye level) and 74 mm above basic plane for headform J or 85 mm above for headform A. "Retention systems shall be adjustable to produce tension on straps between all shell fixing points when the retaining strap is properly fastened."
CPSC: With thickest pads in place, select headform size that partially compresses all sizing pads. Place helmet on ISO full chinpiece headform according to manufacturer's instructions. Tilt headform forward 45 degrees, attach hook to rear rim and strap run over helmet and down to a test apparatus permitting a 4 kg weight to drop .6 meters and hit a stop, jerking the strap. Test is repeated with headform face pointing upward, jerking helmet from front to rear. Strap elongation cannot exceed 5 mm per 300 mm when loaded with a 22 kg weight. The helmet must not come off of the test headform.
Europe: Helmet placed on headform, in accordance with manufacturer's instructions. Headform to be "smallest and largest claimed for that helmet type." A hook is attached under rear edge and wired over a pulley to a stop under a 10 kg weight which is dropped 250 mm onto the stop to produce the jerk. Helmet must not come off the headform or tilt forward more than 30 degrees.
Record of Tests
ASTM: Complete test record must be kept for all certification testing performed by manufacturer or independent lab on paper, electronic format or photographs. Original paper copy of test summary must include manufacturer's name and location, model and size of helmets tested, identifying code for each helmet in each conditioning environment, observed temperatures in each conditioning environment, relative humidity and temperature of the laboratory, impact test results in sequence with location of impact, anvil, velocity and maximum acceleration. Also requires record of the parameters and results of retention tests, name and location of the test lab, signature of the technician performing the test, test date and calibration test results.
Australia/NZ Various records for different parts of test protocols. Most require identity of helmet under test, details of headform, number of standard, and performance data such as degree of penetration, deflection of visor in mm, whether or not positioning test band was obscured or exposed during test, elongation of strap, headform acceleration at intervals specified in standard, details of damage to helmet and its components.
CPSC: Must keep records on paper or electronic media showing that helmet was certified under a "reasonable testing program." Must keep records for three years and make available to CPSC if requested within 48 hours if not on factory site. Record to identify helmets tested, production lot, results including precise nature of any failures and specific actions taken to address any failures. Original test record to be kept on paper by the test lab. Must show: (1) Identification of helmets tested and production lot; (2) Test results, including failures and actions taken; (3)test description including Helmet Positioning Index used, (4)Manufacturer's name and address; (5) Model and size of each helmet tested; (6) Identifying information including production lot; (7) Environmental condition for each helmet, including temperature, duration of conditioning and the laboratory temperature and relative humidity; (8) Results of peripheral vision clearance test; (9) Any failures to conform to labeling or instruction requirements; 10) Results of the positional stability test; (11) Results of the retention system strength test; (12) Impact test results in sequence stating location of impact, type of anvil, velocity prior to impact, maximum acceleration in g's; (13) Name and location of the test lab; (14) Technician's signature; (15) Test date; (16) Calibration test results verifying the operation of the test rig, Records to be provided to CPSC upon demand on paper or by email.
Europe: Must record identification details of helmets tested, including sizes, as well as results of impact and retention system tests, date of testing and name of testing authority.
Retention System Strength
ASTM: Dynamic yank. Helmet is supported on a headform and preloaded with bean bag filled with 5 kg of lead shot. Chin strap is fastened under two metal bars 12 to 13 mm in diameter and separated by center distance of 75 to 77 mm, representing the jaw, from which hangs the test apparatus, weighing 7 kg +/- 5 per cent. A sliding weight of 4 kg is dropped down a bar for .6 m impacting against a stop at the bottom to dynamically load the retaining system. Strap must remain intact and not elongate during or after test more than 30 mm.
Australia/NZ Static pull of 225 5 N for 30 seconds, "and then an additional force of 500 5 N applied for 120 seconds." Strap shall not separate or elongate more than 25 mm.
CPSC: Dynamic yank. Helmet is supported on a headform and preloaded with bean bag filled with 5 kg of lead shot. Chin strap is fastened under two metal rods 12 to 13 mm in diameter and separated by 75 to 77 mm, representing the jaw, from which hangs the test apparatus, weighing 10.5 to 11.5 kg, including the 4 kg drop weight. The 4 kg weight is dropped for .6 m to dynamically load the retaining system while the pre-load falls away. Strap must remain intact and not elongate more than 30 mm (1.2").
Europe: Introduction says helmet "is intended to remain on the head in a bicycle accident and may cause strangulation by entrapment." Test is a dynamic yank. Four samples already impact tested (two large, two small, one of each the UV- wet conditioned sample) are suspended from a 12 mm diameter hook through a hole (drilled?) in the helmet with a curved plate 100 mm in diameter underneath the liner. The plate must be 3 to 4 mm thick and conform somewhat to the curvature of the headform, with a radius of 100 mm. A headform and drop apparatus weighing 15 kg (total preload) is positioned in the helmet and buckled in, then yanked by a 10 kg weight dropped 300 mm. Impact speed must be at least 95 per cent of theoretical, implying requirement for velocity sensor. Dynamic extension must not exceed 35 mm, and residual extension two minutes later must not exceed 25 mm. Extension includes any buckle slippage. Buckle must release after test "by normal operation of the release system." Separate test requires that the retention system open with one hand when it is loaded with 50 kg, and "the force for opening shall not exceed 30 N." Recommends that opening mechanism be marked with red or orange. No green permitted because green is mandated by child standard.
Sequence of Testing
ASTM: Retention system tests before impact tests. Four samples (ambient, hot. cold, wet) are tested for impact attenuation on flat and hemispherical anvils, with four impacts each, on any anvil. A fifth (ambient) sample is tested with a single impact on the curbstone anvil
Australia/NZ Impact attenuation tests before retention system tests. Acknowledges that helmets may fail a test due to damage from prior tests, but the failure is to be considered a valid test result.
CPSC: Two sets of four samples required. 1)Peripheral vision test on first ambient sample. 2)Second ambient sample subjected to retention system stability (rolloff) test. 3)Retention system strength tests on each of the first set of ambient, cold, hot and wet samples. 4)First set of ambient, hot, cold and wet samples subjected to 2 impacts each in different locations on flat and hemispherical anvils. 5)Second set of ambient, hot, cold and wet samples tested for impact attenuation with a single impact on the curbstone anvil.
Europe: Detailed sequence beginning with rolloff test of retention system effectiveness, then impact (table details conditioning and anvil for each sample), then strap strength. Five samples of largest size and five of smallest sizes required, each impacted in two locations. Impacts on sites selected by the testing authority to represent worst case conditions. Kerbstone anvil used "without restrictions on its orientation." Impact sites separated by at least 150 mm. Testing authority must confirm helmet's sizing is correct on label.
Test Area or Required Coverage
(Dimensions usually vary with head size. These comparisons are for size medium, ISO J headform. "Basic plane" (Frankfort Horizontal Plane) is a horizontal plane through the upper edges of the skull's ear opening and the lower edge of the eye socket. It is marked on ISO headforms.)
ASTM: Entire area above the test line must meet impact attenuation standard, but center of impact of the test apparatus must be at least 25 mm above the line. Resultant test line is parallel to the basic plane and begins in front 85 mm above the basic plane, stepping down to 60 mm at a point two thirds back. Does not vary with head size. (Elimination of 25 mm offset and variability with head size has been approved but not yet published.)
Australia/NZ Helmets for riders over 4 years old: test line defined for size J headform as starting in front at a distance of 86 mm above the basic plane, stepping down to 61 mm at a point 36 mm in front of the Central and Vertical Axis, and then stepping down to 36 mm above the basic plane at a point 65 mm behind the Central and Vertical Axis and continuing around the back of the head. Helmets for riders four years old and younger: test line on the AA headform begins in back of head at 8 mm above basic plane. At a point 36 mm behind the Central and Vertical Axis it begins rising and at 30 mm behind the axis it reaches 31 mm above the basic plane. At 28 mm in front of the axis it begins to rise again and at 34 mm in front of the axis it reaches 54 mm above the basic plane. It then angles downward toward the front at a 15 degree angle, with the final dimension above the basic plane not called out, but appearing in the drawing to be about 42 mm above the basic plane.
CPSC: Entire area above the test line must meet impact standard, with impact sites centered on or above the test line. For helmets for riders aged 5 and over, the test line for J size headform starts in front at a distance of 68.5 mm above the basic plane, stepping down at a point 54 mm behind the cg to 54.5 mm above the basic plane. For helmets for riders under 5 years of age, line begins on the ISO E size headform in front at a point 57.5 mm above the basic plane, dropping at a point 27 mm in front of the cg to 40.2 mm above the basic plane and dropping again at a point 32 mm behind the cg to a point 11.5 mm above the basic plane.
Europe: Two uniquely shaped test areas, one for flat anvil impacts and a less extensive one for kerbstone anvil impacts. We are not able to describe the lines with the info we have. The method for calculating the lines is described, but dimensions are not included in the standard, and in another clause buried under procedure the area is modified by the statement that "the headform shall never be turned so that the vertical axis comes below the horizontal plane even if the test area allows." Even assuming that the statement refers to the vertical axis as it emerges from the bottom of the headform, the effect on the test area cannot be determined.
Velocity or Energy Level Confirmation of Test Drop
ASTM: Velocity measured in last 40 mm of free fall and must be within 3 per cent of specified velocities.
Australia/NZ No velocity sensor specified. (May have been updated for 1996)
CPSC: Velocity must be measured to an accuracy of 2 per cent within last 40 mm of free fall. Velocity for flat anvil test to achieve 6.2 m per s and for hemispheric anvil 4.8 m per s, corresponding to theoretical drops of 2.0 and 1.2 meters. Tolerance is 3 per cent.
Europe: Requires velocity sensor within 60 mm of impact accurate to 1 per cent. Velocity of headform must be equivalent to a drop height of 1.49 to 1.51 m.
ASTM: Peripheral vision of 105 degrees from centerline required on both sides.
Australia/NZ Peripheral vision of 105 degrees on both sides, and front edge clearance 25 mm above basic plane (bottom of eye socket) through same 105 degrees peripheral vision clearance area.
CPSC: Peripheral vision of 105 degrees from centerline required on both sides after helmet positioned on headform according to manufacturer's helmet positioning index and weighted with a 5 kg ballast weight.
Europe: Peripheral vision of 105 degrees required on both sides. Forward vision must be unobstructed at 45 degree angle downward from the basic plane and 25 degree angle upward from the reference plane above it.
Visors and Accessories
ASTM: Visors and face shields optional. Helmets tested in condition as offered for sale, and must pass all tests with or without any included attachments.
Australia/NZ Visors ("peaks") permitted. Considering a requirement that visor deflect at least a minimum amount when loaded with a weight, or be detachable. Introduction notes that "concern has been expressed that rigid peaks may cause rotational injuries to the head or neck during some falls, and facial injuries if they shatter or break off."
CPSC: Helmets must pass all tests both with and without any attachments that may be included.
Europe: Must be designed and shaped not to injure user during normal use.
Biomechanical Evaluation of Motorcycle Helmets: Protection against Head and Brain Injuries, John D. Loyd, Journal of Forensic Biomechanics
Development of rotational Brain Injury Criterion (BrIC), Human Injury Research Division, UNECE
Development of Brain Injury Criteria (BRIC), Stapp Car Crash Journal
"The effect of the scalp on the effectiveness of bicycle helmets' anti-rotational acceleration technologies" by Dimitris Zouzias , Guido De Bruyne , Aisling Ni Annaidh , Antonia Trotta and Jan Ivens