Cycle helmet safety
Helmets for cyclists and skateboarders in the EU must undergo rigorous testing and EC type-examination.
Image © British Cycling
Owing to the nature of sports such as cycling, roller skating and skateboarding, many of the accidents involve collisions at speed and, therefore, participants in these activities are always advised to wear protective clothing and headgear to help prevent serious injuries. The current standard for such head protectors is EN 1078:2012.
EN 1078 contains a number of general requirements. For example, materials must be safe and innocuous – that is, not be hazardous to either the wearer or anyone else who comes into contact with the product. An important aspect of helmets is that the material characteristics must not be changed if placed in contact with substances typically found in toiletries, as some of these can reduce the strength of plastics typically used in helmet manufacture.
Helmets should be of low weight, ventilated, easy to put on and take off, be usable with spectacles and not impair hearing. They should offer a clear field of vision. Other requirements of a general nature include a minimum width for the retention system straps of 15mm. Also, the retention system should have no parts that are coloured green as this conflicts with some EU member states' national safety legislation.
Main performance requirements
EN 1078 requires that helmets are subjected to a range of pre-treatments before testing. These pre-treatments include exposure to high temperatures (50ºC), sub-zero temperatures (-20ºC) and artificial ageing against sunlight using a high intensity xenon lamp to rapidly simulate weeks of sunlight. The number of samples required for testing depends on the claimed or marked size range of the helmet. Four helmets must be submitted for each head-form size specified. Out of each set of four helmets, three helmets are tested and one reserved in case a test needs to be repeated.
For example, for a helmet claimed to fit size 59-61cm heads, only four helmets would be required for testing, whereas for a helmet claiming to fit size 59-63cm heads, eight helmets would be required. This is because, in the second case, two head-forms are needed to cover this size range.
Impact testing must be carried out on a drop rig using instrumented head-forms incorporating tri-axial accelerometers. Both a flat anvil and a kerbstone anvil are used. The drop height for the head-form with the flat anvil is nominally 1,500mm, which is theoretically what is needed to achieve an impact velocity of 5.42m/s. With the kerbstone anvil, the head-form drop height is a nominal 1,064mm, which is required for an impact velocity of 4.57m/s. In each impact, the resultant deceleration of the head-form must not exceed 250g (where g = 9.81m/s2).
Image © British Cycling
All impacts must be carried out inside the defined protective coverage area. The impacts are carried out in a set order. For example, helmets subjected to the high temperature conditioning are impacted on the kerbstone anvil first and then on the flat anvil. The centres of any impacts must be no closer together than 150mm.
The test house must, in each series of tests, ensure that all perceived weak areas of the helmet are impact tested (provided they are within the test area). Typical weak areas could include anchorage points for retention systems or ventilation slots. In particular when testing with the kerbstone anvil, test houses should position the head-form/helmet with no restriction on the orientation of any ventilation slots compared to the long axis of the anvil. However, for helmets with very long and wide slots it is prudent to check that the kerbstone anvil cannot make contact with the surface of the head-form through a slot so as to avoid damaging equipment during testing.
There are two test procedures for the retention system, each with its own requirements. The retention system strength test is designed to ensure that under a dynamic loading situation the retention system will not stretch nor slip significantly and can be unfastened after any incident. The retention system effectiveness test aims to ensure that the helmet will remain on the head when subjected to a sudden rotational force.
Marking and instructions
EN 1078 is due to be amended to clarify an important safety issue regarding warnings and instructions. The amendment concerns the marking, which must be placed on the helmet before it is put on the market in the EU. Previously, there have been fatal accidents involving children playing on climbing equipment or in trees while wearing EN 1078-compliant helmets. There is the potential in such situations for the child to get caught or trapped by the helmet, resulting in strangulation.
The proposed amendment, which is in its final draft form, provides for a stronger warning about these dangers and requires that these warnings, plus other information, are also copied into the user’s information leaflet. It is now SATRA’s policy to insist that manufacturers comply, in their marking and instructions, with the requirements in the draft amendment before a helmet can be CE marked.
Within Europe, all such helmets are regarded as intermediate category personal protective equipment. This means they must be subject to an EC type-examination involving the satisfactory assessment of the ‘technical file’ which will include details of drawings, design specifications and materials plus the instructions for use and relevant markings, before the manufacturer is issued with an EC type-approval certificate. The manufacturer can then make an EC declaration of conformity (a statement that all subsequent production will be the same as the model type approved) apply the CE mark and place product on the market.
How can we help?
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SATRA can carry out the necessary testing and EC type-examination work on helmets for cyclists, roller-skaters and skateboarders. Please email firstname.lastname@example.org for further information.