Impact Zone Diagrams
We listened to your feedback, which told us that you’d like more information regarding the performance of helmets; in particular those areas where a helmet has performed well or could be considered as lacking protection. We have responded by providing an IMPACT ZONE DIAGRAM as part of each helmet data page.
In each diagram, the SHARP test point has been attributed a colour to show the level of performance measured against a flat surface in our high speed test (8.5m/s). You are able to cycle through the images to get a better understanding of the all round protection offered by each helmet.
The impact zones have been graded in six colours which are marked as being from 'Very good' to 'Poor'. The boundary for each colour is linked to understanding of the risk of injury established in the “COST 327 Research” (the most thorough investigation of motorcycle crashes conducted in Europe).
Analysis of more than 350 individual crashes was supplemented by further research that reconstructed a sample of those crashes to determine the relationship between the forces experienced by the rider’s brain and the injury received.
The impact zone colours are based upon discrete brain acceleration values:
Green - Peak acceleration up to 275g: the ECE 22.05 test limit at 7.5 m/s.
Yellow - Peak acceleration up to 300g: the British Standard 6658:1985 test limit at 7.5 m/s used by SHARP as the maximum permitted value for a 5–Star rating.
Orange - Peak acceleration up to 400g
Brown - Peak acceleration up to 420g
Red - Peak acceleration up to 500g
Black - Peak acceleration in excess of 500g.
Manufacturers are advised of the SHARP rating before it is published and they are able to lodge an appeal if our measured data does not match what they have seen in development or production testing. This process ensures that the SHARP rating is representative of their helmet’s performance.
It should be remembered that SHARP carries out 32 impact tests on a helmet model before awarding the SHARP star rating. Helmets that offer good levels of protection uniformly around the head rate highly in SHARP. That’s not to say a 1-star helmet won’t protect you. Regardless of its SHARP rating, every helmet on sale in the UK meets at least one recognised standard, ensuring it offers at least a minimum level of protection.