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Motorcycle helmetsMotorcycle helmet is basically a protective gear which is used by motorcycle riders. The helmet is primarily meant to safeguard rider's head in case of accident. Nowadays, motorcycle helmets also serve many other purposes such as face shields, ear protection, HUDs, intercom etc. Since motorcycle helmets reduces the injuries caused by accidents therefore many countries have made laws making wearing of helmet compulsory. Some countries have laid down standards to judge the effectiveness of motorcycle helmets. Some of these standards are AS 1698 in Australia, CSA CAN3-D230-M85 in Canada , JIS T8133 in Japan , DOT FMVSS 218 in USA, BS 6658:1985 in United Kingdom , ECE 22.05 in Europe , NZ 5430 in New Zealand.
There are basically three types of motorcycle helmets. All these types of helmet has a chin strap to tightly grip the helmet on the head. Various types of motorcycle helmets are as follows:
Full Face
As it is clear from the name itself this type of helmet protects the whole head. It has a rear to cover the skull and a protective cover in front of the chin. These helmets have an open section in front of eyes and nose which is covered by a movable plastic face shield which is usually clear. Most of the full face helmets have vents so as to increase the amount of airflow inside the helmet. These helmets are quite popular since they are most protective. However, some people don't like them because it increases heat and reduces air inside the helmet. These helmets are proven to be the most effective one since studies has shown that of all the accidents that occur across the globe, 35% of all accidents showed major impact on the chin-bar area. A variant of these helmets which are termed as convertible are also available in the worldwide market. In these types of helmets the chin bar section can be either lifted upwards or can be removed allowing the rider to eat or drink without the need of unfastening the straps.
Open Face
These types of helmet also have a rear section covering the skull but don't have any chin armor to protect the chin bar section. It also does not have any face shield. Many companies offer an optional visor that can be attached with the helmet so as to get protection from sunlight and headlights. These helmets not only lacks the full protection as offered by the full face helmets but it also allows bugs, dust and wind to the face and eyes which may cause disruption at the time of driving. Therefore, most of the riders wear sunglasses in order to supplement eye protection both from dust and light. These types of helmets are quite often used by police officers so that their eye site is not reduced.
Half Helmet
Half helmets are also termed as "shorty". These helmets have more or less the same design as an open face helmet but with a raised rear. Half helmets provide a very little protection but are generally allowed by law in the US. As in the case of open helmets, people use other means to augment their eye protection. The major disadvantage of these types of helmet is that they are prone to shifting and sometimes coming off the rider's head in case of accident.
Besides the above three types of motorcycle helmets there are some other types of head gears which are termed as novelty helmets. These are not certified by the law and hence can't take the place of motorcycle helmets. These helmets are much smaller and lighter than the normal DOT certified motorcycle helmets and are unsuitable for protection from accidents since they lack the energy absorbing foam that protects the brain. These helmets protect the rider from the sun and also from abrasion caused due to accidents but don't protect head or skull.
The color of the motorcycle helmet is quite important from the point of visibility. The black helmets are hard to pick from a distance. It has been seen that wearing white helmet reduces the chance of collision by 24%. The visibility of other colors mainly depends on the amount of white content in them. Motorcycle helmets are manufactured from plastic which is reinforced with Kevlar or carbon fiber. The interior part of the helmet is made up using foam and fabric so as to provide both comfort and protection. Not many people know that motorcycle helmets are designed so as to break in case of fatal accidents thereby expending the energy destined for the wearer's skull. It is always advisable to replace the motorcycle helmet after any impact or after a period of three years.
justify">A motorcycle helmet basically consists of two protective components, a hard outer shell which is made up of polycarbonate plastics, fiberglass or Kevlar and a soft, thick inner liner which is usually made up of polystyrene or polypropylene foam. The very purpose of the foam is to crush at the time of the impact. This increases the time and period of time over which the helmet stops and also reduces its acceleration. The ideal motorcycle helmet liner is made such that it is stiff enough to decelerate the head to an abrupt manner in a uniform manner just before it crushes the liner. The stiffness factor basically depends on the impact speed of the head which is by no means known at the time of manufacturing. Therefore, the manufacturer has to choose the most likely speed of the impact and optimize the stiffness according to that speed. If the impact speed of head is more than what the helmet was designed for then the head will completely crush the liner.
The standards test motorcycle helmets at speeds between 4 and 7 m/s. These speeds are chosen keeping in mind the knowledge about the tolerance of human head in case of impact. The price of the helmet varies from company to company, with good brands costing more.
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