What is your motorcycle helmet made of?
UK Helmet safety standards
According to the Gov.UK site : All motorcycle helmets, regardless of material, have to pass one of these standards:
Because of mass production for at least the past decade, most helmets adhere to the ECE 22.05 regulation (it will be interesting to see if this changes in the coming years in the UK due to Brexit!) This standard establishes minimum performance requirements for helmets designed for use by motorcyclists and other motor vehicle users. The purpose of this standard is to reduce deaths and injuries to motorcyclists and other motor vehicle users resulting from head impacts. This standard applies to all helmets designed for use by motorcyclists and other motor vehicle users.
Regulation No. 22 requirements and tests for helmets ECE 22 defines what manufacturers must do to produce and test an effective motorcycle crash helmet. All ECE 22.05 standard helmets and visors must carry the type-approval mark. A helmet approved under ECE 22 displays a capital E in a circle followed by a number representing the country whose certified authority granted its approval. This is followed by a series of numbers and letters representing type approval, approval number and production serial number. E = ECE 22-05 Certified by 2 = French authority; 051018 = ECE 22-05 + Approval Number 1018 issued in France; P = “Protective”, i.e. chin bar tested and approved as a protective full-face helmet; J – although not visible in this example, would, for instance, signify “Jet” style open face approval; 320678 = Batch Test control number – identifies the production batch for which test results are available. Helmet - impact - rigidity -friction - ventilation Visor - scratch resistance - refraction - light transmission - field of vision Lid - solvents - temperature - moisture - ultraviolet Chinstrap - strength - retention Approved their label can easily identify motorcycle helmets: Use only motorcycle helmets approved according to UN Regulation No. 22. Inland Transport Committee (ITC) – Centre of United Nations Transport Conventions
Basically, the above shows there is a stringent test for all motorcycle helmets to pass to be used (and sold for use) on British roads. The ECE testing also offers safeguarding against fake helmets with the robust coding system (detailed above)
Helmet basics
Despite the differing types of materials all helmets feature a rigid outer shell, an impact-absorbing liner (usually EPS - Expanded Polystyrene as shown above) and a comfort liner. This lining determines the sizing of the helmet and nowadays tends to absorb moisture and even regulate temperature.
Outer materials
The hard outer material of the helmet is designed to spread the force of an impact - this is then absorbed by the next layer (usually EPS). Obviously, all helmets have to pass the above safety standards but the outer materials do differ in quality, but also in weight. Most helmets fall into two categories. Thermoplastics such as polycarbonate, ABS and plastic compounds (ie both!) or composite materials such as fibre and resins such as Fibreglass, Kevlar, Carbon Fibre and composite blends of all or some of these fibres and resins.
Poly/Thermo
The heading of this category should really be plastic – as this is basically the shared defining factor between all these different materials, but plastic is also a bit too vague. While plastic helmets provide rigidity and flexibility, they are not as strong as their woven counterparts. Thus manufacturers create plastic helmets larger and heavier. However, plastic helmets come at a lower cost. In addition, upon impact, plastic allows the force of the impact to travel through the helmet easier – but then this goes to the next layer – the EPS. These are the different materials in this category:
Polycarbonate
Polycarbonate is a type of plastic. It is very tough; therefore, very hard to break. Furthermore, it is a polymer, and the monomer unit of this has carbonate groups. Thus, they are named polycarbonates. Polycarbonate is a thermoplastic made from a synthetic plastic resin that contains carbonate groups in its chemical makeup. By itself, polycarbonate is a clear plastic that's the primary ingredient in strong, lightweight helmet visors, eyeglass lenses etc. The critical difference between polycarbonate and plastic is that polycarbonates are lighter but much stronger than plastic. As a result, polycarbonate blends offer higher impact resistance than ABS plastic blends, so if you're looking for good value on a helmet to protect you at speed, polycarbonate is a good choice. The Frank Thomas FT39SV offers a Polycarbonate shell.
Advanced Thermoset Resins
Thermoset is a material that strengthens when heated, but cannot be remoulded or heated after the initial forming Therefore, thermoset resin helmets require the addition of a curing/hardening agent to create the chemical reaction necessary for the plastic to harden into its final form. After the epoxy is added, the mix is heated and forced into a helmet mould via an injection moulding process. Once the chemical reaction is complete and the helmet shell hardens, it is final. In other words, it could not be melted down and reformed again the way thermoplastics can. Thermosets are among the harder types of plastics – but again, this is a cheaper final product.
Thermoplastic
The primary difference between thermo-resin and thermoplastic is that thermoplastics can be reheated, remoulded, and cooled as necessary without causing any chemical changes. Thermoplastic helmets do not require a hardening agent, and therefore can be melted down and reshaped without chemical decomposition, leading them to be recycled. Materials in the "thermoplastics" category are plastic compounds made of simpler oil-based polymers. Because a chemical reaction is not necessary to cure these plastic mixes, they simply need to be heated into liquid form and poured into a helmet-shaped mould where they will cool and harden. Because thermoplastics can be melted down and reshaped again without chemical decomposition, they are easy to recycle.
ABS Plastic
ABS plastic is a thermoplastic blend that combines the strength and rigidity of specific polymers with the ruggedness of polybutadiene rubber. Because ABS plastic is chemical- and heat-resistant and offers good protection against dents, it's widely used in helmets. In addition, like all thermoplastics, ABS plastic is less expensive and heavier than woven compounds.
Fibreglass
Fibreglass is lightweight and strong and doesn't cost the earth - a great combination when creating a motorcycle helmet. The lightest helmets out there will be composed of either Fibreglass or carbon fibre. However, it can be pretty brittle, shattering upon impact. This is why Fibreglass tends to be used in conjunction with other materials to create the safest helmets. Many fibreglass helmets combine with additional high-strength materials such as carbon fibre and Kevlar/Aramid in the weave pattern. Helmet prices rise with an increase in materials. A big plus point of fibreglass composite is greater flexibility under the impact, which allows the impact to be spread out more evenly across the helmet. Because of its brittleness, that greater flexibility translates into the shell cracking on impact. When this happens, the Styrofoam layer collapses so your head doesn't connect with the inside of the hard shell. Therefore, less foam padding is used - allowing the helmet to be lighter and smaller overall.
Carbon Fibre / Kevlar / Aramid
Carbon Fibre
Because of the unique way carbon atoms align and bond together along fibres in a crystal formation, a naturally occurring high-strength bond forms. When thousands of these high-strength fibres are woven together and combined with plastic resin and other aramid fibres, that fabric is known as reinforced "carbon fibre" material. Carbon Fibre as well as being extremely durable and lightweight can be woven into different patterns depending on the desired final look. It is exceptionally lightweight (lighter than fibreglass) and strong, and resistant to pressure and compression. It can withstand impact and not shatter or crack. Carbon Fibre allows the force of an impact to be spread over a larger area of the helmet, allowing more of the impact-absorbing liner to do its job. This durability is also beneficial if a carbon fibre helmet is dropped because it will be more resistant to scratches and cracks. Carbon Fibre is more expensive than the other helmet materials due to higher production and manufacturing costs. It is often combined with other materials such as fibreglass and kevlar.
Kevlar/Aramid
DuPont Kevlar is a brand name. Kevlar has an aramid-type fibre weave base. The fibres' molecular structure naturally occurs in even, parallel lines; Kevlar ends up with a much higher tensile strength than fibreglass. It doesn't tear easily and is abrasion-resistant. Ideal for motorcycle kit – and in bulletproof vests! The material used in Kevlar helmets is produced with the same weave methods as fibreglass ones, then mixed with a very strong plastic compound. While Kevlar is strong, it does not hold up well against compression. Therefore, Kevlar is generally added to carbon fibre helmet shells to increase overall tensile strength, while the carbon fibre is there to counteract Kevlars weak compression rate. Kevlar's extra strength allows the weave to be less dense; therefore, helmet safety levels can be met with 20% less weight than fibreglass.
Composite Fibre
Composite fibre helmets are constructed by weaving or crisscrossing different fibre strands together. Manufacturing composite helmets require more materials and labour, causing them to be more expensive than their plastic counterparts. Technically, most helmets are composite helmets, but it's easier to differentiate in these categories for the classification of different helmet types. To make composite fibre helmets, the crisscrossing layers of fibre strands are placed into an existing mould, adding resins or other fillers, then heated. This process is repeated with strands at different angles until a weave pattern is reached and very high strength is achieved. This is not only labour-intensive but also material-intensive, so, therefore, costs more. Composite fibre helmets are made from various fibres such as Kevlar, fibreglass, and carbon fibre; however, helmets marketed as "fibreglass", "carbon fibre", etc., usually contain a mix of more than one of these fibre types. Unless otherwise indicated, official helmet designation will follow whatever material is most prevalent in the composite mix used. For example, a carbon fibre helmet will feature more carbon fibre material than anything else – whereas composite fibre helmets will boast this as they generally make an extraordinarily protective and lightweight helmet—the best of all worlds.
Helmet cleaning
No matter what material your helmet is, it is essential to keep your helmet in good order. Follow these tips from Sharp to make sure you are getting the best from your helmet:
VISORS
A good quality visor is an essential equipment for the motorcyclist. It is important that you look after it so as to maintain good vision in all weather and lighting conditions. Your visor will often become soiled with dead flies, bugs and road debris even after short distances, and as a result, will need regular cleaning. It is important that this should be done with care so you avoid damaging the front surface of the visor. A scratched visor can cause dazzle from oncoming vehicle headlights. You should also make sure that when you go out to ride, you have the correct visor fitted for the conditions. Visors with heavy tints can be dangerous, both for you and other road users. Visors that transmit less than 50% of visible light do not fully comply with any of the standards and cannot legally be used on the road. For more information on the legal and technical aspects of the visor and goggle use, visit GOV.UK: Motorcycle helmet law .
All in all, every single helmet has to pass stringent safety tests in order to be sold and to be used on the road. Yes, the more expensive ones are more lightweight, but it is definitely worth a try-on as another important factor is the fit of your helmet. For more information about helmet sizing check out this blog here.
Until next time, stay safe,
Alex