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Why is polystyrene used for helmets?
This is the helmet’s most active ingredient. The liner is made from expanded polystyrene (EPS), which compresses in an impact, reducing the deceleration forces experienced by the brain. Modern helmets have holes to allow air to come through from external vents and channels to help the air to circulate around the head.
Is EPS foam good for helmets?
Why EPS foam? Expanded Polystyrene (EPS) is a rigid, lightweight, closed-cell foam. “EPS foam’s superior ability to absorb impact energy and its extreme light weight make it the best material for use in bicycle helmets and an excellent choice for protective safety devices such as child car seats and sports pads…
How is helmet padding made?
Bike helmet liners are made from Expanded Polystyrene (EPS). Cheaper helmets – which make up most of helmet sales worldwide – are made using standard techniques. Granules of EPS foam are placed in molds and expanded using pressure and steam.
What type of foam is used in bike helmets?
Most use some variation of EPS – expanded polystyrene foam. This stuff is stiff and lightweight, but also perfectly crushable during impact. Some advanced helmets will use multiple densities of EPS in various layers and locations.
What is expanded polystyrene?
EPS is a rigid, closed cell, thermoplastic foam material. It is produced from solid beads of polystyrene. Expansion is achieved by virtue of small amounts of gas contained within the polystyrene bead. The gas expands when heat in the form of steam is applied, thus forming closed cells of EPS.
What does EPS stand for helmet?
Expanded polystyrene (EPS) is a crushable foam, widely used in helmet liners (and other energy management applications like automobile bumpers). EPS is sometimes called “Styrofoam”, though that particular name actually refers to a single trademarked brand of EPS owned by Dow Chemical.
What materials are used to make strong helmets?
Materials like Kevlar and carbon fiber makes an exceptionally strong motorcycle helmet. These materials are proficient in absorbing greater impacts; the impacts that could easily break a normal helmet into pieces. These helmets are for those who keep the safety point at the top of the list.
How do you make expanded polystyrene?
EPS is produced in a three stage process:
- Pre-expansion. Upon contact with steam the pre-foaming agent found within the polystyrene beads (usually a hydrocarbon such as pentane) starts to boil and the beads are expanded to between 40 to 50 times their original volume.
- Conditioning.
- Moulding.
How is polystyrene used to make bicycle helmets?
PolyStyrene pellets arrive at the factory loose, in oversized bags, and are treated with high-pressure steam at temperatures up to 200 ° Celsius until they expand to fill a mould that bonds them together and shapes them into a solid helmet liner. Designers vary the thickness and density of the EPS to account for the helmet’s shape and vents.
How is the liner of a bike helmet made?
Designers vary the thickness and density of the EPS to account for the helmet’s shape and vents. The Expanded Polystyrene (EPS) liner of a bike helmet — the small round dotted areas are escape channels in the tooling for the steam to make it’s way out of the mold as the Polystyrene is expanded to make the helmet liner
What makes up the foam of a bike helmet?
One of the most often asked questions cyclists ask is “What is EPS helmet foam?” So, What is EPS helmet foam? EPS foam (expanded polystyrene foam) is the material that makes up the inner lining of a bike helmet is called EPS. A polycarbonate shell is fused onto the EPS lining to make up what you know as a bike helmet.
What happens to polystyrene beads after a crash?
Additionally, EPS maintains its protective characteristics over time, (within limits, of course.) Once those expanded polystyrene beads collapse, however, they do not regain their shape (or ability to absorb energy); for that reason, EPS is strictly suited to single impacts. This is why helmets with EPS liners should be replaced after a crash.