Crash helmets have been compulsory in Formula One racing since 1953, but like F1 cars, their design and construction have evolved enormously since then. Nevertheless, head and neck trauma remains the greatest single injury risk to drivers.
To counter that risk a modern F1 helmet must be supremely light - around 1250 grams is the norm - and strong. The lighter the helmet, the less weight it adds to the drivers head under the extreme G-forces experienced in accelerating/braking/cornering, hence the smaller the risk of whiplash-type injuries. And the stronger the helmet, the greater its ability to absorb impacts and resist penetration during a crash.
Only helmets authorized by the FIA may be used in races. To ensure they meet the strict safety standards required, Formula One helmets are subjected to extreme deformation and fragmentation tests. To pass the tests the helmet is made principally of carbon fibre, polyethylene and fire-resistant aramide, and is constructed in several layers.
The outer shell has two layers, typically fibre-reinforced resin over carbon fibre. Under that comes a layer of aramid (usually Kevlar®, the same material used in many bullet-proof vests). Then there is a softer, deformable layer made from polyethylene (a plastic based on polystyrene), covered with the same flame-proof material used in the drivers overalls.
The helmets visor is made of a special clear polycarbonate, combining excellent impact protection with flame resistance and excellent visibility. Most drivers use tinted visors, the insides of which are coated with anti-fogging chemicals to prevent them misting up, particularly in wet conditions. Several transparent tear-off strips are attached to the outside. As the visor picks up dirt during the course of the race, the driver can remove these to clear his vision. Ventilation for the driver is provided by small air intakes in the helmet. These include filters to prevent small particles of track debris entering.
From 2011, helmets will feature a new Zylon strip across the top of the visor to enhance protection significantly. The strip, which is 50mm tall across the full width of the visor, overlaps the top 25mm of the visor itself and extends 25mm above the helmet shell edge. The strip adds about 70 grammes to the helmet, but doubles the impact performance of the visor.
As well as safety tests, F1 helmets also undergo wind-tunnel testing to help achieve a design that minimises the drag produced when the driver is travelling at speed.
Did you know that despite the cutting edge materials used in their construction, Formula One helmet liveries are still painted by hand? Its an incredibly skilled job requiring hundreds of hours of work for more complicated patterns and designs.