Watch as motorcycle helmets endure extreme testing so they can protect wearers from weather, debris, and hard impacts.

JONNY PHILLIPS: This time on testing testing, motorbike helmets

NARRATOR: This is a specialist testing laboratory in Hoevelaken, Holland

NARRATOR: First up, the weather test. This helmet has to endure 6 hours of driving rain and 6 hours in 50 degree heat.

NARRATOR: 12 hours of punishment later, it's a pass

NARRATOR: To test the outer shell's resistance to sharp objects,

a 3 kilogram weight is dropped onto the helmet from a height of 3 meters. There's no room for manoeuvre - even momentary contact with the head form means a fail.

RENÉ STEENBEEK, TESTING ENGINEER: When this sharp point hits the head you hear a beep.

[Sensor Beeps] Only the smallest touch, you already give a beep.

NARRATOR: The helmet's dented, but the buzzer doesn't sound. It's a pass.

NARRATOR: It must also be tested for penetration of the visor.

NARRATOR: And imagine if you were happily riding along and a load of sand blew in your face. Well, the visor has to be scratch resistant too.

NARRATOR: A section of the visor is taken out. - 3 kilos of sand should do the trick.

NARRATOR: And after it's cleaned, the visibility still has to be 75%.

OLAF VAN SCHINJNDEL, ARAI HELMETS: The inner shell is made of polystyrene with 3 kinds of densities. The reason is because of the fact that the human skull on the top is quite thin and on the front side it's quite hard actually so you can have a different impact on the front side of the helmet or on top of the helmet.

NARRATOR: The inner shell acts like a cushion to absorb impact energy. Polystyrene beads are compressed one by one extending the time of impact and providing a stopping distance for the person inside, much like body panels being crushed in a car accident.

NARRATOR: And how to test it? You drop it head first.

NARRATOR: Sensors in the 5 kilo head form measure its acceleration when it strikes. The inner shell is there to slow the impact, so the lower the acceleration the better the shock absorption of the helmet.

NARRATOR: And the test doesn't even damage the surface.