Sunday, September 26, 2010

Lightning Strike on a Rear-Dumper

This photo was sent in this week by a reader. It's a rear-dumper that's been hit by lightning.

Update 30/10: A reader noticed that this incident is from NSW a couple of years ago, and pointed me to the DPI report, which has lots of interesting information. From the DPI safety alert:

A large rear dump truck (RDT) was struck by lightning while stationary and unattended. No employees or personnel were injured.

Three tyres were blown off the truck between 2 to 5 minutes after the lightning strike. Two tyres exploded (position 1 and 3 tyres) on the driver’s side of the truck, sending debris several hundred metres from the vehicle and causing extensive damage to the truck and other equipment.
One complete wheel base (weighing 1.6 tonnes) was thrown about 100 metres from the truck. A solid wheel flange (weighing 250kg) was thrown to the top of the stockpile about 275 metres from the truck. The air blast and shock wave caused damage to the operator’s cabin, other equipment and buildings up to 230 metres from the truck. The tyres were ejected and finished between 50 to 60 metres from the truck.

Damage to the truck
1.    The truck operator’s rear cabin window was blown into the cabin and all other windows were blown outwards from the cabin. The driver’s door was blown open.
2.    The final drive was extensively damaged. The rear outer position 3 wheel base exploded off the final drive breaking 57 one-inch grade 10.9 bolts in tension with a calculated force of approximately 270k Newtons. The final drive outer planetary carrier and axle were blown off the truck.
3.    Position 1 tyre (new tyre) had one complete side wall blown out.
4.    Position 3 tyre had the side wall blown out for three-quarters of the circumference.
5.    Position 4 tyre was inspected with no visual damage. This tyre was scrapped due to oil contamination inside the tyre.
6.    The engine sump was cracked and damaged. The oil cooler was damaged.
7.    The front position 1 wheel strut mounting was distorted, and the front wheel hub was bent.
8.    Fuel tank mountings were significantly damaged.
9.    The three wheel bases were damaged and scrapped.

Other damage

The operator’s cabin windscreen of a water truck parked 20 metres from the RDT was blown out. A window of a car parked in the employee car park was broken. Some washery office windows were broken by the shock wave, and damage was caused to some sheeting on the outside of the elevator building.
Some bath house windows were broken. Five windows in the main office were also broken.


Anonymous said...

for those that dont know, when a truck gets struck by lightning the electricity earths out of the truck through the steel wire in the tyres. The extreme heat generated by this causes a chemical reaction in the tyre which casuse an internal tyre fire, the pressure within the tyre expands exponentialy to the point where the casing can no longer withstand the pressure and fails like this incident. normal operating pressure for these is just above 100 Psi. The tyre casings are designed to withstand 10 times the operating pressure before exploding. That is around 1000 Psi of pressure.

Anonymous said...

I was there that day. And it was quite scary. Didn't see it but was in the workshop about a hundred meters away so definatlty heard it.

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