Vehicle investigation


When relatively new or valuable vehicles catch fire, DBIís fire investigators are often asked to determine the cause.

An electric arc in the engine compartment
In one case the assignment was to find the cause of fire of a relatively expensive car which had recently undergone extensive repairs. The fire had apparently started on one side of the engine compartment, where hydraulic fluids for the brakes and power steering had resulted a great deal smoke and carbon. However, there were no electrical components or the like that could reasonably have started a fire.

The investigation also showed that the fire actually had initiated on the opposite side of the engine casing, where the insulation surrounding an electric cable had become frayed, creating in a powerful electric arc. This suggested that during the car's previous repair, the cable had not been properly secured to keep it from moving.

A read-out of the carís electronic memory supported the theory of the frayed cable. Immediately prior to the fire, the battery voltage dropped drastically, which is precisely what happens when a voltage-carrying cable shorts against the chassis, producing a powerful electric arc.

A trace of petrol in the cabin
Each year in Denmark alone, several thousand automobiles suffer minor or major fires.

These fires are primarily due to defects in older, poorly maintained models. But there are other causes as well.

This is why technicians from the auto manufacturer called DBIís fire investigators when they found a soft drink can bearing the clear odour of petrol inside the car.

The investigation showed that the damages were concentrated in the carís cabin. The engine compartment was untouched by the flames, and even though smoke had penetrated the boot, there were no traces of fire there.

There was also a clear odour of petrol beneath the floor mats, and several bottles were found that had contained petrol. These traces were relatively easy to locate, as the fire had not caused severe damage inside the cabin.

Based on the conclusions of the investigation Ė and despite the fact that petrol can naturally be found in cars Ė the fire was most likely intentionally started and was scarcely an accident.

Gert Jakobsen
Fire investigator

Phone : 29 25 65 73
Mail : gja|

Jernholmen 12
DK-2650 Hvidovre
Tlf. +45 36 34 90 00
Fax +45 36 34 90 01
E-mail: dbi|

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