Forensics

Container Fires

Introduction

Much of the worlds goods are transported in the standard sea shipping container. These are sometimes referred to as steel containers, although the floors are always of wood. Despite the wooden floor, the doors and small ventilation holes, a container is well sealed. If a container falls overboard it is expected to float for at least three days.

Fire

By container fires we mean fires that begin in individual containers from the cargo therein. These can occur during road transport, storage or on board a vessel. Sometimes there is an explosion and usually this results in deformation of the sides of the container, which remains together, although one exception is shown in the examples.

Left: Container that exploded while in the hold of a vessel. The container cargo was flammable liquid.
Right: Inside view of container.
Container on wharf exploded, killing two guards believed to have opened the doors. Cargo was drums of toluene.

A common first question is whether the fire initiated within or without a particular container. The steel walls conduct heat readily and under the right conditions fire can spread easily in either direction.

Fire spread to the container (left) by heating of the steel side, with ignition of the goods inside (right).

Spread from container to container can occur when they are close packed. Sometimes the contents might be a flammable liquid or might be converted to a flammable liquid (eg, margarine or thermoplastic resin). When the wooden floor is breached a pool of flaming liquid spreads fire quickly over a large area, perhaps involving adjacent containers. The origin is easier to determine if examination can be carried out at the original undisturbed site. It is more difficult if the container is moved and examined in isolation.

Fire Cause

A pallet-load of rechargeable handphone batteries that spontaneously ignited during transport in a container.

If it has been established that the fire is from within, the ignition source has to be determined. The question of inherent vice can arise. In days past this invariably meant self-heating agricultural product such as soya beans or wheat. A modern equivalent are pallet-loads of batteries with a residual charge.

Container that caught on fire while being transported, then later exploded while stored. Cargo was nitrocellulose.

With some containers the packaging is crucial and inadequate packaging can result in fire. Examples are batteries and nitrocellulose. Fires can also arise from interaction between goods. Examples would be contact between a strong oxidiser such as hydrogen peroxide and a combustible organic material; the accidental mixing of a thermosetting material, or the wetting of slaked lime.

Container Trailer Fires

Damage pattern on a container, following ignition at a tyre minutes after the trailer came to a stop.

Some container fires occur while they are on a moving trailer. Often these have nothing to do with the container, with fires starting at tyres or brakes and spreading to the container. In the case of the former, heat generated in the tyre while the vehicle is moving is removed by the slipstream. When the vehicle stops, the internal heat 'comes out' and the surface of the tyre can ignite. This explains the phenomenon of ignition some minutes after the trailer stops.


Other Links For

Forensic Services - Marine Cargo Claims Investigation Category

Container Fires| Marine Cargo Claims | Corrosion of Steel in Transit