Case Study: Separating Origin from Spread in an Industrial Equipment Fire

When a fire involves multiple large pieces of industrial equipment operating side by side, determining where the fire started is not always straightforward. Damage can quickly spread between machines, especially where conveyors, fuel loads and wind conditions all play a role.

In this case, a fire at a recycling operation involved two large processing units that worked together as part of the same production line. Material moved from one machine to the other by conveyor, which meant the investigation had to carefully separate origin damage from spread damage.

Staff had been on site earlier in the day and carried out their normal shutdown procedures, including cleaning residual material from the conveyor systems and clearing debris beneath the machines. No faults or operating issues had been reported. The fire was discovered several hours after the site had been vacated, and there was no indication that anyone was present when the fire occurred.

The physical evidence became critical.

One of the machines displayed directional fire damage and heat effects concentrated on the side nearest the adjoining unit. Burn patterns and severe rusting around the conveyor area suggested that the damage to this machine was consistent with fire spread, not origin. A whitish burn pattern at the end closest to the second machine indicated exposure to significant heat, further supporting that conclusion.

The second machine told a different story.

On one side of that unit, near a switchboard enclosure, the fire damage was notably more severe. The switchboard door had failed, exposing the interior. Inside, the components had been destroyed to the point that only wiring remained, with insulation consumed. Arc damage and damage to contact points were also identified. Importantly, components located behind the switchboard, including hoses and adjacent wiring, showed only minor fire effects. That pattern helped narrow the origin area to the switchboard itself.

Based on the evidence, the first fuel involved was wiring associated with the switchboard. While the precise ignition point within the enclosure could not be isolated, the findings supported an unspecified electrical fault within the switchboard as the cause of ignition. No other viable ignition sources were identified.

Wind direction also helped explain the final damage profile across both machines. The available weather information indicated wind conditions that would have driven fire from the machine containing the switchboard toward the adjoining unit. That aligned with the observed burn patterns and directional damage across the site.

Another important consideration was the timeline. The fire was not discovered until hours after the machinery had stopped operating. This raised the possibility that the initial failure may have begun as a hidden electrical smoulder within the switchboard, progressing undetected before transitioning to open flaming. It was also considered possible that the fault developed while the machine was moving into idle, sitting in idle, or during shutdown.

Outcome

The fire was determined to be accidental, with evidence indicating a fault in the switchboard of one processing unit as the cause. The adjoining machine was damaged as a result of the spread of fire.

This investigation is a strong example of why industrial and machinery fires require a methodical approach. In complex plant losses, the most heavily damaged area is not always the origin. Equipment layout, fire patterns, exposure pathways, weather conditions and the condition of electrical components all need to be assessed together.

It also highlights an important issue in machinery fire investigations: not every electrical failure results in immediate visible flaming. Some faults can begin as slow, concealed overheating or smouldering events, only becoming apparent long after personnel have left site.

For fire investigators, insurers and plant operators alike, cases like this reinforce the need for detailed scene analysis and a strong understanding of how industrial equipment systems interact during fire development.