LIFT TRUCK FIRES
by
Charles C. Roberts, Jr.
Fires originating in lift trucks can result in significant property damage since many
lift trucks are used in industrial environments that encompass equipment of
substantial value. The failure of fuel cylinders on lift trucks can cause personal
injury or death when a lethal fragment separates during a BLEVE (Boiling Liquid
Expanding Vapor Explosion). Sometimes a fire is incorrectly attributed to a lift
truck malfunction when a fire nearby the lift truck results in severe damage to the
truck because of the highly volatile fuels onboard. Sorting out the evidence often
starts with a burn pattern analysis. In Figure 1 the localized burn pattern on the
engine compartment cover suggests that the fire started inside the vehicle. The
Figure 1
Figure 2
vehicle was parked outside of a plant. Figure 2 shows a badly damaged block
heater that was installed on a radiator hose to keep the vehicle warm during cold
weather. Figure 3 is a close-up of the badly damaged heater housing that is a likely
Figure 3
Figure 4
cause of the fire. Figure 4 is a close-up of one of the 120 volt wires connected to
the heater. Beading on the conductor is indicative of molten copper, a result of an
electrical fault or short circuit. Burn patterns on engine components indicate a
localized origin of the fire in the block heater. The electrical faulting is most likely
a result of insulation breakdown in that area.
The lift truck shown in Figure 5 was engulfed by flames while being used inside a
plant. Substantial damage occurred to the lift truck as well as to the building. Burn
Figure 5
Figure 6
pattern analysis, along with witness accounts, indicates that the fire started in the
vehicle. Figure 6 shows the engine compartment. Examination of burn pattern
evidence in the engine compartment shows a fire origin near a reinforced propane
fuel line as shown by the arrow. Figure 7 is a close-up of a faulted metal
reinforcing mesh that contacted the positive terminal on the battery post.
Figure 7
Figure 8
Apparently, the fuel line was misrouted and was sandwiched between the engine
cover and the battery post. As a result of engine vibration, the outer polymer
covering eventually wore away, allowing the wire reinforcement of the fuel line to
contact the battery post. Improper routing of the fuel line was the ultimate cause of
the loss.
The lift truck in Figure 8 sustained an engine compartment fire while being
operated in a freight yard. Figure 9 shows the badly damaged engine and
transmission area under the operator’s seat. Residual hydraulic oil around the
Figure 9
Figure 10
transmission is characteristic of oil leakage in the form of a spray of liquid onto the
exhaust manifold. Atomized hot oil is easily ignited by hot surfaces (see Claims,
April 1995). Wear-out of the hydraulic hoses was the likely cause of the loss.
Figure 10 shows a fuel cylinder mounted on the back of a lift truck. Figure 11 is a
top view of the fuel cylinder the sustained a BLEVE during a warehouse fire. Heat
transfer from an external source weakened the aluminum propane cylinder walls,
Figure 11
causing the release of propane. Many fires and explosions are incorrectly attributed
to lift trucks based on the fact that a BLEVE occurred. In many instances a
BLEVE is a result of a fire from another source.
To aide in the determination of the involvement of a lift truck in a fire,
maintenance records, recall notices, witness statements and information regarding
fuel cylinder replacement and inspection is helpful. It is not unusual to find a lift
truck buried under an unrecognizable pile of building rubble where burn pattern
recognition is virtually impossible, leading to a conclusion of undetermined cause.
Careful handling of evidence is a must to avoid complications brought on by
spoliation (See Claims, June 1992).
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