CH 6 - Foul Waters / Forest For Trees
Apr 15, 2009

CH 7 - "Hit and Run" Homicide / No Batch Experiments!
Apr 15, 2009

CH 8 - The dose makes the poison even with non-toxic paints!
Apr 15, 2009

CH 9 - Automotive Engine Evaluations from Oil Filters
Apr 15, 2009

CH 10 - Powder on the Peanuts / Contamination of Foodstuffs
Apr 15, 2009

CH 2 - Automotive Fires Gasoline or Electrical
Automotive Fires Gasoline or Electrical

The burnt out hulk of a Porsche 914 sports car was delivered to a near by repair facility for our examination and comments. The insurance investigator's report contained the following information. The owner had just parked the vehicle in an elevated lot, locked it and was approximately ten to fifteen paces down the ramp when he heard a loud "whoosh". On turning around his vehicle was "just a ball of flame and black smoke".

Visually the appearance of the damage on the vehicle was consistent with an engine compartment fire and inside the engine compartment was indeed a mess. With the aid of service manuals most of the burnt and heat damaged parts and pieces found lying inside were identified and their pre-fire position located. A neat round hole was found in the remains of a wire-reinforcing web surrounding what had once been the rubber core of a high-pressure fuel hose. The flexible connector compensated for engine vibration as fuel under pressure was transferred from the rigid metal fuel system fixed to the chassis. When the remnant was visually examined under low power magnification the edges of the hole were dished as one would expect from abrasion against a relatively hard, tightly curved surface.

The curvature of the edges was about the same, as one would expect to find on the outer surface of the spark plug ignition wires. A hard rubber ignition lead and road dust had probably worn through the relatively thin protective metal web and breached the flexible soft inner hose permitting pressurized gasoline to escape into the engine compartment. The owner had been very lucky to be out of the vehicle when the fuel ignited.

A surprising number of vehicle fires involve the fuel system only after a fire has started elsewhere. The lead acid storage batteries, which power starters for internal combustion engines, are able to store an amazing amount of electrical energy that can quickly be converted into very high heat. Normally a battery releases its energy in a controlled manner. Simplistically the flow of electricity through a starter is restricted by the windings inside the motor and the amount of work the starter motor must do to spin the engine.

Common fires in which a carbon based fuel burns in air to produce heat and light rarely reach metal melting temperatures. Fires characterized by red, orange and yellow flames are generally not hot enough to melt steels, irons or copper alloys.

A call from an adjuster sent us to examine the badly burnt remains of the diesel powered, tractor portion of an expensive and higher quality, cross-country rig. A report from the responding fire company indicated a fire of suspicious nature. On further investigation it was found that the firemen arriving on the scene found the interior of the vehicle "burning with a fierce, brilliant white light" and had suggested that perhaps gasoline had been involved in the fire. Once this suggestion had been made by the responding fire company the adjuster decided to have the matter investigated.

The interior of the burnt vehicle was devoid of any combustible material, seat cushions; door liner panels, floor and ceiling liners, instrument panel coverings and all the electrical wire insulation were gone. The heat had been sufficient to cause the metal core ring inside the plastic covering on the steering wheel to sag but not melt. The bulk of the copper wire for the instruments and controls was intact but portions of the heavier wiring on the left side of the cab had melted and flowed like syrup. The fused copper was at the point were the wiring connected to the vehicle's batteries, entered the cab section, carrying sufficient current to power instruments, windshield wipers, interior lighting and heater/defroster motors.

The remnants of an interior trim strip were found on the right side of the cab but not on the left. The left side remnant ended in a fused mass of friable oxide and it was obvious that it had burnt while melting. The fire appeared to have begun with an electrical short circuit that melted the copper wire on the left-hand side of the cab interior. The arc probably created enough heat and temperature to ignite the aluminum magnesium trim strip which contributed to the fire and produced the brilliant white light reported by the responding fire company. The adjuster subsequently found on further investigation a long history of "off road" time for electrical repairs.