Case Studies

Residential Fire A fast-moving fire fully involved a house in under ten minutes, fatally injuring a child. The local fire investigator reported that the cause of the fire was potentially the evaporative cooler mounted on the roof. Plaintiff’s counsel retained our consultants to provide fire cause and origin expertise, as well as to evaluate the effectiveness of fire retardants and the flammability of plastics. We constructed and then fire-tested a section of roof to demonstrate how the fire resulted in an out-of-control event in under 2 minutes. During the test, the plastic evaporative cooler unit ignited and burned vigorously, which led to a major roof fire. This test demonstrated how the melting, burning plastic of the evaporative cooler ran down the roof, onto the porch, igniting the steps, the porch, and then rapidly spread into the rest of the house. Information gained from our investigation of the evaporative cooler plastic material demonstrated that simple fire retardant additives were available to reduce the flammability of the evaporative cooler. We presented this information in court using state-of-the-art visuals that depicted the spread of fire. The verdict was for our client.

Residential Garage Fire A fire began in an exterior wall outlet on the windward side of a residence in San Francisco and quickly developed into a major house fire. Three fire fighters entered the grade level garage and began fighting the fire through a pedestrian door to the house. The automatic garage door closed behind them and onto the fire hose reaching into the garage. The garage door did not reverse on the fire hose, and all three firefighters were trapped in the garage. Due to the difficult weather conditions and poor communications with the incident commander, one firefighter died and the other two were seriously injured. Retained by the makers of the automatic garage-door opener, Exponent provided a detailed inspection of the accident garage door opener and the site as well as performed laboratory testing of garage door openers under high heat conditions. From modeling of the fire growth which provided information on temperatures in the garage during the firefighting operations, and from our experimental work, Exponent concluded that the garage door closed due to heat-caused shorting of the control wires mounted high in the garage. Exponent also tested a full-scale mockup of the garage door, identifying the reasons why the garage door did not reverse on the fire hose. Testimony was provided on our work in deposition and in trial. Our client was found to have no liability in this matter.

Fire on Board a DC-10 Smoke detectors located in the main cabin of a Boston-bound Federal Express DC-10 activated at an altitude of 33,000 feet over New York City. With the assistance of Air Traffic Control, the aircraft successfully executed an emergency descent and landing, and the crew was able to evacuate before the aircraft was completely consumed by the fire. In the early stage of the investigation, local fire investigators traced the origin of the fire to a piece of equipment in the main cargo cabin near the leading edge of the wing. Exponent engineers were asked by the equipment manufacturer to perform an independent investigation of this accident and to identify the area of origin of the fire. Based on a review and analysis of the evidence of the early stages of this fire, including the cockpit conversation recorded on the Cockpit Voice Recorder and the Flight Data Recorder information, Exponent determined that the initial area of origin alleged by the local fire investigators was not consistent with the factual evidence and that the fire started 20-30 feet aft of the leading edge of the wing. Photographs and video taken of the first breakthrough of smoke through the fuselage confirmed the actual area of origin of the fire.

Fire in a High-Rise Building A fire occurred in the 6th floor mailroom of the Pennsylvania Department of Transportation and Safety Building. As a result, the highrise building was declared contaminated with asbestos and later demolished. The total loss for this fire was estimated to be 20 million dollars. The Commonwealth of Pennsylvania alleged the fire originated in a copying machine inside the mailroom. Exponent was retained by the manufacturer of the copying machine to perform an investigation of this fire. Exponent’s investigation included site inspections, analysis of the operation and alleged failure modes of business machines, image analysis of photographs, and video recordings of the fire and analysis of the penetration of light through smoke. Exponent investigated the origin and cause of this fire and determined that the fire was not started by the alleged business machine. Rather, the fire originated in an entirely different area. This testimony was given in federal court. Our client was not held liable for the damages to the building.

Explosion at Ammonium Nitrate Plant Two massive detonations leveled portions of the Sioux City ammonium nitrate plant owned and operated by Terra Industries. Four plant workers were killed, eighteen others suffered serious injury, and damage to the plant and surrounding community was estimated in the hundreds of millions of dollars. The first detonation originated in a neutralizer vessel, where ammonium nitrate was produced from the exothermic reaction of nitric acid with gaseous ammonia. The resultant ammonium nitrate solution flowed from the neutralizer into a rundown tank, the origin of the second detonation. Exponent was retained to conduct an engineering analysis of the accident. The investigation revealed that the detonations occurred due to unsafe plant operations including poor maintenance and inadequate employee training. Specifically, Terra employees allowed the ammonium nitrate within their 18,000 gallon-capacity neutralizer vessel to become contaminated and highly acidic. Furthermore, Terra employees injected superheated steam directly into the neutralizer vessel. Contrary to previously published theories concerning the Terra Industries accident, Exponent established that the detonation did not initiate inside a “sparger” pipe within the exploding vessel. Several independent parties including government agencies and a court appointed metallurgist agreed with these findings, resulting in a settlement of a several hundred million dollar lawsuit.

Boiler Explosion An explosion occurred at a power plant in Dearborn, Michigan, that supplies electricity to assembly plants and a steel mill at a production plant. The explosion and fire killed six employees and severely injured 14 others. A team of Exponent engineers from the Boston, Houston, Detroit, Chicago, San Francisco, and Washington, D.C. offices led this six month long investigation and coordinated with insurance representatives, state and federal officials, union representatives, and attorneys to conduct a detailed investigation into the cause of this accident. Exponent's investigation revealed that during attempts to shut down boiler number six, a natural gas supply line allowed natural gas to accumulate inside the boiler. A combustible mixture was formed inside the boiler and associated ductwork and was subsequently ignited. Exponent engineers performed engineering analyses to evaluate the sequence of events.

Warehouse Fire A fire originated in an open ceiling loft area above office space in a large warehouse storage facility. The fire spread and completely destroyed the warehouse and damaged nearby structures. Renovations had been made to the warehouse before the fire, and an outside fire protection company had been contracted by the building owners to design and install a security and fire alarm system. Exponent engineers reviewed the fire detection system design and specifications after the fire and determined that the fire detection system had been inadequately designed and installed and that the design did not follow good fire protection engineering practice as it failed to detect the fire before it grew past its incipient stage. In addition, Exponent engineers determined that had proper design techniques been utilized, and the local building and fire code requirements been followed, the extensive damage to the warehouse could have been prevented.

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