Category Archives: FIre Investigation Science

On November 9th in 1872, a fire in Boston destroyed hundreds of buildings and killed 14 people. In the aftermath, the city established an entirely new system of firefighting and prevention. The fire also led to the creation of Boston’s financial district.

The fire began in the basement of a warehouse at the corner of Kingston and Summer streets. At the time, this area of the city contained a mix of residences and light industry. Its buildings and most area roofs were made mainly of wood, allowing the blaze to spread quickly as the wind blew red hot embers from rooftop to rooftop. In addition, as Boston streets were narrow, large flames from one structure could literally leap across them to nearby buildings.

Firefighting units from Maine to New Haven, Connecticut, arrived to help, but efforts to fight the fire were plagued by difficulties. There was not enough water on hand to get the fire under control; the hydrant system did not work well because much of the equipment was not standardized; and even when firefighters got their hands on an adequate supply of water, the height of the buildings and the narrowness of the streets made it difficult to direct the water at the blaze from the optimum angle. Because a local equine epidemic had struck the city fire department’s horses, it was difficult to get the fire engines to the correct locations at the right times. In addition, some of the efforts were counter-productive. Explosions were used to attempt fire breaks, but this high-risk strategy was not executed with enough precision and served only to further spread the fire.

The fire was finally stopped at the doors of Fanueil Hall the following morning, but it had already destroyed much of the downtown area. Boston’s officials realized that their fire-prevention efforts had been ineffective and, in the aftermath of the disaster, began to revise and strengthen all of the city’s fire laws and regulations. An inspection system was instituted and the local fire departments began to coordinate their efforts.

The fire also helped fuel Boston’s growth. The business community saw the burned area as an opportunity to expand its presence downtown. The city’s financial district was established where the fire had hit hardest and Boston soon became a key business center of the late 19th-century United States.

Source: History.com
Photo Source: Wikipedia.com

Vytenis (Vyto) Babrauskas, Ph.D.
Fire Science and Technology Inc., Issaquah WA

Presented at International Symposium on Fire Investigation, 2014

ABSTRACT
A significant fraction of US structure fires originate in electrical wiring, and there is also reason to believe that these numbers may be systematically undercounted. The role of voltage surges and damaged insulation in creating the potential for fire is discussed. That damaged electrical insulation may lead to fire has been known for a century, yet details of the mechanisms by which this occurs have not been extensively studied. UL recently published a study on damage due to poor workmanship in stapling of cables, specifically cases where the insulation is damaged but the conductors are not split. This study establishes that damage which may not appear visually striking may result in dielectric failure; such failures can be a direct cause of fire. Case histories are presented illustrating how mechanical damage associated with stapling of NM cables can result in serious fires. Two preventive measures are described: (a) installation by use of staplers and not hammers, and (b) testing the dielectric withstand voltage of branch circuits after installation and prior to energizing. Both of these measures, if implemented, should reduce the prevalence of electrical fires. However, given the immense amount of fixed wiring installed in buildings, fires due to damaged insulation do not imply that current wiring methods are a low-reliability technology. Only when serious installation defects are present does fire become a foreseeable event.

Keywords : dielectric strength of cables; electrical fires; forensic failure analysis; electrical installation defects; NM cables; voltage surges.

Download the complete paper here

The most devastating fire in United States history is ignited in Wisconsin on October 7th, 1871. Over the course of the next day, 1,200 people lost their lives and 2 billion trees were consumed by flames. Despite the massive scale of the blaze, it was overshadowed by the Great Chicago Fire, which began the next day about 250 miles away.

Peshtigo, Wisconsin, was a company lumber and sawmill town owned by William Ogden that was home to what was then one of the largest wood-products factories in the United States. The summer of 1871 was particularly dry across the northern Midwest. Still, settlers continued to set fires, using the “slash and burn” method to create new farmland and, in the process, making the risk of forest fire substantial. In fact, the month before had seen significant fires burn from Canada to Iowa.

Peshtigo, like many Midwestern towns, was highly vulnerable to fire. Nearly every structure in town was a timber-framed building–prime fuel for a fire. In addition, the roads in and out of town were covered with saw dust and a key bridge was made of wood. This would allow a fire from outside the town to easily spread to Peshtigo and make escaping from a fire in the town difficult. On September 23, the town had stockpiled a large supply of water in case a nearby fire headed in Peshtigo’s direction. Still, they were not prepared for the size and speed of the October 7 blaze.

The blaze began at an unknown spot in the dense Wisconsin forest. It first spread to the small village of Sugar Bush, where every resident was killed. High winds then sent the 200-foot flames racing northeast toward the neighboring community of Peshtigo. Temperatures reached 2,000 degrees Fahrenheit, causing trees to literally explode in the flames.

On October 8, the fire reached Peshtigo without warning. Two hundred people died in a single tavern. Others fled to a nearby river, where several people died from drowning. Three people who sought refuge in a water tank boiled to death when the fire heated the tank. A mass grave of nearly 350 people was established because extensive burns made it impossible to identify the bodies.

Despite the fact that this was the worst fire in American history, newspaper headlines on subsequent days were dominated by the story of another devastating, though smaller, blaze: the Great Chicago Fire. Another fire in Michigan’s Upper Peninsula that consumed 2 million acres was an even smaller footnote in the next day’s papers.

Source: History.com

Karrie J. Clinkinbeard, J.D., CFEI
Armstrong Teasdale LLP
and
Gerald A. King, J.D., CFEI
Armstrong Teasdale LLP

Presented at International Symposium on Fire Investigation, 2014

ABSTRACT
After an expert completes the origin and cause investigation, has carefully reviewed all available data and thoroughly researched the methodology and conclusions, the upcoming deposition should be easy, right? Not if you are unaware of tricks lawyers use to shape the testimony in the manner the adverse lawyer desires. Even the most qualified experts who have followed all elements of the scientific method in formulating their opinions are at risk if they are not sufficiently prepared to handle the opposing lawyer’s tricks. An adverse lawyer’s goal during a deposition is to have the expert say something they did not mean to or say it in a way that harms that party’s case. Lawyers craftily lay a myriad of traps when questioning an expert, especially with experts who are strong advocates for their clients. This article highlights some of the most effective lawyer tricks and provides advice on how to successfully navigate them. The presentation will contain video clips of actual depositions where these lawyer tricks are used, providing real world examples of what to do (and not do) and how to recognize when the adverse lawyer is setting you up.

Download the complete paper here

R. Thomas Long Jr. and Andrew F. Blum
Exponent, Inc., USA

Presented at International Symposium on Fire Investigation, 2014

ABSTRACT
Fires involving cars, trucks, and other highway vehicles are a common concern for emergency responders. Between 2009 and 2011, there was an average of approximately 187,500 highway vehicle fires per year.  Fire Service personnel are accustomed to responding to conventional vehicle (i.e., internal combustion engine [ICE]) fires, and generally receive training on the hazards associated with those vehicles and their subsystems. However, in light of the recent proliferation of electric drive vehicles (EDVs), a key question for emergency responders is, “what is different with EDVs and what tactical adjustments are required when responding to EDV fires?”

The overall goal of this research program was to develop the technical basis for best practices for emergency response procedures for EDV battery incidents, with consideration for suppression methods and agents, personal protective equipment (PPE), and clean-up/overhaul operations. A key component of this project goal was to conduct full-scale fire testing of large format Lithium-ion (Li-ion) batteries as used in EDVs.

This article summarizes the full-scale fire tests performed, reviews the current emergency response tactics, and discusses what, if any, tactical changes relating to emergency response procedures for EDV battery incidents are required.

Download the complete paper here

On this day in (August 19) 1980, a fire aboard a plane bound for Saudi Arabia forces an emergency landing.

The Saudi Airlines flight began in Karachi, Pakistan, headed for Jidda, Saudi Arabia, with a stopover in Riyadh. The first leg of the flight was uneventful, and the Lockheed L-1011 took off from Riyadh with no problems. Shortly after takeoff from Riyadh, the pilot reported a fire onboard the plane and told air-traffic controllers that he needed immediate clearance to head back to the airport.

The fire started while passengers onboard were cooking with a portable butane stove. Apparently, this was not unusual, as Middle Eastern airlines are often willing to accommodate their Muslim passengers’ needs to follow the strict dietary laws of their religion. The pilot was able to land the plane back at Riyadh safely and headed to the end of the runway where a rescue crew was waiting.

When the plane reached the end of the runway, however, it burst into flames. The crew sprayed fire-fighting foam at the fire, but it was no match for the intense blaze. None of the 301 people onboard escaped the fire. It is still unclear why there were no survivors. Bodies were found piled up near the escape hatches. One theory is that panic on the plane caused a stampede that prevented the hatches from being opened. Another possibility is that the crew failed to depressurize the cabin, which would have prevented the hatches from opening. It is also possible that everyone on the flight was overcome by fumes before they could save themselves.

Source: History.com

Alfonso Ibarreta, Ph.D., PE, CFEI,
Timothy Myers, Ph.D., PE, CFEI, CFI,
James Bucher, Ph.D., CFEI and
Kevin Marr, Ph.D., CFEI
Exponent, USA

Presented at International Symposium on Fire Investigation, 2012

ABSTRACT

Natural gas, composed mainly of methane, is in some ways similar to propane gas. Both fuels have similar energy densities per unit mass, and similar laminar premixed flame burning velocities. However, propane explosions have been shown to produce higher overpressures in unconfined explosion tests when compared to methane. In vapor cloud explosion modeling, methane is considered to be a “low” reactivity fuel, while propane is listed as a “medium” reactivity fuel. In closed vessel explosion testing, the maximum rate of pressure rise for propane is almost twice than that for methane (based on KG  values reported in NFPA 68 (2007) Standard for Explosion Protection by Deflagration Venting , table E.1).

This study provides a direct comparison of the explosion severity between commercial propane and natural gas. Empirical correlations available for vented vessel explosions and unconfined Vapor Cloud Explosions (VCEs) are used to predict the difference in overpressure expected for a commercial propane explosion versus natural gas explosion. Although the maximum laminar burning velocity associated with propane is only about 15% higher than that associated with methane, commercial propane explosions are expected to result in overpressures that are about 40% higher than that of a natural gas explosion under identical conditions with a perfectly-mixed nearstoichiometric fuel-air mixture, based on empirical correlations.

In addition to the laminar burning velocity, other fundamental differences in the fuels may also play an important role in the explosion severity. Propane has a slightly higher expansion ratio than methane when undergoing combustion. The mass diffusivity of propane and methane are also quite different, making the premixed propane flame more prone to wrinkling under turbulent conditions. Future testing in the 20-L explosion chamber is suggested.

Download the complete paper here

Elizabeth C. Buc, PhD, PE, CFI
Fire and Materials Research Laboratory LLC

Presented at International Symposium on Fire Investigation, 2014

ABSTRACT

Under some conditions, chemicals that are otherwise stable can react, evolve heat and cause a fire, detonate or explode. The fire investigator has to identify the chemical reactants, the reaction products and conditions that supported ignition and flame spread. A chemical fire investigation flow diagram and real-world examples of fires involving chemicals are presented to assist the fire investigator in processing chemical fires. Examples of chemical fires include self-heating, a thermite reaction, a runaway reaction from mixing incompatible materials and reactions generating hydrogen gas. Factors contributing to chemical fires such as size or quantity of material, confinement, contamination and upset process conditions are identified. Sampling, chemical analyses, literature review, and/or testing proposed or potential adverse chemical reactions are required to establish the root cause of a chemical fire.

Download the complete paper here

A coal-mine fire kills 262 workers in Marcinelle, Belgium on August 8, 1956. This highly publicized disaster was the worst ever in a Belgian mine and led to many policy changes.

The disaster itself was typical of coal-mine tragedies. An accident began at 8:10 AM when the hoist mechanism in one of the shafts was started before the coal wagon had been completely loaded into the cage. Electric cables ruptured, starting an underground fire within the shaft. The moving cage also ruptured oil and air pipes which made the fire worse and destroying much of the winch mechanism. Smoke and carbon monoxide spread down the mine, killing all the miners trapped by the fire. With the families of the miners waiting aboveground at the scene, it was not until August 23—more than two weeks later—that rescue workers could reach the deepest level of the mine. Reportedly they said, “tutti cadaveri” immediately, which is Italian for “all corpses.”

The rescue workers were speaking Italian because the majority of workers at the Le Bois du Cazier mine were Italian. At the time, Belgium was experiencing a labor shortage and had made agreements with Italy to trade work visas for coal. The tragic fire resulted in 136 Italian workers losing their lives; the immigration agreement between the two countries was terminated immediately. Despite an attempted rescue from the surface, only 13 of the miners who had been underground at the time of the accident survived. 262 were killed, making the mining accident the worst in Belgian history.

Belgium also called a conference on safety in coal mines in the aftermath of the disaster. In September 1956, the Mines Safety Commission was established. It was charged with monitoring safety procedures and developing new regulations. The country’s prompt response to the disaster led to much improved safety in Belgian and other European mines.

Source: History.com and Wikipedia.com
Photo from: MinedHistoires.org