A Study of Calcination of Gypsum Wallboard

Christopher L. Mealy
Daniel T. Gottuk
Hughes Associates, Inc.

Presented at International Symposium on Fire Investigation, 2012


The prevalence of gypsum wallboard in fire scenes makes it a potentially valuable source of information to fire investigators when assessing a fire scene. The exposure of gypsum wallboard to heat from a fire can result in calcination, which in turn can theoretically be correlated to the total heat exposure to that area. Therefore, if properly characterized, a calcination depth profile of a given enclosure could provide fire investigators with a detailed history of the total heat exposure to the walls and ceiling of the space. This history, when combined with other findings, could provide valuable insight as to where the area of origin was located or how the fire developed. The approach taken in this work incorporated small- and full-scale testing to accomplish several goals: 1) develop an objective method for measuring the calcination depth of gypsum wallboard, 2) assess the utility of the calcination depth surveys in full-scale fires, and 3) characterize the impact of suppression water on calcination depth measurements. In this work a probing pressure of 0.86 kg/mm2  (1175 psi) was identified as providing accurate calcination depth measurements. The benefit of calcination depth surveys in full-scale enclosure fire scenarios was realized primarily for cases where visual patterns were not obvious. The application of water to calcined GWB was found to alter the measured depth of calcination by an average 18 percent, when collected 24 hours after heating/water application and less than five percent after 30 days. This data suggests that if measurements are to be collected in areas that have been wetted by suppression activities for any extended period of time, it would be advisable to delay measurements until the water has been removed.

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1968, Nov 20th:  Explosions rock West Virginia coal mine

Methane gas explosions in a West Virginia coal mine kill 78 men on November 20th, 1968. The damage to the mine was so extensive that it had to be sealed with the bodies of the men still inside.

The Consol No. 9 mine was located about 10 miles from the town of Monongay, between Farmington and Mannington in West Virginia. It was a large mine, approximately eight miles by six miles, with untapped oil and natural gas below the coal. At midnight on November 20, the workers descended 600 feet below the earth’s surface to begin the night shift. At 5:40 a.m., a large explosion was quickly followed by three smaller ones. The blasts were so powerful that the lamphouse near the entrance to the mine was demolished.

Twenty-one men working in one section of the mine were able to escape in the early morning light even though dense smoke continued to billow from the nine entrances for hours. As rescue and relief workers arrived on the scene, it was unclear how many men remained in the mine, as the list of late-shift workers had been stored in the now-destroyed lamphouse. Since it was still impossible to enter the mine, the rescuers surveyed the families of the mine workers to get a complete list of the trapped miners.

At 10 p.m., as the would-be rescuers waited for an opportunity to enter the mine, there was another explosion; yet another occurred overnight. Given that the mine had only two working ventilators and the fire continued to burn, it became clear that it was unlikely the mine workers were still alive. Furthermore, the only way that the fire, smoldering in the coal deposits, could be extinguished was to cut off its air supply, which would suffocate any survivors. It was decided to drill a hole down to the area of the mine that was the only possible location of survivors.

When there was still no indication of life 10 days after the explosions first ripped through the mine, it was decided to seal the mine completely, with the 78 victims still buried inside it.

Source: History.com

Scientific Method-Use, Application, and Gap Analysis for Origin Determination


Gregory E. Gorbett, MScFPE, CFEI, IAAI-CFI, CFII, CFPS
Eastern Kentucky University, USA
Wayne Chapdelaine, CFEI, IAAI-CFI, CFII
Metro-Rural Fire Forensics

Presented at International Symposium on Fire Investigation, 2014

The fire investigation industry is considered to be lagging behind the rest of the forensic science fields in its assessment of the performance of methodological approaches and conclusions drawn by practitioners within the field. Despite the best efforts of certifying bodies and industry members, there are still many unknowns within the profession. This paper will present practical uses of the scientific method as it relates to Origin Determination. Several recommended practices have been identified and formatted to reflect the scientific method as utilized in NFPA 921. In addition, where practical, a gap analysis has been conducted on these processes with recommendations provided.

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Great Boston Fire of 1872 – November 9, 1872

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

Fires Originating in Branch-Circuit NM Cables Due to Installation Damage

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

Presented at International Symposium on Fire Investigation, 2014

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.

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