Authors: R.A. Ogle, John L. Schumacher
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REQUEST FULL PUBLICATIONAuthors: R.A. Ogle, John L. Schumacher
REQUEST FULL PUBLICATIONAuthors: R.A. Ogle, John L. Schumacher
REQUEST FULL PUBLICATIONA research project into odor fade in new and used 500-gallon propane tanks was undertaken as a result of litigation related to a catastrophic explosion and subsequent fire that occurred in a modular home in the Rocky Mountain area. The test program involved twelve 500-gallon tanks of various classifications. Six tanks were new, three tanks were converted from anhydrous ammonia to propane and three tanks were old and seasoned.
Authors: John L. Schumacher, Jay M. Freeman
REQUEST FULL PUBLICATIONFires, explosions and carbon monoxide poisoning incidents occur every year with customers of natural gas and propane companies. When incidents do occur, gas companies typically conduct an investigation into the losses to assess liability and to prepare for potential future claims. The severity of the incident, to some degree, determines the type and sophistication of the investigation. In many cases, investigation into less severe accidents is conducted in-house. With the more serious incidents, engineers are customarily hired to conduct and direct the investigation. This paper addresses the role of the forensic engineer in the investigation of fires, explosions and carbon monoxide incidents related to potential gas company claims.
Authors: John L. Schumacher, Jay M. Freeman
REQUEST FULL PUBLICATIONFire and explosion incidents occur far too frequently every year in the United States. They occur in residences, commercial buildings, manufacturing facilities and chemical plants alike. These incidents cause serious injury, fatality, and large dollar loss as a result of property damage and business interruption. Determining the root cause of the fire and/or explosion is important in the prevention of future recurrences, assessing liability and preparing for potential future claims. This paper addresses the role of the forensic engineer in the effective investigation of fires and explosions involving gas and flammable liquids.
Authors: John L. Schumacher, Jay M. Freeman
REQUEST FULL PUBLICATIONThe investigation of a gas-related fire or explosion typically involves testing the integrity of the gas system. Oftentimes this testing reveals one or more leaks of various sizes. The investigator must then evaluate the cause of each leak and/or its potential in contributing to the cause of the incident. Two methods commonly used to evaluate the potential causal role of a leak are full scale testing and mathematical modeling. Although full scale testing is preferred, it may be cost prohibitive and impractical. In these cases, the alternative is mathematical modeling. The question that arises with the use of a mathematical model, however, is how accurately it predicts the gas concentrations that were actually present during the incident under investigation.
Authors: John L. Schumacher, Dennis E. Shelp, Zach J. Jason, Jay M. Freeman
REQUEST FULL PUBLICATIONAuthors: Charles B. Sullivan
REQUEST FULL PUBLICATIONRegulators and gas control valves are at the heart of gas pressure regulation. The regulators are designed to limit the pressure delivered to the gas control valves to a specified maximum, typically 1.7 kPa (7 inches water column gauge (w.c.)) for natural gas and 3.2 kPa (13 inches w.c.) for propane. The gas control valve allows gas to flow to its associated appliance burner when there is a call for operation. The gas control valve usually has internal regulation, which reduces the manifold pressure below that of the incoming pressure, typically about 0.87 kPa (3.5 inches w.c.) for natural gas and 2.5 kPa (10 inches w.c.) for propane.
Authors: John L. Schumacher, Dennis E. Shelp, Zach J. Jason, Jay M. Freeman
REQUEST FULL PUBLICATIONUnder certain conditions the ability of a regulator to properly regulate fuel gas pressure can be affected. If a regulator problem occurs that sends high pressure gas downstream, gas-fired equipment and system components can potentially fail, which may result in a fire or explosion. This study describes the basic construction and operation of a lever-style service regulator, the type commonly used on residential and light commercial gas systems. Then, considering the mechanics of how regulators work, problematic conditions that can produce higher than normal outlet pressures are discussed and experimentally demonstrated. These examples are then discussed with regard to actual overpressure failures observed by the authors.
Authors: Dennis E. Shelp, John L. Schumacher, Zach J. Jason, Jay M. Freeman
REQUEST FULL PUBLICATIONThere are situations that occur when customers and servicemen have difficulty lighting pilots on appliances after the natural gas or propane system has been shut off or following an out-of-gas call in a propane system. The inability to light the pilot light is believed to be due to air getting into the gas system. In some circumstances customers or servicemen will purge the gas line in order to get the “air” out of the lines. Sometimes this results in flammable gas entering the structure resulting in an explosion, flash fire or fire, which causes property damage, serious injuries, and sometimes death.
Authors: John L. Schumacher, Dennis E. Shelp, Zach J. Jason, Jay M. Freeman
REQUEST FULL PUBLICATIONRaw agricultural commodities, such as corn, soybean, rice and wheat, are typically stored in bins and silos prior to shipment. During storage, it is often necessary to protect the commodities from damage by insects and pests. A common protection method utilized is the addition of solid fumigant pellets or tablets to the commodity. One of the most common solid fumigants employed is a blend of aluminum phosphide, ammonium carbamate and other inert ingredients.
Authors: John L. Schumacher, Zach J. Jason
REQUEST FULL PUBLICATIONPolyethylene (PE) pipe has been used as a proven means of conveying and distributing fuel gases since the 1960s.1 In the United States and Canada, PE pipe accounts for over 90% of the natural gas distribution system and has become the de facto industry standard. Although PE pipe is so prevalent, industry codes and regulations do not allow plastic pipe to be installed within a structure as a suitable means to convey fuel gas. Therefore, a coupling or fitting is used to transition from the exterior PE pipe to the metallic pipe
associated with distribution within a structure.
Authors: Zach J. Jason, John L. Schumacher, Dennis E. Shelp, M.L. Brown
REQUEST FULL PUBLICATIONThere are situations that occur when customers and servicemen have difficulty lighting pilots on appliances after a natural gas or propane system has been shut off or following an out-of-gas call in a propane system. The inability to light the pilot light is believed to be the result of air getting into the gas system. In some circumstances, customers or servicemen will purge the gas line in order to get the ‘‘air’’ out of the lines. Sometimes this results in flammable gas entering the structure leading to an explosion, flash fire or fire, and subsequently property damage, serious injuries, and sometimes death.
Authors: John L. Schumacher, Dennis E. Shelp, Zach J. Jason, Jay M. Freeman
REQUEST FULL PUBLICATIONIt is well known that cigarettes are the leading cause of fire deaths in the United States.1 The National Fire Protection Association (NFPA) reports that in 2011 alone, there were over 90,000 smoking-related fires, contributing to over 540 civilian deaths, 1,640 civilian injuries, and $621 million in direct property damage. However, the NFPA statistics, collected from The National Fire Incident Reporting System (NFIRS) and the NFPA annual survey, define “Smoking Materials” as lighted tobacco products (typically tobacco cigarettes). There is little to no data regarding fires caused by cannabis, or what will hereafter be referred to as marijuana cigarettes.
Authors: Zach J. Jason, Dennis E. Shelp, John L. Schumacher, T.J. Hedglin
REQUEST FULL PUBLICATIONAuthors: John L. Schumacher, S.G. Davis
REQUEST FULL PUBLICATIONThis paper reviews recent survey data related to grill ownership and usage, an references National Fire Incident Reporting System (NFIRS) data related to gas grill fires. The basic anatomy of gas grills is presented, and standards and safety devices relevant to gas grills are discussed. This background and baseline information is followed by a discussion of the causes of gas grill fires. Potential causes are considered and discussed in great detail than the generalized information available through NFIRS data, and observations based on investigation results and demonstrative tests are provided.
Authors: Dennis E. Shelp, John L. Schumacher, Zach J. Jason, Jay M. Freeman
REQUEST FULL PUBLICATIONFires that occur in restaurant kitchens typically involve electric, gas, and solid fuel cooking appliances. In some cases, the fire may involve the associated ventilation system.
Determining what component(s) of the commercial cooking operation caused the fire is only one part of the investigation. A potentially equally important aspect of the investigation is the evaluation of the restaurant hood, fire extinguishing system, and ventilation control from a fire spread standpoint. As it relates to commercial cooking operations, this paper outlines the extinguishing system components and operation, ventilation control system components and operation, applicable codes and standards, installation and service requirements, and common failure modes.
Authors: Charles B. Sullivan, John L. Schumacher
REQUEST FULL PUBLICATIONAuthors: Charles B. Sullivan, John L. Schumacher
REQUEST FULL PUBLICATIONIn the early morning hours of December 10, 2007, the high school in Jones, Oklahoma, burned down in the midst of a massive ice storm that had knocked out power to most of the town. First responders made entry into the building and encountered heavy fire overhead near the intersection of the main north-south and east-west hallways in the north end of the building. The fire resisted suppression efforts and spread through the building via the ceiling and common enclosed roof spaces. The following day the burned-out remains of a second smaller fire were discovered in a locker room in a separate gymnasium building adjacent to the destroyed main building. The doors of both buildings were locked and no signs of forced entry, other than those made by firefighters, were observed.
A fire investigation was subsequently conducted. Given the numerous power outages and lightning associated with the storm, an electrical fire cause was hypothesized. After several days of investigating the fire, however, no evidence was found to indicate that the electrical systems in either building were energized during the fire, and witnesses and alarm records indicated the power to the high school had been out for hours before the fire was discovered. Just as it started to look like the fire would be classified as undetermined, a unique fire pattern was identified on the front of a gas-fired water heater that changed the course of the investigation.
Authors: Dennis E. Shelp
REQUEST FULL PUBLICATIONAuthors: B. Newton, John L. Schumacher
REQUEST FULL PUBLICATIONWith the ongoing legalization of marijuana, a new and potentially dangerous trend of extracting the cannabis plant oils is sweeping across the United States. The concept of making marijuana extracts (commonly referred to as “hash oil”) is not a new idea and in the past, traditional “hash” was produced by mechanically separating the natural resins from the plant through sieving, milling, crushing, and/or pulverizing of the raw material. However, the advent of “blasting,” a relatively new method of passing a flammable solvent through the plant material, has led to a brand new hazard associated with the extraction process. Whether it be in a regulated commercial facility or a clandestine extraction laboratory, the potential for an uncontrolled release of flammable vapors has led to an increased number of flash fires and explosions associated with the extraction process.
Authors: Zach J. Jason, John L. Schumacher, Shawn A. Sapp
REQUEST FULL PUBLICATIONAuthors: John L. Schumacher, Scott D. Raszeja
REQUEST FULL PUBLICATIONAuthors: Charles B. Sullivan
REQUEST FULL PUBLICATIONAuthors: Matthew G. Strader, Trevor Borth, Rick Jones, Gregg Gorbett, Ph.D.
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