Fire Protection Engineering Theses and Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/1903/2772

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End date: 2009Subject: search.filters.subject.Engineering, Materials Science

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    PYROLYSIS MODEL PARAMETER OPTIMIZATION USING A CUSTOMIZED STOCHASTIC HILL-CLIMBER ALGORITHM AND BENCH SCALE FIRE TEST DATA
    (2009) Webster, Robert Dale; Trouvé, Arnaud C; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    This study examines the ability of a stochastic hill-climber algorithm to develop an input parameter set to a finite difference one-dimensional model of transient conduction with pyrolysis to match experimentally determined mass loss rates of three sample materials exposed to a range of constant incident heat flux. The results of the stochastic hill-climber algorithm developed as part of the present study are compared to results obtained with genetic algorithms. Graphical documentation of the impact of single parameter mutation is provided. Critical analysis of the physical meaning of parameter sets, and their realistic range of application, is presented. Criteria are also suggested for stability and resolution of solid phase temperature and fuel mass loss rate in an implicit Crank-Nicolson scheme with explicit treatment of the heat generation source term.
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    Quenching Limits and Materials Degradation of Hydrogen Diffusion Flames
    (2008-04-25) Morton, Nicholas Ryan; Sunderland, Peter B; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    This study examines the types of hydrogen leaks that can support combustion and the effects on various materials of long term hydrogen flame exposure. Experimental and analytical work is presented. Measurements included limits of quenching, blowoff, and pilted ignition for burners with diameters of 0.36 to 1.78 mm. Flow rates of 0.019 to 40 mg/s for hydrogen, 0.12 to 64 mg/s for methane, and 0.03 to 220 mg/s for propane were studied. Materials degradation experiments were conducted on carbon steel, stainless steel, aluminum alloy, and carbon fiber. Noticeable corrosion is present on 304 and 316 stainless steel, galvanized 1006 - 1008 carbon steel. Silicon carbide fibers perform relatively similarly for hydrogen and methane flame exposure.
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    An Assessment of the Use of Flame Retardant Plastics for Museum Applications
    (2007-12-18) Leikach, Danielle Caryn; Mowrer, Frederick; Brostoff, Lynn; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Halogenated flame retardant plastic sheeting may help to reduce flame spread in museums; however, the plastics contain chemicals that may be harmful to museum objects in situ, particularly metals. This study assesses historical and contemporary problems and benefits associated with flame retardant plastics with respect to museum applications. This issue was addressed by pairing statistical data on museum fires with standard and novel methods for assessing corrosivity, while also creating a format for future assessments of fire-safety related practices as they are applied in museum settings. Flame retardant plastics were found to cause small rates of corrosion in copper, approximately 1.2 milli-inches per year (mpy), compared to pure polyethylene which corrodes at approximately 0.83 mpy. Conventional testing methods show that flame retardant plastics can be considered safe for limited museum use and that they delay ignition from small heat sources, but they must be assessed for each individual scenario.
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    A Methodology for Flammability Diagrams
    (2004-12-09) Panagiotou, Joseph; Quintiere, James G; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    The current state of fire safety regulations in the United States Department of Transportation is examined, along with some of the associated flammability test methods. The applicability and overall usefulness of these tests is evaluated along with their ability to accurately capture and describe fire performance. Theoretical relationships are shown for the fire phenomena ignition, energy release and flame spread in terms of incident flux to demonstrate the ability to extract meaningful data from calorimetry and flame spread tests. This is done for sample materials to obtain a general overview of their fire performance. This general overview is presented in the form of a Flammability Diagram. A Flammability Diagram is a single plot showing the energy release rate, time to ignition and flame spread rates for a material all as a function of the incident heat flux. Effects of melting, dripping, thickness, sooting and other factors may not be fully described, but the experimental framework captures the overall result of such effects. This study shows the feasibility of developing a measurement methodology that can be followed for the creation of Flammability Diagrams, providing a clear picture of a material's fire performance.