Fire Protection Engineering
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Item DESIGN AND PERFORMANCE EXPLORATION OF A SCALED-UP MILLIGRAM-SCALE FLAME CALORIMETER(2024) Cromwell Reed, Kyra; Raffan-Montoya, Fernando; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Fire causes thousands of lost lives and injuries, as well as billions of dollars of property damage, each year. It is critical to understand the fire hazard associated with materials used in the built environment. One method to evaluate the flammability properties of a material is through bench- scale and milligram-scale testing with apparatus such as the Milligram-Scale Flame Calorimeter (MFC). The MFC has previously been used to test samples ranging from 30 mg – 50 mg in mass. The small samples were useful for testing materials under development or materials cost prohibitive to test at larger sizes, but presented some difficulties in testing, including in sample preparation and as inconsistency in the results of testing on inhomogeneous materials. Furthermore, the small size of the MFC caused difficulty in heater manufacturing, requiring laborious by-hand construction. The size of the MFC crucible and apparatus was increased in this work to allow testing on larger sample masses, ranging in size from 90 mg – 150 mg, and for the exploration of five alternate heater manufacturing techniques. The MFC was rebuilt with a larger heater and optimized to create the best possible test conditions for this work. Tests were conducted on five polymers: polymethyl methacrylate (PMMA), polyethylene (PE), polyvinyl chloride (PVC), and polyether ether ketone (PEEK), and on a wood-based material: oriented strand board (OSB). The tests showed general consistency when materials were tested at different sample masses and sample presentations. The results for the heat release rate and heat of combustion of the materials also aligned well with testing conducted using the previous version of the MFC apparatus. The updates to the MFC conducted in this work constitute an improvement to the versatility of the apparatus, allowing for testing on larger sample masses, but future work is needed to resolve flow and exhaust issues that caused some inconsistency in the test results and to further explore and develop alternate heater manufacturing techniques.Item PYROLYSIS MODELING AND MATERIAL PROPERTY VALIDATION WITH FLAME HEAT FEEDBACK MODEL APPLICATION(2021) Bhatia, Deepanshu Kishan; Milke, James A; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Materials used in the built environment specially in upholstered furniture in business and residential occupancies act as primary fuel load in fires. This is a cause of concern not only for the building developers but for fire investigators, fire researchers and fire modelers. NIJ Technology Working Group’s Operational Requirements for Fire and Arson Investigation have laid out research needs with respect to knowledge of the thermo-physical properties of materials that are common in the built environment. To fill the gaps that limit the analysis capability of fire investigators and engineers, one of the requirement outlined is of adequate material property data inputs for fire modeling as well as fire model validation. The objectives of this study are to measure thermo-physical material properties of five materials viz. polyurethane foam, polyester batting, polyester fabric, medium density fiberboard and oriented strand board that are used in the built environment. Subsequently using the properties, model the response of these materials to fire using the condensed phase solver in the numerical solver Fire Dynamics Simulator (FDS) developed by National Institute of Standards and Technology (NIST) with flame heat feedback application. Heat flow meter (HFM) and Integrating sphere were utilized to measure thermal conductivities and emissivity values for the materials. Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Microscale Combustion Calorimetry (MCC) tests were carried out to develop a pyrolysis model and present reaction mechanism. Kinetic parameters were determined using inverse analysis with the Kinetics Neo (NETZSCH GmbH) software and the properties were used to populate the one-dimensional cone model. Flame heat feedback was applied to the model to determine the suitability of model to predict the heat release rate and compared against the cone calorimeter test data.Item Investigation of the Effect of Oxygen Concentration on the Pyrolytic Decomposition of Polypropylene(2018) Turner, Brent Allen; Stoliarov, Stanislav; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Limited research exists on the effect of oxygen on the species production during the controlled surface area pyrolytic decomposition of polypropylene. In this study, the pyrolytic decomposition of polypropylene was conducted in 0% O2, 5% O2, and 15% O2. The pyrolyzate produced during the experiments was analyzed using three methods. First, a custom tube-furnace reactor, auto-sampling system, and unique sample boat were developed to pyrolyze, collect, and deliver pyrolyzate to a GC-BID/MS for species identification and quantification. Data collected were converted to rates of production and mass evolved for individual species identified. Second, using the same tube-furnace reactor pyrolyzate was sent directly to a stack of IR and FID analyzers to measure O2, CO, CO2, and total hydrocarbon production. This data was converted and used to compare with and verify the data from the GC-BID analysis. Thermogravimetric analysis was used as a third technique to measure the mass loss of the polypropylene under the three O2 scenarios. For all three analytical methods, the effect of O2 was studied and was found to have a profound effect on species evolution and the temperature at which the reactions initiated.Item Pyrolysis of Reinforced Polymer Composites: Parameterizing a Model for Multiple Compositions(2015) Martin, Geraldine Ellen; Stoliarov, Stanislav I; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)A single set of material properties was developed to describe the pyrolysis of fiberglass reinforced polyester composites at multiple composition ratios. Milligram-scale testing was performed on the unsaturated polyester (UP) resin using thermogravimetric analysis (TGA) coupled with differential scanning calorimetry (DSC) to establish and characterize an effective semi-global reaction mechanism, of three consecutive first-order reactions. Radiation-driven gasification experiments were conducted on UP resin and the fiberglass composites at compositions ranging from 41 to 54 wt% resin at external heat fluxes from 30 to 70 kW m-2. The back surface temperature was recorded with an infrared camera and used as the target for inverse analysis to determine the thermal conductivity of the systematically isolated constituent species. Manual iterations were performed in a comprehensive pyrolysis model, ThermaKin. The complete set of properties was validated for the ability to reproduce the mass loss rate during gasification testing.Item A Model for Non-Oxidative and Oxidative Pyrolysis of Corrugated Cardboard(2013) Semmes, Molllie Rose; Stoliarov, Stanislav I; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Corrugated cardboard is widely used in warehouse facilities. The flammable nature of the material, coupled with its ubiquitous presence makes the material a serious fire hazard. As a result, there is interest in developing a universal pyrolysis model that can accurately predict the burning characteristics of the cardboard. Pyrolysis of a double-wall corrugated cardboard was studied in anaerobic and oxygen containing atmospheres using thermogravimetric analysis and a newly developed Controlled Atmosphere Pyrolysis Apparatus (CAPA). The effects of moisture were also examined under non-oxidative conditions. A previously developed cardboard pyrolysis model was demonstrated to reproduce anaerobic gasification. This model was extended to include oxygen diffusion, oxidation reactions, and modified evaporation reactions. The modified model was validated against the mass loss rate data collected in the CAPA at 10.5 vol.% of oxygen and at 2.2 vol.% oxygen with moisturized samples under incident radiant heat fluxes of 20, 40, and 60 kW m-2.Item 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.