Two trends in merchant vessel design have generated interest in the localized fire extinguishing system (LFES) concept: the increasing volumes of machinery spaces aboard the larger vessels, and the ...greater amounts of automation being incorporated into vessels of all sizes. This report describes fire tests with two mockups of machinery space equipment: a small semi-enclosed machinery with an internal fire and a main propulsion unit with an external fire. In both mockups, the fuel was Number 2 fuel oil. The extinguishing system was a low pressure carbon dioxide LFES. In the small semi-enclosed machinery with an internal fire mockup, tests were conducted with projection nozzles and conventional horn nozzles. The fire was extinguished in seven out of thirteen tests. In one of the unsuccessful tests, the carbon dioxide discharge rate dropped due to either clogging or freeze-up inside the piping. In the main propulsion unit with an external fire mockup, only projection nozzles were used. The fire was extinguished in four out of nine tests. LFES using horn nozzles and projection nozzles are a feasible fire protection system. Projection nozzles permit the nozzles to be placed further from the machinery being protected. This facilitates maintenance and inspection of the machinery. Carbon dioxide; extinguishment; fire protection; fire tests; hydrocarbon fires; localized extinguishing systems; machinery space fires; merchant vessels; nozzles; projection nozzles; U.S. Coast Guard.
Automated self‐supporting rack warehouses are becoming increasingly common in the international logistics sector. Their static and seismic design has been studied in the literature; however, the fire ...design still needs to be improved. Some Standards, such as the Eurocodes or Italian Fire Code, accept the collapse of rack warehouses during fires but require avoiding a progressive collapse or obtaining an implosive collapse regardless of any other active or passive fire protection systems. A hierarchy that guides the kinematics of collapse needs to be defined appropriately but without any Code going into further details. Moreover, the scientific literature focuses more on optimizing fire protection systems for racks, such as sprinklers, rather than preventing fire‐induced progressive collapse. Here, a case study is presented, which, using finite element modelling, provide a first robustness evaluation and highlights some possible aspects to be considered in the structural design to avoid a progressive collapse in the event of a fire. The analyses are performed using the LOCAFI method for localized fires and nonlinear dynamic finite element simulations.
AbstractReal fires start from localized burning and will not develop to flashover in an open space or in large open-plan compartments. Temperatures of gas and exposed steel columns in localized fires ...are not uniform. Current structural fire design methods are based on uniform heating and, therefore, do not account for temperature gradients in real fires. This paper presents a numerical investigation of the behavior of bare steel columns subjected to a localized fire. The buckling behaviors of steel columns surrounded by and adjacent to a localized fire are investigated. Simple approaches are provided to calculate the temperatures of steel columns surrounded by and adjacent to a localized fire. Sequentially coupled thermal-mechanical simulations were conducted. Unrestrained, axially restrained, and rotationally restrained steel columns of various load ratios and dimensions subjected to different heating conditions were considered. The study found that the behavior of steel columns subjected to a localized fire may be completely different from that of columns subjected to a standard International Organization for Standardization (ISO) 834 fire. The steel columns surrounded by a localized fire fail by local buckling, while the same columns subjected to a standard ISO 834 fire fail by global buckling. The temperatures at which steel columns buckled (buckling temperature) when surrounded by a localized fire are higher than those of columns subjected to both a standard ISO 834 fire and an assumed uniform steel temperature condition. However, the buckling temperature of steel columns adjacent to a localized fire may be much lower than that of the columns subjected to both a standard ISO 834 fire and an assumed uniform steel temperature condition. The location of the localized fire relative to the column has a significant effect on the temperature and buckling behavior of steel columns. Structural fire design for steel columns based on a standard ISO 834 fire or a uniform steel temperature may be conservative if the potential real fires are localized fires surrounding the columns and may not be conservative if the potential real fires are localized fires adjacent to the columns.
Advanced simulation methods are needed to predict the complex behavior of structures exposed to realistic fires. Fire dynamics simulator (FDS) is a computational fluid dynamics code, developed by ...NIST for fire related simulations. In recent years, there has been an increase in use of FDS for performance-based analysis in the area of structural fire research. This paper discusses the FDS–finite element method (FEM) simulation methodology for structural fire analysis. The general methodology is described and a validation study is presented. A data element used to transfer data from FDS to FEM codes, the adiabatic surface temperature, is discussed. A tool named fire-thermomechanical interface is applied to transfer data from FDS to ANSYS. A high temperature stress–strain model for structural steel developed by NIST is included in the FEM analysis. Compared to experimental results, the FDS–FEM method predicted both the thermal and structural responses of a steel column in a localized fire test. The column buckling time was predicted with a maximum error of 7.8%. Based on these results, this methodology has potential to be used in performance-based analysis.
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