The fire growth rate index (FIGRA), which is the ratio of the maximum value of the heat release rate (Qmax) and the time (tmax) to reach the maximum heat release rate, is a general method to evaluate a material in the fire-retardant performance in fire technology. The object of this study aims to predict FIGRA of the polyethylene foam pipe insulation in accordance with the scale factor (Sf), the volume fraction of the pipe insulation (VF) and the ignition heat source (Qig). The compartments made of fireboard have been mock-up with 1/3, 1/4, and 1/5 reduced scales of the compartment as specified in ISO 20632. The heat release rate data of the pipe insulation with the variation of Sf, VF, and Qig are measured from 33 experiments to correlate with FIGRA. Based on a critical analysis of the heat transfer phenomenon from previous research literature, the predictions of Qmax and tmax are presented. It is noticeable that the fire-retardant grade of the polyethylene foam pipe insulation could have Grade B, C, and D in accordance with the test conditions within ±15% deviation of the predicted FIGRA. In case of establishing the database of various types of insulation, the prediction models could apply to evaluate the fire-retardant performance.
With an increase in the use of eco-friendly vehicles such as hybrid, electric, and hydrogen vehicles in response to the global climate crisis, accidents related to these vehicles have also increased. Numerical analysis was performed to optimize the safety of first responders responding to hydrogen vehicle accidents wherein hydrogen jet flames occur. The influence range of the jet flame generated through a 1.8-mm-diameter nozzle was analyzed based on five discharge angles (90, 75, 60, 45, and 30°) between the road surface and the downward vertical. As the discharge angle decreases toward the road surface, the risk area that could cause damage moves from the center of the vehicle to the rear; at a discharge angle of 90°, the range above 9.5 kW/m2 was 1.59 m and 4.09 m to the front and rear of the vehicle, respectively. However, at a discharge angle of 30°, it was not generated at the front but was 10.39 m to the rear. In response to a hydrogen vehicle accident, first responders should perform rescue activities approaching from a diagonal direction to the vehicle front to minimize injury risk. This study can be used in future hydrogen vehicle design to develop the response strategy of the first responders.
The fire performance of shear connections is essential to maintain a composite action in composite beams, for which studies have previously focused on solid slab structures.Despite the popularity of profiled steel sheeting in modern construction, the behaviour of shear studs embedded in transverse deck slabs still needs to be confirmed under elevated temperatures. High-temperature push-out tests were conducted according to the ISO 834 standard fire condition with customised electric furnaces, which showed a failure mode transition with rising temperature. A three-dimensional thermomechanical numerical model was developed and compared with the experimental results for verification. A parametric study revealed that the shear connections were primarily influenced not by the deck thickness or stud welding method but by the temperature distribution, especially around the stud root area.Eurocode 4 utilises a thermal degradation factor as well as shear resistance at ambient condition to calculate the load-bearing capacity at fire condition, resulting in a highly conservative
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