Full-scale hot smoke test standards have been issued in a number of countries, but the common method of judgment is a visual determination. As Marine Museum K has used a performance-based fire safety design and a numerical simulation during its design stage, this study employs instruments to measure and obtain quantitative comparisons, while enhancing the performance of the smoke exhaust system in different vent-opening modes. The results prove that the measured performance is consistent with the simulation results. The existing model observed that light attenuation is slight at less than 2%, 6% and 10% on the third, fifth and seventh floors, respectively. The effects of the open state of the front and rear vents on the first floor and the vent on the third floor are also discussed. The open mode of the upper and lower vents in Case 2 created a better performance than the other cases due to the excellent flow pattern. In Cases 3 and 4, the fire plumes were significantly disturbed by makeup-air through the vents on the lower floor after all fans were actuated, and the smoke diffused everywhere in the lower floors. This paper also found the disadvantages caused by the makeup air.
Tainan, a city that prospered early in Taiwan, has a hot and humid atmosphere. Hence, the grilled doors in numerous old buildings for ventilation and lighting to conserve energy. This study analyzed a fire incident that occurred during the late night of March 17, 2019 in a 38-year-old dwelling, where three residents were severely covered with soot. The site investigation showed that eight staircases lead to the same basement, which apparently created a stack effect and a makeup air phenomenon. Numerical simulations have been performed in this study to reconstruct the fire scene, whose results were consistent with the actual fire scene. In particular, the results showed that some staircases in the fire were blackened by smoke, while others acted as makeup air inlets. The temperature at the households’ doors on all floors of Staircase 2, which was closest to the fire, exceeded 60 °C after four minutes. Furthermore, two immediately feasible improvement strategies according to the control volume theory of fluid mechanics were proposed in this study. Firstly, changing the grilled doors in the basement to a closed flat door style could effectively prevent smoke from flowing up in the staircases. Secondly, residents may consider closing the windows of the stairs at night to improve fire safety. The results showed that the chimney effect can be significantly reduced. These improvements could be a reference for other old dwellings to enhance their fire safety.
Purpose The purpose of this paper is to analyze the variations in the neutral plane when a tall space with unsymmetrical openings is on fire. The neutral plane of the fire scene is an important index of a natural smoke exhaust system. The numerical simulation method and the Schlieren photography technique were used as analysis tools. The results of model experiments and numerical simulation were compared with each other to confirm the rationality of the conclusions. The results were to discuss the characteristics of various cases and showed that the neutral planes of the fire scene were not always horizontal. Design/methodology/approach The numerical simulation method and the Schlieren photography technique were used as analysis tools. The flow patterns of hot air in various cases were recorded using the flow visualization technique. In addition, the renowned simulation software, fire dynamics simulator (FDS), was used for case analysis. The Schlieren photography technique was used for 1/12.5 model experiments with six smokeless candles burned, and FDS was used for a numerical simulation. In terms of the case of unilateral vents, the exhaust efficiency was discussed when the exhaust vent and air inlet were located on the same side or different sides. Findings This study demonstrates that makeup air flowing in from the inlets and openings has a significant impact on the effectiveness of natural smoke exhaust systems. The results illustrated that the neutral planes were tilted in some cases. In some cases, the results showed that one side was the air inlet and the other side was the exhaust vent, even if the openings were at the same height in some cases. These phenomena have rarely been discovered or studied in the past. The exhaust efficiency was not always better when the vent was located in the rooftop. Originality/value This study analyzed the neutral plane of a fire scene using the common unsymmetrical opening spaces in the Taiwan region as an example. The phenomenon of non-horizontal neutral plane has rarely been studied in the past. The temperature of the discharged hot gas was low because of an efficient exhaust effect, which reduced the heat and smoke storage in the space. The results obtained by these two methods were consistent, and showed that the cases with the same opening area had different smoke extraction efficiencies, meaning the smoke extraction effect cannot be judged only by the opening areas.
The number of elderly living in small-scale senior citizen welfare institutions in Taiwan has been increasing. Hence, enhancing the quality of care and safety of the residents in these institutions is a pressing issue. Our research team visited and reviewed data on 53 small-scale institutions in Tainan based on in-depth fire protection defense strategies and proposed a three-layer protection mechanism. The results showed that: (1) half (50%) of these institutions only meet the old anti-seismic system; (2) 26 (49%) institutions have multi-story buildings, thus, more staff needs to be arranged for night shifts to enable emergency responses on each floor; (3) all institutions have fire detectors; (4) 84% of the elderly living in these institutions are mobility-impaired and need to rely on the assistance of staff for evacuation; (5) most institutions (91%) employ foreign female caregivers which mostly work on night shifts; thus, routine training of emergency response should also consider the abilities of the foreign caregivers; (6) 35 (66%) institutions arrange only 50% of the day-shift manpower for the night shift; (7) 37 (70%) institutions should evaluate whether the function of their fire detectors is affected by fan air; and (8) 11 (21%) institutions use inflammable materials for furnishings to create a “cozy” atmosphere. This study also suggests that preventing smoke from spreading from a room that is on fire to other areas is an important evaluation item. Hopefully, these findings can serve as a reference for countries that are facing an increasingly aging population.
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