Search Results (27)

This study explores the impact of key evacuation features on occupant safety in complex buildings with underground connections in Seoul, the city with the highest concentration of such buildings in the country. By analyzing factors like exit spacing, exit width, stairwell distances, and stairway configurations, the study assesses evacuation safety using fire and evacuation simulations, comparing available safe egress time (ASET) with required safe egress time (RSET). Reducing interior exit facility spacing from the legal standard of 100 m to 50 m improved evacuation time by 77.5% (from 36 min to 8 min and 7 s), with a further reduction to 40 m improving performance by an additional 23.3% (to 6 min and 13 s). In downward evacuations, reducing the walking distance to exterior exits from over 50 m to 30 m cut evacuation time by at least 59.9% (from 23 min and 55 s to 9 min and 35 s), ensuring successful evacuations. These findings demonstrate that optimizing evacuation routes, addressing bottlenecks, and improving evacuation feature standards can significantly enhance safety and minimize casualties. By adjusting building design and fire safety regulations, these optimizations promote resilient urban infrastructure, reduce disaster-related socio-economic impacts, and inform evidence-based policies, offering valuable insights for policymakers and guiding future improvements in fire safety and evacuation protocols. Full article

Measuring the airtightness of high-rise buildings presents significant challenges due to the effects of wind and thermal lift (stack effect). Small indoor/outdoor temperature differences, combined with the building’s height, can create substantial natural pressure differences on the building envelope, while winds induce pressure fluctuations. The international standard ISO 9972 provides insufficient guidelines for dealing with these high and fluctuating natural pressure differences. In addition, it is crucial to achieve a uniform internal pressure distribution during the test. This paper discusses the airtightness testing of high-rise buildings up to 125 m tall using portable blower door devices, following the “airtightness measurement of high-rise buildings” Passive House guideline. Differential pressure sensors were placed on the ground and top floors to record the effects of wind and thermal lift, and additional sensors helped to achieve a uniform pressure distribution within the building. The readings from the ground and top floors ensured full depressurization and pressurization during testing. The setup of the measuring fans, mainly on the ground floor, was supplemented with additional fans on higher floors to maintain pressure uniformity within a 10% tolerance. To be able to conduct a multi-point regression test, it is recommended to limit the product of the indoor/outdoor temperature difference and building height to ≤1250 mK and to achieve a coefficient of determination of 0.98 or higher, a wind speed ≤ 3 Beaufort. The study concludes that an airtight building envelope and larger internal flow paths, such as stairwells and elevator shafts, simplify the measurement. Full article

The current study was based on two simulations conducted in FDS that examined the influences of an office fire on the ground floor of a 10-story building (with 9 above-ground floors) and its impact on air and smoke flow. After reviewing the literature, we observe a significant gap in current research addressing the dynamic interdependence between fire development and the stack effect in multi-story residential buildings. It was found that the fire significantly intensified the stack effect, increasing the temperature in the stairwell, particularly on the ground floor. Gas velocities within the building increased but do not endanger the lives of the occupants. Visibility remained sufficient for evacuation from the apartments, except in critical areas such as the fire-affected apartment and the stairwell. Lethal concentrations of CO and CO₂ were rapidly reached, severely impairing evacuation capability within the fire-affected apartment and the stairwell. Natural ventilation proved insufficient for controlling smoke and toxic gasses, highlighting the need for additional sealing measures and forced ventilation. Full article

The structural deformation monitoring of civil infrastructures can be performed using different geomatic techniques: topographic measurements with total stations and levels, TLS (terrestrial laser scanning) acquisitions, and drone-based SfM (structure from motion) photogrammetric surveys, among others, can be applied. In this work, these techniques are used for the floodgate gaps and the rubber joints deformation monitoring of the MOSE system (Modulo Sperimentale Elettromeccanico), the civil infrastructure that protects Venice and its lagoon (Italy) from high waters. Since the floodgates are submerged most of the time and cannot be directly measured and monitored using high-precision data, topographic surveys were performed in accessible underwater tunnels. In this way, after the calculation of the coordinates of some reference points, the coordinates of the floodgate corners were estimated knowing the geometric characteristics of the system. A specific activity required the acquisition of the TLS scans of the stairwells in the shoulder structures of the Treporti barrier because many of the reference points fixed on the structures were lost during the placement of elements on the seabed. They were replaced with new points whose coordinates in the project/as-built reference system were calculated by applying the Procrustean algorithm by means of homologous points. The procedure allowed the estimation of the transformation parameters with maximum residuals of less than 2.5 cm, a value in agreement with the approximation of the real concrete structures built. Using the obtained parameters, the coordinates of the new reference points were calculated in the project reference system. Once the 3D orientation of all caissons in the barrier was reconstructed, the widths of the floodgate gaps were estimated and compared with the designed values and over time. The obtained values were validated in the Treporti barrier using a drone-based SfM photogrammetric survey of the eight raised floodgates, starting from the east shoulder caisson. The comparison between floodgate gaps estimated from topographic and TLS surveys, and those obtained from measurements on the 3D photogrammetric model, provided a maximum difference of 1.6 cm. Full article

Bluetooth devices have been widely used for pedestrian positioning and navigation in complex indoor scenes. Bluetooth beacons are scattered throughout the entire indoor walkable area containing stairwells, and pedestrian positioning can be obtained by the received Bluetooth packets. However, the positioning performance is sharply deteriorated by the multipath effects originating from indoor clutter and walls. In this work, an ultra-wideband (UWB)-assisted Bluetooth acquisition of signal strength value method is proposed for the construction of a Bluetooth fingerprint library, and a multi-frame fusion particle filtering approach is proposed for indoor pedestrian localization for online matching. First, a polynomial regression model is developed to fit the relationship between signal strength and location. Then, particle filtering is utilized to continuously update the hypothetical location and combine the data from multiple frames before and after to attenuate the interference generated by the multipath. Finally, the position corresponding to the maximum likelihood probability of the multi-frame signal is used to obtain a more accurate position estimation with an average error as low as 70 cm. Full article

In 2009, the International Building Code (IBC) introduced a new requirement for an additional exit stair or evacuation elevators in buildings (except residential buildings) over 420 ft. (128 m) tall. This new requirement has emerged as a critical innovation in occupant evacuation in supertall buildings, offering the potential for faster egress during emergencies. In the 2018 edition of the IBC, the analysis of full building evacuation with elevators is further required to demonstrate an evacuation time of less than 1 h. This paper examines the implementation of evacuation elevators in accordance with recent building code developments, such as the International Building Code (IBC), Chinese “General Code for Fire Protection of Buildings and Constructions” (GB 55037-2022), and the Korean Building Code (KBC). This study provides a comparative analysis of these regulations, highlighting the evolving acceptance of elevator-based evacuation methods. Since the requirements on means of egress in the codes in China and Korea follow similar concepts in the IBC, case studies of supertall buildings in China and Korea, where evacuation elevators were integrated into the overall egress strategy, are carried out to demonstrate the capability of evacuation elevators in achieving the IBC’s requirement for full evacuation within one hour. Using computer-based egress modeling, the study evaluates practical solutions for reducing evacuation times, exploring factors such as elevator capacity, speed, and coordination with traditional stairwell egress. The results suggest that, while evacuation elevators can significantly improve evacuation efficiency, achieving the one-hour target remains a challenge in complex, high-occupancy environments. The study indicates the importance of optimizing the balance between stair and elevator usage and explores the future role of artificial intelligence (AI) in enhancing evacuation systems. Full article

Output-only modal analysis using ambient vibration testing is ubiquitous for the monitoring of structural systems, especially for civil engineering structures such as buildings and bridges. Nonetheless, the instrumented nodes for large-scale structural systems need to cover a significant portion of the spatial volume of the test structure to obtain accurate global modal information. This requires considerable time and resources, which can be challenging in large-scale projects, such as the seismic vulnerability assessment over a large number of facilities. In many instances, a simple center-line (stairwell case) topology is generally used due to time, logistical, and economic constraints. The latter, though a fast technique, cannot provide complete modal information, especially for torsional modes. In this research, corner-line instrumented nodes layouts using only a reference and a roving sensor are proposed, which overcome this issue and can provide maximum modal information similar to that from 3D topologies for medium-rise buildings. Parametric studies are performed to identify the most appropriate locations for sensor placement at each floor of a medium-rise building. The results indicate that corner locations at each floor are optimal. The proposed procedure is validated through field experiments on two medium-rise buildings. Full article

This study examines how building space, materials, and structure affect the microclimate of Liu Tong Xinglongzhuang in central Anhui, known for its hot, humid climate and distinct architecture. Using qualitative and quantitative methods, including field monitoring, PHOENICS simulation, and Ladybug Tools, the following conclusions were drawn: (1) Building materials: wood reduces indoor temperature; a glass roof over the patio lowers temperature and improves wind speed; and reducing tile area decreases solar radiation. (2) Building space: optimal comfort in stairwells is achieved with a length-to-width ratio of 1.5:1 and height-to-width ratio of 2:1; courtyards are most comfortable with a length-to-width ratio of 2.5:1 and height-to-width ratio of 1.5:1; walk-through halls are optimal with a length-to-width ratio of 2:1 and height-to-width ratio of 1.5:1; and wings achieve the highest comfort with a length-to-width ratio of 2.5:1 and height-to-width ratio of 1.5:1. (3) Building structure: optimal wind speed and temperature are achieved with specific window height-to-width ratios of 1:1 for exterior and 1.5:1 for interior windows; the lowest temperatures occur at 2:1 ratios; hexagonal exterior and circular interior windows maximize wind speed and temperature reduction; and smaller exterior door openings lower indoor temperatures and are best achieved with an interior door ratio of 2:1. These findings offer valuable data and methods for optimizing the microclimate of traditional houses, with significant practical implications. Full article

Recently, in high-rise buildings, pressurization systems have been installed in emergency stairwells to prevent the ingress of smoke. However, in older buildings, these stairwells often lack pressurization systems, while in buildings with fewer stories, such systems are not typically installed. This study conducts simulations and a hot smoke test to evaluate the performance of air curtains in blocking smoke and toxic gases in outdoor emergency stairwells where additional pressurization equipment cannot be installed. The simulation results showed that air curtains installed perpendicular to the floor were useful at preventing smoke ingress, and higher wind speeds increased their effectiveness. It is believed that air curtains can partially reduce smoke ingress in stairwells of older buildings or low-rise structures without pressurization systems, thereby ensuring fire safety. Full article

Emergency exit lights in public buildings are necessary for safety and evacuation. International safety standards require such lighting in many public places, like airports, schools, malls, hospitals, and other spaces, to prevent human casualties in emergencies. Emergency exit lights have become an essential part of casualty reduction projects. They can pose several application problems, including fire safety concerns. The issue of providing a safe way and operating emergency exit lights along one side of a long path arises during an emergency. Many studies in this field consider the case in which emergency exit lights’ battery or main power fails. Power failures in dangerous situations such as fires or terrorist attacks make it difficult for people to escape. The lighting in open areas and stairwells during an emergency should be at least 2 lux. This work proposes an innovative technique for wirelessly powering emergency lights using microwave energy. Specifically, the study designed and fabricated a new wirelessly powered emergency lighting prototype. This prototype’s wireless power transfer (WPT) base comprises an RF/DC converter circuit and an RF microwave transmitter station. The device can harvest RF microwave energy to energize the emergency light. This research aimed to develop a compact device that captures maximum RF strength to power emergency lights. As a prototype, the proposed device was designed to provide sufficient microwave energy to power an emergency light at 3 W over a 62 m distance. Full article

School buildings gather a large number of underage students, and the disastrous consequences of fire in such buildings are very serious, which is one of the key concerns of society in fire prevention and control. This study takes a “[” type kindergarten teaching building as the background and constructs a BIM–FDS building fire simulation model to reveal the fire smoke dispersion law under the coupling of the typical building structure and fire protection systems. The results show that the stairwells on both sides of the “[” type building are the main channels for the diffusion of fire smoke, and the asymmetry of the stairwell structure will cause apparent differences in the diffusion of smoke. Using the natural smoke exhaust in the stairwells of low-rise buildings does not aggravate the spread of smoke in the building and is conducive to smoke emissions. The high-pressure water mist system is superior to the water spray system in fire extinguishing and controlling room temperature. While it reduces smoke exhaust performance, it does not adversely affect personnel evacuation. This study systematically reveals the law of diffusion of fire smoke from “[”-type teaching buildings, which can support the design of similar building structures, ventilation, fire protection, and the formulation of fire escape plans. Full article

A fire egress system is one of the most critical aspects of fire emergency evacuation, which is the cornerstone technology of building fire safety. The high-rise teaching buildings on campus, where vast crowds of people gather, need to be qualified for rapid evacuation in the event of a fire especially. Conventional teaching building egress system design places more emphasis on individual elements (e.g., stairwells, evacuation doors, and evacuation walkways) rather than on their co-regulation as a whole. Furthermore, there are not enough holistic and effective optimal design strategies, which is because most of the existing studies rely on experiments or simulations and often suffer from a lack of sufficient data to fully reveal the interactions of individual variables. In this study, the co-effectiveness of stairwells, walkways, and room doors in reducing total evacuation time was investigated by simulation and machine learning. We selected a typical high-rise teaching building as an example and integrated two simulation software, Pyrosim and Pathfinder, to compare the available safe evacuation time (ASET) and required safe evacuation time (RSET). Then, a framework consisting of five factors—stair flight width (SFW), stairwell door width (SDW), corridor width (CW), room door width (RDW), and location of the downward stair flight (LDSF)—was established for the optimization through statistical analysis of big data obtained by the preferred machine learning algorithm. Results indicate that (1) By modifying just one factor (SFW), the total evacuation time (TET) can be reduced by at most 12.1%, with the mortality rate dropping from 26.5% to 9.5%; (2) although ASET could not be achieved either, among 4000 cases of multi-factor combinations, a maximum TET improvement degree, 29.5%, can be achieved for the evacuation optimization compared to baseline model, with a consequent reduction in mortality to 0.15%; (3) it shows that the emphasis of the egress system optimization is on the geometric features of the evacuation stairwell; furthermore, the multi-factor combination approaches have better compromised evacuation performances than the single-factor controlled schemes. The research results can be applied as rational design strategies to mitigate fire evacuation issues in high-rise teaching buildings and, in addition, the methodology suggested in this paper would be suitable to other building types. Full article

Regulatory acoustic requirements for hospitals exist in several countries in Europe, but many countries have either no or few regulatory limits or only recommendations. The purpose of limit values is to ensure optimal acoustic conditions for the patients under treatment and for the personnel for the various tasks taking place in many different rooms, e.g., bedrooms, examination and treatment rooms, corridors, stairwells, waiting and reception areas, canteens, offices, all with different acoustic needs. In addition, some rooms require special considerations such as psychiatric rooms and noisy MR-scanning rooms. The extent of limit values varies considerably between countries. Some specify few, others specify several criteria. The findings from a comparative study carried out by the authors in selected countries in various geographical parts of Europe show a diversity of acoustic descriptors and limit values. This paper includes updated criteria for reverberation time, airborne and impact sound insulation, noise from traffic and from service equipment for hospital bedrooms. The discrepancies between countries are discussed, aiming at potential learning and implementation of improved limits. In addition to regulations or guidelines, some countries have hospitals included in national acoustic classification schemes with different acoustic quality levels. Indications of such class criteria are included in the paper. Full article

In order to cope with limited land availability and the increasing urban population, more high-rise buildings are being built throughout cities, but this has also led to new challenges in the emergency evacuation of people. Therefore, we conducted an evacuation experiment of a group of people in the stairwells of high-rise buildings to explore the movement law of groups in stairwells. The experiment had 18 scenes, including the evacuation movement of an independent group and the crowd evacuation movement of different groups. Analyzing the independent groups’ movement showed that regardless of the type of group, the average speed of the crowd was more than 1.2 m/s, which was longer than that of previous studies. The more constraints in the evacuation process, the smaller the speed difference between males and females. Group cohesion was mostly concentrated at about 1 s. Moreover, group velocity and cohesion were found to have no significant correlation in stairwell movement. Analyzing the crowd evacuation time of eight different scenes showed that it took longer for crowds bearing weight to evacuate than those not bearing weight. According to the spatiotemporal evolution of crowd evacuation in stairwells, the crowd moves intermittently in the evacuation process, especially in the early and middle stages of evacuation, and the influence of group factors on this process was not obvious. Regardless of the kind of scene or stairwell, the number of pedestrians generally first increased and then decreased to a significantly low value, and the number of pedestrians reached about 30 in the scenario of people without any load. Additionally, the speed of the pedestrians entering the stairwell in the back of the group was not faster than that of the pedestrians in the front, which showed that pedestrians rarely engaged in overtaking behavior. The research results of this paper not only enrich evacuation research but also provide support for the design of high-rise stairs. Full article

The preservation and definition of the correct retrofitting interventions of historic masonry buildings represents a relevant topic nowadays, especially in a country characterized by high seismicity zones. Considering the Italian Cultural Heritage, most of these buildings are constructed in ancient unreinforced masonry (URM) and showed a high level of vulnerability during the recent 2009 (L’Aquila), 2012 (Emilia Romagna) and 2016 (Centro Italia) earthquakes. In this paper, the seismic assessment of an historic masonry building damaged during 2016 Centro Italia seismic event is presented considering different types of retrofitting interventions. Starting from the results obtained by the post-earthquake survey, different finite element models have been implemented to perform linear and non-linear analyses useful to understand the seismic behaviour of the building and to define the appropriate retrofitting interventions. In particular, reinforced plaster layer and cement-based grout injections have been applied in each masonry wall of the building in order to improve their horizontal load-bearing capacity, and an additional wall made with Poroton blocks and M10 cement mortar has been built adjacent to the central stairwell. In addition, in view of the need to replace the roof seriously damaged during the seismic event, a cross-laminated roof solution characterized by a thickness equal to 14 cm (composed by seven layers, each 2 cm thick) has been proposed. The results show that the proposed retrofitting interventions have led to a significant improvement in the seismic behaviour of the building. Full article