Observation study of pedestrian flow on staircases with different dimensions under normal and emergency conditions

Compared with horizontal motion, there were several characteristics in staircase movement. This study focused on the movement characteristics in staircases of typical student crowds and the quantitative relations of flow rate-speed-density in different dimensions of staircases and different circumstances were obtained. Basic data concerning daily movement when classes were over and an evacuation drill for college students was collected through analysis of video observation. From the analysis, the following conclusions can be given: some typical characteristics of pedestrian movement in staircases were found, such as queuing behavior at platform, merging flow at staircase entrance, and subgroup behavior. Movement on stairs was markedly slower than the horizontal motions. In normal condition, the number and initial speed of students entering the staircase affected observably the pedestrians flow, and the impact of staircase attributes (riser, tread, slope, etc.) cannot be neglected. In different conditions, the characteristics of pedestrian movement were quite different, and the influence of the speed on the density was more significant in the emergency condition. The study highlighted the amassment phenomenon at the bottom of the staircase and the potential influence of stair widths to evacuation efficiency in evacuation drill.     

Occupational accidents while walking on stairways

Nagata, H., 1991. Occupational accidents while walking on stairways. Safety Science, 14: 199–211.An analysis of occupational injury data related to falls while walking on stairways, and the causes associated with these stair accidents is described. The study was based on labour casualty reports. A total of 1486 stair accidents including 10 deaths, were collected from occupational accidents occurring within greater Tokyo. From these reports 425 cases were selected to undertake actual surveys including personal interviews, direct observations and field measurements. For the purpose of comparison with stairs where no accidents had been reported, a total of 1043 stairs were selected at random from drawings of various buildings.Nine fatal victims had received head injuries. Nearly half of the non-fatal victims received bruises mostly to the legs and feet. Most accidents occurred while descending stairways in haste. Young female employees wearing high or semi-high heeled footwear were relatively prone to fall on stairs. In winter, more stair accidents tended to occur to some extent. The proportion of female accidents was relatively higher than for males when compared to their population ratios. Employees were especially prone to receive injuries by misstep on straight flights of stairs.     

Preferred Handrail Height for Spiral Stairs—A Fitting Trial Study

Stairways are, in general, a thoroughly studied subject, but there is almost no scientific data available about spiral stairs. They are, however, widely used in homes, industrial sites and public buildings. The purpose of this study was to determine preferred handrail heights for a spiral stairway. The most preferred handrail height for descent was 105 cm. On the other hand, 95% of the participants regarded handrail heights between 95 and 100 cm satisfactory for descending. Participants’ anthropometric data was combined with the handrail height preference to develop a draft of a model to predict preferred handrail height for other user populations.     

地铁枢纽车站大客流疏散性能评估及策略优化研究*

为分析大型地铁枢纽车站人员疏散通过能力、疏散瓶颈位置和车站疏散策略优化方案,利用数值模拟研究某大型整体式站厅枢纽换乘车站人员疏散过程。研究结果表明:楼扶梯和出入口是车站疏散过程中的关键瓶颈,当疏散通过能力较大的出入口E或楼扶梯组8停止使用时,导致站厅疏散时长和站台疏散时长大幅增加;采用引导乘客均匀使用各楼扶梯疏散以及站厅增加应急出口等优化措施,可显著提高车站疏散效率。     

能见度降低条件下楼梯上行疏散实验研究

为探究地下公共建筑能见度降低场景中,个体及小群体楼梯上行疏散特征,在某公共建筑楼梯间进行个体疏散和小群体疏散实验,分析不同能见度条件下个体在梯段及平台上的疏散速度、疏散行为、小群体特征等关键参数。研究结果表明：梯段速度受能见度影响程度大于平台速度,在正常能见度条件下,小群体行为会对疏散移动速度产生负面影响,在低能见度条件下,小群体行为有助于提升疏散效率,表现在小群体平均速度高于群体中最慢个体速度且小群体和个体之间的速度差异较小。     

近十年中国民航事故及事故征候的统计分析

对1996—2005年我国民航发生的32起事故及1147起事故征候进行统计分析,其结果表明:我国民航事故和事故征候的万架次率及万时率均呈下降态势,机组、机械和机务原因是我国民航事故和事故征候的主要原因,事故征候的主要类型是鸟击、空中停车、偏出/冲出跑道/场外接地,事故征候发生阶段依次为巡航、起飞、着陆、爬升和进近。该研究成果有助于寻找事故和事故征候成因和规律。明确安全管理重点和难点;采取有效的预警和预控对策。     

Do industrial incidents in the chemical sector create equity market contagion?

IntroductionThis paper examines a number of US chemical industry incidents and their effect on equity prices of the incident company. Furthermore, this paper then examines the contagion effect of this incident on direct competitors.MethodEvent study methodology is used to assess the impact of chemical incidents on both incident and competitor companies.ResultsThis paper finds that the incident company experiences deeper negative abnormal returns as the number of injuries and fatalities as a result of the incident increases. The equity value of the competitor companies suffer substantial losses stemming from contagion effects when disasters that occur cause ten or more injuries and fatalities, but benefit from the incident through increasing equity value when the level of injury and fatality is minor.ConclusionsPresence of contagion suggests collective action may reduce value destruction brought about by safety incidents that result in significant injury or loss of life.Practical ApplicationsThis research can be used as a resource to promote and justify the cost of safety mechanisms within the chemical industry, as incidents have been shown to negatively affect the equity value of the not just the incident company, but also their direct competitors.     

地铁站细水雾幕挡烟效果的数值模拟研究

地铁站台层发生火灾时,烟气会从站台层经过楼扶梯开口蔓延至站厅层,因此, 楼扶梯开口处的挡烟效果对人员安全疏散影响重大。通过搭建全尺寸地铁站数值模拟模 型,对细水雾幕和排烟系统作用下楼扶梯开口处的挡烟效果进行了模拟研究,结果表明 :当仅设置挡烟垂壁时,挡烟垂壁有一定的蓄烟作用,但仍有大量烟气通过楼扶梯开口 从站台层蔓延至站厅层;设置细水雾幕可在一定程度上阻止烟气通过楼扶梯开口从站台 层蔓延至站厅层,有效降低烟气温度,但由于细水雾向下的冲量破坏烟气层的稳定性, 使得细水雾幕附近的烟气层高度降低;同时设置细水雾幕和排烟系统可实现良好的挡烟 效果,在楼扶梯的中段附近已基本不受火灾烟气的影响。     

Influence of an oblique path of staircase descent on toe placement and foot clearance

During their commute, pedestrians encounter a variety of staircase designs. One such design is the oblique staircase that allows pedestrians to descend at an angle. The purpose of this study was to assess the influence of an oblique path of descent on heel and toe clearance, and toe placement on a step. Sixteen participants descended a staircase on an angled path at three angles: 0° (perpendicular), 25°, and 45°. Toe placement and foot clearances were compared between the descent angles and feet. An increase in descent angle demonstrated increased clearance of the heel apex compared with straight descent; however, the aspect of the foot closest to the stair changes in angled descent, moving from the apex to the side of the heel. A greater portion of the foot was placed on the stair tread during angled descent. Future work should address the influence of angled descent on fall risk.     

Subsea pipelines incidents prevention: A case study in Brazil

There are more than 4000 subsea pipelines in Brazil. These pipes include umbilicals, drilling risers, flexible risers, rigid risers, hybrid risers, flowlines, and export pipelines. Despite all standards, regulations, guides, and risk management tools designed to avoid events, subsea pipeline incidents still occur, revealing possible failures in companies' risk control. Identifying similarities between different subsea pipeline failure events is crucial to improving the design, risk management practices, and regulation requirements, besides promoting accident prevention. This paper proposes applying the life cycle and management practices combined to analyze subsea pipeline incidents from the RDI (Detailed Incident Report) and investigations reported to ANP (Brazilian National Agency of Petroleum, Gas, and Biofuels), the Brazilian safety regulatory agency. Furthermore, subsea pipeline incidents data were analyzed: correlated circumstances, consequences, and causes. The results show that most riser and flowlines causal factors are related to equipment failures, and recurrent root causes are design errors and integrity control. Based on the proposed approach, it was possible to identify gaps in most riser and flowlines accident investigations since there are few causal factors, root causes, and the absence of riser and flowlines failure mode and mechanisms. Therefore, the development of accident recommendations can be compromised. Thus, this paper proposes improvements to current Brazilian regulations to clarify the minimal subsea pipeline accident investigation requirements.     

Analysis of laboratory incident database

With the growth of academic institutions, the number of labs handling hazardous chemicals has increased. Although the chemicals used in academic institutions are well-known, the dosage, usage, and management of these chemicals pose significant threat to researchers at all levels. As a step towards incident prevention, a laboratory incident database was developed to record incidents at universities and secondary schools. The data consisted of 128 entries occurring during the years 2012–2015. Incidents were classified by institution type, hazard type, consequences, substance type, body parts injured and direct causes. Of 128 incidents, 65% of the incidents were taking place in universities. Chemical spills were observed to be the most recurrent hazard type contributing to 45% of the incidents following by explosions (23%) and fires (21%). The consequence which most frequently occurred in incidents was personal injury and hazmat response contributing to 22% each. It was observed that in 41% of the incidents, the body parts injured in the incident was not known or reported. Of the total 128 incidents, about 50 incidents occurred due to improper storage and handling.     

The prevention of occupational injuries in two industrial plants using an incident reporting scheme

INTRODUCTION: The aim of this study was to examine whether the introduction of an incident reporting scheme with feedback in two industrial plants had an effect on the number of major incidents. METHOD: An intervention design with measurements before the implementation of the incident reporting scheme and two years later was used to examine the relationship between incident rates, safety climate, the willingness to report incidents and perceived management commitment to safety. RESULTS: The results showed that a successful implementation of an incident reporting scheme was followed by a decline in the incidence of major incidents at a Danish metal plant. A key factor in implementing the scheme was top management commitment, which was lacking at another plant, where the implementation of a similar scheme failed. CONCLUSION: Although the study shows some encouraging results concerning the use of incident reporting schemes to prevent occupational accidents, the possibility to draw causal conclusions is limited in the present study, and further studies are needed before the effectiveness of such schemes can be evaluated with certainty.     

Utilization of state-wide hospital separations data and the injury impairment scale to assess the incidence of spinal cord injury arising from motor vehicle traffic crashes

The objectives of this study were to determine whether routine state-wide hospitalization data can be used for population level surveillance of the incidence of spinal cord injury (SCI) from motor vehicle traffic crashes (MVTCs) and to verify the coverage of the Australian Spinal Cord Injury Register. A method was developed to identify new injury incidents from routine South Australian hospitalization data. Mapping software was then used to derive the Abbreviated Injury Scale (AIS) and Injury Impairment Scale (IIS) codes for each incident case of spinal injury using the principal diagnosis code on the hospital data file. IIS code values in the range from 3 to 6 were considered to be comparable with the SCI coding criteria utilized by the Australian Spinal Cord Injury Register (ASCIR) which were based on the criteria of the American Spinal Injury Association. The number of estimated new incident cases of SCI based on the IIS coding of hospitalization data was compared with the actual number reported from the ASCIR. The case numbers were highly comparable overall and also by time and age group suggesting that the coverage of the ASCIR was very high. The results of the study support use of the IIS for estimating incident case numbers of MVTC-related SCI from routine state-wide hospitalization data. If routine hospital separations data elsewhere were suitable for the purpose and the IIS also proves to be applicable to non-MVTC-related SCI, the incidence of SCI could be monitored in state and national populations using the IIS and this could provide an alternative data source where registers of SCI do not exist. In addition, the IIS provides a means to assess coverage where registers do exist.     

Risk management of cost consequences in natural gas transmission and distribution infrastructures

A critical aspect of risk management in energy systems is minimizing pipeline incidents that can potentially affect life, property and economic well-being. Risk measures and scenarios are developed in this paper in order to better understand how consequences of pipeline failures are linked to causes and other incident characteristics. An important risk measure for decision-makers in this field is the association between incident cause and cost consequences. Data from the Office of Pipeline Safety (OPS) on natural gas transmission and distribution pipeline incidents are used to analyze the association between various characteristics of the incidents and product loss cost and property damage cost. The data for natural gas transmission incidents are for the period 2002 through May 2009 and include 959 incidents. In the case of natural gas distribution incidents the data include 823 incidents that took place during the period 2004 through May 2009. A two-step approach is used in the statistical analyses to model the consequences and the costs associated with pipeline incidents. In the first step the probability that there is a nonzero consequence associated with an incident is estimated as a function of the characteristics of the incident. In the second step the magnitudes of the consequence measures, given that there is a nonzero outcome, are evaluated as a function of the characteristics of the incidents. It is found that the important characteristics of an incident for risk management can be quite different depending on whether the incident involves a transmission or distribution pipeline, and the type of cost consequence being modeled. The application of this methodology could allow decision-makers in the energy industry to construct scenarios to gain a better understanding of how cost consequence measures vary depending on factors such as incident cause and incident type.     

What can the trove of CSB incident investigations teach us? A detailed analysis of information characteristics among chemical process incidents investigated by the CSB

Understanding the commonalities among previous chemical process incidents can help mitigate recurring incidents in the chemical process industry and will be useful background knowledge for designers intending to foster inherent safety. The U.S. Chemical Safety and Hazard Investigation Board (CSB) reports provide detailed and vital incident information that can be used to identify possible commonalities. This study aims to develop a systematic approach for extracting data from the CSB reports with the objective of establishing these commonalities. Data were extracted based on three categories: attributed incident causes, scenarios, and consequences. Seventeen causal factors were classified as chemical indicators or process indicators. Twelve chemical indicators are associated with the hazards of the chemicals involved in the incidents, whereas five process indicators account for the hazards presented by process conditions at the time of the incident. Seven scenario factors represent incident sequences, equipment types, operating modes, process units, domino effects, detonation likelihood for explosion incidents, and population densities. Finally, three consequence factors were selected based on types of chemical incidents, casualties, population densities, and economic losses. Data from 87 CSB reports covering 94 incidents were extracted and analyzed according to the proposed approach. Based on these findings, the study proposes guidelines for future collection of information to provide valuable resources for prediction and risk reduction of future incidents.     

Footedness and Mounting—Short Review and Two Case Studies

Footedness is a personal quality like handedness. Footedness may be associated with moving ability during mounting, dismounting, and jumping movements. Occupational accidents have occurred during movement at different working levels, during the use of access and exit systems, and during the mounting of vehicles. Aging can also affect accident risk and body laterality. For example, falling accidents on stairs are common among the elderly. One reason for accidents may be that the structure of the access system or stair system is unsuitable for individual moving patterns depending partly on body laterality. Footedness and the way the feet are used may be contradictory to the demands of the moving situation, especially during uncommon or rapid situations. This contradiction may trigger disturbance during moving. The aims of this pilot study were (a) to review the literature briefly and (b) to describe the use of the dominant and nondominant foot by farmers and the elderly when mounting a tractor and stairs, respectively. The study also gives ideas for future studies based on both (a) and (b).     

Cardiovascular stress, energy expenditure and subjective perceived ratings of fire fighters during typical fire suppression and rescue tasks.

The study determined physiological and psychophysical responses to fire fighters' typical activities. Self-reported assessment of the most demanding fire fighting/rescue tasks were collected with a questionnaire. Then 19 voluntary fire fighters performed 3 simulated fire fighting/rescue tasks in protective clothing. Heart rate (HR), blood pressure and energy expenditure were measured; the rating of perceived exertion (RPE) was assessed with the Borg scale. The questionnaires showed that carrying out victims, fire suppression and resuscitation were classified as heavy load; climbing stairs with a hose as moderate load. According to RPE the subjects considered their effort during ladder climbing fairly light and only somewhat harder during stair climbing and carrying out injured people. The study demonstrated that typical fire fighting/rescue tasks were associated with high energy expenditure and imposed considerable cardiovascular stress. The Borg scale appeared not suitable for assessing perceived exertion in fire fighters during simulated tasks.     

考虑群组行为的楼梯瓶颈处行人流模拟

为探究楼梯瓶颈处群组行为对行人流通行效率的影响,基于校园内的观测试验获取群组运动参数,采用Anylogic仿真平台建立考虑群组行为特征的楼梯瓶颈处人员运动模型,根据不同的群组运动参数、楼梯几何参数和障碍物布置方式对行人流通行时间与密度分布的影响开展数值模拟。结果表明:较大的群组比例和群组规模均会延长行人流通行时间,增加通行过程中的拥堵持续时间;在链状构型下,群组通行效率较高,而并排构型对人员通行造成的负面影响最大;在有群组和无群组情况下,楼梯位置变化会产生相反的通行效果;平行放置障碍物可以有效降低人群密度,提高群组行人流的通行效率。     

Motor vehicle towing: An analysis of injuries in a high-risk yet understudied industry

Objectives: National fatality rates for commercial tow truck operators exceed those of other first responders who also perform traffic incident management services. The objectives of the current study are to (1) characterize causal factors associated with injuries among commercial tow truck operators engaged in roadside assistance through analysis of coded and free text data obtained from U.S. Occupational Safety and Health Administration (OSHA) investigation files, and (2) utilize supplemental data sources to analyze environmental factors for injuries in which commercial tow truck operators were struck by roadway traffic. Methods: Searches of OSHA’s online IMIS database were performed to identify investigations of incidents in which tow truck operators were injured while performing roadside assistance duties. Freedom of Information Act (FOIA) requests were submitted to obtain full investigation files for each case. Coded and narrative text analyses were performed to identify causal themes across the identified cases. Results: One-hundred and six cases of tow truck operators being killed or severely injured were identified in IMIS; 41 FOIA requests for related investigation documents were fulfilled. Two major event type themes were identified which accounted for 9 in 10 of the cases identified. These were (1) ‘struck-by’ incidents, which were primarily injuries resulting from contact with roadway traffic, rolling vehicles and equipment or other non-motorized objects; and (2) ‘caught-in or -between’ incidents, which were primarily injuries resulting from being pinned beneath and between vehicles and being caught in moving parts. Conclusions: The towing industry should provide initial and refresher safety training on vehicle loading and unloading, defensive techniques when exposed to traffic on roadways, and proper wheel chocking and braking procedures. States should include tow trucks as a first responder vehicle type in their “Move Over” laws and implement public awareness campaigns to protect all first responders, including tow truck operators.