An uncertainty and sensitivity analysis of dynamic operational risk assessment model: A case study

In Dynamic Operational Risk Assessment (DORA) models, component repair time is an important parameter to characterize component state and the subsequent system-state trajectory. Specific distributions are fit to the industrial component repair time to be used as the input of Monte Carlo simulation of system-state trajectory. The objective of this study is to propose and apply statistical techniques to characterize the uncertainty and sensitivity on the distribution model selection and the associated parameters determination, in order to study how the DORA output that is the probability of operation out-of-control, can be apportioned by the distribution model selection. In this study, eight distribution fittings for each component are performed. Chi-square test, Kolmogorov–Smirnov test, and Anderson-Darling test are proposed to measure the goodness-of-fit to rank the distribution models for characterizing the component repair time distribution. Sensitivity analysis results show that the selection of distribution model among exponential distribution, gamma distribution, lognormal distribution and Weibull distribution to fit the industrial data has no significant impact on DORA results in the case study.     

Organizational practices and workplace health and safety: A cross-sectional study in manufacturing companies

We report the results of a mail questionnaire for 312 manufacturing firms in the province of Ontario (Canada). We conducted a cross-sectional analysis of workplace level health and safety policies, practices and attitudes. Analyses were conducted across firm categories based upon lost-time frequency rate (LTFR) data. Lower LTFRs were associated with paternalistic initiatives, recording of occupational health and safety (OHS) measures, greater involvement of workers in decision-making, and better managerial attitudes concerning the importance of OHS. The composition of the Joint Health and Safety Committee (JHSC), a committee mandated in all workplaces we sampled, differed according to injury rate: the mean number of worker (vs. management) members on the JHSC was higher for lower injury sites, and the mean number of worker members attending JHSC meetings was also higher for lower injury worksites. In addition, workplaces with lower LTFR benefitted by having JHSCs with more executive functions and greater worker involvement. In conclusion, managerial and worker participation in OHS initiatives characterizes safer workplaces. Also, general concern of management towards OHS—illustrated by both attitudes and concrete actions—is also associated with lower injury rates.     

Long-term consequences of burnout: An exploratory study

The aim of this study was to explore the relationship between degree of burnout experienced during the first year of the career and career adaptation during the next decade. Subjects were 25 human service professionals originally working in the fields of public service law, public health nursing, high school teaching, or mental health. They were studied during the first year of their careers and again 12 years later. Early career burnout was assessed via ratings of interviews that were highly correlated with the Maslach Burnout Inventory. Career adaptation variables included career stability, work satisfaction, attitudes towards recipients, and flexibility as measured at the time of follow-up. Each of these variables was measured via interview ratings, a questionnaire, and ratings made hy confidants of the subjects. Results showed that subjects who were more burned-out early in their careers were less likely to change careers and more flexible in their approach to work as rated by confidants at the time of follow-up. The results suggest that early career burnout does not seem to lead to any significant, negative, long-term consequences. However, burnout occurring later in the career might have more serious long-term effects.     

Organizational socialization: A stress perspective

This paper examines socialization and adjustment processes of newcomers to organizations. While scholars in this area agree that the socialization process is a stressful event, few have empirically approached the process from this perspective. In addressing this problem, a theoretical synthesis of the literatures of organizational socialization and organizational stress is proposed. From this integration, a model is developed which facilitates an examination of the task, role, and interpersonal demands which individuals face in the stages of socialization and an analysis of the interrelationships of these demands and their effects upon individual and organizational outcomes of the socialization process. Finally, directions for future research are proposed for extending understanding of this crucial part of organizational entry.     

The development and evaluation of accident prevention routines: A case study

Information resulting from the occurrence of accidents and near-accidents is the basis for most accident prevention efforts. However, such information may not normally be incorporated into local safety activities. A group to assist supervisors in their investigations of accidents and a procedure to prompt the reporting of near-accidents by employees were tested at one company as means of improving local safety activities. The accident investigation group was in operation in all departments and was associated with improved accident reporting and prevention activities as well as a reduction in accident severity. The near-accident reporting procedure was tested in one department and led to improved knowledge about risks, although no reductions in accident frequency and severity were shown. On the basis of these results, the company safety committee decided at the end of the first year to extend the mandate of the investigation group but not to continue with near-accident reporting. Follow-ups after 2 and 3 years indicated that improvements in prevention activities had been maintained and that accident severity had been further reduced.     

A decade's experience with the Scanlon Plan: A case study

This field study examined the operation and impact of the Scanlon Plan at a large manufacturing facility. An interrupted time-series research design, augmented by extensive qualitative data analysis was used to analyse the productivity and employment experience over a nine-year period. The plan resulted in modest increases in productivity and stable employment, while improving the overall union-management relationship. Through the Scanlon structure for employee involvement, over 5000 suggestions have been made. Moderate and consistent productivity sharing bonuses were paid.     

Work-related road safety: A case study of Roche Australia

Fleet, work-related or occupational road safety has the potential to make a major contribution to reducing both human harm and asset damage. To date, however, there would appear to be a dearth of well researched and evaluated case studies in the public domain in this area.This paper provides an on-going, documented, real-world case study of work-related road safety within an Australian company that has sought to manage, monitor and improve its road safety performance over the last 5 years through a range of proactive, fleet manager, insurance and risk-led initiatives.Roche Australia has successfully implemented a Company Motor Vehicle Safety Program with support from its fleet insurers and risk management advisors. Four key initiatives are set out covering: (1) Driver risk assessment, monitoring and improvement. (2) Policy development and communications. (3) Process and outcomes evaluation. (4) Continuous review and refinement of policies, processes, programs and future developments.The program has led to a range of process and performance-based outcomes. Typical barriers to success in work-related road safety have been identified and overcome. Almost 100% risk assessment and improvement process compliance by drivers has been achieved. A predictive relationship between risk assessment outcomes and collision history has been identified. Reductions in insurance claims, collision costs and claims ratio have been sustained. A detailed project plan is in place to continue the program for the next 3 years.The paper concludes that with effective management, a well developed work-related road safety program can result in performance improvements within the initiating organisation. Several limitations in the case study methodology, as well as areas for further work and lessons for policy makers, researchers and practitioners are also identified.     

Business Process Reengineering of emergency management procedures: A case study

The production and storage of dangerous substances in an industrial establishment creates risks for man, environment and properties in the surrounding area. Safety regulations require the establishment of a preventive information campaign regarding industrial risks and self-defence measures to adopt in an emergency situation. In the case of a major accident, people must be promptly made aware of the appropriate self-defence actions and behaviours to adopt. This strategic activity can reduce the panic effect, make citizens more cooperative and guarantee the effectiveness of any emergency plan. In this paper, the information chain is studied as an industrial process modelled by the IDEF0 language. Through this method, each link in the chain has been deeply analysed. For each function of the process, the inputs, outputs and necessary controls and resources have been identified. Starting from a clear view of the current state, the process of re-engineering has been implemented to minimise or eliminate downtime, deficiencies and illnesses and, thus, consequent time losses. The main contribution of the IDEF0 application in emergency management is to provide a clear view of the whole system, a communication system between emergency actors, a rich information source and a structured base for the re-engineering process.     

Antecedents and consequences of role stress: A covariance structure analysis

An earlier model of the consequences of role conflict and role ambiguity is expanded to incorporate antecedent job conditions and the outcome of organizational commitment. This newer model clarifies the impact of role stressors on commitment and other established outcomes (i.e. tension, job dissatisfaction, and turnover intention). The antecedent job conditions are added in consideration of research indicating that role conflict and ambiguity do not directly influence affective and behavioral reactions when other perceptions of the work environment are included in the analysis. A LISREL analysis of this model with cross-validation on an independent sample indicated that the direct effects of participation and co-worker social support on job satisfaction may account for the direct effects of role conflict and role ambiguity on satisfaction and turnover intention observed in previous studies. In addition, organizational commitment appeared to mediate the effects of other variables on turnover intention. Implications for theories of role-related variables and directions for future research are discussed.     

Exploring the social and organisational aspects of human factors integration: A framework and case study

In this paper we first outline a framework which aims to capture some of the social and organisational aspects of human factors integration (HFI) which have been outlined by previous research. The framework was partly used to design a set of interview questions that were used with a case study of a human factors team working with the UK defence industry. The findings from the case study revealed a number of barriers which accord with previous research in the domain of HFI (e.g., attitudes and perceptions towards HF), as well as providing insights into the improvement strategies used by the HF team in order to improve HFI. These included attempts to build relationships and establish a working rapport with other groups in the company, as well as other activities aimed at addressing the organisational culture within the company as a whole (e.g., attempts to raise the profile of HF within the company). We use the framework for social and organisational aspects of HFI to discuss our findings alongside other research on group behaviour and boundary management within large organisations. The conclusions of the paper point to the utility of the framework as a means of planning HFI improvement strategies which can help to overcome some of the social and organisational barriers to HFI.     

Maintenance-related major accidents: Classification of causes and case study

The potential for major accidents is inherent in most industries that handle or store hazardous substances, for e.g. the hydrocarbon and chemical process industries. Several major accidents have been experienced over the past three decades. Flixborough Disaster (1974), Seveso Disaster (1976), Alexander Kielland Disaster (1980), Bhopal Gas Tragedy (1984), Sandoz Chemical Spill (1986), Piper Alpha Disaster (1988), Philips 66 Disaster (1989), Esso Longford Gas Explosion (1998), Texas City Refinery Explosion (2005), and most recently the Macondo Blowout (2010) are a few examples of accidents with devastating consequences.Causes are being exposed over time, but in recent years maintenance influence tends to be given less attention. However, given that some major accidents are maintenance-related, we intend to concentrate on classifying them to give a better insight into the underlying and contributing causes.High degree of technological and organizational complexity are attributes of these industries, and in order to control the risk, it is common to deploy multiple and independent safety barriers whose integrity cannot be maintained without adequate level of maintenance. However, maintenance may have a negative effect on barrier performance if the execution is incorrect, insufficient, delayed, or excessive. Maintenance can also be the triggering event.The objectives of this article are: (1) To investigate how maintenance impacts the occurrence of major accidents, and (2) To develop classification schemes for causes of maintenance-related major accidents.The paper builds primarily on model-based and empirical approaches, the latter being applied to reports on accident investigation and analysis. Based on this, the Work and Accident Process (WAP) classification scheme was proposed in the paper.     

Toluene removal biofilter modeling: Optimization and case study

Based on the model proposed by De Visscher and Van Cleemput for methane oxidation in landfill cover soils, a simulation model for biofiltration of toluene-contaminated air has been developed for biofilters with substrate inhibition. A convenient way to optimize biofilter performance was developed assuming Haldane kinetics. It was calculated that for a typical oilsands operation emitting 200 ton of toluene annually, 90% of the toluene can be removed by a 740 m³ biofilter, if the waste gas sent to the biofilter has a toluene concentration of 2.25 g m⁻³. The optimal initial concentration increases with increasing target efficiency.     

CFD simulation study on gas dispersion for risk assessment: A case study of sour gas well blowout

Compared with general blowout, the process of sour gas well blowout is more complex. The exchange of gas state is affected by many factors, and the consequences of the accident are serious. It is difficult to find out the rule of gas dispersion and predict the distribution of toxic gas. Fluent code was used to model the sour gas dispersion in the atmosphere after well blowout. The “12.23” sour gas well blowout, which was happened in Kai County, Chongqing, Sichuan, China, was the research background. The blowout accident model was set up to simulate the real process. Models were built based on real topography. Wind speed and atmospheric stability of the day which the accident happened were set as the operation conditions, and the composition, injection rate, and temperature of the gas at the actual time were set as the boundary conditions of numerical simulation. The analysis of gas dispersion based on simulation results conducted from two aspects, height and dispersion time. A comparison of field data with simulation data demonstrated that CFD technology can be an effective aid to describe the process of sour gas dispersion and can also predict the tendency of gas dispersion and gas distribution. Furthermore, it can provide guidance on design emergency response zone (ERZ).     

Prioritizing highway safety improvement projects: A multi-criteria model and case study with SafetyAnalyst

This paper presents a multi-criteria model for prioritizing highway safety improvement projects, in which a set of criteria related to the project’s technical, economic, and social impacts are properly weighted in consideration. The proposed model features an Analytical Hierarchy Process (AHP) framework to tackle the multi-criteria decision making problem. Different from the conventional AHP, this paper adds a fuzzy scale level between the criteria level and the alternative level, which offers the advantage of preventing the vagueness and uncertainty on judgments of the decision-maker(s). Such a unique modeling feature is further embedded with a non-linear optimization formulation to maximize the consistency in pair-wise comparison and weight estimation for each criterion. Case study results reveal that the proposed model is efficient not only for selecting the most suitable project for a specific site, but also for determining the priorities for implementing those suitable projects among multiple sites given the budget constraint. Comparative study between the proposed model and the existing ranking methods has also indicated its capability to capture the comprehensive impacts of all contributory factors which have been neglected by most existing single multi-criteria approaches during the safety project selection process. The clarity of model inputs, ease of synthesizing the final score of each candidate project, and the interpretation of results with respect to different selection criteria offer its best potential to be used as an effective tool for highway safety managers to assess and refine the safety improvement investments.     

Life extension reliability analysis of decommissioned transportable seamless steel gas cylinders: A case study

Life extension reliability analysis process of decommissioned transportable seamless steel gas cylinders is proposed based on reliability index and applied to a case study in this paper. The index was calculated in terms of material stress, material strength and their probabilistic distributions. Stresses were determined by membrane equations for cylindrical shell and finite element analysis for neck, shoulder and bottom. Yield strength was measured and chosen as material strength. Probabilistic distributions were determined by distribution of material hardness. Decommissioned gas cylinders, which corrode relatively more seriously than others, could be used in the analysis for conservatively determining life extension reliability. In addition, service life of gas cylinders could be extended on condition that their reliability was more than 0.99999. Finally, the proposed analysis process was applied to determine whether some decommissioned transportable seamless steel oxygen cylinders which were manufactured in 1970s could be life extended and shown to be effective.     

The successes and challenges of implementing high reliability principles: A case study of a UK oil refinery

Research conducted on organisations that are able to sustain excellent safety records over long time periods suggests that there are a number of practices that organisations can adopt to achieve high levels of reliability and safety. These practices are often discussed in the context of major incidents to highlight the safety standards that high hazard organisations should try to emulate. However, previous research has predominantly focused on non-profit organisations, and comparatively little research has examined whether high reliability practices may be meaningfully applied to commercial contexts. This paper addresses this gap by using a qualitative approach to explore the types of reliability-enhancing practices implemented in a UK-based oil refinery in its attempt to achieve its ethos of ‘safe and reliable operations’. The findings illustrate the successful application of reliability-enhancing practices in several domains, including: hazard identification and control; emergency preparedness and collection; and analysis of incidents and near misses. Management commitment to safety emerged as an important factor underpinning the successful implementation of reliability-enhancing practices, highlighting its potential significance in the context of commercial organisations. However, promoting an open reporting culture and maintaining high levels of management visibility may be some of the challenges encountered by organisations striving to implement reliability-enhancing practices.     

The role of production and teamwork practices in construction safety: A cognitive model and an empirical case study

Problem

In construction, the challenge for researchers and practitioners is to develop work systems (production processes and teams) that can achieve high productivity and high safety at the same time. However, construction accident causation models ignore the role of work practices and teamwork. This study investigates the mechanisms by which production and teamwork practices affect the likelihood of accidents.

Method

The paper synthesizes a new model for construction safety based on the cognitive perspective (Fuller's Task-Demand-Capability Interface model, 2005) and then presents an exploratory case study. The case study investigates and compares the work practices of two residential framing crews: a 'High Reliability Crew' (HRC)—that is, a crew with exceptional productivity and safety over several years, and an average performing crew from the same company.

Results

The model explains how the production and teamwork practices generate the work situations that workers face (the task demands) and affect the workers ability to cope (capabilities). The case study indicates that the work practices of the HRC directly influence the task demands and match them with the applied capabilities. These practices were guided by the 'principle' of avoiding errors and rework and included work planning and preparation, work distribution, managing the production pressures, and quality and behavior monitoring.

Summary

The Task Demand-Capability model links construction research to a cognitive model of accident causation and provides a new way to conceptualize safety as an emergent property of the production practices and teamwork processes. The empirical evidence indicates that the crews' work practices and team processes strongly affect the task demands, the applied capabilities, and the match between demands and capabilities.

Impact on Industry

The proposed model and the exploratory case study will guide further discovery of work practices and teamwork processes that can increase both productivity and safety in construction operations. Such understanding will enable training of construction foremen and crews in these practices to systematically develop high reliability crews.     

Identification, analysis and dissemination of information on near misses: A case study in the construction industry

Near misses are well-known for providing a major source of useful information for safety management. They are more frequent events than accidents and their causes may potentially result in an accident under slightly different circumstances. Despite the importance of this type of feedback, there is little knowledge on the characteristics of near misses, and on the use of this information in safety management. This article proposes guidelines for identifying, analyzing and disseminating information on near misses in construction sites. In particular, it is proposed that near misses be analyzed based on four categories: (a) whether or not it was possible to track down the event; (b) the nature of each event, in terms of its physical features (e.g. falling objects); (c) whether they provided positive or negative feedback for the safety management system; and (d) risk, based on the probability and severity associated with each event. The guidelines were devised and tested while a safety management system was being developed in a healthcare building project. The monitoring of near misses was part of a safety performance measurement system. Among the main results, a dramatic increase in both the number and quality of reports stands out after the workforce was systematically encouraged to report. While in the first 4 months of the study – when the workforce was not encouraged to report – there were just 12 reports, during the subsequent 4 months – when the workforce was so encouraged – there were 110 reports, all of them being analyzed based on the four analytical categories proposed.     

Remediation procedure used for contaminated soil and underground water: A case study from the chemical industry

This is a case study of contamination by a non-aqueous phase liquid (NAPL) that leaked from a chemical plant. The remediation procedure adopted for the initial phase of the plume migration was a plastic diaphragm wall coupled with a series of water extraction wells designed to avoid environmental impact on the surrounding ecosystems. Monitoring has shown that the containment is successful, and additional measures that contribute to accelerating remediation have been adopted. The authors wished to investigate how remediation might be further enhanced. The use of in situ aeration coupled with a system of soil vapor extraction (AS/SVE) has been chosen, since the remediation of sites with characteristics similar to those in this study, if based exclusively on dissolved-phase control, would take several decades to be completed. The transport of contaminant plumes has been simulated by using an analytical model to evaluate the effectiveness of the natural attenuation of the contaminant. The results of the simulation have confirmed the limited effectiveness of the natural attenuation of the contaminant, as well as the effective increase of remediation that would occur if the AS/SVE system is applied. A sensitivity analysis that included several combinations of increments of parameters that correspond to the decay rate of the source and the dissolved plume has simulated what might happen if the AS/SVE system is implemented.