Bow-tie Diagram Research Articles

RISK ANALYSIS OF FALLING FROM HEIGHTS IN THE GROWING CONSTRUCTION INDUSTRY

Based on the data released by the Australian Bureau of Statistics, the number of injuries and fatalities caused by falls from height (FFH) accidents at construction sites is one of the highest making the construction industry relatively unsafe compared to other industries. This study has been made to find out the causes, consequences, and probabilities of construction fall incidents in New South Wales (NSW), Australia. The Bowtie (BT) diagram will be used to illustrate various accident situations in order to evaluate the risk of FFH in NSW, as it has not been used in previous studies. The BT diagram, which is made up of a fault tree (FT) and an event tree, represents the logical interconnections between the causes and consequences of the accidents (ET). FTs are used to calculate the odds of different accident situations. The ET analysis is then used to assess the various outcomes of these accidents, as well as their probabilities. Following that, the schematic modeling will be entered into GeNIe software for results validation, and sensitivity analysis will be used to find the main contributor of FFH incidents. The outcome will aid in the prevention of particular incidents and increase the overall level of safety on construction sites. Based on the data released by the Australian Bureau of Statistics, the number of injuries and fatalities caused by falls from height (FFH) accidents at construction sites is one of the highest, making the construction industry relatively unsafe compared to other industries. This study has been made to find out the most common causes, probabilities, and appropriate mitigation measures in construction fall incidents in New South Wales (NSW), Australia. The findings obtained from NSW Construction Blitz in 2019 was used to analyze the probability of the common potential causes of falling from ladders, voids and edges, scaffolds, formworks and, mobile scaffolds and fall restraints. Five fault tree (FT) diagrams were used to illustrate various accident causes in order to determine the probability of risk of FFH in NSW. Following that, a schematic modeling was entered into Genie software for results validation and to determine the main contributor of FFH incidents. From this study, falling from voids and edges has the highest likelihood of falls in NSW with a probability of 27.15%. This is followed by falling from mobile scaffolds and fall restraints with 7.92%, which is closely followed by falling from scaffolds with 7.68%. While falling from ladders and falling from formworks were not too far behind, with 2.17% and 1.05% respectively. Preventative measures were then discussed for FFH accident scenarios. These findings will aid in the prevention of particular incidents and increase the overall level of safety on construction sites in NSW.

Process Flow Modeling for an In‐Time Aviation Safety Management System

AbstractIn 2018, the National Academies challenged the National Aeronautics and Space Administration (NASA) to lead the development of an In‐Time Aviation Safety Management System (IASMS). This IASMS would enable increasingly autonomous aviation operations by automating the safety monitoring, assessment, and mitigation functions currently performed manually as part of the Safety Management System (SMS) process. In this paper, we detail today's SMS processes. We will also be drafting a process flow of today's SMS based on the International Civil Aviation Organization (ICAO)'s guidelines. Furthermore, we will be developing bowtie diagrams for two use case scenarios identified by the Flight Safety Foundation (FSF) in their Disaster Monitoring and First Response studies.

Engineering Poster E8: Dynamic Risk Advisor – real time bowtie risk assessment monitoring system

Poster E8 This paper describes the development of a Dynamic Risk Advisor to improve safety of operations in fleet marine construction and production oil and gas vessels, well, and subsea equipment in process safety management, providing rig management onshore and offshore tools to assess health, safety, and environment (HSE) performance in real time. This tool uses the bowtie methodology, and provides a useful framework to present a risk ‘picture’ and to satisfy management of health and safety at work regulations. The focus of the methodology is the relationship between safeguards (control systems/equipment, process controls, and human factors) and an overview of the safety process monitoring in a simple and visual form. As facilities and equipment age, those safeguards may become less effective or degraded (different from the condition at the moment of risk assessment creation/revision), risks may increase and that is why they must be monitored using an effective, continuous, and temporal-aware method. Ocyan and Viasat/Intelie created a solution to identify and analyse the hazards dynamically (in real time) using the LIVE streaming data platform, providing an interface that allows the client to manage the current risk profile of their assets using a bowtie diagram. Additionally, this also provides a way for the user to assess the effect of degraded safeguards on complex operations in real time, by monitoring the actual residual risk. The study started in 2019 and was developed together with the Ocyan HSE team and was extended to all fleet due to the positive results. The tool can be accessed from mobile phones and tablets. To access the poster click the link on the right. To read the full paper click here

RISK ANALYSIS OF FALLING FROM HEIGHTS IN THE GROWING CONSTRUCTION INDUSTRY

Based on the data released by the Australian Bureau of Statistics, the number of injuries and fatalities caused by falls from height (FFH) accidents at construction sites is one of the highest making the construction industry relatively unsafe compared to other industries. This study has been made to find out the causes, consequences, and probabilities of construction fall incidents in New South Wales (NSW), Australia. The Bowtie (BT) diagram will be used to illustrate various accident situations in order to evaluate the risk of FFH in NSW, as it has not been used in previous studies. The BT diagram, which is made up of a fault tree (FT) and an event tree, represents the logical interconnections between the causes and consequences of the accidents (ET). FTs are used to calculate the odds of different accident situations. The ET analysis is then used to assess the various outcomes of these accidents, as well as their probabilities. Following that, the schematic modeling will be entered into GeNIe software for results validation, and sensitivity analysis will be used to find the main contributor of FFH incidents. The outcome will aid in the prevention of particular incidents and increase the overall level of safety on construction sites. Based on the data released by the Australian Bureau of Statistics, the number of injuries and fatalities caused by falls from height (FFH) accidents at construction sites is one of the highest, making the construction industry relatively unsafe compared to other industries. This study has been made to find out the most common causes, probabilities, and appropriate mitigation measures in construction fall incidents in New South Wales (NSW), Australia. The findings obtained from NSW Construction Blitz in 2019 was used to analyze the probability of the common potential causes of falling from ladders, voids and edges, scaffolds, formworks and, mobile scaffolds and fall restraints. Five fault tree (FT) diagrams were used to illustrate various accident causes in order to determine the probability of risk of FFH in NSW. Following that, a schematic modeling was entered into Genie software for results validation and to determine the main contributor of FFH incidents. From this study, falling from voids and edges has the highest likelihood of falls in NSW with a probability of 27.15%. This is followed by falling from mobile scaffolds and fall restraints with 7.92%, which is closely followed by falling from scaffolds with 7.68%. While falling from ladders and falling from formworks were not too far behind, with 2.17% and 1.05% respectively. Preventative measures were then discussed for FFH accident scenarios. These findings will aid in the prevention of particular incidents and increase the overall level of safety on construction sites in NSW.

Dynamic Risk Advisor – real time bowtie risk assessment monitoring system

This paper describes the development of a Dynamic Risk Advisor to improve safety of operations in fleet marine construction and production oil and gas vessels, well, and subsea equipment in process safety management, providing rig management onshore and offshore tools to assess health, safety, and environment (HSE) performance in real time. This tool uses the bowtie methodology, and provides a useful framework to present a risk ‘picture’ and to satisfy management of health and safety at work regulations. The focus of the methodology is the relationship between safeguards (control systems/equipment, process controls, and human factors) and an overview of the safety process monitoring in a simple and visual form. As facilities and equipment age, those safeguards may become less effective or degraded (different from the condition at the moment of risk assessment creation/revision), risks may increase and that is why they must be monitored using an effective, continuous, and temporal-aware method. Ocyan and Viasat/Intelie created a solution to identify and analyse the hazards dynamically (in real time) using the LIVE streaming data platform, providing an interface that allows the client to manage the current risk profile of their assets using a bowtie diagram. Additionally, this also provides a way for the user to assess the effect of degraded safeguards on complex operations in real time, by monitoring the actual residual risk. The study started in 2019 and was developed together with the Ocyan HSE team and was extended to all fleet due to the positive results. The tool can be accessed from mobile phones and tablets.

Identification of reference scenarios for security attacks to the process industry

The possibility of inducing severe security-related events with damage to people, property, and the environment by deliberate malicious attacks to chemical and process plants handling large quantities of hazardous materials received an increasing attention in recent years. The identification of the credible security scenarios is required by Security Vulnerability/Risk Assessment (SVA/SRA) methodologies. However, the current availability of supporting tools is limited. This may hinder a proper management of the risks, especially in the European context where security threats are only marginally recognized under the Seveso legislation. The present study aims at supporting a harmonized identification of the scenarios triggered by deliberate malicious physical attacks to chemical and process plants. An approach based on Bow-Tie formalism is proposed to identify reference security scenarios. The Bow-Tie diagram is used to link the attack modes (Attack Tree) to the relevant release scenarios (Security Events) and to the physical damage scenarios (Event Tree). Reference Bow-Tie diagrams were defined considering substances commonly present in process plants (e.g. flammable substances and oxidizing solids). The validation of the reference scenarios (both attack scenarios and physical damage scenarios) was provided by the analysis of more than 20 security-related incidents that occurred in chemical and process facilities worldwide in the last 50 years. Application to a case-study proved the effectiveness of the results achieved in supporting SVA/SRA studies and in promoting integration among safety and security management.

BowTie analysis of rooftop grid‐connected photovoltaic systems

AbstractWith the rapid growth of the worldwide photovoltaic (PV) installation, the number of fire incidents involving PV systems also shows an increasing trend. Several studies revealed that installing PV systems on the rooftop has introduced an additional fire risk to the building. Therefore, risk assessment is required to identify the possible cause of fire initiation involving PV systems and subsequently provide the solar industry with fire risk information regarding PV faults. A BowTie analysis of rooftop grid‐connected PV systems was conducted, where initiation of ignition was determined as the hazard and PV fires as the loss event. Four threats in the BowTie analysis were identified using fault tree analysis, that is, arc fault, ground fault, hotspot effect at PV modules, and overheating. Arc fault contributes the most to PV fire incidents, while poor installation of PV systems was found to be the primary underlying cause of all PV fault scenarios. The main factor is due to lack of fire safety knowledge and negligence behavior of the installers. The consequences of PV fires in the BowTie diagram were investigated from the event tree analysis. Twelve possible outcomes were identified and regrouped to five consequences, that is, respiratory poisons, electrical shock, fall from heights, asset damage, and fire propagation. The evaluation of the consequences of PV fire shows that electrical shock poses a very high risk to the surrounding people, including firefighters. Additional measures are proposed to reduce the impact of electric shock.

Visualizing primary cooling system risks with bowtie diagram for RSG GAS operator guidance

AbstractThe G.A. Siwabessy Multipurpose Reactor (RSG GAS) is a pool‐type research reactor. When the reactor operates, the heat released in the core is removed by the primary cooling system. It is necessary to evaluate this system, because failure can cause worst events such as the melting of reactor fuel and the release of radioactivity to the environment. Due to the possibility of radioactive material releases, safety issues are important to be evaluated. Several studies using event tree analysis (ETA), fuzzy fault tree analysis (FFTA) describe the results quantitatively. The varied educations of operators will provide various responses to quantitative results, and a need to create qualitative results that are simple and easy to understand using bowtie analysis that visualizes the risk scenario. Failure of this system causes loss of coolant accident (LOCA) and loss of flow accident (LOFA). The results show that the relationship between the consequences and causes of the risk occurrence LOCA and LOFA, and the controls used to prevent and reduce the hazard based on safety and emergency system at RSG GAS, can be depicted in a bowtie diagram. The bowtie diagram is simple and easy for an RSG GAS operator to carry out their duties and increase awareness regarding the safety of reactor operations.

Using a Proposed Risk Computation Procedure and the Bow-Tie Diagram as a Method for Maritime Security Assessment

Using a Proposed Risk Computation Procedure and the Bow-Tie Diagram as a Method for Maritime Security Assessment

Establishing an onshore pipeline incident database to support operational risk management in Brazil - Part 2: Bowtie proposition and statistics of failure

In part 1, which is complementary to this article, an appropriate data collection architecture was proposed in order to support the establishment of an onshore pipeline incident database in Brazil. Reflecting the current context of pipeline industry in this country, this structure was built based on the state of art regarding several international databases followed by an interdisciplinary survey submitted to pipeline experts from different areas of specialization. According to their favorability, a criteria was applied in order to select the collection parameters that, finally, compose the proposed architecture. In this second paper (part 2), a bowtie diagram was elaborated inspired on the results obtained in part 1 in order to support the management of onshore pipelines operational risks. In addition to defining causes and consequences, prevention and mitigation barriers along with respective leading and lagging indicators were elucidated based on the literature allowing pipeline operators to monitor the status of these controls over time and contributing to the improvement of their risk management systems. Additionally, failure statistics similar to those presented by international benchmark reports were developed through historical failure data obtained from a Brazilian pipeline operator. Among other metrics, it is reproduced the behavior of failure rates along the period in analysis (from 1978 to 2008), as well as distributions of incidents by categories of causes and exposure (extension) evolution of the pipeline network considered. In sequence, a comparison between Brazilian and international benchmarks failure frequencies is performed. Finally, illegal tapping statistics from 2016 to 2020 are also addressed, indicating some prevention and mitigation measures that were implemented in this period in order to better manage operational risks associated with pipeline theft.

Establishing an onshore pipeline incident database to support operational risk management in Brazil - part 1: Defining architecture

This work aims to propose an interdisciplinary research for establishing a national onshore pipeline incident database. The creation of a failure database has the potential to allow effective demonstration to control authorities and the society of safety improvements implemented by operators over time, support the development of dynamic risk assessment and management models and comparison with international benchmarks metrics, among other benefits. Therefore, in this part 1 a robust approach is proposed in order to previously define an appropriate data collection architecture that reflects the current context of this activity in Brazil. Defining architecture properly is a key issue to ensure that future data collection would be able to generate relevant information (and them knowledge) to support and strengthen operational risk management. Through a systematic literature review, the state of art regarding several international benchmarks was established for mapping the parameters that typically compose pipeline incident databases taxonomies. Categories regarding events of failure, pipeline network and database management were identified. In sequence, an anonymous survey was carried out considering this information, involving 180 pipeline specialists of different profiles/backgrounds. Statistical tests were proposed for assessing consistency of its results and selecting the parameters that would finally compose Brazilian pipeline database architecture according to expert elicitation. Based on it, in part 2 a bowtie diagram is elaborated, depicting causes, consequences, prevention and mitigation controls associated with pipeline failure events. In addition, the calculation of failure statistics from historical data obtained from a Brazilian pipeline operator demonstrates that the architecture proposed in part 1 has practical applicability and can be used for the purposes of this work.

RISK ASSESSMENT FOR VIOLATION OF ANTI-TRUST LEGISLATION BY STATE EXECUTIVE AUTHORITIES

The article deals with a problem of building an anti-trust compliance system in state executive authorities from the point of view of contemporary risk management. The authors expound a well-known instrument based on the bow-tie diagram construction which successfully helps to develop effective measures to prevent violation of anti-trust legislation cases by state executive authorities. They also give some numeric results of statistical modelling of anti-trust legislation violation risks by state executive authorities by means of the Monte-Carlo method.

Writing ‘usable’ Nuclear Power Plant (NPP) safety cases using bowtie methodology

Historically, the majority of Nuclear Power Plants (NPP) Safety Cases have been produced and implemented under highly prescriptive regulatory regimes, with emphasis placed on demonstrations of the robustness of the facility’s design basis against a set of deterministic criteria and technical standards and rules set by the Regulatory Body. This has resulted in Safety Cases that are technically sound, but at the same time too complex and not easily accessible to and usable by persons responsible for ensuring safe operations; i.e. operations and maintenance staff who are in direct control of the plant as well as managers who are accountable for safety – the key end-users.Shortcomings regarding the ‘usability’ of the Safety Cases are not new and have been the subject of discussion in recent years. They are deeply rooted in the way these documents are produced and implemented. It means that in order to overcome these difficulties attention should be focused primarily on the Safety Case process, affording it the same importance that is given to the final product – the documented Safety Case. This paper explores the advantages that incorporation of the Bowtie risk management methodology into the Safety Case (production) strategy can bring to the delivery of a fit-for-purpose, accessible and usable Safety Case, supporting current efforts undertaken by the nuclear industry to ensure ‘Right First Time Safety Cases’.The paper also suggests that the conduct of Bowtie workshops - in the author’s opinion, the most important part of the Bowtie building process – provides vital input from the people who have most knowledge and experience of the plant and its current operational status. It enables the Bowtie diagrams to reflect the ‘operational reality’ in the plant, by providing a real picture of the actual barrier condition and, more importantly, to identify those barriers that need to be strengthened. The latter will have a direct effect on the usability of the resultant Safety Case product during plant operation.A generic Advanced Boiling Water Reactor (ABWR) design has been taken as an example to highlight the claimed advantages. The paper reflects how Bowtie diagrams can be built within a workshop setting that depicts how a particular accident scenario can be managed through appropriate barriers and controls. It also shows how the use of Bowtie diagrams can make the Safety Case process a true ‘aid’ to thinking and deliver a final product that is accessible and easy-to-understand by key end-users.

Development of a predictive accident model for dynamic risk assessment of propane storage tanks

Investigation of past accidents has shown that LPG tank accidents cause significant damage to the industry due to the storage of large volumes of flammable materials in them. This study aimed for developing a predictive accident model for dynamic risk assessment of propane storage tanks of the refinery. Hazards and safety barriers were identified using MIMAH methodology. The basis of MIMAH methodology is Bow-tie method. To construct the Bow-tie diagram, first, accidents that occurred on LPG tanks were extracted from the databases of accidents and valid sources. The top events of the accidents were identified and analyzed by the fault tree. The Bow-tie diagrams were constructed and the barriers on the diagrams were identified and verified by refinery experts. According to the SHIPP model, safety barriers were categorized into seven main barriers. The failure rates of the fault tree basic events were extracted from reliable sources and the prior probability of barriers was calculated. Based on the failure or success of safety barriers, 6 levels of severity of consequences, safe, near miss, mishap, incident, and catastrophic accident were considered. Using the prior probability of failure of the barriers, the probability of occurrence of each level of severity of consequences was calculated with the event tree. In the next step, this paper employed LPG storage tanks past accidents to construct a likelihood function and update prior probability using the Bayesian equation. Finally, the posterior probability of occurrence of the consequences was calculated using the posterior probability of failure of the barriers. Because LPG accidents occur with low probability and high severity, predicting accidents dynamically helps people to always be prepared to prevent their occurrence.

Locating urban CNG stations using quantitative risk assessment: using the Bayesian network

Due to the increasing need for fuel and the construction of compressed natural gas (CNG) refuelling stations in urban areas, the importance of accurate risk management in these stations has increased. This study is locating urban CNG stations using quantitative risk assessment in Hamedan, Iran using the Bayesian Network. In this study, the causes–consequences analysis of methane gas leakage from CNG storages was investigated by the Bowtie (BT) method. To quantitate this diagram, the Bayesian network (BN) was used. Finally, the quantitative risk was calculated and evaluated in a case study. Findings of the BT diagram showed that the probabilities (in year) of occurrence of VCE, Jet fire and Flashfire were 1.82 × 10−2, 1.532 × 10−2 and 1. 213 × 10−2, respectively. These values were calculated as 2.9 × 10−3, 2.2 × 10−2 and 1.9 × 10−3 in year, respectively, in the BN. The mortality area affected by these consequences was also calculated as 14.2, 44.5 and 1930 m2, respectively. The risk assessment results estimated the risk as unacceptable in most affected areas. Accurate risk management in process accidents requires high-precision risk assessment in the urban design phase. The findings showed that the use of the Bayesian network and PHAST modelling can be used in this risk assessment.

Using the BOW-TIE method in analysis of aerological risks of coal mines

The coal industry in Ukraine remains one of the most dangerous industries. It is characterized by a wide range of accidents and emergencies, a high level of industrial injuries and occupational morbidity. The aim of improving production safety is not only to reduce the risk of injury and occupational morbidity (cases of high probability and insignificant), but also mine accidents, which occur relatively rarely, but are characterized by much more significant consequences. It is necessary to develop and use a risk analysis method that would take into account all aspects of the occurrence and course of a possible accident and would forecast in detail the elimination of its consequences. Ukraine still does not have an comprehensive legal and methodological support for assessing and managing emergency risks, and international standards on these issues, adapted to Ukrainian conditions, are not always brought to practical use. Risk assessment, especially aerological analysis, of a coal mine is a rather complicated process associated with the use of working methods in conditions of insufficient information, there are not enough specialists familiar with the methods of expert assessment, therefore, risk assessment methods well-known abroad are not used in the coal industry of Ukraine in full measure. One of these methods is the BOW-TIE diagram, which allows to simply and visually assess the advancing of a hazard from the place of the risk occurrence to the event that causes undesirable consequences, to determine the stages at which it is necessary to take emergency measures, the nature and reliability of such measures. The article presents the methods for constructing the BOW-TIE diagrams with different level of detail, routes of hazards advancing, establishment of risk control barriers, “brainstorming” during the analysis of aerological risks in order to reduce them to the acceptable level. Examples of using the BOW-TIE diagram are given. The use of foreign developments in domestic practice indicates the promising nature of this approach and the need to continue the work with the aim of wider introduction of this method at coal enterprises in Ukraine. Key words: coal mine, aerological risk, hazard, unwanted outcome, BOW-TIE method.

The Bowtie diagram: a simple tool for analysis and planning in anesthesia.

Purpose of reviewThe purpose is to show the advantages of a Bowtie diagram as a versatile tool for displaying and understanding the evolvement and management of critical incidents.Recent findingsThe Bowtie diagram has been used recently in anesthesia to depict critical incidents having been used in high-risk industries for several decades. This diagram displays the progression from latent factors to potential harm in five steps.SummaryThe Bowtie diagram combines the features of a fault tree and an event tree with the adverse event, known as the Top Event separating the two sections. The fault tree is similar in concept to a Swiss Cheese diagram and the event tree similar in concept to an emergency management algorithm. Preventive barriers and escalation measures are used to detect and trap abnormal states. If these fail, the event proceeds to a crisis, leading to the Top Event, a time for making decisions. A recovery state follows, which depicts an emergency state mandating immediate life or limb-saving management to recover from the crisis. Finally, in the aftermath state, a time for reflection and learning, ultimate outcomes are shown in the right-hand column.Video abstractThe Bowtie Diagram. Designed and created by Yasmin Endlich, Martin D. Culwick and Stavros N. Prineas.

Dynamic Safety Management on the Key Equipment of Coal Gasification Based on Dbt-Dbn Method

Gasifier system is one of the important components of coal gasification device. The technical characteristics of this system mainly lie in the following facts as huge technical scale and high complexity, and there is a dynamic correlation between the failure modes of gasification equipment. Traditional safety analysis methods such as fault tree and bow-tie diagram suffer from drawbacks as being static and ineffective in handling uncertainty, which hamper their application to risk analysis of process systems. This paper presents a newly developed model based on Dynamic Bow-Tie (DBT) and Dynamic Bayesian network (DBN) for quantitative dynamic risk assessment of gasifier system. In the meantime, in order to cope with the uncertainty of the failure data, fuzzy numbers and the defuzzification method are used to transform the experts' language into the failure rates. The results showed that dynamic risk assessment can solve the difficulties dealing with complex dynamic systems which have process variables and characteristics such as multiple, failure correlations, and noncoherence. And it also has important theoretical significance and application value for coal chemical industry to improve the scientificity of risk assessment.

Risk Analysis of Decommissioning Process: Case Studies of Lima-Compresor Platform

The process of petroleum exploration and exploitation is a crucial activity in the fulfillment of energy needs in the world. The process of petroleum exploration and exploitation is currently centred on shallow water regions in the continental shelf. In the process of petroleum exploration and exploitation in shallow waters, the structure of which is commonly used is the jacket structure. In Southeast Asia there are about 1300 platforms, of which 80% is over 20 years old. When the platform has reached its operational limit, according to the ministerial regulation of ESDM number 1 year 2011 The platform must be decommissioning in accordance with existing technical standards. In the process of demolition, there are certainly risks and hazards that can interfere with the process of decommissioning. It is necessary to do a risk analysis to map the risks that can occur while preparing the mitigation steps. In this study, risk analysis arel conducted by determining the activity that has a significant degree of hazard where it is concluded that activities that have a significant risk level are activities related to construction, lifting, maintenance, well service, and maintenance. From each activity that has a significant hazard level, there was a process of determining the cause of risk using the Fault Tree Analysis (FTA) method while determining the barrier that serves to prevent a risk occurring. The next is to determine the impact that can be inflicted from risk by using the Event Tree Analyis (ETA) method while determining the barrier that serves to prevent and reduce the impact that occurs when there is a peril. These two FTA and ETA diagrams are combined to create a Bowtie diagram to explain in detail the risk management performed at each stage of the decommisiioning process.

Cumulative Effects and Boreal Woodland Caribou: How Bow-Tie Risk Analysis Addresses a Critical Issue in Canada's Forested Landscapes

Boreal caribou (Woodland Caribou, boreal population; Rangifer tarandus caribou) is a prominent mammal at the heart of a decades-long conflict between a growing resource sector and the associated risks to biodiversity. We employed the ISO 31010 Bow-tie Risk Assessment Tool (BRAT) to evaluate the cumulative effects of anthropogenic and natural factors that may affect the risk of self-sustainability to the boreal caribou herds of Northeastern British Columbia. We used the BRAT to produce a visual synthesis of the cumulative effects causing the growth rate of boreal caribou herds to persistently fall below a level corresponding to a 60% chance of being self-sustaining (λ < 1.025). The BRAT diagram provided the basis for a quantitative Layers of Protection Analysis (LOPA) of risk probabilities for three caribou herds. We combined threat assessments from the Species at Risk Act recovery strategy (Environment Canada 2012) with data from published landscape experiments (e.g. restoration of seismic traces, maternal penning, and wolf culls) to parameterize the LOPA in three study areas. We report the implications of a combination of mitigation options versus current risk conditions, as well as the implications of uncertainty in threat prevention. Our analysis indicates that a combination of mitigation scenarios will best facilitate caribou herd recovery, that barriers preventing predation threats could also aid in recovery success, and that compensatory predation may account for a significant proportion of both adult and juvenile female mortality across different herds. We estimated the minimum annual cost for effective mitigation and recovery to be $CDN 224K within any of the study areas. Bow-tie diagrams are a flexible and quantifiable tool that can translate resource management solutions to the diverse audience involved in conservation decision-making: scientists, land managers, policy makers, and concerned stakeholders.