Technical safety: use of concept risk assessment for field development certainty

2019 ◽  
Vol 59 (2) ◽  
pp. 549
Author(s):  
Colin Crowley ◽  
Dave Ashton

As technology advances and field development possibilities grow, the need for earlier guidance on the safety performance of concept designs is greater than ever. The SNC-Lavalin concept risk assessment (CRA) tool is a transparent and rapidly deployable model that is based on sound, industry-accepted quantitative risk assessment (QRA) principles. From the earliest stages of field development, when conceptualisation may be vague and data sparse, a wide range and variety of design options can still be assessed effectively and ranked on their safety performance. The CRA tool is proprietary software initially developed with BP and Shell. The model was first calibrated against 10 detailed QRAs, but is regularly benchmarked and updated with the most current failure rate data and has been used on nearly 50 projects globally. The database now incorporates established rule sets from hundreds of detailed QRAs performed, including floating liquefied natural gas and floating storage regasification units. This paper presents a CRA case study for a generic remote offshore field with a range of development options from conventional to minimal offshore facilities. The model calculates the associated risks for the options considered and is presented in terms of individual risk per annum, temporary refuge impairment frequency and potential loss of life. The results highlight the effects of each individual design feature on risk levels by comparison of similar options side by side, noting the main risk contributors and allowing investigation of the benefits of risk reduction measures. This enables identification of the best design features from each of the options and allows an optimised design to be carried forward.

Author(s):  
Maher Nessim ◽  
Shahani Kariyawasam

Abstract The lack of established acceptance criteria has been one of the key challenges to the application of quantitative risk assessment (QRA) techniques in the Canadian pipeline industry. While a wide range of such criteria have been developed and published, it remains difficult for most operators to commit to specific criteria because such criteria may not be acceptable to all stakeholders. Recognizing this limitation, the Canadian Standards Association formed a Risk Management Task Force (RMTF) under the Technical Committee for the Z662 Standard on the Oil and Gas Pipeline Systems to propose criteria for potential inclusion in its non-mandatory Annex on Risk Assessment. This paper describes the criteria that have been developed by the RMTF and provides the background information needed for users to understand and use them correctly. The discussion includes: a summary of the measures used to quantify the safety risk associated with an ignited product release; a summary of established international and Canadian criteria that have been considered; a description and interpretation of the ALARP (As Low As Reasonably Practicable) principle; and the rationale used by the RMTF to select specific individual risk and societal risk criteria for CSA Z662. The proposed criteria are also compared to the criteria underpinning other risk-based parts of the Z662 Standard, including Annexes C and O. Guidance is provided on the analysis assumptions, methods and parameters required to ensure that the risk calculations produce results that are consistent with the definition and intent of the criteria. Key issues addressed by the guidance include the definition of individual risk (i.e. location risk versus personal risk), the pipeline length over which the frequency versus number of fatalities (F-N) relationship representing societal risk is calculated, and the effect of population density averaging over the pipeline length.


Author(s):  
Saravanan Muthaiyah

Access control methods have been improvised over time, but one area that remains quite grey is the concept of assessing risk levels before any type of access rights are granted. This is relatively a new paradigm in the research of semantic Web security, and new methodologies for this effort are being studied. In this chapter, we will see how qualitative risk assessment (Nissanke & Khayat, 2004) and quantitative risk assessment are carried out. The purpose is to have different methods of assessment for better grant of access control rights and permissions. New examples based on the model described (Nissanke & Khayat, 2004) are used to illustrate the concept. A new quantities technique is also added to complement the qualitative techniques.


1993 ◽  
Vol 56 (12) ◽  
pp. 1043-1050 ◽  
Author(s):  
JOAN B. ROSE ◽  
MARK D. SOBSEY

Human pathogenic viruses have been detected from approved shellfish harvesting waters based on the fecal coliform indicator. Until recently it was difficult to assess viral contamination and the potential impact on public health. Risk assessment is a valuable tool which can be used to estimate adverse effects associated with microbial hazards. This report describes the use of quantitative risk assessment for evaluating potential human health impacts associated with exposure to viral contamination of shellfish. The four fundamental steps used in a formal risk assessment are described within and include i) Hazard identification, ii) Dose-response determination, iii) Exposure assessment, and iv) Risk characterization. Dose-response models developed from human feeding studies were used to evaluate the risk of infection from contaminated shellfish. Of 58 pooled samples, 19% were found to be positive for viruses. Using an echovirus-12 probability model, the individual risk was determined for consumption of 60 g of raw shellfish. Individual risks ranged from 2.2 × 10−4 to 3.5 × 10−2. These data suggest that individuals consuming raw shellfish from approved waters in the United States may have on the average a 1 in 100 chance of becoming infected with an enteric virus. Using the rotavirus model which represents a more infectious virus, the risk rose to 5 in 10. The potential for use of a risk assessment approach for developing priorities and strategies for control of disease is immense. Epidemiological data have demonstrated the significance of shellfish-associated viral disease and, although limited, appropriate virus occurrence data are available. Additional information on virus occurrence and exposure is needed, and then scientific risk assessment can be used to better assure the safety of seafood.


2021 ◽  
Vol 13 (21) ◽  
pp. 12169
Author(s):  
Robertas Alzbutas ◽  
Mindaugas Vaisnoras ◽  
Inga Saruniene ◽  
Ricardas Krikstolaitis ◽  
Mindaugas Valincius ◽  
...  

One of the goals of any oil terminal is to make a business while avoiding hazardous events and harmful effects for both humans and the environment. This can be achieved by creating a safe working place as well as by performing safe and acceptable activities regarding the impact on surrounding objects, including residential and industrial areas. The aim of the hazard analysis of the oil terminal is to assess the risks related to hazardous events or phenomena and to evaluate whether the assessed risks are acceptable. The hazard analysis and assessment of risk are also used for risk reduction while examining and limiting hazardous scenarios that, for instance, involve the loss-of-containment of flammable or combustible material. In this paper, the authors aim to contribute to risk research by providing a comprehensive methodology of risk assessment for oil terminals with case study results and discussion on features of the methodology, risk aggregation, its applicability for risk reduction, and industrial interests. The performed study considered the “Klaipedos Nafta AB” (an operator of the Klaipeda Oil Terminal, Lithuania) case study regarding hazardous materials that might be released from various tanks, devices, and associated pipelines. The performed quantitative risk assessment has enabled the determination of the probability regarding whether releases would ignite and, for instance, cause explosion. In the case study, the estimate of probability, i.e., the frequency, and the possible consequences of the hazardous events were evaluated, and both mitigation and risk reduction measures were also considered.


Author(s):  
David Mangold ◽  
W. Kent Muhlbauer ◽  
Jim Ponder ◽  
Tony Alfano

Risk management of pipelines is a complex challenge due to the dynamic environment of the real world coupled with a wide range of system types installed over many decades. Various methods of risk assessment are currently being used in industry, many of which utilize relative scoring. These assessments are often not designed for the new integrity management program (IMP) requirements and are under direct challenge by regulators. SemGroup had historically used relative risk assessment methodologies to help support risk management decision-making. While the formality offered by these early methods provided benefits, it was recognized that, in order to more effectively manage risk and better meet the United States IMP objectives, a more effective risk assessment would be needed. A rapid and inexpensive migration into a better risk assessment platform was sought. The platform needed to be applicable not only to pipeline miles, but also to station facilities and all related components. The risk results had to be readily understandable and scalable, capturing risks from ‘trap to trap’ in addition to risks accompanying each segment. The solution appeared in the form a quantitative risk assessment that was ‘physics based’ rather than the classical statistics based QRA. This paper will outline the steps involved in this transition process and show how quantitative risk assessment may be efficiently implemented to better guide integrity decision-making, illustrated with a case study from SemGroup.


Author(s):  
Dongliang Lu ◽  
Alex Tomic ◽  
Shahani Kariyawasam

Abstract Risk assessment is the process of risk analysis and evaluation. It is a required component of pipeline integrity management programs (IMP) and is generally the first step in most IMPs. For the risk assessment of natural gas pipelines, the primary concern is the safety of population near the pipeline right of way (ROW). TC Energy’s SWRA uses a quantitative risk assessment model that considers the effect of the thermal radiation due to ignited pipeline rupture and evaluate the consequence on the surrounding population. The overall risk is then evaluated using two specific risk criteria: societal risk and individual risk, with the societal risk measuring the overall level of risk to a community or a group of people and the individual risk measuring the level of risk to specific individuals who are present within the pipeline hazard zone. Natural gas pipeline systems often extend hundreds or even thousands of miles. As such, societal risk criteria for pipelines are typically defined based on a given length of pipeline segment, usually in 1 km or 1 mile (1.6 km). To assess the societal risk of actual pipelines, different approaches are taken on how the risk along the length of a pipeline should be aggregated and compared to the criteria. For example, the PD8010-3 standard in the UK recommends the societal risk of a pipeline through a community to be aggregated and then normalized to the unit length to be compared with criteria; whereas the Dutch regulation requires societal risk at the worst location to be used. In the current SWRA, the societal risk along the length of a pipeline going through development areas or communities is aggregated following the recommendation of the UK PD8010-3, where the risk is aggregated and normalized to the pipeline length. Due to the vast scale of the pipeline system, it is impractical to manually review all development along the pipelines for conducting societal risk assessment on a system wide basis. As such, extent of communities and development areas is determined by a computer program using a simple set of rules. It was found to have led to unsatisfying granularity in the societal risk assessment in certain situations, with some interaction lengths being too long and thus failing to identify the more critical section within the interaction length, and certain development lengths being too short and thus not very meaningful from a societal risk perspective. To overcome issues with the current societal risk assessment method in SWRA, an alternative method largely following the direction of the Dutch approach is introduced in this paper. In this alternative approach, the societal risk is evaluated continuously along a pipeline with a predefined a sliding length, and thus variations in the societal risk levels along the entire length of a pipeline, including the locations with the highest societal risk levels, can be identified. Implantation details and computational efficiency were discussed. The results from the alternative method were compared to that from the current method. The sensitivity of the sliding length method to the predefined sliding length was also investigated. The study showed that this alternative method improves the accuracy and granularity of the societal risk assessment in the SWRA, and, although it is relatively computational commanding, with an efficient implementation, is still practical even for very large gas transmission systems.


2020 ◽  
Vol 57 (3) ◽  
pp. 337-353 ◽  
Author(s):  
Renato Macciotta ◽  
Chris Gräpel ◽  
Tim Keegan ◽  
Jason Duxbury ◽  
Roger Skirrow

We present a quantitative risk assessment (QRA) to guide decision-making for selection of rock fall protection strategies. The analysis corresponds to a section of highway near Canmore, Alberta, Canada; where rock falls are common. Environmental concerns, tourism, and economic activities overlap the project area, which increased the complexity of the decision-making process. QRA was adopted to improve highway user safety and minimize effects on natural, social, and economic environments. Uncertainty was associated with hazard and consequence quantification, and the study elicited plausible ranges of input variables for risk calculation. Expected and range in risk were calculated for current conditions and after mitigation. Individual risk to highway users was found to be low, following the limited exposure of any particular individual. Current total risk was calculated at 2.9 × 10−4probability of fatality and a plausible range between 2.0 × 10−5and 5.5 × 10−3. The slope protection configuration selected had a residual total risk between 9.0 × 10−4and 2.9 × 10−6, and a best estimate of 4.5 × 10−5. The risk levels were evaluated against criteria previously used in Canada and were considered an appropriate balance between project costs, public safety, environmental concerns, tourism, and economic activities after mitigation.


Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 189
Author(s):  
Hee Jin Kim ◽  
Kyeong Min Jang ◽  
In Seok Yeo ◽  
Hwa Young Oh ◽  
Sun Il Kang ◽  
...  

Wind direction and speed are the most important factors that determine the degree of damage caused by a jet fire. In this study, the metal hose used to extract/supply fuel was identified as the component with the highest risk for a jet fire occurring at an aerospace facility. A risk assessment was performed to evaluate the individual risk of a jet fire from the metal hose according to the wind direction and speed. HSE failure data was applied for calculating the jet fire probability including metal hose failure, ignition frequency, and jet fire frequency. Which was 3.0 × 10−4. The individual risk of different fatality probabilities was calculated according to the wind rose data for the aerospace facility. The individual risk from jet fire in the aerospace facility was calculated with a maximum risk of 3.35 × 10−5 and a minimum risk of 1.49 × 10−6. The individual risk satisfied HSE ALARP criteria. In addition, firewalls, extinguishing systems, and an emergency shut off system were enhanced, and it was thought that the risk from jet fire could satisfy acceptable criteria.


2021 ◽  
Author(s):  
Luca Decarli ◽  
Anna Crivellari ◽  
Laura La Rosa ◽  
Enrico Zio ◽  
Francesco Di Maio ◽  
...  

Abstract For the design and operation of Oil and Gas (O&G) facilities, a Quantitative Risk Assessment (QRA) should be performed to quantify the risk of major accidents due to multiple hazards and sources at the plant level, thus allowing the effective identification and allocation of safety barriers. In this work, a novel approach for the multi-hazard and multi-source aggregation of risks is proposed, accounting for the uncertainties typically unexpressed in a conventional QRA (both on the frequency and severity of the accidental scenarios). The multi-hazard risk assessment framework proposed is applied to assess the Location-Specific Individual Risk (LSIR) for a representative Upstream O&G plant (case study), using a model based on multistate Bayesian Networks (BNs) for different functional units, each one undergoing an initiating event of Loss Of Primary Containment (LOPC). Estimates of frequency and severity for each possible accident scenario are aggregated to eventually calculate the overall LSIR. Moreover, LSIR's confidence intervals are provided to describe the uncertainty associated to the estimates, and the frequency and severity contributions to risk are derived for targeted prioritization of the safety barriers in view of the risk reduction.


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