Safety instrumented systems are used to reduce the risk of major accidents in the process industr... more Safety instrumented systems are used to reduce the risk of major accidents in the process industry. To claim a certain risk reduction from such systems, it is necessary to perform reliability analyses, within internationally accepted frameworks, such as the IEC 61511. The main factors that influence the reliability are the failure rates of the components, the level of redundancy of hardware and software, and the frequency of periodic functional tests. The need for regular periodic functional testing has always been a challenge for the industry, as the tests often mandate a shorter or longer stop of the production. For those safety instrumented systems that must respond to rather frequent demands, the industry has started to ask if it is possible to replace functional testing with thorough inspection after demands, and how information from responses to demands and the following inspection may be credited in the reliability analyses. In this paper, the authors discuss the main charact...
Journal of Loss Prevention in the Process Industries, 2015
ABSTRACT Accident investigations indicate that inadequate barrier management has been a main caus... more ABSTRACT Accident investigations indicate that inadequate barrier management has been a main cause of many accidents in the process industry. In 2013, the Norwegian Petroleum Safety Authority issued a barrier management framework for the offshore oil and gas industry. The framework describes principles related to barrier management and may be a valuable guide for the entire process industry. However, the offshore industry faces several challenges when implementing the framework. This paper discusses these challenges and clarifies the central concepts and steps of barrier management. A key message is the need for clarity and integration in a systematic approach to risk and barrier management.
2012 IEEE International Conference on Industrial Engineering and Engineering Management, 2012
ABSTRACT Safety-instrumented systems (SISs) are often crucial in the prevention of accidents. In ... more ABSTRACT Safety-instrumented systems (SISs) are often crucial in the prevention of accidents. In this study, several reliability assessment methods, including the approximation formulas in IEC 61508 and in the PDS handbook, and Markov and Petri net methods, are used to determine the reliability of a redundant SIS configuration with three parallel channels. The average probability of failure on demand (PFDavg) is used as reliability measure, and common cause failures and proof tests are considered in the modeling. The results obtained by the different methods are compared, and characteristics of these methods in SIS reliability analysis are discussed.
2012 IEEE International Conference on Industrial Engineering and Engineering Management, 2012
ABSTRACT This paper gives an overview of common risk metrics, maps them into a decision context, ... more ABSTRACT This paper gives an overview of common risk metrics, maps them into a decision context, and suggests a set of evaluation criteria. The motivation is that risk analysis is carried out to inform decision-making, and that the content and perceived legitimacy of information from a risk analysis hinge on the metrics that are used to express the results. A tabular overview of the most common metrics for harm to people, assets, and the environment is given, with emphasis on clarifying their meaning, pros and cons. The metrics are linked to different decision contexts and stakeholder needs, and eleven criteria are established to aid in the choice thereof. Principal issues concerning the adequacy of single as well as sets of risk metrics are finally raised and make the basis for further work.
ABSTRACT Reliability centred maintenance (RCM) is a method for maintenance planning that was deve... more ABSTRACT Reliability centred maintenance (RCM) is a method for maintenance planning that was developed within the aircraft industry and later adapted to several other industries and military branches. A high number of standards and guidelines have been issued where the RCM methodology is tailored to different application areas, e.g., IEC 60300-3-11, MIL-STD-217, NAVAIR 00-25-403 (NAVAIR 2005), SAE JA 1012 (SAE 2002), USACERL TR 99/41 (USACERL 1999), ABS (2003, 2004), NASA (2000) and DEF-STD 02-45 (DEF 2000). On a generic level, IEC 60300-3-11 (IEC 1999) defines RCM as a “systematic approach for identifying effective and efficient preventive maintenance tasks for items in accordance with a specific set of procedures and for establishing intervals between maintenance tasks.” A major advantage of the RCM analysis process is a structured, and traceable approach to determine the optimal type of preventive maintenance (PM). This is achieved through a detailed analysis of failure modes and failure causes. Although the main objective of RCM is to determine the preventive maintenance, the results from the analysis may also be used in relation to corrective maintenance strategies, spare part optimization, and logistic consideration. In addition, RCM also has an important role in overall system safety management.
Safety instrumented systems are used to reduce the risk of major accidents in the process industr... more Safety instrumented systems are used to reduce the risk of major accidents in the process industry. To claim a certain risk reduction from such systems, it is necessary to perform reliability analyses, within internationally accepted frameworks, such as the IEC 61511. The main factors that influence the reliability are the failure rates of the components, the level of redundancy of hardware and software, and the frequency of periodic functional tests. The need for regular periodic functional testing has always been a challenge for the industry, as the tests often mandate a shorter or longer stop of the production. For those safety instrumented systems that must respond to rather frequent demands, the industry has started to ask if it is possible to replace functional testing with thorough inspection after demands, and how information from responses to demands and the following inspection may be credited in the reliability analyses. In this paper, the authors discuss the main charact...
Journal of Loss Prevention in the Process Industries, 2015
ABSTRACT Accident investigations indicate that inadequate barrier management has been a main caus... more ABSTRACT Accident investigations indicate that inadequate barrier management has been a main cause of many accidents in the process industry. In 2013, the Norwegian Petroleum Safety Authority issued a barrier management framework for the offshore oil and gas industry. The framework describes principles related to barrier management and may be a valuable guide for the entire process industry. However, the offshore industry faces several challenges when implementing the framework. This paper discusses these challenges and clarifies the central concepts and steps of barrier management. A key message is the need for clarity and integration in a systematic approach to risk and barrier management.
2012 IEEE International Conference on Industrial Engineering and Engineering Management, 2012
ABSTRACT Safety-instrumented systems (SISs) are often crucial in the prevention of accidents. In ... more ABSTRACT Safety-instrumented systems (SISs) are often crucial in the prevention of accidents. In this study, several reliability assessment methods, including the approximation formulas in IEC 61508 and in the PDS handbook, and Markov and Petri net methods, are used to determine the reliability of a redundant SIS configuration with three parallel channels. The average probability of failure on demand (PFDavg) is used as reliability measure, and common cause failures and proof tests are considered in the modeling. The results obtained by the different methods are compared, and characteristics of these methods in SIS reliability analysis are discussed.
2012 IEEE International Conference on Industrial Engineering and Engineering Management, 2012
ABSTRACT This paper gives an overview of common risk metrics, maps them into a decision context, ... more ABSTRACT This paper gives an overview of common risk metrics, maps them into a decision context, and suggests a set of evaluation criteria. The motivation is that risk analysis is carried out to inform decision-making, and that the content and perceived legitimacy of information from a risk analysis hinge on the metrics that are used to express the results. A tabular overview of the most common metrics for harm to people, assets, and the environment is given, with emphasis on clarifying their meaning, pros and cons. The metrics are linked to different decision contexts and stakeholder needs, and eleven criteria are established to aid in the choice thereof. Principal issues concerning the adequacy of single as well as sets of risk metrics are finally raised and make the basis for further work.
ABSTRACT Reliability centred maintenance (RCM) is a method for maintenance planning that was deve... more ABSTRACT Reliability centred maintenance (RCM) is a method for maintenance planning that was developed within the aircraft industry and later adapted to several other industries and military branches. A high number of standards and guidelines have been issued where the RCM methodology is tailored to different application areas, e.g., IEC 60300-3-11, MIL-STD-217, NAVAIR 00-25-403 (NAVAIR 2005), SAE JA 1012 (SAE 2002), USACERL TR 99/41 (USACERL 1999), ABS (2003, 2004), NASA (2000) and DEF-STD 02-45 (DEF 2000). On a generic level, IEC 60300-3-11 (IEC 1999) defines RCM as a “systematic approach for identifying effective and efficient preventive maintenance tasks for items in accordance with a specific set of procedures and for establishing intervals between maintenance tasks.” A major advantage of the RCM analysis process is a structured, and traceable approach to determine the optimal type of preventive maintenance (PM). This is achieved through a detailed analysis of failure modes and failure causes. Although the main objective of RCM is to determine the preventive maintenance, the results from the analysis may also be used in relation to corrective maintenance strategies, spare part optimization, and logistic consideration. In addition, RCM also has an important role in overall system safety management.
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Papers by Marvin Rausand