Consistency Checking of the IEC 61508 PFH Formulas and New Formulas Proposal Based on the Markovian Approach

Omeiri, Hanane; Innal, Fares; Liu, Yiliu

doi:10.18280/jesa.540609

Cited by 2 publications

(2 citation statements)

References 9 publications

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“…To perform these calculations, IEC 61508 provides simplified analytical formulas that are valid under some assumptions [14]. Furthermore, several simplified formulas can be found in the literature [15][16][17]. It should be noted that conventional quantitative methods, such as the fault tree analysis and Markov chains [18], are more suitable due to their wide range of validity.…”

Section: Real Safety Integrity Level Of the Sis (Real Sil)mentioning

confidence: 99%

Evaluation of Safety Instrumented System in a Natural Gas Facility According to IEC 61508 Standard

Boudjoghra,

Innal

2023

IJSSE

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The work presented was aimed primarily at contributing to the control of risks relating to an industrial installation by means of a safety instrumented system (SIS), through a global approach defined by the IEC 61508 standard which goes from risk analysis to the evaluation of SIS. The IEC 61508 approach consists of industrial risk analysis which is a process used to identify the risks inherent in an industrial system and estimate the levels of these risks using several methods, tools and software. Then, the reduction of risks deemed unacceptable in the risk analysis phase to an acceptable level using SIS. The extent of the reduction to be achieved determines the level of performance that the SIS must have to achieve this reduction assigned to it (required SIL). The real performance of SIS (real SIL) must meet the corresponding requirements. Otherwise, technical modifications must be made to the SIS. The application of the IEC 61508 approach addresses the risk analysis of butane product overflow stored in a tank and the verification of the ability of an SIS installed at this tank to control this risk. And if necessary, propose technical modifications to optimize the performance of the SIS. Risk analysis conducted using the HAZOP (HAZard and OPerability) method to identify critical accident scenarios, PHAST (Process Hazard Analysis Software Tool) software and risk matrix to estimate risk level of a given accident. Verification of the ability of an SIS installed at the tank to control the risk deemed unacceptable in the risk analysis phase is carried out by The LOPA (Layer Of Protection Analysis) method for the allocation of the required SIL for the SIS and SIL module of the GRIF (GRaphical Interface for reliability Forecasting) software to calculated real SIL of SIS. Depending on the results obtained (required SIL > real SIL), recommendations likely to strengthen the reliability of SIS are proposed (modification of the test policy and the architecture of the constituent elements of the SIS) in order to achieve the required SIL. And thus secure our system.

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Section: Real Safety Integrity Level Of the Sis (Real Sil)mentioning

confidence: 99%

Evaluation of Safety Instrumented System in a Natural Gas Facility According to IEC 61508 Standard

Boudjoghra,

Innal

2023

IJSSE

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“…In [14]- [16], the authors propose Markov chain to represent the unavailability of redundant SIS while excluding the consideration of common cause failures. In [17], [18], the authors suggest to review the IEC 61508 PFH formulas and introduce new ones based on the Markovian approach. The 2oo3 model used in this approach does not illustrate the different states that the system can take.…”

Section: Introductionmentioning

confidence: 99%

Development and evaluation of a 2oo3 safety controller in FPGA using fault tree analysis and Markov models

Nadir,

Bsiss,

Amami

2024

IJECE

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The Safety integrity level (SIL) is a measure of the reliability and availability of a safety instrumented system. SIL determination involves qualitative and quantitative analysis based on international standards such as IEC 61508 and IEC 61511. Several techniques can be used to analyze safety instrumented systems, including reliability block diagrams, fault tree analysis, and Markov models. The aim of this paper is to design and evaluate a pressure control system for a compressed nitrogen tank using a PID controller implemented in a field programmable gate array with 2 out of 3 architecture. This architecture ensures the safety of measurements and command of the system through a voting arrangement. The availability of the system is determined by the redundancy and the one hardware failure tolerance. The quantitative analysis is performed by calculating the probability of failure on demand per hour using Markov models or a relevant probabilistic approach based on fault tree analysis. The Markov model method gives the probability of failure of the system in different states during the system life cycle. The fault tree analysis method determines the probability of failure of the system using its equivalent failure rate. Furthermore, this paper compares the SIL result obtained by each model.

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Consistency Checking of the IEC 61508 PFH Formulas and New Formulas Proposal Based on the Markovian Approach

Cited by 2 publications

References 9 publications

Evaluation of Safety Instrumented System in a Natural Gas Facility According to IEC 61508 Standard

Evaluation of Safety Instrumented System in a Natural Gas Facility According to IEC 61508 Standard

Development and evaluation of a 2oo3 safety controller in FPGA using fault tree analysis and Markov models

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