An Optimal Design Procedure based on the Safety Integrity Level for Safety-related Systems

( Sung Kyu Kim ),( Yong Soo Kim ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.12

Safety-related systems (SRSs) has widely used in shipbuilding and power generation to prevent fatal accidents and to protect life and property. Thus, SRS performance is a high priority. The safety integrity level (SIL) is the relative performance level of an SRS with regard to its ability to operate reliably in a safe manner. In this article, we proposed an optimal design procedure to achieve the targeted SIL of SRSs. In addition, a more efficient failure mode and effects diagnostic analysis (FMEDA) process and optimization model were developed to improve cost efficiency. Based on previous IEC 61508 diagnostic analyses that revealed unnecessary costs associated with excessive reliability, the new approach consists of two phases: (i) SIL evaluation by FMEDA, and (ii) solution optimization for achieving the target SIL with minimal cost using integer-programming models. The proposed procedure meets the required safety level and minimizes system costs. A case study involving a gas-detection SRS was conducted to demonstrate the effectiveness of the new procedure.

Safety integrity level (SIL) determination for a maritime fuel cell system as electric propulsion in accordance with IEC 61511

Ahn, Junkeon,Noh, Yeelyong,Joung, Taehwan,Lim, Youngsub,Kim, Juneyoung,Seo, Youngkyun,Chang, Daejun Elsevier 2019 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.44 No.5

<P><B>Abstract</B></P> <P>This study investigates the safety integrity levels for an electric propulsion system based on a molten carbonate fuel cell in a liquefied hydrogen tanker. The electric propulsion system necessitates multiple electronic and electric elements; thus, the functional safety of the system should be considered. Additionally, a maritime fuel cell system is nonconventional propulsion machinery. This system should follow a risk-based ship design framework, and IEC 61511 is a suitable standard for evaluating the functional safety of the system. Hazardous operability studies provide basic information for determining the safety integrity. In this work, a safety layer matrix and calibrated risk graph are generated, and a layer of protection analysis is conducted for a molten carbonate fuel cell stack. Eight guidewords are used to describe accidental scenarios and compare the results of the three methods in an unbiased manner. The most severe consequences are fire and explosion caused by overflows or a control failure in the stack, and the safety integrity levels are mutually different.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A maritime fuel cell system consumes the boil-off hydrogen gas in a LH<SUB>2</SUB> tanker. </LI> <LI> The functional safety of a fuel cell should be considered as SIL. </LI> <LI> HAZOP is the proper technique to address potential hazards in fuel cell stack. </LI> <LI> Even for identical risks, three SIL methods produce different results. </LI> <LI> IEC 61511 is useful for determining the SILs for a maritime fuel cell system. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

기능 안전(Functional Safety) 관련 국제 표준에 대한 연구

김병철(Kim Byung Chul) 표준인증안전학회 2014 표준인증안전학회지 Vol.4 No.1

Recently, complexity and interaction of electrical, electronic and programmable electronic (E/E/PE) systems increase, a growing emphasis has been placed on the concept of functional safety during product development. IEC 61508 is called a mother standard for functional safety that provides guidelines and standardized procedures in the development of reliable and dependable E/E/PE systems to assure functional safety. Determining risk classes (i.e., SILs(Safety Integrity Level) or ASILs(Automotive Safety Integrity Level)) associated to a specific E/E/PE item may be recognized as one of the most crucial activities in the product development per IEC 61508, ISO 26262, ISO 13839, ISO 15998 or IEC 61511 etc., since SILs or ASILs are used to specify necessary safety requirements for achieving an acceptable residual risk. This paper is focused on introduction the international standards for functional safety which are based on IEC 61508 and ISO 26262.

Risk Graph에 의해 할당된 SIL에 따른 철도 승강장 도어 시스템의 정량적 Risk 저감 모델

송기태 ( Ki Tae Song ),이성일 ( Sung Ill Lee ) 한국안전학회(구 한국산업안전학회) 2016 한국안전학회지 Vol.31 No.5

There exists required safety integrity level (SIL) to assure safety in accordance with international standards for every electrical / electronics / control equipment or systems with safety related functions. The SIL is allocated from lowest level (level 0) to highest level (level 4). In order to guarantee certain safety level that is internationally acceptable, application of methodology for SIL allocation and demonstration based on related international standards is required. Especially, in case of the SIL allocation method without determining of quantitative tolerable risk, the additional review is needed to check whether it is suitable or not is required. In this study, the quantitative risk reduction model based on the safety integrity allocation results of railway platform screen door system using Risk Graph method has been examined in order to review the suitability of quantitative risk reduction according to allocated safety integrity level.

기능안전을 위한 IEC 61508의 안전수명주기에 관한 연구

김성규(Sung Kyu Kim),김용수(Yong Soo Kim) 한국신뢰성학회 2014 신뢰성응용연구 Vol.14 No.1

The IEC 61508 standard was established to specify the functional safety of E/E/PE safety-related systems. Safety life cycle to provide the framework and direction for the application of IEC 61508 is included in this standard. In this paper, we describe overviews, objects, scopes, requirements and activities of each phase in safety life cycle. In addition, we introduce safety integrity level(SIL) which is used for verifying the safety integrity requirements of E/E/PE system and perform a case study to estimate hardware SIL by FMEDA. The SIL is evaluated by two criteria. One of them is the architectural constraints which restrict the maximum SIL by combination of SFF and HFT. The other is the probability of failure which is classified into PFD and PFH based on frequency of demand and calculated by safe or dangerous failure rates.

유사장치의 건전성데이터 분석을 통한 수소충전소 기능안전 추론방안

오봉식(Bong S. Oh),박상철(Sang C. Park),장중순(Joong S. Jang) 한국신뢰성학회 2021 신뢰성응용연구 Vol.21 No.4

Purpose: There has been a substantive expansion of FCEV in the hydrogen economy. According to the government’s policy, the installation and operation of HRSs (Hydrogen Refueling Station) are expected to be carried out rapidly. However, the types of failures among the major devices of HRS such as compressors, coolers, and dispensers, and technologies related to the safety and reliability of data are not well disclosed. In the case of foreign (Germany, France, etc.) products of HRS in Korea, it is not easy to access technology, and to reduce risks in operating HRS, it is necessary to solve the problem in this area. Methods: HRSs are required to have the highest level of safety and reliability, but due to certain terms and conditions among suppliers, the main characteristics of the technology are not openly available. Based on the analysis done, in this paper we suggest improvement plans to curb the problems mentioned above. Results: PHM(Prognostics and Health Management) through failure type analysis of similar devices and safety-based real-time risk severity rating of HRS through technology that collects, analyzes, and evaluates and judges functional safety real-time safety risk data based on operational data are extremely important. A monitoring technique was presented to collect results through the methods mentioned above. Conclusion: In order to secure safety for safety-based risk reduction for an HRS’s operation, site selection for an HRS that meets functional safety and construction requirements is needed. It is also important that the required technology selected for this purpose, presented by the HRS standard, be applied to design. In addition, post-maintenance technology that can sustain risk reduction is also required.

ISO26262 기능안전 대응 HILS 시스템을 이용한 자동차 E/E 부품의 소프트웨어 V&V 방안 연구

김선희(Kim Sun-Hee) 표준인증안전학회 2014 표준인증안전학회지 Vol.4 No.2

Electric and electronic parts have been increasing in the automotive industry and developing as a single or an integrated one. In addition, all the control modules are connected to the communication line and the functional error is likely to occur due to its complexity increased further. In this regard, the safety is well defined in detail on IS026262 functional standard declared as ISO standard in order to ensure the functional safety of electric and electronic system. The standard analyzes the risk factors for all the functions related to electric and electronic parts, determines the risk level, and then defines ASIL rating(A-D). The standard classifies system level, hardware level, and software level at product development and describes process, development and validation for the functional safety which may occur in each level. The purpose of the standard is to minimize any unexpected accident due to functional errors in the vehicle. The verification method by HILS system, which is the previous step before testing electric and electronic parts on the vehicle, has the advantage of less risk and lower cost than actual vehicle test. This paper shows how to verify and validate the functional safety of software by HILS system which is much used in car manufacturers as a validation method.

Case Study on the Assessment of SIL Using FMEDA

김병철,김영진 대한산업공학회 2012 산업공학 Vol.25 No.4

As the number, complexity and interaction of electrical, electronic and programmable electronic (E/E/PE) systems increase, a growing emphasis has been placed on the concept of functional safety during product development. IEC 61508 provides guidelines and standardized procedures in the development of reliable and dependable E/E/PE systems to assure functional safety. Determining risk classes (i.e., safety integrity levels, SILs) associated to a specific E/E/PE item may be recognized as one of the most crucial activities in the product development per IEC 61508 since SILs are used to specify necessary safety requirements for achieving an acceptable residual risk. This article presents a case study on the assessment of SILs applying failure modes, effects and diagnostic analysis (FMEDA) from which failure rates may be derived for each important failure category by combining a standard FMEA with online diagnostic techniques.

Case Study on the Assessment of SIL Using FMEDA

Byung Chul Kim(김병철),Young Jin Kim(김영진) 대한산업공학회 2012 산업공학 Vol.25 No.4

As the number, complexity and interaction of electrical, electronic and programmable electronic (E/E/PE) systems increase, a growing emphasis has been placed on the concept of functional safety during product development. IEC 61508 provides guidelines and standardized procedures in the development of reliable and dependable E/E/PE systems to assure functional safety. Determining risk classes (i.e., safety integrity levels, SILs) associated to a specific E/E/PE item may be recognized as one of the most crucial activities in the product development per IEC 61508 since SILs are used to specify necessary safety requirements for achieving an acceptable residual risk. This article presents a case study on the assessment of SILs applying failure modes, effects and diagnostic analysis (FMEDA) from which failure rates may be derived for each important failure category by combining a standard FMEA with online diagnostic techniques.

철도제품 국제인증관련 정부 정책 및 인증획득 사례 분석을 통한 실효적 정책 개선안에 관한 제언

최요철,Choi, Yo Chul 한국시스템엔지니어링학회 2021 시스템엔지니어링학술지 Vol.17 No.2

Today, the market and customer requirements for safety-related products in the Railway industry are continuously increasing, and companies that supply these products continue to make related efforts. However, the international standard requirements for making safety-related products are high, so small and medium-sized business companies are having difficulty developing them due to problems in time and cost to achieve them. This study examined government-centered international certificate policies and cases and suggested improvement measures based on the research results. In addition to supporting international certification costs, the government needs to expand technical consulting and expert training for them to solve problems in obtaining an international certificate.