JPSRA 2011 Volume 2, Number 3
Kołowrocki Krzysztof, Soszyńska-Budny Joanna
Current problems of technical systems reliability and safety Aktualne zagadnienia niezawodności i bezpieczeństwa systemów technicznych
Integrated Safety and Reliability Decision Support System - IS&RDSS is presented in the form of detailed and clear scheme-algorithm. There is also presented the methodology of IS&RDSS that is composed of the methods of complex technical systems operation processes modelling, their unknown parameters concerning operation, reliability, availability, safety models identification, their reliability, availability and safety evaluation and prediction, their reliability, availability and safety improvement and their operation, reliability, availability, safety and cost optimization. The newest trends in the reliability and safety of complex technical systems analysis directed to the critical infrastructures and the nanosystems are describe as well.[full text]
Kosmowski Kazimierz T.
Risk analysis and functional safety management Analiza ryzyka i zarządzanie bezpieczeństwem funkcjonalnym
This article addresses current issues concerning the risk analysis and functional safety management. Some cost-benefit analysis methods (CBA) are presented oriented on optimizing the safety-related solutions on example of functional safety technologies reducing risk based on programmable systems E/E/PE (PN-EN 61508) and SIS (PN-EN 61511). The importance of safety-related criteria, such as tolerability of risk (TOR) in the context of cost-benefit analysis (CBA), is emphasized to reach rational decisions as regards safetyrelated solutions to be sufficiently reliable, safe and preferably economically justified. [full text]
Dźwiarek Marek, Hryniewicz Olgierd
Frequency of periodical inspections of safety-related control systems of machinery – practical recommendations for determining methods
In preventing the accidents due to improper operation of the control systems the periodical inspection of their functioning is of crucial importance. Therefore, the control system designer should specify how often the system should undergo the periodical inspection. The paper presents some recommendations for the determination of periodical inspection frequency of safety related control systems in machinery. The recommendations are based on simple and easy to use mathematical models which have been developed by adaptation and simplification of models used for the determination of maintenance policies of complex systems. Practical implementation of the proposed recommendation is illustrated on some actual case studies. [full text]
Śmierzchalski Roman, Kolendo Piotr
Computerized control and protection systems in technical objects and installations
The article presents some safety-related problems of the computer control systems and overall automation. The development of automation and information technology in recent years has forced to develop a number of new technologies and solutions for advanced process control and other technical installations. It seeks for automation of complex technical installations, conceived as means of controlling all subsystems and devices automatically, without human intervention. However, if we consider the economic aspects, the maintenancefree concept is not justified. The partial automation of selected systems is also of interest. This work considers some general aspects of control system design with emphasis on safety aspects. As an example of the protection system, the installation of diesel engine oil lubrication is presented. [full text]
Barnert Tomasz
Determining required safety integrity level
One of the most important stage of technical system functional safety analysis is defining the safety-related functions as well as determining a safety integrity level (SIL) for each defined function. A properly carried out hazard identification process is the necessary condition for correct definition of the safety-related functions. Determining the safety integrity level (SIL) is based on risk assessment taking into account risk acceptance criteria. It guarantees accurate results which means that the risk associated with technical system is under good control and the risk level can be reduced to acceptable one. There are several safety integrity level determination methods and techniques described in normative documents and many papers. This article is aimed at presentation of some of them and in addition a new approache are outlined. [full text]
Porzeziński Michał
Software quality and reliability management in safety-related systems
This article is concerned with the methods of ensuring the required quality and reliability of software in safetyrelated systems. The basic types of software reliability models and their specific properties are presented. The principles of managing the process of software development, based on the "Model V" life cycle, with particular emphasis on the role of inspection and testing processes are discussed. Also the methodology of quality management and reliability of the software recommended by the PN-EN 61508-3 are outlined. At the end the concept of application to support the process of assessing the quality and integrity of the safety-related software is described. [full text]
Kosmowski Kazimierz T.
Human factors and functional safety analysis
In this article some issues concerning the safety management in computerized complex hazardous plant are presented in the context of human factors. It has been shown that the risk of losses can be significantly reduced using appropriate technical solutions in the form of a layer protection system, which includes a basic process control system, human-operator and protection automatics. The significance of appropriate designing of interfaces including functions of the alarm system is emphasized. It will contribute to reducing the humanoperator error probability. The functional safety management, which includes the risk control in a life cycle of complex plant, should be carried out in relation to requirements associated with possible avoiding of software systematic failures in programmable systems and reducing the frequency of hardware random failures. [full text]
Zawalich Jacek
Determining diagnostic coverage of elements and analysis of subsystems’ architectural constraints
Performing a safety related function by E/E/PE system requires proper operation of its subsystems. Its structure has to guarantee effective and fast detection of failure. The estimation of average probability of dangerous failure on demand (PFDavg) requires the knowledge concerning the value of diagnostic coverage (DC) for all elements and/or subsystems. It is preferable when subsystems are of type A. In such case the failure modes of all components and their behavior in case of some faults are well defined. This is the reason why the design of safety-related systems should use the devices adapted to execution of diagnostic tests to detect majority of failures that lead to serious consequences. In the article some theoretical and practical aspects of determining diagnostic coverage are outlined. [full text]
Śliwiński Marcin
Integrity level verification for safety-related functions
This article describes methods for the safety integrity level (SIL) verification of safety-related functions with regard to probabilistic criteria given in international standards IEC 61508 and IEC 61511. These functions are realized using the electrical, electronic and programmable electronic (E/E/PE) systems or safety instrumented systems (SIS). Some methods are proposed for quantitative probabilistic modelling taking into account potential dependent failures in redundant systems with diverse channels within subsystems. The analyses of safety-related systems include testing and maintenance planning of subsystems, in particular the sensors and actuators with regard to the probabilistic criteria defined for given SIL. The methods are illustrated on some examples of systems from industrial hazardous plants.[full text]
Kacprzak Przemysław
Layer of protection analysis in industrial hazadous installations
In this article the Layer of Protection Analysis (LOPA), as a technique for the risk evaluation relating to the hazardous industrial installations performance, is presented. The results of analyses are important in the terms of the safety management process in such installations. Based on obtained estimations the decisions might be undertaken which solutions to apply in order to mitigate the risk of hazardous installations performance to a tolerable level. The risk mitigation is provided by properly designed layers of protection, particularly the alarm system, treated as a part of protection layer. The alarm system should be designed and implemented with comprehensive consideration of the human factors. The role of the operator in hazardous installations is crucial mainly during abnormal and alarm situations in order to provide and/or recover system to normal or safety state. In the article some selected aspects of alarm systems designing process with special treating of human operator are outlined. Moreover, an example of the LOPA analysis for the accident sequence within a reaction container with consideration of human reliability analysis (HRA ) is carried out. [full text]
Barnert Tomasz, Kacprzak Przemysław, Kosmowski Kazimierz, Kozyra Maciej, Porzeziński Michał, Śliwiński Marcin, Zawalich Jacek
ProSIL software for computer aided functional safety management
In this article a prototype ProSIL software system for computer-aided functional safety management is discribed. The software consists of three modules for: determination of the required SIL level (ProSILen), veryfication of the SIL level (ProSILver), and layer of protection analysis (ProSIL/LOPA). In ProSIL the methods concerning functional safety analysis in the process of the design and operation of Safety Instrumented Systems (SIS) are implemented according to PN-EN 61508 and PN-EN 61511 standards, and some new methods, e.g. the calibrated risk graph method for determining required safety integrity level (SIL) based on the risk assessment. Moreover, methods of veryfying the SIL level of SIS. The Layer of Protection Analysis (LOPA) method with regard to Human Reliability Analysis (HRA) are also included in the software. [full text]
Cieślakiewicz Waldemar
Process modelling and simulation in industrial systems using FLOWNEX SE software
The recent focus on reliability and safety of industrial systems has raised the need for system simulations and analysis. The intrinsic capabilities of modern computational software development have made it possible to predict trends in various system operations more exactly. The present simulation methodology also allows for the analysis of non-measurable numbers, like the Reynolds Number (Re), which hasn’t been taken so often into consideration during past analyses. The main purpose of this article is to overview the system simulation methodology, focusing primarily on System Computer Fluid Dynamic (SCFD) method as the most effective approach to simulate the flow-thermal networks. This article makes use of system simulation models, which depict real industry problems. [full text]
Rogala Ireneusz
Safety management in installations with explosion hazardous areas
The article presents the current state of knowledge on explosion protection based on ATEX EC Directives, as well as the processes occurring in Polish industry, which refer to the issue considered. The activities of different subjects operating on the Polish market exert diverse influences on the way of implementing the minimal level of ATEX requirements as well as on optimizing investments in the safety measures. On the basis of experience gained by the ASE company on Polish industrial market in the field of explosion protection equipment the design and delivery as well as experience in carrying out training programs, providing consulting services and expertise, it is possible to propose a comprehensive set of measures aiming at achieving a permanent state of the acceptable level of explosion protection. [full text]
Gołębiewski Dariusz
Risk assessment of industrial plants’ operation for insurance purposes
The process of comprehensive insurance of technical objects/plants requires a deep knowledge of the insurer as regards the hazards and risk factors. Therefore, any insurance company uses a methodology of risk assessment before undertaking the insuring decisions. The object/plant specific factors cause that each case should analyzed and assessed individually and appropriate insurance conditions should be offered. The article presents some fundamental parts of the risk assessment methodology of objects/plants for insurance purposes. [full text]
Wojas Marta, Kosmowski Kazimierz T., Kościelny Jan M.
Certification system of persons responsible for functional safety
This article describes a certification system of persons responsible for functional safety developed by the Office of Technical Inspection (UDT-CERT) in Poland in cooperation with members of the Programme Committee No. 8 and representatives of two technical universities: in Gdansk and Warsaw. The system is consistent with standard ISO/IEC 17024 concerning the conformity assessment, and includes requirements of EN 61508 and some sector standards. The certification and training programs include two levels of qualification: I – general and II – expert, and four specializations in functional safety: A – hardware and software, B – process industry, C – machinery, and D – nuclear power plants. [full text]