Functional safety methodology

The technical requirements of the lEC 61513 standard and the various phases of lEC 61508 were used as a framework for the project. Regarding specific aspects of functional safety, the various phases listed in the table below have been followed. 

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The detailed functional safety requirements specification should include all necessary functions during all modes of operation of the process being protected. Additionally, the periodic testing of all the safety instrumented functions should be provided. This typically requires the definition of maintenance override capabilities so the sensors and final elements can be tested without shutting down the process. The same methodology described in the paragraph above can be used to document these requirements. 

Bamert T., Kosmowski K.T., Sliwinski M. 2006. Methodological aspects of functional safety assessment. Radom Institute for Operation Technologies - National Research Institute ZEM, Vol. 4 (148) 150-176. 

Kosmowski K.T., Sliwinski M. 2005. Methodology for functional safety assessment. London Taylor Francis Group, European Safety Reliability Conference, ESREL 2005, Gdynia - Sopot - Gdansk. 

Systematic capability Each element or component carrying safety function and methodology. 

Safety, Health, and Environment Committees Safety Committee Functions, Responsibilities, and Authorities Permanent Safety Committees Ad Hoc and Temporary Safety Committees System Safety Program Hazard Identification and Risk Management System Safety Methodology... 

In order to translate ISO 26262 there are currently various standardization projects in progress in different countries worldwide. The aim is to translate ISO 26262, provide further guidelines and develop additional methodologies for functional safety based on ISO 26262. 

Functional safety is essentially the same as system safety and utilizes most of the same tools and techniques. Functional safety applies the SIL methodology to system design and development. Functional safety provides a major focus on safety instrumented systems (SISs). 

C icci, R. H. V., 1980, A Methodology for Evaluating the Probability for Fire Loss of Nuclear Power Plant Safety Functions, Ph.D. Thesis at Rensselaer Poly. Inst., Troy, NY. 

PLC-based systems are similar to solid-state systems. They nse the same field interface cards and have the same level of certification but the logic functions are performed by software. They are also easier to interface to other systems (via serial commnnications) in order to notify the system of a failnre. The PLC used is subject to rigorous source code (machine level) inspection and testing by an independent certification body (e.g., TUV in Europe) to examine the safety integrity of the code, inclnding all possible failure paths. The PLC system (application software and hardware) should be developed and tested using a formal, hfe-cycle methodology. ... 

Finally, the current available elaborated knowledge and the proposed test methodologies are suitable to serve for national or federal authorities and industry as a basis for safety evaluation, establishing criteria and guidelines for the appropriate functional barrier protection design of recycled plastics for food packaging. 

Phase IV studies can also take the form of retrospective pooled analyses which are designed to reflect the totality of clinical research experience with a new drug which is usually obtained via analysis of pooled clinical trial databases. Such data-mining efforts should not be considered inferior to data obtained from the conduct of an individual clinical trial. In fact, there are substantial benefits of such an approach, as the results of a given trial, especially if the end point is not prespecified to be primary because of power limitations, can be a function of chance. To assure that the results obtained from pooled analyses are not biased, a prespecified data analysis plan is often formulated as the first step, outlining the clear goals of the proposed analysis as well as its methodology. Key to this type of analysis is the definition of the outcome measure. Both efficacy and safety measures can be the focus of these types of analyses. 

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