Realization phase safety

The lEC 61508 safety lifecycle prescribes that planning for all maintenance testing and maintenance activities must be accomplished in the realization phase. To a certain extent this work can proceed in parallel with safety instrumented system design. This lifecycle diagram also shows that operation and maintenance responsibilities focus on periodic testing and inspection as well as management of modifications, retrofits, and eventual decommissioning. 

Figure 1-8. Detailed Realization Phase of the Safety Lifecycle...

Figure 11 - Application software safety life cycle (in realization phase)...

E/E/PE system safety life cycle realization phase. 

Software safety life cycle in process industries. (A) Software in realization phase (B) safety life cycle relation between software and safety instrumented system. 

Note the stages of the lEC model. The first 4 phases are concerned with design, then the realization phase is reached. This term describes in very general terms the job of actually building the safety system and implementing any software that it contains. 

Large sections of lEC 61508 are concerned with the details of the realization phase and there are whole life cycle models for the activities contained within this stage. Some sections of the lEC standard are dedicated to these specialized tasks. Bear in mind that some of the deeper parts of this standard will be applicable to manufacturers of certified safety PLCs and their associated software packages. A process engineering project would not be expected to dive into such depths. 

The SIS safety requirements specification should be developed in association with the non-SIS protection layers. The lEC 61508 standard calls for the overall safety requirement to be defined first in phase 4 followed by an allocation phase 5, which defines the sharing of protection duties across the layers of protection. The final SRS for the safety-instrumented system is then part of the detail design activities for the SIS known in lEC terms as the realization phase (phase 9). This procedure can be rather confusing at first but it appears to be designed to ensure that the basics of the SRS are in place and verified before the design team goes too far with the technical specifications for the SIS. 

The safety lifecycle from the ANS1/1SA84.00.01-2004 (lEC 61511 Mod) standard is shown in Figure 1-5. Although the drawing looks quite different from Figure 1-4, the fundamental requirements are much the same. Again, there are clear analysis, realization, and operation phases. 

The standards [l]-[3] concern the entire life cycle of a plant ( safety life cycle ), i.e. all activities required for realizing safety functions during a period which begins with the concept phase of a project and ends when aU safety functions are no longer available for use. In addition to quantitative requirements the standards contain numerous qualitative requirements, which are not discussed here. However, it must be borne in mind that fulfilling the qualitative requirements does not automatically lead to the quantitative requirements being fidfilled. 

The required SIL designates the methods and measures that have to be executed during the overall safety lifecycle phases. The SIL is a probabilistic quantitative concept. If certain techniques and measures are applied one expects on average that a certain reliability of the safety functions is realized. Besides statistic and systematic hardware errors this concept also takes systematic software failures into account. 

Such an assessment may in fact affect the management of the project and the entire quality system required for the design assessment and the construction phase, by ensuring that the design assumptions in terms of global plant safety are realized in the design. 

Attributes of Required Port and Provided Port realize the interface of a function. The ASIL is inherited from the function to the ports, realizing the communication of safety relevant information. If a function fulfills safety requirements with different ASILs, all ports of the function get the highest ASIL unless criteria the for coexistence is applicable. Regarding the development of the FN in the phases of EEA modeling, this concerns more compositions (systems of functions) than functions. Functions are atomic elements from the EEA point of view. Compositions outline the demanded functionalities and can be detailed during the EEA modeling, which is strongly correlated to the explained scenario. 

The students will be given topics/themes related to the subject they have to explore an interesting problem of their choice in the context of the course. Projects can be done individually or in teams of two/three students. The students will be given various themes related to automotive electronics like the realization of control algorithms required for specific automotive applications using MATLAB/Simulink and the implementation of communication protocols automotive sensors emission control systems safety, security, and driver assistance systems etc. The activity involves different phases like the following ... 

A nuclear power plant embarking on an EOF project will need significant utility support during all phases of the EOF s development and implementation. The utility s support role is crucial because an EOF project is labour intensive, requires specialists and financial support and lasts for a number of years. Management should be fully committed to and supportive of EOF development and implementation because of the increase in operational safety that can be realized. 

The conceptual design of the advanced reactor plant BN-1600 was completed in 1992, in full compliance with the up-to-date requirements for safety and economic efficiency of the new generation NPPs. It is expected that this design can be realized in Russian Federation not earlier than 2020, taking into account the fact that in the near future the fast reactor development programme in this country will be primarily focused on construction of the pilot BN-800 reactors, and creation of the closed nuclear fuel cycle production plants. This phase is of exceptional importance for the subsequent development of fast reactors and should precede their wide incorporation into the nuclear power park. 

Realization (requirements) phase for E/E/PEs (HW others ), safety related system Yes Yes ... 

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