Safety critical/related

Failure leading to injury or a more safety critical related problem with secondary back-up... 

To further complicate matters, there are significant advantages in ensuring that suspension design continues to be the domain of vehicle dynamicists. The use of domain specialists in the production of control systems means that safety-related software development techniques need to be readily accessible to non software specialists. The commonly proposed safety critical related techniques, such as formal methods, are undoubtedly required in this domain. However, they must be presented as part of an environment which is acceptable to the target user. The CBASS environment will therefore have usability as a prime requirement. 

Figure i provides a diagrammatic overview of the proposed development environment. This environment will aim to provide support for safety critical related technologies within a framework which is acceptable to the end user, specifically a vehicle dynamicist. This framework will combine advanced software development techniques and sophisticated vehicle test rig technology to provide users wdth an integrated, and hopefully seamless, development and test environment. 

Lead partner of the CBASS consortium is KBSL, a specialist software engineering company who have been involved in safety critical related technologies since formation in 1985. Further software expertise is being provided by Design in Computing, a software house specialising in industrial and control applications. 

The specific character of NDT related to the quality assessment of safety critical products and objects requires constant analysis and continuous improvement of processes and their interconnection. Sometimes interaction of processes is very complicated (Figure 3) therefore the processes have to be systematized and simplified when possible to realize total quality management in NDT. 

From an FMEA of the system design, a Severity Rating S) = 1 was allocated, relating to a safety critical failure in service. It is required to find the optimum unequal angle section size from the standard sizes available. It is assumed that the load is carried at the section s centre of gravity, G, and only stresses due to bending of the section are considered, that is, the torsional effects are minimal. The combined weight of the beam and tie rod are not to be taken into account. 

Unfortunately, the gap has not been spanned by these approaches. As far as I know, only JRC Ispra has once financed a project of EWICS TC7 (European Workshop on Industrial Computer Systems, TC7, Safety, Reliability and Security, an expert group in this area), on Study of the Applicability of ISO/IEC 17799 and the German Baseline Protection Manual to the needs of safety critical systems (March 2003)(www.ewics.org) (3), where the gaps between the security standards and the safety-related system evaluation requirements have been analyzed for several sectors (medical, railways, nuclear, electric power networks) and in general. 

It has been demonstrated, that mass deployment of networked, dependable embedded systems with critical control functions require a new, holistic system view on safety critical and security critical systems. Both communities have to interact, communicate and integrate at the end. A unified approach to address the safety AND security requirements of safety related systems is proposed, based on the functional safety standard IEC 61508 and IT-Security management standards, handbooks and guidelines. 

Critical Relates to major enviroiunental or safety risks. 

Further problems are the increased cost of additional safety measures related to the need to improve profit margins. Many users of HACCP systems define four levels of concern if there is a failure at a critical control point. These are as follows ... 

The debate about what is acceptable risk has existed outside of HIT for decades and was famously tested in the UK court of appeal in 1949 [4], The case related to an industrial accident rather than healthcare delivery but the ruling by Lord Asquith of Bishopstone had far reaching consequences across many safety-critical industries. The judgement concluded that it was appropriate to consider the sacrifice in money, time or trouble in the measures necessary for averting an incident. 

For safety-critical systems, constraints should be further separated into safety-related and not safety-related. One nonsafety constraint identified for TCAS, for example, was that requirements for new hardware and equipment on the aircraft be minimized or the airlines would not be able to afford this new collision avoidance system. Examples of nonsafety constraints for TCAS II are ... 

Strengthen or create an inventory control system for safety-critical parts at the corporate level. Ensure that safety-related equipment is in stock at all times. 

Figure 12.1 shows the interactions between development and operations. At the end of the development process, the safety constraints, the results of the hazard analyses, as well as documentation of the safety-related design features and design rationale, should be passed on to those responsible for the maintenance and evolution of the system. This information forms the baseline for safe operations. For example, the identification of safety-critical items in the hazard analysis should be used as input to the maintenance process for prioritization of effort. 

Provide physical and personnel resources for safety-related activities. Ensure that those performing safety-critical activities have the appropriate skills, knowledge, and physical resources. 

Create management of change procedures and ensure they are being followed. These procedures should include hazard analyses on all proposed changes and approval of all changes related to safety-critical operations. Create and enforce... 

Suggested Evaluation of indicators related to backlog ofpreventive and corrective maintenance - especially related to safety critical equipment should be established. These indicators should be supported by a risk assessment from the local workforce, to get their human assessment of the criticality of maintenance. 

The Nominal Task Analysis was linked to the risk assessment analysis for the critical scenarios identified as relevant to the case study while the hnk between the safety barriers and the activities identified in the task has been also estabhshed. Additionally the task analysis has been used to describe in detail the actions connected with a specific safety barrier related to a relevant accidental scenario and the mode the latter can be represented in the VR experiments. 

ABSTRACT The paper describes the results from a sub-project within a Nordic research project dealing with probabilistic risk criteria for nuclear power plants (NPP). In order to provide perspective on the project s detailed treatment of probabihstic risk criteria for NPP s, and to make it possible to relate these to risk criteria defined and applied in other safety-critical industries, criteria defined and used within the European railway and offshore oil and gas industries have been discussed in some detail and compared to NPP criteria. 

Decision criteria relates to the safety critical deterioration level. It is necessary to determine this level to be able to make appropriate decisions regarding further action. Usually a first basic intervention level is defined according to relevant codes, standards or internal company requirements. A minimum required wall thickness is usually determined due to a stress criterion and depends on allowable stress, design pressure, pipe dimensions and material strength. When deterioration beyond this basic intervention level is revealed through inspection, further actions must he decided. When the basic intervention level is reached, there may... 

The improvements proposed by the two groups ate listed in Tables 6 and 7. The proposed improvements fall into two groups (1) measures to improve safety critical decision making in operational contexts in general, and (2) measures to improve decision specifically related to discormection of the riser. 

This paper investigates possible relations between the AOP 52 and the standard lEC 61508 (lEC 61508 1998-2005). The lEC 61508 is a framework standard in the domain of safety-critical applications of electri-cal/electronic/programmable electronic (E/E/PE) systems. The following more domain specific standards are not considered to be suitable for comparison the lEC 61513 (lEC 61513 2002) for nuclear power plants, DIN EN 50129 (DIN EN 50129 2003) for railway applications, lEC 61511 (1EC61511 2003) forthe process industry sector and lEC 62061 (IEEE 61012-1990 1990) forthe manufacturing sector. 

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