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Before privatisation, UK utilities managed infrastructure works with large direct labour forces. Over the last 15 years these works have been increasingly outsourced to a new industry. Work patterns and cultural factors have changed significantly. Health, safety and environmental management are important parts of the contracting process. Outsourcing requires both the operational (engineering) and...
This paper discusses practices for risk assessment from different application domains and proposes an engineering approach towards risk assessment starting from user requirements. A new approach for a semi-quantitative risk assessment method based on sound engineering principles is proposed.
Accidents and incidents are extensively analysed. The results of the analyses are used to provide recommendations for avoidance of accidents in the future. Work by Leveson and Rasmussen seeks to extend such analyses to take account of the processes used to deal with the conflict between safety and efficiency. This paper notes that there appears to be little published work analysing successful systems...
The public private partnership (PPP) contract was put in place to manage and upgrade the infrastructure of the London underground network in addition to recovering the backlog from years of underinvestment. Tube lines, as the company responsible for the Jubilee, Northern & Piccadilly Lines, have developed an innovative approach to modelling safety risks as part of our overall asset management...
The need for measurement to support the development and operation of safety- and security-critical systems is being increasingly recognised, and there is a growing body of reported work. Management systems are required by applicable standards in both fields, with implied codification and quantification, where appropriate. This paper summarises an on-going effort to apply a systematic measurement method...
This paper presents the document about draft guidance on how to ensure and manage the competence of those involved with electrical, electronic and computer-based safety-related systems. The rest of this paper introduces the main features of a competence management system as recommended by the guidance. It discusses issues that arose during the development of the guidelines and many of the issues raised...
Electronic devices are increasingly used in safety-related and safety-critical applications. But all electronic devices are susceptible to electromagnetic interference (EMI), making their electromagnetic compatibility (EMC) with their environments over their lifecycle a safety issue. So one of the challenges of dealing with these new technologies and more complex systems must be to ensure that EMI...
The safety of railway signalling systems depends on the correctness of the programming of a logical controller known as an interlocking. Assurance of correctness is usually achieved by a combination of testing, both on simulation systems and on the target hardware, and manual or tool-assisted checking of the data, with use being made in some cases of techniques of static analysis and formal methods...
This paper presents a means to determine in-service availability of systems and equipment in a rigorous and consistent manner so that the predicted reliabilities and/or levels of safety can be assured. In addition to validation of predicted system reliability performance, overall levels of safety can be improved by providing clear evidence to support reductions in the amount of intrusive maintenance...
This paper shares the author's experiences of a study and subsequent practical application of structured methods, including goal structuring notation and Bayesian networks, in developing safety arguments.
In the domain of software development, agile techniques are increasingly being used to improve the development process. Agile software development relies in part on rapid feedback of working software products to validate user requirements. There has been some effort to introduce agility in security-critical systems, using an explicit representation of security concerns known as an iterative security...
The basic principles and lessons learned from the cross-acceptance of signalling equipment in that era are presented here for typical products of the rail automation division of Siemens transportation systems in accordance with pre-CENELEC era regulation. The EN 50126/1/, EN 50128/2/ and EN 50129/3/ standards describe the requirements for the safety-related hardware and overall system. The future...
There are several key words used throughout various industries when relating information important to safety. Modern safety practitioners may be unaware of the meaning these words have and the perception of them in the general public. The Engineering Council has suggested that public perception eventually results in regulation, in media treatment and in government decisions affecting industry. So...
There is an important interface between requirements and safety engineering, but its very existence causes a problem: it belongs to neither discipline. This paper looks at identifying failure modes from a requirements perspective, and considers how the two disciplines can most effectively collaborate. Requirements techniques have evolved rapidly in the last 10 years from the traditional hit-and-miss...
This paper discusses an experiment that measured the effectiveness of a hazard identification process used to support safety in Defence Standard 00-56 project. The experimental case study utilised a Ministry of Defence project that assessed simultaneously two potential suppliers who were competing for a MOD equipment contract. The UK MOD Corporate Research Programme funded the comparison work and...
Techniques for defining system functional operation by the generation of state-transition models in a graphical environment will be described. This will include emulation of functions to provide iterative requirements definition at a stage which is generally consecutive in the system lifecycle, thereby reducing latent systematic errors. These techniques allow any system to be defined or redefined,...
High integrity applications, such as those performing safety or security critical functions, are usually built to conform to standards such RTCA DO-178B or UK Def Stan 00-55. Typically such standards define ascending levels of criticality each of which requires a different and increasingly onerous level of verification. It is very common to find that real systems contain code of several different...
Swarm Intelligence provides us with a powerful new paradigm for building fully distributed decentralised systems in which overall system functionality emerges from the interaction of individual agents with each other and with their environment. Such systems are intrinsically highly parallel and can exhibit high levels of robustness and scalability; qualities desirable in high-integrity distributed...
The thinking behind human factors guidance in support of IEC 61508 and 61511 is outlined. The structure and content of the guidance is described as being in two major parts. The first part comprises qualitative guidance on human factors within the safety lifecycle, human factors integration plans and the principal concerns of employing human factors processes techniques and knowledge for safety-related...
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