What is Assurance?
Assurance is the comfort in quality – the more assured of the quality we are, the greater our level of trust in the future performance. The less assured we are, the larger the safety factors we feel we need to apply to be safe. To put it simply, how willing are we to be wrong in the judgement we have made about the safety of a component or structure? This is not the same as a false-positive through random chance, in a truly scientifically understood system there is no need for estimation as all outcomes are predictable. The ideal future is one in which no faith or empirical demonstration is required as the future performance is completely assured though understanding.
Assurance is the opposite of ignorance:
- The balance is not to be optimistic about future performance. Individually we are incredibly optimistic about personal risk, but as a company/community we are incredibly risk averse.
- Safety factors in design codes are simply a means of expressing the level of ignorance we have in the quality systems that we employ or the level we are willing to tolerate.
- If we can be better assured that the assessment methods available (the paper interpretation of reality) is fully representative, then we can trust the predictive capabilities to unlock step changes in claimable materials performance.
Assurance is often considered as an overcheck on the quality systems employed – a random audit or witness of a process to ensure that the quality system is being adhered to; however, these quality systems have evolved rather than being designed. Assurance that the existing system is being followed is not the same as an in-depth understanding of the physical phenomena that greatly widens the applicability of the data already available. I.e. a mechanical property test within a specification will only provide assurance of the material at a set location within the component being tested, we use our empirical knowledge that a component that has passed this previously has not failed in service. But what do we do for a new component design or material? How can we optimise if each iteration requires a full test of the component?
A similar situation exists in medical trials when comparing extant and new medications, is it ethical to not progress with a new medicine as the extant medication is sufficient? If the new medication is demonstrably better for the same cost or produces similar results to the extant at a reduced cost, it is adopted. The choice is based on data and is made based in scientific merit. The same does not happen in materials engineering often due to the cost of trialling a new solution to an existing problem, as such the resources that can be released by adopting the new material/design are locked into the old methods, this greatly slows progress in the development in industry. By improving the virtualisation and trust of the assessment, the optimisation can happen long before the cost of trials is incurred, the adoption of new technology is therefore much more likely.
Assurance is not assessment; it is a combination of the appropriateness to the future use and quality of the assessment, the manufacturing process, and the validation tests employed. Successfully passing all these stages provides a level of comfort, but complete assurance comes from a full scientific understanding of how the variability in the material is developed as response to the manufacturing routes used.
Design, Codes and Standards for Assurance of Structural Integrity
Objective review of industrial design codes and standards to establish how these design codes provide assurance of structural integrity though design limits, inspection and assessment. What are the metallurgical factors considered in assessment and how are these demonstrated? What are the written versus real factors of safety? Where the codes apply conservatisms and why? A Strengths, Weaknesses, Opportunities and Threats assessment per industry and key component will be undertaken as part of the review.
Assurance in Manufacture of High Integrity Components
How is assurance achieved in practice through physical inspection of components? Develop a register of the methods used across different industries and relate to the TAGSI four-legged approach to building a robust safety case in support of operation. What is the relative importance of the four legs (manufacturing pedigree, proof testing, analysis of failure, and forewarning of failure) assigned to high integrity components? Can a common methodology be established or shared across a wide range of industries?
Certification of Critical Systems
Demonstrating that regulatory and legislative requirements are met though the application of robust processes is key to a successful business implementation of any engineering product. Not only is safety paramount from a legal perspective; all companies have a duty of care to customers, user of products, the environment and society in general to ensure that products are safe. This is commonly achieved through a certification process for a design and product. A better understanding of how this is achieved for all engineering products would be advantageous and the methods that are used within industry and regulators to demonstrate compliance with legislation would be of benefit to the next generation of industrial and academic leaders. This will be achieved through discussion and knowledge capture exercises with key individuals identified by the steering committee.
Operational Concerns
All components are subject to operational concerns, the design/producer will always attempt to take account of expected in-service issues; however, the understanding of what these issues are can change during the lifetime of a component. A key example here is the irradiation damage behaviour of low alloy steels used in the nuclear industry; where changes in the mechanical properties can now be shown to be due to nano-precipitates that could not be observed when these materials were first put into service. This task will provide an overview of the development of this type of in-service change to understanding and how best to provide assurance that the component is still safe to operate under a changing level of confidence in the end-of-life properties.
Decommissioning of High Value Products
The value of many high integrity products lies in the use of the component with little thought to how the materials used for it can be harvested or recycled. Some industries do this very well, for example the introduction of legislation in the automotive sector has greatly reduced the number of materials used and recovery/recycling has gained a place on the list of considerations when selecting a material. This task is to develop an understanding of the decommissioning process and the feedback it has on future design choices, this in turn will act as an input to activities on responsible innovation.
Product Failure – What Happens When Assurance Fails?
No system is perfect and failures of products do happen. Previously failures were dealt with by companies in a responsive and measured way, meeting legislative requirements and altering designs as appropriate; however, the rise of social media means that the world may know about the failure before the manufacturer is even aware of the issues. In order to keep ahead of issues and prevent visible failures of products, the quality of the products must be even higher than that required to meet minimum requirements. The public nature of addressing issues, if not handled correctly, can damage the position as technical authority of owner/operator/manufacturer.
Cost of Assurance
The costs of providing assurance need to be considered in the product life cycle. These costs are not only financial but relate to:
The effort placed in providing this assurance, is it better placed elsewhere such as new product development rather than further demonstration of existing products or materials?
The energy used in manufacture, and the type of energy that is being used. This is also a key factor in responsible innovation.
The environmental impact of the product throughout the life cycle and what costs does this incur.
How sustainable is the product and is the material it is made from truly sustainable/recyclable?
Is the knowledge sustainable to produce the product; what are the costs associated in re-learning how to manufacture a product with a very long-life cycle? Should planned obsolescence be considered in high integrity products to force future development.
