Forward View
machinery),” says Catmur. “When you create more operating modes or features that have additional hazards associated with them, you may need to add control measures to reduce the existing risks. As a result, the overall risk can be reduced and the situation made safer, even though the total number of hazards has increased.”
Where to start
Catmur cautions against starting a project by estimating the risks: “If people go straight into risk estimation they often get it wrong, which has implications for the design of the product or system. It is better to just focus on the outcomes and bear the following questions in mind as you work on the design: What could go wrong? What are the possible consequences? Are you building in enough barriers for the higher- consequence hazards? Will those barriers last throughout the life of the product/system? Will those barriers be effective however the product/system is used or abused?” Returning to the question of how to establish the
acceptable level of risk, Catmur states: “Deciding what level of risk is acceptable can involve a huge debate, so people often just prefer to avoid the issue or fall back on standards or legal definitions. In some cases standards and/or legal definitions are a good route forward but I always suggest that a proper debate is had about what the acceptable level of risk is, as this can help give some clarity – even if in the end the answer is not a firm one.”
Safety bubbles
Even if a company thinks it is managing risk effectively, it is easy to be lulled into accepting a level of risk that is actually higher than it is thought to be or rising as risk controls cease to be effective. “Arthur D Little has developed the concept of ‘safety bubbles’ to describe what can happen,” says Catmur. “These have striking parallels with the ‘economic bubbles’ found in financial markets. “A safety bubble is a slowly growing set of conditions,
fostered by certain behaviours and assumptions in the organisation. When the safety bubble bursts it can result in catastrophic disruption to the business and even fatalities. Typically a safety bubble will develop as a company attempts to cut costs, such as by using cheaper materials, fewer safety devices, longer maintenance intervals and so on. If the first round of cuts is successful, with improved margins and no significant incidents, then the company may seek to make further cuts. However, if operational cost cutting proceeds to such an extent that there is no longer adequate contingency based on objective risk pricing, the result is an unsustainable condition in which inherent safety margins are progressively eroded. Hence the safety bubble develops. Importantly, as the safety bubble grows, there is an atmosphere of self- congratulation and investor plaudits, as the company appears to be performing well.” When it comes to managing risk as part of the design
process, various tools can help to remove some of the subjectivity. FMEA (Failure Modes and Effects Analysis) and HAZOP (Hazard and Operability Analysis) are two well known examples, but Catmur has reservations about these, especially with the way they are being performed in today’s cost-conscious businesses: “Done well, these can be very useful
but, if they are not done properly, they can be very bad. Ideally each should be undertaken using a team consisting of the right people; today, however, they are sometimes done by one person who then circulates the analysis for review. FMEAs and HAZOPs are, to be honest, boring, so it is easy to miss things. Really you need proper brainstorming sessions, led by the people who have in-depth knowledge of the design. Even then, it is not guaranteed that all possible failure modes will be identified. Nevertheless, it would be unrealistic to expect every company to undertake complete, rigorous FMEAs and HAZOPs, as the costs would be prohibitive. The answer, therefore, is to use a mix of methods with which people are comfortable. For example, start by identifying all of the potential failure modes and consequences, then filter these so that you only pursue the most critical (based on consequence, not risk at the early stages). And be prepared to think about the many different ways that a product or system can be abused, and what the consequences could be; just because you think a person would have to be very stupid to do something, that does not mean that it will never happen.” While products are under warranty, manufacturers have a good opportunity to monitor failures and use this as feedback to check the validity of their risk assessments. However, depending on the product, consumers today might simply discard the faulty item and purchase a replacement from another manufacturer. Furthermore, the feedback loop is lost once the product is out of warranty, and this valuable source of information simply does not exist for competitor products. To sum up, Catmur offers these five tips:
l Have a rough idea of where you are heading by thinking in terms of consequences and what level of risk might be acceptable;
l Appreciate that you do not have a very good understanding of risk (and in-house experts and external consultants are likely to be not that much better);
l Avoid being too focused on risk estimates, as doing so can lead to a false sense of security;
l Continue to manage risk, even after the product is launched or the system is commissioned; and
l If you build in safety from the outset you will achieve a better result than any safety expert can by ‘bolting on’ safety afterwards.” l
www.engineerlive.com 7
“The first step in risk
management is to recognise that you do not understand risk.”
James Catmur,
Director and Global Head Arthur D Little
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