Risk Assessment

Written by Nicholas Kamuda
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Effective risk assessment has, to some degree, always been equated with success. In basic terms, risk is computed as a product of two factors: the probability of failure of an asset and the consequence of failure of an asset. Modern risk assessment has seen the development of different tools for computing risk, including probabilistic risk assessment as well as different practices for managing risk, such as RCM2.

In the early days of manufacturing, when manufacturers lacked practical or cost-effective risk analysis tools, some accidents were viewed as unpredictable, incalculable or unmanageable. "Act of God" accidents, or major accidents comprised of multiple failures, were considered unmanageable, and effective maintenance techniques for such failures were almost unheard of. As risk analysis and assessment tools evolved, and maintenance practices improved, one common method that developed for dealing with multiple failures for a system was to modify the system itself by adding more and more safety features.

Risk Assessment Using RCM Practices

Beginning with the development of the principles of reliability centered maintenance in the 1960s, a new outlook emerged. By adopting maintenance policies that closely suit the asset involved, it is possible to greatly reduce the probability of multiple failures within a single system. In this case, suitable maintenance policies include management policies that declare the tolerable levels of risk for a system.

In order to decide what levels of risk are tolerable, all aspects of risk--from energy efficiency to safety---should be carefully considered. For some types of systems, governing bodies, standards associations, or other authorities decide what levels of risk are considered tolerable. According to RCM2 though, the primary users of assets may be the best judges of risk as they are most often the ones directly exposed to the risks involved. Notwithstanding, the RCM review groups also represent the interests of the owners, government agencies, standards associations and any other authority whose decisions may also influence the outcome of the failure management policies.

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