Let us assume that the stakeholders are willing to consider taking the risk of occasional latent hazards, for the sake of reducing the system price. It is a good idea to provide them with an estimate about the risk. Because the incidences are unpredictable, and because they are very sensitive to the circumstances ( Hollnagel et al., 2006 ), we cannot provide reliable estimates of the costs of incidences. What we can do is calculate an estimate of the Mean Time Between Incidences ( MTBI).
To get a rough idea about probable MTBIs, consider a system with 120 non-critical components, each component with an MTBF of ten years. Because these components are not regarded as critical, they are not equipped with safety indicators. Using the calculation as above, the estimated MTBI is 1 month. This estimate should be presented to the stakeholders, and they need to decide if they are willing to take the risk.
Updated on 21 Nov 2016.