Keywords: RBI, Risk Based Inspection, risk, inspection, consequence, probability.
Four years ago Yara started implementing Risk Based Inspection (RBI) in a uniform way for all the ammonia, urea and nitric acid production units within the Company.
The primary purpose of RBI is to manage risk at an equipment level based on expected degradation mechanisms through efficient and effective planned inspection with the scope to reduce the probability of failure of the assessed equipment thereby avoiding any major process safety incidents and los of production.
With RBI Yara is sharing knowledge and experiences within similar units creating deeper knowledge of the actual equipment conditions and an improved understanding of current plant risks. This gives the opportunity to focus resources on higher risk equipment in order to reduce the cumulative risk level of the plant itself and improving plant safety and reliability performances.
Remembering that only that which is measured can be improved, RBI provides a tool to quantify plant safety and reliability performances. With RBI we can compare risk results, quantify the actual risk levels and the risk we can mitigate through inspection. Further, knowing how individual items may dominate overall plant risk and how risk increases with time, by implementing different inspection plans we can optimise our inspection activities, saving inspection cost.
Finally, the use of financial figures to express the overall plant risk (cumulative risk curves) is useful to illustrate in a simple way the benefit of preventive maintenance and inspection activities and how they should be seen as an investment rather than as a cost.
Giuseppe Franceschini, Process Owner Inspection, Yara International ASA, Piazzale Donegani 12, 44100 Ferrara, Italy.
30 pages, 26 figures, 8 tables, 5 references.