Risk-based Inspection (RBI) is a logical and structured process of condition assessment, inspection planning, and inspection evaluation. RBI has been adopted worldwide as a complementary tool for time-based activities to minimize not only an asset's risk regarding its integrity, but also its economic risk. A client approached ROSEN with a fire water system suffering degradation. Maintenance priorities were focussed on hydrocarbon systems. Consequently, alterations to the site led to a lack of effective planning for the inspection and maintenance of fire water and other safety systems. The customer's challenge was the development of a replacement inspection scheme for all systems.
Scope of Work
ROSEN developed a structured methodology to assess corrosion and mechanical degradation mechanisms commonly observed in process plant, based on best practice as described in API 580 & 581. This methodology generates a risk rating for each component together with an inspection interval that is then used in the compilation of a plant-wide inspection schedule. Within the project the following activities took place:
- The pipework system was divided into sections for assessment, based on asset operational zones, threat parameters and other identified criteria.
- Identification and assessment of credible threats for each system section was carried out, including MIC, internal O2, atmospheric exposure, lining breakdown, etc.
- An inspection plan was created, prioritizing to sections based on criteria developed together with the client.
The client now has a well-structured scheme containing the following:
- A system-wide inspection plan delivered as overall and section-specific inspection schedule
- An assessment identifying credible threats and in-place mitigations
- A database of design/operational data and archived inspection records
- An indication of appropriate inspection techniques and threat locations for inspection.