During the engineering phase it is important to correctly assess the top-events related to the project because top-events identification is the foundation of the following activities to be done in sequence:
If top-events identification is not exhaustive the risk evaluation would be partial. The latter usually leads to the identification of improvements and actions to be applied to the project in order to mitigate the residual risk. So, an incomplete top-event identification could miss some required improvements that have to be addressed in later stages: during EPC or, worse than anything else, after the start-up delaying the project and increasing the costs. Where formal authorization has to be granted from the authorities there is also the risk of a denial due to the incomplete analysis.
Top-events identification, to be exhaustive, has to be carried on using a collection of techniques each one best tailored for different kind of top-events. Eidos uses the following techniques:
- HazOp analysis using IEC 61882
- FMEA/FMECA/DFMEA/PFMEA analysis
- Case history analysis using International Databases
- Random rupture using proprietary methods
Other methods (What If, Check List, etc.) when they are the best suited.
Each of the aforementioned techniques best suites different kind of units, Eidos experience can advise the customer on the best mix for each unit/equipment (p.e. FMECA analysis is better suited for the study of the mechanical side of a compressor than HazOp, but became cumbersome when applied to a distillation column).
The recording of the HazOp sessions is done using HazOp+ software from Isograph Ltd.
The recording of the FMEA sessions is done using XFMEA software from Reliasoft.
Eidos, on customers’ request, can also provide an additional analysis focused on the identification of top-event arising from:
- Ancillaries. The ancillaries required by the projected plant can be source of top-events either inside the projected plan or at the ancillary location
- Risks coming from “outside the battery limit” activities
- Risks coming from wide-area events (earthquakes, typhoons, etc.)