Since 1987 – Safety Consultancy

Top-events Identification

The task of identifying the top-events of a refinery is usually related to:

  • A collection of plants/isles. In this case please refer to Plant Safety
  • Ancillaries. For example: Pipe-racks interconnecting different plants and/or tank farms facilities, fuel-gas/fuel-oil networks, etc. Due to their own nature, the top-events related to these ancillaries are better investigated developing refinery-wide safety review than duplicating the analysis for every single plant. The resulting top-events differ markedly from the ones identified in the QRA of a single plant and they led to different top-events (p.e. the loss of the instrument air to a control loop, studied in the QRA of the Alkylation Unit, is a different scenario than the loss of instrument air to all the users). The top-events identification of the ancillaries refinery-wide is complementary to the one carried on focused on a single plant
  • Sources of risk coming from wide-area events (floods, tsunamis, etc.) because they impact the whole site
  • Sources of risk coming from “outside the fence” activities because they can act on more than one plant inside the site. This study is relevant especially for Refineries inside or in the nearby Petrochemical site

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
  • Case histories analysis using Refinery specific databases. This technique is particularly suited when the data is referred to a well populated and quite standardized field. The Downstream perfectly fit this statement. It is important to underline that the Refinery field has always been open to disclose safety related information directly between corporations or through the licensors own databases
  • Random rupture using proprietary methods

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 strongly believes in doing Top-events identification at the customer’s premises to collect the maximum amount of information with the minimum effort on the customer side.

We know: the time of our customer is precious and always scarce!