Safety-integrity allocation level
Oil & gas

Allocating safety-integrity levels for a larger Italian Petrochemical company


The client asked Arthur D. Little to assess the safety-integrity level (SIL) for a safety function implemented in existing plants.


  • The activity was carried out in three phases. 
  • Firstly, preparation, collection and analysis of reference documentation (process description, PFDs, P&IDs, cause-effect diagrams, HAZOP-study worksheets) were conducted. 
  • Secondly, analysis with the client was facilitated in order to determine the allocation of the required safety-integrity level.
  • Finally, the final report was issued.


  • A thorough assessment was made of the safety, environmental and economical risk of the plants. 
  • Critical process equipment and assets (based on associated risk) were highlighted. 
  • Specific and comprehensive recommendations resulting from the assessment were delivered, enabling the client to develop a detailed action plan.