Offshore QRA

BakerRisk has performed safety and risk assessments for offshore facilities through all phases of design life-cycle from Conceptual to Detailed Design Engineering.

The Safety Case is the means of both ensuring and demonstrating that suitable and sufficient measures are in place to prevent a major accident and to reduce their effects in case of occur. This is achieved by a detailed analysis of the identified hazards, an assessment of the resulting risks and by demonstrating that there are adequate safeguards in place to manage the risks effectively.

The Safety Case presents the results of the safety assessment process and gives details on identified risk reduction measures, based on the results of the safety assessment.  Such risk reduction measures, if implemented, would demonstrate how the risk levels can be “as low as reasonably practicable” (ALARP) or be reduced to meet the company’s risk criteria. The process of developing and maintaining the Safety Case should be applied throughout the life cycle of a major hazard facility.

A typical QRA for an offshore facility consists of several phases beginning with hazard identification onto a quantitative risk analysis.  The following are the typical areas of study contained in an Offshore QRA.

• Hazard identification
  • HAZID
  • HAZOP
  • SIL assignment
  • SIS calculations
• Consequence modeling
  • Fires (screen and detailed)
  • Explosion (screen and detailed)
  • Toxics
• Frequency Analysis
  • Process loop releases (equipment failure, venting) using industry average failure rate data
  • Releases from impacts (dropped objects, 3^rd party impacts)
  • As needed, event tree and fault tree for specific scenarios. (not performed for every release case).
• Quantitative risk analysis
• Population Risk
  • Individual
  • Societal
• Sub studies to feed the overall analysis include:
  • Dropped objects
  • Occupied building reviews
  • Egress routes to temporary safe refuges
  • Temporary safe refuge analysis
  • Ship collision
  • Riser studies
  • Structural analyses

BakerRisk utilizes several key technologies while performing the QRA.  These technologies have been developed over time using experimental data and a database of industry experience.  They include the BakerRisk failure rate database and discharge, dispersion, explosion, and consequence models.  The figure below shows the classic QRA method of assessing and managing risk that will be adopted.

 

The figure above shows that if calculations show risk to be significant, calculations can be refined and/or mitigation strategies can be implemented until a satisfactory level of detail, confidence, accuracy and resolution has been achieved, or mitigation strategies can be implemented and risk re‑assessed.  This process is repeated until risk is determined to be acceptably low or reduced as much as practical.