process risk and safety specialists

nuclear and radiation consultants

Quantitative Risk Assessment (QRA)

A Quantitative Risk Assessment (QRA) is a very detailed analysis of a process plant to ensure that the risk to neighbouring sites, plants or residences meet planning guidelines. A common requirement is that the fatality risk at nearby residential properties must not exceed 1 in a million per year (1 x 10-6 p.a.)

A QRA is commonly considered the best approach for modern complex processing facilities handling hazardous materials. The standard industry methodologies for QRA are presented in the following publications:

  • ‘Guidelines for Chemical Process Quantitative Risk Analysis’, Centre for Chemical Process Safety, 2000
  • ‘Guideline for Quantitative Risk Assessment ‘Purple Book’ CPR 18E’, VROM, December 2005.

The Bow-Tie Consulting personnel have developed QRA’s for a large number of process plants. This experience will ensure that your site is modelled at an appropriate level of detail. This will reduce the cost associated with the model development while still providing detailed models of the significant risks. This understanding allows future risk reduction actions to be targeted in the most effective manner possible.

There are many parts of a QRA, such as hazard identification and consequence modelling. We will help you in any or all of these aspects. 

Major Hazard Facilities and Safety Case Development

The Major Hazard Facilities regulations now extend throughout Australia and require a Safety Case or Safety Report to be prepared that documents the safety management system on a MHF site. Our personnel work with our clients to assist them in the demonstration that their management systems are adequate to meet their requirements.
 
Bow-Tie Consulting will assist you in all of the steps to develop a safety case (also called a safety report) demonstrating the adequacy of the major accident risk controls and management systems.  This safety case/report will clearly demonstrate that:
 
  • You have identified all major accident hazards
  • You have effective controls are in place to manage the hazards
  • You have reduced the risk associated with each major accident hazard As Low As Reasonably Practicable (ALARP)
  • You have implemented robust management systems are in place to ensure that critical controls are maintained in good condition.
  • You have both leading and lagging measurements of the state of process safety in your plant.
 

Layers of Protection Analysis (LOPA)

Layer of Protection Analysis (LOPA) is used to assess the risk of major accidents by detailed consideration of the safeguards or controls that prevent or mitigate these accidents.  LOPA is a semi-quantitative method and fits between simplified qualitative techniques (such as a simple risk matrix) and complete quantitative assessment (QRA).  LOPA is often required where a higher degree of quantification of causes and controls is required due to the potential severity of the consequences. LOPA is also the preferred technique for SIL allocation studies due to the clear identification of independent layers of protection.

 

LOPA provides clear linkages between causes, controls and outcomes, analyses the effectiveness of individual controls and can demonstrate that the controls are adequate against simple risk criteria.
 
Bow-Tie Consulting’s personnel have experience in facilitating LOPA studies, whether alone or in conjunction with HAZOP studies or SIL allocation studies. Our Exida certified facilitator has undertaken numerous LOPA/SIL assessments and verification studies for clients in Australia and South Korea.
 

 

Our industry experience:

  • Aviation
  • Chemical
  • Mining
  • Nuclear & Radiological
  • Oil & Gas (Downstream)
  • Paper
  • Petrochemical
  • Process industries

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