Quantitative Risk Assessment – QRA
A Quantitative Risk Assessment (QRA) is a formal and systematic risk analysis approach to quantifying the risks associated with the operation of an engineering process. A QRA is an essential tool to support the understanding of exposure of risk to employees, the environment, company assets and its reputation. A QRA also helps to make cost effective decisions and manages the risks for the entire asset lifecycle.
QRA Process
QRA Process
Objectives for a QRA study
F-N Plot
- To identify the hazards associated with a facility
- To determine the potential frequencies and consequences of the identified hazards
- To determine the system availability of the protection systems
- To quantify the risks associated with a facility (e.g. Risk Contours, Individual Risk Per Annum (IRPA), Potential Loss of Life (PLL) and F-N Plots)
QRA Consultants
A typical QRA study conducted by one of ESC’s range of QRA Consultants consists of the following processes:
Fault Tree Analysis
- A HAZOP study to identify a series of hazardous scenarios that could lead to significant adverse consequences
- A SIL Determination study, typically done using the the Layers of Protection Analysis (LOPA) method
- A Fault Tree Analysis (FTA) to determine the event frequencies associated with the hazardous scenarios from the HAZOP and LOPA study
- A consequence analysis to determine the consequences of the hazardous release from a facility (including flammable, explosion and toxic). The consequence analysis is carried out with the use of the Det Norske Veritas (DNV) Process Hazard Analysis Software Tool (PHAST) software
- An Impact Analysis to determine the frequency of a specific hazardous impact using Event Tree Analysis (ETA). ETAs are ‘bottom up’ analytical tree diagrams that determine the overall likelihood of a particular impact following a hazardous release (i.e. Jet Fire, Flash Fire Vapour Cloud Explosion (VCE))
- A Risk Assessment conducted using DNV PHAST Risk software to determine the risks associated with hazardous scenarios
- Risk Reduction Measures to identify the options to reduce or mitigate the risks
- Lifecycle Cost Analysis to provide a Cost Benefit Analysis (CBA) based on different risk mitigation measures
Further Information
Our Functional Safety FAQs are a great place to start if you have any questions.
If you’d like any further information or would like to talk to one of our consultants please Contact Us via our contact form and we’ll be glad to help.
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