What is a Quantitative Risk Assessment?

What is a Quantitative  Risk Assessment (QRA)?

The objective of Quantitative Risk Assessment (QRA) – is to determine the consequence and likelihood of occurrence of a particular hazardous event. Once these parameters are understood and quantified, informed decisions can be made as to how risk reduction can be implemented.

Before a Quantitative Risk Assessment can be carried out, it is necessary to identify the hazards that should be assessed. HazID, HazOP, studies of environmental impacts and other techniques can be used to determine which hazards should be taken forwards for further analysis.

Quantitative Risk Assessment would include specific activities to understand the worst-case consequence of the hazardous events (such as Occupied Building Risk Assessments, Fire or Explosion Modelling, etc). These activities should be carried out so that the consequences are ultimately expressed in the same format as that used by the Tolerable Risk criteria – to allow comparison between the two and so that risk reduction requirements to be easily identified. Depending on the consequence being considered, specialist software tools may be used to carry out the modelling.

QRA can also include various activities to determine the likelihood of the hazardous event. Layer of Protection Analysis (LOPA), Fault Tree Analysis (FTA) and others may be used. (Note, LOPA is considered a “semi-quantitative” technique, but discussion of such finer points as this are beyond the scope of this text).

Once the QRA is complete and risk reduction requirements have been identified, it may be necessary to carry out Sensitivity, Cost Benefit and ALARP analysis to confirm the acceptability of the proposed risk reduction.

Quantitative Risk Assessment with =Method

=Method and our partners can facilitate or deliver the various elements of QRA and provide training or mentoring as part of competency development. If you understand your QRA requirements, we will be happy to quote – if you need help in understanding how to best solve your QRA needs, please contact us and we will advise you as you need.

Title: What is a Quantitative Risk Assessment (QRA)?
Published by: Method Functional Safety


The objective of Quantitative Risk Assessment (QRA)

To determine the consequence and likelihood of occurrence of a particular hazardous event.

About =Method

The =Method team has the capability and competence to support all aspects of the functional safety lifecycle for IEC 61508, IEC 61511 and IEC 62061. More about =Method.

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