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This tutorial is offered for public live-streamed delivery. It is also available for in-house live-streamed delivery.


Risk matrices are used widely in process safety to rate and rank risks posed by processes to help with decision making. For example, commonly they are used in process hazard analysis (PHA) to rank the risks of hazard scenarios and determine the need for risk reduction. However, there are no standards for risk matrices. Companies develop their own without the benefit of established industry guidelines.

Risk matrices are deceptively simple but various pitfalls await even experienced users. Invalid risk ratings can result from poorly designed and improperly used risk matrices, which often pass unrecognized. The results of an otherwise well- performed study may be invalidated by poor design and use of risk matrices. The issue is important for any risk analysis method that employs risk matrices.

This tutorial provides guidance on constructing and using risk matrices to avoid these pitfalls. Attendees receive an electronic copy of the tutorial materials.

What you will learn:

  • Uses of risk matrices
  • How to set the number and ranges of severity and likelihood levels
  • How to set risk levels for proper decision making
  • How to incorporate the ALARP principle
  • How to calibrate risk matrices for risk tolerance
  • Need for risk matrices for both individual and group risk to people
  • How to assign severity and likelihood values consistently
  • How to address uncertainties in severity and likelihood estimates
  • How to address subjectivity in risk estimates
  • Guidelines for designing and using risk matrices¬†

Who Should Attend

PHA and LOPA Team Leaders.


An understanding of PHA or LOPA.