Definition:
Hazard and Risk Analysis (H&RA) is the formal process of identifying hazards, assessing associated risks, and determining necessary risk reduction to achieve tolerable risk levels. It is the formal terminology used in IEC 61508 and IEC 61511. There are many ways to achieve these requirements which can be confusing. These could be HAZOP or a Risk Matrix.
Key Points:
- H&RA is an umbrella term that includes qualitative, semi-quantitative, and quantitative methods.
- Required early in the safety lifecycle to define Safety Instrumented Functions (SIFs) and assign Target SILs.
- Broader and more formal term compared to “Process Hazard Analysis (PHA)” used under OSHA regulations.
Example:
A Hazard and Risk Analysis done via a HAZOP identifies overpressure scenarios in a reactor system, determines the initiating event frequency, evaluates the existing protection layers, and assigns a SIL 2 requirement for a high-pressure shutdown SIF.
See also: PHA, HAZOP, HAZID, risk matrix
Cited Source:
- IEC 61511-1:2016, Clause 8.