What is a CHAZOP?

Control Hazards and Operability Analysis (CHAZOP) is a highly structured hazards identification tool for instrument control and computer systems. The basis of the methodology is very similar to typical a HAZOP used in the process industry.

When should you use CHAZOP?

This methodology is used to identify potential flaws and weaknesses of instrument control and computer systems by reviewing how the system deviates from design intents. It is commonly used for proposed and existing Safety Critical Software and Instrument Control Systems. It supports the risk analysis requirement in IEC 61508, Functional Safety of Electrical/Electronic/Programmable Electronic Safety-Related Systems.

CHAZOP Methodology

1. Collect applicable documents and drawings.
2. Break system into manageable sections (Nodes).
3. Prepare list of Guidewords, Parameters and Operations to be examined.
4. For each Node create Deviations.
5. List and record causes for each Deviation.
6. List and record Consequences for each Cause.
7. List and record Safeguards or Controls that may prevent either the Cause or the Consequence.
8. List any future Actions or recommendations you think should be implemented.