Hazard Identification Study (HAZID)
We have considerable Hazard Identification experience; our approach is to facilitate multi-disciplinary workshops to identify and rank major accident hazards (MAH) to personnel and to the environment. Safeguards for each MAH are documented – often with cause and effect charts – and any shortfall is a subject for action. A facilitator leads a structured analysis of a design or operation using guidewords. The Hazard Identification analysis is recorded by the scribe and projected on to a screen to gain ready endorsement of the analysis and any actions arising.
Environmental Aspects Identification Study (ENVID)
For planned releases, an ENVID study is convened, as risk ranking parameters differ to those for accidental releases. Aspects of an operation which are known to impact the environment are identified.
The effect of the impact is assessed with the duration of the impact taken into account. Combining the two parameters gives a semi-quantitative assessment of the unavoidable impact to the environment.
Hazard and Operability Study (HAZOP)
A HAZOP review examines process P&IDs using primary and secondary guidewords to describe deviations from design intent. Specific requirements include:
- Flare and relief systems;
- Batch operations;
- Cause and Effect Charts;
- Interlock Systems;
- Start up and Shutdown.
In Detail Design, the P&IDs are used to divide the process into discrete sections called nodes. Each node is analysed rigorously and design issues should not arise as with FEED. HAZOP provides input to the Safety Integrity Level (SIL) Study, and so the HAZOP record is sufficiently detailed and well organised for this purpose.
Safety Integrity Level Study (SIL)
A Safety Integrity Level (SIL) Study analyses Instrumented Protective Functions (IPF) to ensure they are designed for the worst consequences of foreseeable control failures. A Safety Integrity Level for each IPF is determined in a workshop environment using a Layers of Protection Analysis (LOPA) approach.SIL verification follows on in detail design and is a reliability analysis of the IPF architecture combined with a testing and inspection interval for it. A Fault Tree Analysis (FTA) or simulation approach is applied to verify whether the IPF reliability results can attain the SIL level requirements.