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HAZID, HAZOP, LOPA & SIL study - Process Engineering Design

HAZID, HAZOP, LOPA & SIL study - Process Engineering Design

I have knowledge on HAZOP but not able to relate other process safety studies like HAZID, LOPA & SIL.
1) I am not sure when these will be done (FEED or EPC) and in which order?
2) Please guide the basis for these studies - HAZID, LOPA & SIL
3) I know for HAZOP process engineers are responsible for closing most of the action items. Is there any such thing in HAZID, LOPA & SIL studies and who is responsible to close action items (process, instrumentation, safety)?

RE: HAZID, HAZOP, LOPA & SIL study - Process Engineering Design

HAZID is preferably done at pre FEED stage and repeated at FEED
A coarse SIL study is usually done at FEED and a detailed one at EPC or Detailed Design Phase.
LOPA is the term used to describe the approach taken in a SIL study for evaluating instrumented safegaurds.

All affected disciplines are involved in closing out these studies, and usually a process safety (or process) engineer takes the lead to coordinate and log closeout actions, seek deviations to study recommendations etc.

For HAZID, a technical safety engineer may take the lead also if such a resource is available.

RE: HAZID, HAZOP, LOPA & SIL study - Process Engineering Design

Thank you Georgeverghese. Are these studies not carried out during EPC phase of a project?

RE: HAZID, HAZOP, LOPA & SIL study - Process Engineering Design

Usually HAZID is limited to FEED only; a revisit in EPC phase may be necessary if there is some big change in risks perceived at earlier stages.

Yes, HAZOP and SIL must be repeated in EPC phase when most of the design work is done and firm vendor data is included.

RE: HAZID, HAZOP, LOPA & SIL study - Process Engineering Design

Many Thanks for your reply.

RE: HAZID, HAZOP, LOPA & SIL study - Process Engineering Design

Hazid usually is conducted during Pre-FEED, FEED and Re-FEED
Hazop usually Conducted during FEED and EPC phase of the project when all documents are finalized as built/as for construction.
SIL/LOPA comes after Hazop. and when all P&IDs Drawings are final, also when Cause and Effect charts are ready. mainly the equipment's or systems having safety instrumented functions. mainly it is integrity, reliability and availability of the safety system.


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