Discussion on Issues in HAZOP Analysis Results
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As the title suggests, how can the issue of numerous sequential action valves at the control points on the main pipe, resulting from HAZOP analysis, along with their high failure probability and the difficulty in meeting SIL requirements, be resolved? Is it necessary to carry out technical modifications to the facility by addressing the issues identified in the HAZOP analysis?
No, it also depends on whether you can accept the risks associated with that probability. Additionally, the reliability of the instruments varies as well
It’s not necessarily the case; you can choose valves with a higher SIL rating to reduce the probability of failure and ensure that the verification is successful. If you’re reluctant to spend this money, then carry out the technical upgrades according to the recommendations put forward by HAZOP.
Are all your interlocked valves connected to the SIS system? If there are many, it’s likely due to an unreasonable design, as this leads to a high failure probability. Raising the SIL level isn’t the best solution; it seems like trying to quench thirst by drinking poison.
The second floor is the correct answer. But since an analysis has been done, why ask whether corrective actions will be taken or not? If no corrective actions are taken, then what’s the point of doing it?
I don’t understand why the SIL level needs to be determined using HAZOP. HAZOP can recommend adopting SIS to control risks. However, the SIS level depends on the complexity of the scenario. Determined via LOPA.
Please contact me if HAZOP/LOPA/SIS are required.
There are too many interlocks in charge, and there is a concern about accidental operations; the interlock signals can be changed to 2oo1 or 3oo1 to reduce the impact of instrument and valve failures
Choose 1 out of 2 – the probability of failure increases, right?
Selecting one out of two signals enhances safety but reduces availability, increasing the probability of incorrect shutdowns. If 2-out-of-2 actuators are used for valve control, with series connection at the inlet and parallel connection for drainage, the activation of a single valve can put the process facility into or maintain it in a safe state
Do HAZOP first, then LOPA