[2025 Process Safety] PHA report and HAZOP, SIL classification, SIL verification timeline
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I. PHA Report in SH/T 3225-2024: SH/T 3225-2024, \"Design Specifications for Safety Integrity Levels of Safety Instrumented Systems in the Petrochemical Industry,\" provides a relatively detailed description of the entire life cycle of SIS systems.
The entire cycle is divided into 5 stages. The first stage is the feasibility study phase, during which a PHA analysis of the process package is required, along with the preparation of a written report. The PHA report mentioned here is probably not well-known to most people, but the HAZOP analysis report is familiar to everyone. Process Hazard Analysis (PHA) is a systematic approach for identifying, assessing, and controlling potential hazards in industrial processes. It is primarily used to prevent process safety incidents and is widely applied in industries such as chemicals, petroleum, and pharmaceuticals, which deal with hazardous materials or processes.
Common PHA methods: 1 Checklist method: A checklist is developed based on past experience or standards, and potential hazards are checked item by item. 2 Fault type and impact analysis (FMEA): Analyze the possible fault types of various components of a device or system, as well as their impact on the overall system. 3 Hazard and Operability Study (HAZOP): By means of \"deviation analysis\" (such as excessive flow rates, abnormal temperatures, etc.), it identifies potential hazards and operational issues in the process; it is one of the methods widely used today. Currently, the most commonly used method for conducting PHA is HAZOP analysis. Therefore, HAZOP analysis is carried out at this stage.
II. Time milestones for HAZOP, SIL classification, and SIL verification: With the issuance of GB/T 45111-2024, clear regulations have been established regarding HAZOP, the preparation of SRS, SIL classification, and SIL verification, resulting in significant changes compared to previous practices.
This post was last edited by zhoudingshengs on 2025-7-18 08:39. LOPA analysis nodes: 5.2.1.1 Control node classification. Quality control for LOPA work is integrated throughout the entire safety lifecycle; quality control should be implemented at the following stages when carrying out LOPA work: Stage 1: Preliminary design (conceptual design) stage； Phase 2: Detailed design (construction drawings) phase, prior to the design of the protective layer ； Phase 3: Operation phase ； Phase 4: Decommissioning and retirement phase.
This post was last edited by zhoudingshengs on 2025-7-18 08:39. 5.2.1.2 After a hazard and risk analysis (such as HAZOP) has been conducted, and before the SRS is developed, it is necessary to determine the protection layer settings and the safety requirements for each SIF for those scenarios where the original risks are considered high, through LOPA analysis.
5.2.1.4.1 After gaining operational experience and having conducted periodic hazard and risk analyses (such as HAZOP), a review of the LOPA work should be carried out.
5.2.1.4.2 When the LOPA input information changes, the LOPA work should be carried out again.
5.2.1.5 When the decommissioning of equipment and facilities may pose risks to the operational system, LOPA work should be carried out on the operational system.
Several key time points: 1. The preliminary design phase – in other words, a LOPA analysis report is required for the preliminary evaluation of a project. Previously, such reports were not necessary for the preliminary evaluation of hazardous chemical projects; only a HAZOP analysis report was required, but that is no longer the case.
2. During the detailed design phase, and specifically during the review stage of the project’s safety documentation, an LOPA analysis report is required. It should be noted that the depth of the LOPA analysis at this stage is much greater than that in the preliminary design phase; it essentially represents the final version of such analysis.