Control & Safeguarding Philosophy — Final Self-Verification Checklist

Use this before the first formal review (internal or external). Applicable to BPCS, SIS/PSD/ESD, and F&G systems across EPC projects.

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Header & Document Control

Document number/title follow project numbering; “Control & Safeguarding Philosophy” clearly stated with unit/area.
Revision index and purpose (IFR/IFA/IFC/IFD) correct; prepared/checked/approved names and dates completed.
Project identifiers, location, client/contractor ownership and confidentiality classification correct per contract.
Unit system declared (SI/US); symbols/abbreviations legend included or referenced (ISA-5.1/client legend).
References listed with numbers & revisions (BEDD/BEDP, PFDs/P&IDs, UDD, Control/Safeguarding Narratives, IPF/LOPA, Area Classification, Alarm Philosophy, Client Specs).

Scope, Objectives & Boundaries

Objectives of BPCS, SIS/PSD/ESD, and F&G stated (control, protection, mitigation) with performance targets.
System boundaries defined (what is included/excluded; ownership split ICSS vs package PLCs vs vendors).
Shutdown hierarchy identified (equipment, unit, train, plant) and relationships mapped to areas/nodes.
Operating modes covered (startup, normal, shutdown, emergency, maintenance/test) and mode-dependent logic indicated.

Basis of Design & Assumptions

Design basis aligned with PFDs/P&IDs, process conditions, relief scenarios, and hazardous area classification.
Assumptions and constraints documented (utilities availability, environment, materials compatibility, SIL targets, project standards).
Dependencies recorded (UPS, instrument air, inert gas, cooling/heating, telecom/time sync) with fail-on-loss behavior.

Control Philosophy (BPCS)

Control strategies defined (single-loop, cascade, ratio, feedforward, override/selectors, sequences, batch states where applicable).
Manual/auto/remote modes, bumpless transfer, output tracking and interlock interactions clarified for operators.
Signal conventions and scaling (LRV/URV, units), square-rooting locations, and engineering range policies stated.
PID tuning approach defined (initial tuning method, typical ranges, integral windup protection, anti-reset windup, output limits, rate filtering).
Interlocks vs permissives vs sequences differentiated; reset/acknowledge behavior and authority levels defined.

Safeguarding Philosophy (SIS/PSD/ESD & F&G)

Safe states defined for all equipment (valves FO/FC/FL, motors tripped/stopped, blowdown open, isolations closed) and linked to shutdown levels.
Protection layers and SIF list referenced; SIL/availability targets stated with rationale (LOPA/IPF register linkage).
Voting schemes and degradation rules described (e.g., 2oo3 → 1oo2 on fault), common-cause & diagnostics considered per IEC 61511.
Trip/latch/reset philosophy defined (who can reset, pre-conditions, key switches), energize-to-trip vs de-energize-to-trip declared and consistent.
Bypass/override/inhibit policy defined (authorization, time-bound, audit trail, compensating measures), with PST strategy for SDVs/ESDVs documented.
Fire & Gas zoning, detector types, votes, and cross-trips summarized; interaction with ESD/BDV/ventilation detailed (NFPA 72/client spec).

HMI, Alarms & Operator Response

Alarm philosophy alignment (EEMUA 191/ISA-18.2): priorities, texts (verb-object), colors, sounds, shelving/suppression rules, standing alarm targets.
First-out, SOE resolution and time sync (NTP/PTP) specified; diagnostic/status annunciation (votes, inhibits, PST status) on faceplates/mimics defined.
Operator guidance provided for critical trips (expected actions, timing); HMI navigation hierarchy and mimic conventions stated.

Interfaces, Architecture & Cybersecurity

ICSS architecture outlined (controllers, networks, segregation BPCS/SIS/F&G, gateways), with single points of failure minimized.
Interfaces defined (hardwired vs serial/Ethernet protocols), heartbeat/diagnostics, and fail-on-loss behavior captured for each link.
Cybersecurity posture summarized (IEC 62443): zones/conduits, user roles & MFA, remote access, patching, backups, disaster recovery, logging.

Utilities & Loss-of-Utility Responses

Instrument air, hydraulic power, UPS/IPS, mains, cooling/heating dependencies defined; failover and degraded-mode behaviors specified.
Power philosophy (E-stop, black start, UPS autonomy) reflected in safeguarding and restart sequences as applicable.

Testing, Proof & Validation

FAT/SAT scope stated (simulation tools, loop checks, C&E testing, failover tests) with acceptance criteria and documentation outputs.
SIF proof test intervals/coverage and PST frequency defined; restoration steps and override clearance after tests included.

Documentation, MOC & Deliverables

Traceability ensured to source documents (HAZOP/LOPA nodes, SRS, narratives, vendor docs); change log maintained with impacts recorded.
Downstream deliverables identified (shutdown keys, logic diagrams, C&E matrix, alarm database, test procedures) and kept in sync.
MOC pathway defined for future changes (approval roles, risk assessment, re-validation of SIL/alarm impacts).

Notes, Attachments & Final Polish

Open items and assumptions clearly listed with closure plan; TBDs minimized and highlighted.
Attachments referenced (narratives, architecture diagrams, zoning drawings, vendor integration notes) with doc numbers & revs.
Grammar, consistency and formatting pass complete; no blank critical fields; page numbers and revision history correct.
Sanity scan: each key requirement traceable within 60 seconds; content consistent across P&IDs/C&E/logic.

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Use this checklist before issuing the Control & Safeguarding Philosophy for first formal review.

Control & Safeguarding Philosophy- Comprehensive I&C Engineering Checklists for EPC Projects