HAZOP Node
Worksheet (Excel)

A HAZOP (Hazard and Operability) node worksheet is the per-node record produced during a HAZOP study per IEC 61882. The plant is broken into nodes (process sections with defined design intent), and for each node the team applies guide words (No, Less, More, Reverse, Part Of, As Well As, Other Than, Early, Late) to process parameters (Flow, Pressure, Temperature, Level, Composition, Reaction, Phase) to systematically identify deviations from design intent. Each deviation is analysed for cause, consequence, existing safeguards, risk rating, and recommendation. The worksheet captures the full per-node record.

IEC 61882 requires: study reference, node number and description, node boundary (from and to), P&ID reference with current revision, design intent, operating conditions, parameter, guide word, deviation, cause, consequence (process, safety, environmental, asset, reputation), risk rating (frequency, severity, likelihood, priority), existing safeguards (prevention, detection, mitigation), recommendation, action item number, action owner, target closure date, SIL classification for safety instrumented functions per IEC 61511. The template column set covers all IEC 61882 attributes plus the OISD 118 cross-reference for Indian petroleum scope.

Pathnovo, an engineering document intelligence platform, auto-preps HAZOP node worksheets in 2 weeks by parsing the P&ID set, proposing node boundaries based on process sectionalisation (separation valves, control valves, equipment boundaries), extracting design intent from line list and equipment list, and pre-populating the worksheet with parameter and guide word permutations. The HAZOP team then runs the study against the prepped worksheet, dramatically reducing facilitator preparation time. See the HAZOP register extraction workflow.

HAZID (Hazard Identification) is the early-phase qualitative study identifying broad hazard categories at concept or FEED stage, typically across the full installation. HAZOP is the detailed node-by-node deviation analysis at detailed engineering stage per IEC 61882, using guide words and parameters. LOPA (Layer of Protection Analysis) is the semi-quantitative follow-up per CCPS methodology, taking HAZOP scenarios that may need a Safety Instrumented Function (SIF) and quantifying initiating event frequency, conditional modifiers, and independent protection layers to determine required SIL. See the HAZID standard reference and the LOPA standard reference.

The HAZOP node worksheet is the per-node record of the study itself: every deviation analysed, every cause and consequence considered, every safeguard credited, every recommendation made. The HAZOP action register is the consolidated list of recommendations extracted from all the worksheets, tracked through closure with owner, due date, status, and closure evidence. The worksheet is the study artifact, the register is the action tracker. See the HAZOP register template for the register format.

For Indian refinery and petrochemical work under MoPNG and PNGRB jurisdiction, the HAZOP node worksheet additionally records OISD 118 clause references for recommendations affecting layout, inter-distance, or hazardous area extent. For brownfield HAZOP revalidation, the worksheet captures superseded P&ID node references explicitly so closed actions can be re-verified against the current plant. Pathnovo's brownfield HAZOP prep handles tag renames, equipment substitutions, and P&ID revisions automatically. See the OISD 118 compliance workflow.

When the HAZOP team identifies a deviation whose risk rating requires a Safety Instrumented Function (SIF) as an independent protection layer, the recommendation triggers SIL classification per IEC 61511. The SIL Classification column on the worksheet captures the target SIL (typically SIL 2 or SIL 3 in refinery and petrochemical scope). The classification is then quantified through LOPA, the SIF is designed against the SIL target, proof test intervals are set, and the SIF feeds the Safety Requirements Specification (SRS). See the SIL standard reference.