What Is Process Safety Information (PSI)?
Process Safety Information (PSI) is the technical and safety information needed to understand process hazards and operate a facility safely. PSI commonly includes chemical data, process chemistry, equipment design basis, relief systems, drawings, and safeguards.
By Enthovion Editorial Team · Published 2026-07-05 · Updated 2026-07-21
Key takeaways
- PSI underpins hazard analysis and operational decisions.
- Incomplete PSI increases review risk during MOC and startups.
- PSI should be maintained and version-controlled.
- Human review is required before relying on PSI for critical decisions.
Common PSI categories
PSI scope can vary by facility type and jurisdiction, but commonly includes:
- Chemicals and SDS
- Process chemistry and safe operating limits
- Equipment design basis and relief systems
- P&IDs, drawings, and electrical classification
- Safeguards and controls
Why PSI completeness matters
Incomplete PSI can lead to gaps in HAZOP, MOC, and PSSR reviews. Teams need a clear view of what information exists, what is missing, and what changed.
Practical example
During a MOC for a heat exchanger change, engineers verify that updated P&IDs, relief system basis, and operating limits are reflected in PSI before PSSR approval.
Limitations
- PSI requirements vary by regulation and internal standards.
- PSI must be kept current as equipment and chemistry change.
- Software can support organization but does not replace engineering judgment.