Comparison
PSM vs PSSR: What Is the Difference?
Vinit Pandey · Published 28 June 2026
In short: PSM (Process Safety Management) is the overarching management system of interrelated elements that prevents catastrophic chemical releases across a facility's entire lifecycle. PSSR (Pre-Startup Safety Review) is one specific PSM element — a checklist-driven review confirming a process is safe to start up after new construction or a significant management-of-change modification.
| Aspect | PSM | PSSR |
|---|---|---|
| Scope | One specific gate review before startup | Entire management system, all lifecycle stages |
| When performed | Before startup after new construction or significant MOC | Continuously, across the facility's operating life |
| Relationship | One element within PSM / RBPS | Umbrella framework containing PSSR |
| Typical output | Pre-startup checklist sign-off | Element-by-element program (MOC, mechanical integrity, training, etc.) |
PSSR (Pre-Startup Safety Review) is often mentioned alongside PSM because it is one of PSM's required elements, but the two operate at very different scopes.
PSM is the overarching management system — under OSHA's 14-element standard or CCPS's 20-element RBPS framework — covering process safety information, hazard analysis, operating procedures, training, mechanical integrity, management of change, incident investigation, and more, across a facility's entire operating life.
PSSR is a single, specific gate review within that system: a structured, checklist-driven confirmation — before a new unit or a significantly modified process is started up — that construction matches design, safety systems are functional, operating procedures are in place, and any open management-of-change items have been closed.
A facility can have a strong PSSR checklist culture while still having significant PSM gaps elsewhere (e.g., weak mechanical integrity tracking), and conversely a facility with mature PSM still needs disciplined PSSR execution at every startup — PSSR effectiveness depends on the quality of the management-of-change process that feeds it.
Frequently Asked Questions
Is PSSR required by OSHA's PSM standard?
Yes — Pre-Startup Safety Review is one of the 14 elements explicitly required under OSHA's Process Safety Management standard (29 CFR 1910.119), and is similarly included in the CCPS RBPS 20-element framework.
When is a PSSR required?
A PSSR is required before introducing a highly hazardous chemical to a new process, and before startup following a modification significant enough to require management-of-change review.