OSHA's PSI requirements include consequence analysis, which is assessment of the consequences of failure of process controls including overpressure, overtemperature, upset conditions, and similar scenarios. This element intersects with the PHA requirement and with facility siting. OSHA has addressed the level of detail expected, whether qualitative or quantitative consequence analysis is required, and how consequence analysis findings must be documented in the PSI package. These letters are relevant to facilities evaluating facility siting, occupied building risk, and control room vulnerability.
What OSHA Has Said
Feb 1, 2005
Consequence Analysis Depth and Qualitative vs. Quantitative
OSHA addresses the level of detail expected in consequence analysis documentation. Qualitative analysis may be sufficient for straightforward scenarios, but complex processes with high consequence potential may require quantitative dispersion or explosion modeling.
Read OSHA Letter ↗
Dec 22, 2003
Consequence Analysis and Facility Siting Requirements
OSHA addresses the interaction between consequence analysis and facility siting evaluation. The PSI consequence analysis provides the input for facility siting, so if consequence analysis is inadequate, the facility siting assessment is also inadequate.
Read OSHA Letter ↗
Feb 7, 1996
Documentation Requirements for Consequence Analysis
OSHA clarifies what must be documented in the PSI package with respect to consequence analysis. Undocumented analyses that exist only in individuals' heads are not compliant. Findings must be captured in written form and retained.
Read OSHA Letter ↗
⚡ Key Compliance Takeaway
Consequence analysis is a documentation requirement, not just a modeling exercise. Results must be captured in writing, incorporated into the PSI package, and used as the basis for facility siting and PHA scenario evaluation. Unwritten analyses do not satisfy the standard.