Piping and instrumentation diagrams must accurately reflect the as-built condition of the process at all times. OSHA has been explicit: P&IDs are not historical artifacts, they are living documents. Facilities that allow P&IDs to fall out of sync with the installed configuration, or that rely on redlines and field marks without formally updating the drawings, create a cascading compliance problem that affects PHA quality, PSSR completeness, and mechanical integrity inspection planning. These letters address what current means, how frequently P&IDs must be verified, and what constitutes an acceptable update process.
What OSHA Has Said
Jun 28, 2019
P&ID Currency and Requirement for As-Built Accuracy After MOC
OSHA addresses the obligation to update P&IDs as part of, or immediately following, any change that modifies the installed configuration. Redlined field drawings do not satisfy the PSI currency requirement for more than a brief interim period.
Read OSHA Letter ↗
Dec 22, 2003
P&ID Accuracy Verification as Part of PHA Preparation
OSHA confirms that P&ID accuracy should be verified before a PHA or revalidation is conducted. A PHA based on inaccurate P&IDs is insufficient because the hazard analysis is only as good as the design basis documents it relies upon.
Read OSHA Letter ↗
Feb 7, 1996
Acceptable Interim Practices for P&ID Redlines
OSHA addresses the acceptable interim period during which a redlined P&ID may be used in lieu of a formally updated drawing. OSHA does not specify a hard timeline but expects the formal update to be completed promptly after construction is finished.
Read OSHA Letter ↗
⚡ Key Compliance Takeaway
A redline is a gap, not a solution. Budget for formal P&ID updates as part of every MOC closure, and verify drawing accuracy before every PHA or revalidation. A PHA conducted on inaccurate P&IDs is a multi-element compliance failure.