🛢️ Oil & Gas · State Machine
Permit-to-Work Lifecycle
The safety permit that controls hazardous work at a refinery or rig: request, risk assessment, isolation, gas testing, work and handback.
Drawing diagram…
What this diagram shows
- Work can't start until isolation and gas testing are done
- Permits are suspended during alarms or shift changes
- Closure needs the area handed back and isolations removed
Prompt used
State machine for a permit-to-work at an oil and gas site: Requested, Risk Assessed, Approved by the area authority, Isolated (energy sources locked out), Gas Tested, Active while work runs. It can be Suspended for an alarm or shift change and revalidated, and when work finishes it goes to Handback, isolations are removed, then Closed. A permit can be Rejected at approval.
Mermaid code
stateDiagram-v2 [*] --> Requested Requested --> RiskAssessed: JSA completed RiskAssessed --> Approved: Area authority signs RiskAssessed --> Rejected: Risk too high Approved --> Isolated: Lockout / tagout done Isolated --> GasTested: Gas test OK GasTested --> Active: Work starts Active --> Suspended: Alarm or shift change Suspended --> GasTested: Revalidate Active --> Handback: Work complete Handback --> DeIsolated: Isolations removed DeIsolated --> Closed Closed --> [*] Rejected --> [*]
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