other LOPCs;or identify others that are meaningful to its operations.A Company shall develop and use Tier 3 Indicators.7.2 Examples of Tier 3 PSEs7.2.1Safe Operating Limit Excursions7.2.1.1 Indicator DefinitionA process parameter deviation that exceeds the safe operating limit (SOL) applicable to the phase of operation.Different operating phases (e.g. regeneration or steps in a batch process) may have different SOLs for the sameequipment. Figure 3 depicts the relationship between normal operating limits, high/low alarm limits, and the SOL.Exceeding the SOL represents the point beyond which troubleshooting ends and pre-determined action occurs toPROCESS SAFETY PERFORMANCE INDICATORS FOR THE REFINING AND PETROCHEMICAL INDUSTRIES19return the process to a known safe state. The predetermined action may range from manually executed operatingprocedures to a fully automated safety instrumented system.