Assess the Safety Integrity Level (SIL) via a Process Hazards Analysis (PHA)

This topic describes how to assess the Safety Integrity Level (SIL) of an Instrumented Function using the risk assessment of a Process Hazards Analysis (PHA), which has been mitigated by one or more safeguards. If a risk has not been mitigated, then the unmitigated risk assessment is used instead.

Steps

Access the Instrumented Function for which you want to assess the SIL value.
In the workspace, select the SIL Assessment tab.

The SIL Assessment section appears.
In the SIL Assessment section, in the upper-right corner of the All SIL Assessments subsection, select Add Assessment, and then select PHA Internal.

A blank datasheet for the PHA Internal assessment appears.
Next to the Hazards Analysis ID field, select .

The Search window appears.
In the upper-right corner of the window, select .

A list of Hazards Analysis appears.
Select the Hazards Analysis that you want to link to the PHA Internal Assessment, and then select OK.
In the upper-right corner of the datasheet, select .

The list of Cause-Consequence pairs linked to the selected Hazards Analysis appears in the PHA Internal Risk Assessment subsection below the datasheet.
Select the check box that corresponds to the Cause-Consequence pair that you want to use for SIL assessment.

Note: You can access the risk matrix associated with the selected Consequence by selecting View Risk Matrix.

The GE Digital APM system calculates the following values in the PHA - Internal datasheet based on the selected Consequence and its overall risk rank:
- Safety Integrity Level (SIL)
- Risk Reduction Factor (RRF)
- Required Probability of Failure
- Failure Rate UOM
- Availability Target

Results

The PHA - Internal record that you have created is listed in the SIL Assessment section.

What's Next?

Associate an SIL Assessment with an Instrumented Function