Determining the SIF Analysis Target PFD

The aim of a SIF Analysis is to design the Subsystems such that the Achieved PFD is equal or higher than the Target PFD. The Target PFDs are typically established during the LOPA study. In some cases, a SIF Analysis can be started independent from a LOPA, e.g., when you have an emergency button. In this case a static Target SIL must be specified during the SIF Analysis.

If the SIF is connected to a LOPA

After a SIF Barrier has been added to the LOPA, the calculated risk gap shown as the Overall PFD in the Assessment Summary is transferred to the SIF Analysis as the Target PFD for the SIF design verification calculations in the SIF Analysis.

The Overall PFD is transferred to SIF Analysis as the Target PFD. 

The SIF name is a hyperlink that will navigate you to the SIF Analysis. 

The LOPA and SIF Analysis are linked. Note: When the Target PFD of the SIF is changed from the LOPA, the SIF Analysis (if Approved) will fall back to Draft.

If connected to multiple LOPAs

It is possible to have multi scenario LOPAs for a SIF Analysis. All LOPAs will show on the SIF Analysis. The worst Overall PFD will be used as the Target PFD for the SIF design verification calculations in the SIF Analysis.A SIF Analysis connected to multiple LOPAs.