SIL assignment

SIL Notes

Objective : SIL assignment establishes the risk reduction needed for each

                    process system to protect against one or more hazards, 

                    The risk reduction is calculated as the gap between the existing risk posed by the                          process or equipment and the risk target.

                    Risk reduction (Layer of Protection) is provided by process and mechanical                                  integrity, Independent Protection Layers (IPLs) and required Safety Instrumented                      Systems (SIS).

Scope :  The SIL level of each Safety Instrumented Function (SIF) is to be calculated,

              Design of Safety Integrated Systems is adequate to protect personnel, environment,                      assets, reputation and local safety against potentially hazardous situation

              This study only performed an assessment of the required SIL levels for each SIF/

              ESD loop of Process Skids,Units et all.

              The SIL assignment( Ex-SIL2/SIL3 like that) included all SIF loops which were                            selected from Cause & Effect and identified from HAZOP study findings

 

Technique : Layer of Protection Analysis (LOPA) method allows the user to determine the risk                       associated with various hazardous events , severity and the likelihood.

Independent Protection Layers (IPLs)

The operator has an adequate alarm system

There are written procedures stating the operator action

The operator regularly completes the action as a drilled exercise

The operator can effectively respond to the alarm within 30 minutes