Critical Path Determination in Network Diagram with Lags/Leads


I am not really clear on how critical path is determined manually from a network diagram with Lags/Leads.


Without lags/leads I understand the critical path is the longest path in the network diagram and each task/activity on the critical path has its Start of Activity (LS-ES=0) and Finish of Activity (LF-EF=0) in short no slack at all. In addition, we can also add the individual duration of activities in the critical path to get the EF of the project.


Now how do we use this same principle on a network diagram attached below with lags to determine the critical path where Start of Activity (LS-ES) and Finish of Activity (LF-EF) have different values on the same activity for some of them? We know the EF of the attached network diagram is 52 once I have completd the backward and forward pass.


Can someone please let me know how the critical path is determined manually. Your input much appreciated. If I were to use MS Project for this network diagram it can clearly highlight the critical path. My question how do we do it on paper. What is rule if any that we need to apply to identify this critical path.


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