Critical Path Analysis

The critical path analysis is used in network planning to determine the optimum route for the project from the time the first activity starts till the completion of the last activity. An activity is a part of the critical path if the Total Float and the Free Float fields are set to zero in the Activities (tppss2100m000) session. You must select the Critical check box in the Project Schedule (tppss2700m000) session to view the critical path on the planning board.

If the activity data is modified, the critical path can change. To view the updated data, you must regenerate the network planning using the Generate Network Planning (tppss2240m000) session.

Float Time:

The critical path analysis considers activity relationships, constraints of activities and milestones, and progress to calculate:

  • The earliest and latest start and finish dates
  • Free float time
  • Total float time
Note: The float time for an activity can vary.

Float types for an activity:

  • Total Float: The number of days for which an activity can be delayed without affecting the next activity.
  • Free Float: The number of days for which an activity can be delayed without affecting the project’s start or end date.

Calculating float time

If the Relationship Type field is set to Finish-to-Start in theActivity Relationships (tppss2510m000), the next activity starts when the preceding activity is completed:

Free float-time (ES)= Earliest start date of the next activity - relation float times - activity duration - earliest start date

If the Relationship Type field is set to Start-to-Start in the Activity Relationships (tppss2510m000), the next activity and the preceding activity start simultaneously:

Free float-time (SS)= Earliest start date of the next activity - relation float times - earliest start date

The float times are calculated using the Generate Network Planning (tppss2240m000) session. If the value of both the float times is zero, the activity is a part of the critical path.

Network planning can be performed for the project only if:

  • The Update Mode option in the Plans (tppss0110m000) session is set to Update.
  • The Project Status Construction is set to Free or Active in the Project (tppdm6600m400) session.