INTRODUCTION TO PRIMAVERA P6 RELATIONSHIPS

To develop the project schedule, the project manager or the scheduler starts introducing project-specific data, such as activities, milestones, and activity durations, into the scheduling tool, Primavera P6 in this case, describing :

• The work to be done (What)
• The required resources to do the work (Who & What)
• Activity sequence, activity starts, finishes (When), and
• The optimum way or the defined sequence to do the work (How)

WHAT IS AN ACTIVITY RELATIONSHIP?

A relationship in Primavera P6 is the logical connection between project activities and milestones. After defining project activities, the project manager or the scheduler studies the activity list and the milestone list and starts connecting them in a logical sequence. In project management, this process is called “Sequence Activities” and the connection is called a relationship.

The technique used is Precedence Diagramming Method PDM and it includes four types of relationships.

TYPES OF RELATIONSHIPS IN PRIMAVERA P6

PDM in Primavera P6 uses four types of relationships: Finish to Start (FS), Start to Finish (SF), Finish to Finish (FF), and Start to Start (SS).

Finish to Start FS :

It is when an activity starts when its predecessor is finished. This is the most common activity relationship type in project management. As indicated in the example: «Testing the air conditioning system» starts only after the «Installation of the electrical cabinet» is completed.

The «Installation of the electrical cabinet» is called Predecessor and the «Testing of the air conditioning system» is the Successor.

Finish to Finish FF:

It is when an activity must be completed before its successor can finish.

For instance«Final cleaning» needs to finish before «Handover» is complete.

Start to Start SS:

It is when an activity can not start until its predecessor has started.
For example, «Install of ground cable sleeves» and «Closing of ground opening

Start to Finish SF:

It is when an activity can not finish until its successor has started. This is the least common activity relation type in project management. For instance, a day shift security can not finish until the night shift security has started.

ADDING AND DELETING RELATIONSHIPS IN PRIMAVERA P6

The easiest way to add or delete an activity relationship in Primavera P6 is:

• Click on the activity.
• Go to the lower pane, activity details
• Click on the icon Assign Predecessor or Assign Successor, then select the relationship from the list.
• Choose the relationship.

• Delete a relationship by selecting a relationship and clicking on the Remove icon.

ADDITIONAL INFORMATION

To prevent open ends, it is recommended that every activity and milestone have at least one predecessor and one successor except for the start milestone (with no predecessor) and the finish milestone (with no successor). You can check if your schedule contains open ends by displaying the Predecessors and Successors columns.

All activities should be linked to make the schedule network diagram. The project manager then estimates activity durations before developing the project schedule using the Critical Path Method CPM.