Lag and Relationships In Primavera P6

Lag and lead

Lag time is a duration that is added to a relationship link to impose a wait time between an activity and its successor in PrimaveraP6.

A lag is a duration that is applied to a dependency to make the successor start or finish earlier or later.

A successor activity will start later when a positive lag is assigned.Therefour an activity requiring a 3 day delay between the finish of one activity and start of another will require a positive la of 3 days.

Conversely a lag may be negative when a new activity may be started before the predecessor activity is finished .this is called a lead or negative lag.

What is Predecessor and Successor?

A predecessor is an activity whose start or finish controls start or finish of another activity. And a successor is an activity whose start or finish is controlled by start or finish of another activity. In process of determining relationships between activities, predecessor and successor activities are identified first and then they are given a relationship type, for example Finish to Start.

Types of Relationships:

There are four types of relationships in Primavera P6.

• Finish to Start or FS
• Start to Start or SS
• Finish to Finish or FF
• Start to Finish or SF

   

 Finish to start or FS

Predecessor must finish before Successor can start. [Land must be purchased before road building can start].

Start to Start or SS

Predecessor must start before Successor can start. [Road excavating must start before Asphalt can be laid].

Finish to Finish or FF
Predecessor must finish before Successor can finish. [Laying Asphalt must be complete before line painting can be completed].

Finish to Finish or FF
Predecessor must finish before Successor can finish. [Laying Asphalt must be complete before line painting can be completed].


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