Float times

The float time is the time in working days between activities. Float times can vary.

Float times that concern an activity:
  • Total Float: The extension allowed for an activity expressed in working days.
  • Free Float: The free float-time between one activity and the next. The free float-time indicates how many days the activity can be extended without jeopardizing the progress of other related activities.

The calculation is done as follows: If the value of the Relation Type field is equal to ES (End-Start) (the next activity starts when the preceding activity has ended) then

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

If the value of the Relation Type field is SS (Start-Start) (the next activity and the preceding activity start simultaneously) then

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

Both float times are calculated after you run the Generate Network Planning (tipcs4210m000) session. If both float times are zero, the activity belongs to the critical path. The absolute relational float between activities is maintained in the Activity Relationships (tipcs4110m000) session.

Float times can be entered in two ways:

  • Float Time (Day) The float time between the preceding activity and the next one expressed in working days. This float time is used to determine the start date of the next activity. The relation type is an important factor: The value ES (End-Start) indicates that the start date of the next activity is equal to the finish date of the preceding activity plus the relative float-time. The value SS (Start-Start) indicates that the start date of the next activity is equal to the start date of the preceding activity plus the relative float-time.
  • Float Time (in Perc) The same float time as the Float Time (Day), but expressed as a percentage of the duration of the preceding activity.

One of the two sorts float-times can be entered in the Activity Relationships (tipcs4110m000) session.