How to perform Time Impact Analysis / Window Analysis in Primavera P6

A Time Impact Analysis is a method used to determine extent of impact from potential delay in construction process. This schedule analysis method involves the insertion or addition of activities indicating delays or changes into an updated schedule representing progress up to the point when a delay event occurred to determine the impact of those delay activities.

Types of Delays

Delays can be categorized in two main areas:

• Excusable Delays
• Non-Excusable Delays

Excusable delays occur when the affected party is allowed to claim for a time extension, compensation or both. Meanwhile, non-excusable delays are delays that the contractor or party affected will need to bear the responsibility.

We have a simple project with the Planned schedule like this:

1st month.

We have delay (21 days) on Excavation due to Unforseen site condition

2nd month.

We have no delay.

3rd month.

We have 2 delays:

• Owner change house design (14 days)
• Subcontractor left job (21 days)

And those are concurrent delay. So 14 days charge to owner, and 7 day charge to contractor

4th month.

We have 1 delay from Contractor in “Garage Walls” but it was not on the critical path. As long as the delay is within available float there is no effect on the final completion date.

5th month.

We have 1 delay (28 days) from Owner in Garage Doors but it only affect 7 days in the critical path. Other 21 days were absorbed by available float.

Last month.

We don’t have any delay.

So we can have the Time Impact Analysis report like this:

• 28 days for time and cost
• 14 days for time

Thank you for your time to read this article.