Scheduling guide
By Firat Acar, Founder and CEO, Plan104 · October 25, 2026
A time impact analysis shows how a change or delay event affects the project completion date. Done well, it is one of the clearest ways to request a time extension. Done poorly, it is easy to reject. Here is how we prepare a TIA that holds up.
Identify the change, delay or disruption, when it started and who is responsible for it. Check the contract for notice requirements and the TIA method it requires. Many contracts specify that a TIA must be submitted within a set number of days.
Use the accepted schedule update in effect just before the event. This represents the project as it was planned when the event happened. Using a later update, or the baseline, mixes in other delays and weakens the analysis.
A fragnet is a short sequence of new activities that represents the event, for example an RFI response, a design revision, a resubmittal and the added work. Give each activity a realistic duration and tie it into the existing work it affects with proper logic.
Insert the fragnet into a copy of the selected update, recalculate the schedule and compare the completion date and critical path before and after. The difference in the completion date is the impact of the event. Check that the critical path now runs through the fragnet, which shows the event is actually driving the delay.
Review whether other delays, by either party, were happening at the same time, and whether resequencing could reduce the impact. Owners will look for both, so address them before they ask.
Write a clear narrative: the event, the update used, the fragnet logic, the result, and the supporting records. RFIs, emails, daily reports and photos turn a schedule calculation into evidence. On projects that use the Plan104 platform, these records are already documented against each schedule activity.
Need a TIA prepared or reviewed? See our time impact analysis services.
A fragnet is a fragment network: a small group of activities and logic added to a schedule to represent a change or delay event in a time impact analysis.
Normally the accepted update in effect immediately before the delay event, so the analysis reflects how the project was planned at that time.
A TIA is usually prospective, prepared when the event occurs and before the work is complete, but it can also be performed after the fact with contemporaneous updates.
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