What is Time Impact Analysis (TIA) in construction?

Time Impact Analysis is a scheduling technique used to predict the effect of delays on a project's completion. It inserts a simulated delay into the current project schedule to analyze how it affects the critical path and overall timeline. TIA is widely used in Extension of Time (EOT) claims and is considered a proactive, forward-looking approach.

How accurate is Time Impact Analysis in measuring delays?

TIA can be highly accurate if the project schedule is regularly updated and the inserted fragnet reflects realistic durations and logical ties. However, its accuracy diminishes if the baseline is flawed or if the delay is poorly documented. Studies and industry experience show that properly applied TIA methods can reduce dispute resolution times by up to 30%.

What is a fragnet (Time Impact Analysis) TIA?

A fragnet is a small, isolated sequence of tasks representing a delay event. It is inserted into the project schedule at the point the delay occurred. The fragnet’s logic, timing, and relationship to other activities are critical for demonstrating how the delay affected the project’s critical path.

When should TIA be used instead of retrospective delay analysis methods?

TIA is best suited for active projects where delays are still unfolding and need to be assessed in real time. It is often required in contracts like FIDIC and NEC for prospective EOT claims. In contrast, retrospective methods like As-Planned vs. As-Built are typically used after project completion.

Does TIA account for concurrent delays?

TIA focuses on the insertion of a single delay event and its effect on the schedule. It does not inherently account for concurrent delays but can be combined with concurrency analysis to address overlapping delay events and determine entitlement more precisely.

Is Time Impact Analysis accepted in legal and arbitration settings?

Yes, TIA is widely accepted in court and arbitration proceedings when applied according to industry standards. Protocols like the SCL Delay and Disruption Protocol and AACEI RP 29R-03 reference TIA as a credible method. However, it must be well-documented and based on a sound, contemporaneous schedule to withstand scrutiny.

What are common mistakes to avoid when performing TIA?

Common pitfalls include using outdated or unrealistic baselines, inserting fragnets without proper logic ties, and failing to maintain detailed delay records. These issues can weaken a claim and may lead to its rejection during dispute resolution or audit reviews.

Time Impact Analysis (TIA) – Construction Delay Method Explained

Introduction

Time Impact Analysis (TIA) is a highly effective method for evaluating the effects of delays on construction project timelines. It’s a prospective analysis method, predicting how new delay events might influence the future project completion date, and frequently required for Extension of Time (EOT) claims.

1. What Is Time Impact Analysis?

TIA involves inserting delay events directly into the current approved schedule to demonstrate their impact. Ideal for real-time delay assessment, it's widely recognized for its fairness and predictive capability.

2. How TIA Is Performed

Key steps include:

Baseline Selection: Use the latest approved schedule.
Insert Delay Fragment: Add a "fragnet" (activities representing the delay) at the date of occurrence.
Recalculate Schedule: Run a Critical Path Method (CPM) analysis to measure delay effects.
Document Impact: Clearly show the impact on critical path or new critical activities.

Example Application:

"If late procurement delays a critical activity by 10 days, inserting this delay into the schedule using a fragnet shows a corresponding 10-day extension to the project completion date."

time impact analysis construction gantt chart critical path time impact analysis tia delay fragnet insertion diagram

3. Key Contractual Considerations

Different contracts have varying TIA requirements:

FIDIC: Timely delay notices (Clause 20.2) and detailed substantiation required.
NEC: Emphasizes early warning and prospective analysis.
JCT: Clear documentation and immediate notification essential.

Common pitfalls:

Failure to notify delays promptly. Ready this about timely notices - Important!
Inadequate documentation or insufficient baseline updates.

4. Comparison with Other Methods

Method	Type	Best Used For
TIA	Prospective	Ongoing projects, real-time delays
As-Planned vs. As-Built	Retrospective	Completed projects, historical analysis
Window Analysis	Retrospective	Complex projects, phased delays

Concurrent Delays: TIA clearly isolates impacts but should be paired with concurrency analysis when overlapping delays occur.

5. Best Practices for Effective TIA

Schedule Quality Checks: Maintain realistic and regularly updated baselines.
Fragnet Development: Ensure logical ties, accurate durations, and realistic sequencing.
Software Tips: Avoid common errors in Primavera P6/MS Project by regularly validating CPM logic.

6. Legal & Dispute Resolution Perspective

Courts and arbitrators widely accept TIA, scrutinizing it closely for signs of manipulation. Following recognized standards such as the SCL Delay & Disruption Protocol and AACEI RP 29R-03 enhances credibility.

7. Common Challenges & Mitigations

Disputed Baseline: Use contemporaneous and regularly updated schedules as supporting evidence.
Concurrent Delay: Integrate TIA with concurrency analysis to clearly delineate responsibilities.

8. Tools & Templates

Use these resources for stronger documentation and submissions:

cashflowpot screen cashflow

Conclusion

Time Impact Analysis is essential for accurately assessing and documenting construction delays. Implementing best practices, understanding contractual requirements, and maintaining proper documentation ensures robust and defensible EOT claims.