Using Construction Scheduling Services: The F9 (Schedule) Function in Primavera P6 to Analyse Multiple Critical Paths

In complex construction projects, scheduling is more than simply updating dates—it’s about understanding the true drivers of project completion. Robust processes in schedule analysis are essential to ensure accuracy and reliability. Primavera P6’s F9 (Schedule) function recalculates the entire programme, updates logic, and identifies critical activities.

However, when your project contains multiple critical paths, relying solely on Total Float ≤ 0 may not give an accurate picture. Different calendars, constraints, lags, and resource allocations can all distort float values across activities, highlighting the need to accurately measure and estimate activity durations and resource allocations.

A smarter approach involves using P6’s advanced schedule options to reveal the actual driving logic of the programme. Analyzing data from multiple sources supports better decision-making throughout the project lifecycle.

Below are four essential techniques for achieving accurate critical path analysis when working with F9. It is important to review schedule data to ensure accuracy at every stage.

Introduction to Project Management

Project management is the backbone of the construction industry, underpinning every successful project from inception to completion. At its core, project management involves the strategic application of knowledge, skills, and proven techniques to guide a project through its entire life cycle. This process begins with early project planning and extends through scheduling, execution, and final delivery, ensuring that every objective is met efficiently and effectively.

For project managers, mastering the project life cycle is essential. It means overseeing project scope, managing costs, and maintaining tight control over schedules to deliver results that meet or exceed client expectations. In the construction industry, where projects are often complex and high-value, robust project controls are especially important. These controls enable teams to monitor progress, manage risks, and ensure that quality standards are upheld throughout the construction process.

Effective project controls are not just about tracking costs and timelines—they are about enabling proactive decision-making and ensuring that every aspect of the project aligns with strategic objectives. By integrating comprehensive project planning, scheduling, and management practices, construction professionals can deliver projects safely, on time, and within budget. This disciplined approach is what sets successful projects apart and is why project controls are considered essential for achieving consistent, high-quality delivery in the construction sector.

1. Use “Longest Path” Instead of Total Float in Scheduling Planning

Total Float-based critical paths can be misleading when calendars, constraints, or resource leveling affect float. The Longest Path option identifies the key sequence of activities that directly drives the project’s final completion.

Why it matters:

• Identifying the key sequence of activities is essential to ensure project success

• Shows the real driving chain of activities

• Helps project teams stay focused on what matters most

Best for:Identifying the primary critical path and staying focused on the key drivers of project completion.

2. Enable “Multiple Float Paths” Analysis for Project Controls

You can access this option from: F9 → Options → Advanced → Calculate Multiple Float Paths

This feature allows you to trace secondary and tertiary critical paths, starting from a selected milestone—usually the project completion activity. It provides a comprehensive set of analytical options for schedule review, enabling deeper insight into project timelines.

You can choose to calculate based on:

• Free Float

• Total Float

Why it matters:

• Helps track activities that may not be on the main critical path but pose significant risk

• Offers a layered view of path importance

• Essential for schedule risk modelling and delay analysis

• Enables evaluation of a wide range of critical paths and scenarios for more robust project planning

3. Adjust Float Thresholds

If several paths appear equally critical, set a Float Threshold (e.g., ≤ 5 days) to identify near-critical activities.

This creates a clearer picture of emerging risks and potential bottlenecks before they impact the main critical path. By setting float thresholds, you support the development of targeted strategies for risk management and enable the team to proactively address issues.

Why it matters:

• Highlights vulnerable areas in the schedule

• Useful during time-impact analysis or risk workshops

• Helps planners prioritise reviews and the development of effective mitigation strategies

4. Project Managers: Check Driving vs. Non-Driving Logic

In Primavera P6, go to: Activity Details → Relationships

Here you can see which predecessors are driving the activity’s start or finish date. Project managers oversee this process to ensure the accuracy of the driving and non-driving logic.

Why it matters:

• Distinguishes genuine drivers from parallel or optional logic paths

• Helps eliminate false critical paths

• Confirms the accuracy of the schedule’s logic network, with various stakeholders involved in the review and validation of the schedule logic

Summary: Why These Tools Matter in Project Management

Relying solely on float can provide misleading results, especially in large, multi-phase construction projects. Using F9 with the right advanced settings ensures that planners and project managers can:

• Identify true critical and near-critical paths

• Evaluate schedule risk more accurately

• Understand logic drivers clearly

• Produce reliable updates for stakeholders

Effective project controls are important for achieving significant saving of both time and money for our clients. Budgeting is a key aspect of project controls, supporting robust cost management and ensuring projects remain within financial targets.

At B Project Ltd., we offer a comprehensive range of services, including contract and contract administration, tender planning, and bid preparation. Our extensive experience and proven success in delivering project controls services allow us to demonstrate our capabilities and engage with clients to ensure project success. Our project controller plays a vital role in managing cost, time, and quality objectives throughout the project lifecycle.

We help clients obtain accurate data and quotations to support informed project decision-making, and our team is skilled in preparing comprehensive bids that meet all tender requirements. Our expertise extends to the development and creating of effective project controls systems and strategies tailored to each client's needs.

If you are interested in exploring how our services can support your next project, or would like to learn more, please contact us for more information or support. We are ready to engage with you and demonstrate how our approach can drive success for your construction projects.