Free Float and Total Float in Critical Path Method for Project Program Schedules

Two essential terminologies are Total Float (TF) and Free Float (FF). Total Float represents the duration an activity can be delayed without impacting the project's finish date. When Total Float is negative or zero, it signifies that the activity is critical for project completion and is known as a Critical Activity. On the other hand, Free Float denotes the amount of time an activity's early start can be delayed without affecting the early start of its successor activity. Activities with Free Float are referred to as Non-critical Activities. These terminologies play a fundamental role in scheduling and managing project timelines, distinguishing critical from non-critical elements in project planning?and?execution.

Critical Path Method (CPM) is a project management technique used to plan, schedule, and manage projects effectively. By identifying the critical path, CPM provides a structured approach to project planning, helping determine the project's minimum duration and optimize resource allocation. Critical Path Method schedule (“CPM”) that was reasonable,? and appropriate. Understanding and utilizing CPM can significantly enhance project management and contribute to successful project completion. Below the example for Critical Path Analyis

Critical Path and Float : Using simple network logic (finish-to-start) only, the critical path of an un-progressed CPM network calculated using the longest path criterion or the lowest float value criterion is the same. It is only when some advanced scheduling techniques are applied to the network model that the paths identified using these different criteria diverge

Project Program Schedule

The project schedule is the primary coordination tool as well as the communication tool, so without a schedule in place early the project is being managed without that primary tool. One of the biggest problems in the industry today is the poor quality of project schedules, which are intended to guide the execution of complex projects.

A project program schedule is a comprehensive document that outlines the sequence and timing of various project activities, illustrating the project's timeline from start to finish. This tool is crucial for project managers to ensure timely completion and effective allocation of resources such as manpower, materials, and finances. It serves as a roadmap, guiding all project stakeholders on the project's progress and what tasks need to be accomplished at each stage. The project schedule must incorporate the full scope of work, from beginning to end of the project. The rolling wave effort can be used to further detail the short-interim plan, but should not be used to replace a detailed schedule, in the single or dual submission model.

Creating a project program schedule involves breaking down the project into manageable tasks, estimating the time required for each task, and identifying dependencies between tasks. This schedule acts as a baseline against which the actual progress of the project can be measured. Through regular updates and adjustments to the program schedule, project managers can maintain control over the project's trajectory and make informed decisions to keep it on track. Here the 8-80 rule come into effect with a detailed activity breakdown applying the 8-80 rule of thumb, activity sequencing can be accurately defined using a Finish to Start relationship. This approach also aids in examining the critical paths and identifying multiple critical paths consistently within the program.

Lack of schedule detail – A lack of schedule detail will impact anyone’s ability to accurate determine schedule progress and will bring guessing into play

?Refer to the GAO-16-89G Scheduling Assessment Guide for Best Practices for Project Schedules or the Guild of Project Controls Compendium & Reference (GPCCaR)

Defining Critical Path and Its Significance

The critical path is the longest sequence of dependent activities within a project, determining the project's minimum duration. It is a crucial concept because any delay in activities along the critical path directly impacts the project's completion date. Identifying and managing the critical path is vital for successful project management.

As a rule of thumb, constructing and sequencing a project offers multiple approaches, with each update reflecting progress or lack thereof, influencing the plan. It's not unusual for the depicted Critical Path to deviate from expectations, influenced by factors like logic accuracy, update frequency, and duration estimates' reliability. The definition of the Critical Path is a question, whether it's the Longest Path, the Zero-Total Float Path, or the Lowest-Total Float Path. There can be disparities between what a CM or Planner believes should be on the Critical Path and what the network calculates. Such variations necessitate a closer evaluation of logic and settings, as discrepancies can arise due to complex network calculations. Adjusting software settings for Critical Path display can introduce further risks.

To determine the critical path, project managers need to analyze the project's network diagram, which illustrates the sequence of activities and their dependencies. By identifying the activities that have no float or slack (i.e., activities that cannot be delayed without delaying the project), the critical path can be established. Managing and monitoring the critical path is essential to ensure that the project is completed within the desired timeframe.

As a rule of thumb, project schedule manipulation is common in engineering and construction, often used to emphasize a particular critical path or compel stakeholders to take actions they might resist otherwise. This practice highlights the importance of maintaining transparency and integrity in project management, as manipulation can have both intended and unintended consequences.

Free Float: Definition and Purpose

Free float, also known as slack, represents the amount of time an activity can be delayed without affecting the project's duration or the start of any dependent activity. It provides flexibility in scheduling non-critical activities, allowing for efficient resource utilization and minimizing project delays. Free float is a valuable tool for project managers as it helps in optimizing resource allocation and scheduling non-critical activities in a way that does not impact the overall project timeline.

Understanding the free float of various activities allows project managers to make informed decisions about how to allocate resources and manage project schedules effectively. It offers the flexibility needed to adapt to changes or unforeseen circumstances during the project while still adhering to the project's overall timeframe.

Calculating Free Float

The free float for an activity can be calculated using the formula:

Free?Float=Earlt Start (ES) (i)?Early Finish (EF) (j)

where ES(i) is the early start time of the succeeding activity, and EF(j) is the early finish time of the current activity.

To calculate the free float accurately, project managers need to have a comprehensive understanding of the project's activity network and interdependencies between tasks. By applying this knowledge, they can optimize the project schedule and ensure efficient use of resources.

Importance of Free Float in Project Management

Free float is critical for project scheduling, resource allocation, and risk management. It allows project managers to optimize resource utilization by identifying activities that can be delayed without affecting the project's critical path. Efficient utilization of free float ensures a more resilient project schedule, accommodating unforeseen changes without disrupting the project timeline.

In a dynamic project environment, changes are inevitable. These changes can range from minor adjustments in task durations to major alterations in project scope. Free float provides the flexibility to incorporate these changes without impacting the critical path and, subsequently, the project's overall timeline. Project managers can strategically utilize free float to adapt to unforeseen circumstances, ensuring successful project completion.

Total Float: Definition and Purpose

Total float represents the total amount of time an activity can be delayed without affecting the project's completion date. It considers both the free float and any delay that can occur without delaying the project's finish. Total float acts as a buffer, providing project managers with the flexibility to manage uncertainties and unexpected events effectively.

In essence, total float represents the available flexibility within the project schedule. It allows project managers to absorb delays, uncertainties, or changes in non-critical activities without affecting the project's overall completion date. This additional time acts as a safety net, providing a margin for potential setbacks while ensuring the project remains on schedule.

Calculating Total Float

The total float for an activity can be calculated using the formula:

Total?Float=Late Start (LS) (i)?Early Start (ES) (i)

where LS(i) is the late start time of the activity, and ES(i) is the early start time.

Precise calculation of total float is essential for project managers to make informed decisions and manage project uncertainties effectively. By understanding total float, they can allocate resources more efficiently and plan for contingencies, enhancing project control and success.

Role of Total Float in Project Control

Total float plays a significant role in managing project uncertainties and variations. It acts as a cushion, allowing project managers to handle delays or disruptions in non-critical activities without affecting the overall project timeline. By strategically utilizing total float, project managers can maintain control over the project and ensure its successful completion.

Whenever the topic comes about free float and total float, then there is a question, the float ownership come to the picture, and who owns the float, the client or the contractor.? Based on industry best practices, when contracts are silent on float ownership, it is typically assumed that float is available to the first user to need it. That means that there is unlikely to be any entitlement on the contractor’s part to that float, and so, yes, the client can delay his work to the end of his float path. Whilst, total float is reported on each activity, it is a path value, not an activity value, so if he uses up all the total float on his activity, that makes all activities that are on the same future path to be immediately critical. That does raise the risk to the contractor for his performance, leaving him with no buffer. That would include any client activities that are on that same future path.

Managing total float involves making strategic decisions to allocate resources optimally and adjust non-critical activities based on project needs. This strategic approach helps in balancing the project's timeline and resource utilization, ultimately contributing to successful project management and on-time completion.

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