A short article from TheP6Pro at Ten Six describing the process for creating a project level constraint in Primavera P6 EPPM Web that will produce negative float, if the schedule slips past this constraint.
It is best to avoid project constraints, however, sometimes they can describe the importance of a constraint that cannot be ignored. If this is your situation, than you want to become familiar with the procedure for creating a project level constraint in Primavera P6 Enterprise Project Portfolio Management (EPPM).
Generally, you want the schedule’s activity durations and corresponding relationships to determine the project completion date. There may be, however, external factors that are critical to consider and that may drive the schedule end date. You may have legal or environmental regulations that cannot be ignored. Environmental regulations include limitations placed on work sites during eagle nesting or salmon spawning seasons. You also may not be allowed to maintain a mobilized work state during race days at the track. Regardless of your restrictions Primavera P6 EPPM Web allows you to define a project constraint, so that you can consider your schedule situation and make adjustments, accordingly.
In this article we describe the process for creating a project level constraint in Primavera P6 EPPM Web that will produce negative float, if the schedule slips past this constraint.
Project Level Constraint
Our project is a steam line expansion joint replacement project. We are provided a small window of opportunity to make the expansion joint replacements, as the steam line services the hospital. If the project does not complete on time, it could delay scheduled hospital operations. These delayed operations could result in a potentially life threatening situation. It is therefore imperative that the expansion joint replacement project complete during the small window of opportunity provided by the hospital.
Our Steam Line Expansion Joint Replacement project is displayed in Figure 1.
As shown in the Figure, the project begins on Monday January 4th, 2016, and completes on Monday January 18th, 2016. The schedule completion date only considers activity duration estimates and the relationships between activities. It does not take into consideration any project constraint dates. The vast majority of activities (except two) on this project have a total float of zero, which indicates they are on the critical path.
The hospital has directed that the project commence on January 4th, 2016 and complete no later than close of business Thursday, January 14th, 2016. The completion date is a mandatory project constraint that must be adhered to or your project will impact the hospital schedule and, possibly, result in a life threatening situation. To make certain the project completes by the critical end date, you set a Must Finish By constraint on the project of January 14th, close of business.
The procedure for inserting this project constraint requires first setting the Time Format to display minutes. To change the preferences to show minutes select Administer | My Preferences. In the Date Format section of My Preferences set the Time Format to show minutes, Figure 2.
Second while in the EPS select the Expansion Joint Replacement project and in the bottom view select the General tab then set the Must Finish by date to January 14th, 2016 at 4:00 PM, Figure 3. Third recalculate the schedule.
Adjusting the Schedule
After recalculating the schedule, the Expansion Joint Replacement project schedule with the Must Finish By constraint is as displayed in Figure 4.
Note that activities on your critical path have a total float of minus 2-days. Your schedule therefore must make up 2 days. Inspection of the schedule reveals the most likely option is for the project manager to work overtime on the weekend to begin writing the quality assurance repost, and to complete it no later than close of business on Wednesday, January 13th.
Fast tracking the schedule by performing the North and South expansion joint removals and installations in parallel is not feasible, as you only have one welding crew. And decreasing the scope of work by only replacing one expansion joint is prohibitive.
The most possible and least impact option is for the project manager to work overtime on the weekend to begin writing the quality assurance report. However, this is an exercise to demonstrate how to apply a project Must Finish By constraint, and how to consider modifying the schedule accordingly. You apply the constraint in the EPS bottom pane General tab. The total float column in the activities view displays the impact the constraint has on the entire project. You then make the necessary schedule adjustments based on this information.
The Must Finish By project level constraint is a helpful feature to describe a completion date that must be adhered to. Inserting the constraint is a straight forward process. The challenge comes when you try to analyze the constraints impact on the schedule’s total float, and when you try to adjust the schedule accordingly. It is best to use project constraints sparingly. However, a project constraint may be needed to better understand a critical completion date’s impact on the schedule.
Source: Ten Six Consulting