Schedule Quality Checks: An important aspect of an effective Turnaround Schedule.
Scheduling is the art of organizing activities and sequencing them against the timeline to achieve your targeted goal. Effective turnaround scheduling involves identifying and organizing essential activities with the necessary precision in a logical order on a feasible timeline, ensuring adequate resources are assigned for the timely and successful completion of the Turnaround Project.
Why is Scheduling important?
The schedule stands as an important outcome of planning and preparing for the Turnaround. It serves as a gauge to assess performance during Turnaround execution promptly and accurately, and reports the outcomes to stakeholders, enabling timely action on any necessary corrective measures.
What constitutes an effective Schedule?
With a good structure: Organized with the correct Work Breakdown Structure (WBS) based on the hierarchical structure of the process system, aligned with shutdown and startup sequences, and clearly defined activity grouping codes to meet reporting requirements.
With good quality: It undergoes standard schedule quality checks. This article is aimed at discussing various quality check points and their impact.
With high achievability: The Schedule needs to be confirmed to have a high probability of success in order to meet the target and be capable of absorbing a certain level of uncertainties in activity durations and those risks anticipated during execution, without compromising the overall completion target.
What are the Schedule Quality Check points?
Schedule checkpoints identify common issues in the schedule that could impact a deterministic plan and schedule risk analysis. An advanced scheduling tool is featured with an automated schedule analyser to obtain integrated Schedule Quality Checkpoints statistics & warnings. Following are the important schedule checkpoints.
1. Missing Logics (Open ended Tasks)
Scheduling best practices dictate that every activity, excluding the first and last, should have at least one predecessor and one successor. If an activity lacks a predecessor, it's likely constraint driven. Conversely, if it lacks a successor, it will exhibit notably high total float, signalling missing logic. Missing logic poses a risk by generating unrealistic float, potentially distorting the true critical path, and absorbing delays invisibly.
2. Hard Constraints
Constraints establish predetermined start or end dates for activities, which can be reasonable in certain cases. Yet, excessive reliance on them suggests scheduling issues, disrupting the logic-driven nature of the schedule, and jeopardizing the accuracy of the critical path. Overuse of constraints may hide delays, resulting in inaccurate finish dates.
3. High durations
High duration activities indicate that a schedule lacks sufficient detail, particularly in certain activities. This poses a risk as it can disrupt the critical path and the proper sequence of work.
Consequently, the true critical path may be obscured, and delays may not be accurately identified. Progress reporting may fail to reflect the actual situation. An optimal turnaround schedule should limit the number of activities with durations exceeding 12 hours or extending beyond one shift to no more than 5% of the total number of activities.
4. Zero duration activities
Activities with zero duration, apart from milestones, indicate that the activity requires no effort and serves purely as informational. Such information can be captured using a user-defined field. Adding such activities in the schedule can introduce unnecessary dependencies and impact the critical path without contributing to progress.
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5. Positive Lags
Positive lag represents non-working time between activities, like curing or drying time. However, excessive use of positive lags can obscure schedule details, hinder progress reporting, and affect the critical path negatively. It's advisable to replace lags with actual activities to ensure clarity and accurate progress tracking.
6. Negative Lags
Negative lags, especially in detailed schedules like Turnaround schedules, are generally not recommended.
7. Negative Floats
Negative float indicates the schedule is constrained manually, suggesting that the current completion dates are unachievable.
Apart from the key points mentioned above, other areas that need careful evaluation include:
· Ensuring there are no open ends by reviewing Start to Start (SS) and Finish to Finish (FF) relationships.
· To enhance value by accurately weighing true activity progress, managing resources, and quantifying impacts, it's important to ensure all activities requiring physical effort have resources assigned.
· Evaluating both high total float activities and the average total float of the schedule, as they can indicate flawed schedule logic or an extremely front-loaded schedule.
· Assessing the percentage of critical path activities, which can indicate either a highly compressed schedule or errors in critical path determination. A schedule with a high percentage of critical path activities will likely have a poor success probability. In an optimal schedule, the number of critical path activities should fall between 5 to 15% of the total activities, with the required level of detail.
· Aim for an average relationship per activity ratio of 2:1 in an optimized schedule.
In summary, ensuring high-quality scheduling is crucial for successful Turnaround Execution Tracking. Thoroughly evaluating the schedule by focusing on the above quality checkpoints to confirm scheduling accuracy, along with careful consideration of critical path activities, is vital for an effective Turnaround schedule.
Article has been authored by Anil Sasi , PMP ( Head Turnaround Excellence @ Maximl )
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