Identifying Critical Mass and Worker Density Constraints when Planning a Maintenance Outage: A Case Study
BoK Content Type:
Presentation Slides
Video
Presentation Paper
BoK Content Source:
MainTrain 2022
Original date:
Friday, February 25, 2022
Continuous processing or manufacturing facilities will occasionally require planned outages to primarily address reliability or maintenance issues. Due to the high cost of these outages (opportunity and real), careful planning and scheduling practices are used to come up with detailed execution plans to reduce the planned duration as much as possible. While outage duration is typically determined using the critical path methodology, large quantities of smaller but similar in nature jobs can lead to unexpected schedule extension. A planning team recently applied this lesson-learned by calculating the schedule impact of such critical mass work. During inspections and maintenance outages, labor cost is usually a significant expense. In order to meet the required cost and duration goals, worker efficiency is critical. As part of the job plans and schedule creation, a planning team was able to model one crucial feature of labor efficiency – worker density, that is the maximum number of workers that can be allocated to a specific work area over a given time span with minimum productivity losses. As a result, small changes were made to the scheduling of individual tasks. This case study will illustrate how both constraints were considered when planning & scheduling a major maintenance outage.