Most operations have down times that are standard. Examples are overnights, weekends, and holidays. The functions of the organization are on hold during those times, so a schedule should not place any activities on the timeline during those intervals. However, some activities can be interrupted temporarily and resumed when the down times are over. Others cannot. For example, you can start digging a hole on one day and finish it the next, but you may not be able to start pouring concrete and stop in the middle of the activity expecting to resume the next day. The same with baking a cake!

Many of our users want to define activities that are long in duration, but are interruptible for down times. Some of those activities are entire work sequences or projects that last several days; others are production runs that can be turned off and on as necessary to accommodate the standard work calendar. The FAST system now has the capability to model either non-interruptible activities or interruptible ones. There is a simple check box that allows the user to select either description.
Here are a few examples that we’ve encountered:

• A product that is molded requires an uninterrupted molding process but can be finished using several steps that can be interrupted and restarted each day.
• A printing run takes several days to complete but can be run over several daytime shifts.
• An event set-up can span an overnight downtime but servicing the event cannot be interrupted.
• Repair of a machine can span several shifts but the flowing acceptance test must be continuous.

The capability to split an activity that requires multiple resources using time-varying requirements within the activity is not easy to split correctly. In the original activity definition there could be a requirement for several resources to be used concurrently. The FAST algorithm is smart enough to split this activity in such a way as to preserve all concurrency requirements. So if in some activity, for example, Joe and Sally have to be working together, and their activity can be split across down times, the FAST scheduler will preserve this concurrency requirement even if both individuals have other assignments and different availabilities.
This new capability now makes the FAST scheduler applicable to numerous environments in which activity descriptions were challenging. Try it out. It’s very powerful.