I suggest you reconsider using the 24-hour calendar. While your operation
might go 24/7 it's highly unlikely that an individual person in your
resource team works like that. Tasks usually represent the work done by a
single individual or a team of individuals who work the side-by-side for the
same hours. By using the 24-hour calendar, you are saying that when poor
old Joe Resource starts working on his next task, a task with a duration of
5 day let us say, he won't get a break, a meal period or even a nap, get to
see his kids, for an entire week until the task is done. While you may very
well have work going on around the clock, when you examine the individual
tasks, work starts and stops as the resources come and go at the start and
end of their shifts. If you have some tasks going on during the day shift
and similar tasks on the swing shift, even if they are tasks on the same
component, they should be split up and managed separately rather than
lumping the work together into one task.
Even if you choose not to take the task breakdown into that much detail,
consider a task that is able to start Monday morning and requires 24
man-hours of work to complete. You have three shifts covering the 24-hour
day; day, swing, and grave. If you assign ONE worker, Joe Dayshift, the
task will start Monday and finish the end of the day Wednesday, stopping
while Joe goes home Monday and Tuesday nights. If TWO workers, Joe and
either Bill Swing or Suzie Grave, the task will end the finish the end of
the day Tuesday, running Mon day, Mon evening or Tue early morning, and then
Tue day until we've worked a total of 24 man-hours split between the two
resources. If you assign THREE workers, one from each shift, the task will
start Mon morning and end Tue morning, the total time being the result of
one shift's worth of work from each person. But in no case will the 24-hour
calendar give you this result. What you need in order to accurately model
the physical reality is the combined results of three separate calendars
describing the work hours for each of the three shifts involved in doing the
work.
