MS Project Overnight Work Calendar & Duration Calculation

Curt C,

You haven't provided the times as well as the dates, nor the 39 tasks before line 40.

However, I can fill in the gaps with some necessary assumptions, more or less.

Consider, for the moment, just one task, your line 40.

Resource Sheet

In the first week, Monday, Tuesday and Wednesday are nonworking, and Thursday is nonworking until 19:00.

First week is a special week, and after that the default shift cycle takes over.

Curt C

Project has three types of calendars, project calendar (Project > Properties group > Project Information > Calendar), task calendars (Task Calendar field on Gantt Chart view), and resource base calendars (Base Calendar field on Resource Sheet).

The project calendar drives everything unless, a task requires specific work days and/or times that differ from the project calendar. A "none" entry in the Task Calendar field indicates that task follows the project calendar. It is best to first set up the project calendar with all common non-working periods (e.g. holidays and work hours). Deviations from that for specific tasks and/or resources are set in custom calendars for those objects.

The Base Calendar field on the Resource Sheet indicates which calendar that resource follows. A resource's calendar will "trump" a task's calendar unless the option "scheduling ignores resource calendars" (Task Information > Advanced tab > Calendar). A resource's calendar will also "trump" the project calendar.

Custom project or task calendars are created via Project > Change working time. As good practice, the Standard, or any other built-in calendar, should NOT be directly modified, rather, a custom calendar, (perhaps based on a built-in calendar), should be given it's own name. Custom task based calendars (project or task calendars) will show up on the Calendars tab in the Organizer.

Resource calendars are created via Resource Information > Change Working time. Resource based calendars do NOT appear on the Calendars tab in the Organizer.

Although Project allows multiple calendars only one can be used as the project calendar. If the plan consists of multiple work shifts across tasks the project calendar should be set to encompass the full work days and times of all custom calendars. This is often done by using the built-in 24 hour calendar as the project calendar.

Project only allows one definition for a "day" (and hours per week and days per month) and that definition is used to calculate the the value in the Duration field and custom Duration fields (i.e Duration1 thru Duration10). The units displayed in the duration field can be in minutes, hours, weeks, and/or months either as working time (default) or calendar time (elapsed time). The default units for the Duration field is set via File > Options > Schedule group. That option applies only to new tasks, it will not "reset" any previously entered duration values.

For reference, Project calculates all time periods to the nearest minute regardless of what unit is selected for duration.

Hopefully that covers a whole lot of questions you might have and clarifies things.

Now a few comments on the screen shots you posted in response to Trevor.

1. It looks like you have directly modified by the Standard and 24 hour built-in calendars. I suggest you rethink that approach. For common non-working time (e.g. holidays) create a custom calendar perhaps based on the Standard or 24 Hour but with it's own calendar name (e.g. XYZ Construction). Make that your project calendar. Then create and apply separate task calendars ONLY if the task requires different work days/hours. The same for resources.
2. You have a custom "Concrete Curing" calendar. I can't in any scenario imagine why a calendar would be created for curing concrete. Concrete curing is not a "scheduled" activity. Curing is the result of a concrete pour and is best defined as a delay after the pour or 7, 14 or 28 days depending on the successor task (e.g. 46 + 3ed), meaning 3 elapsed days after the pour for column 01. As an alternate you can show the cure as a separate task (as you have shown) but with an elapsed duration and no custom calendar.
3. You say you have multiple task and/or resource calendars. Too many or unnecessary custom calendars can drive you nuts. Using what I explained above, take a hard look at what you have and what you need and make adjustments where necessary

John

I have a project that requires work to be completed on a day shift to complete portions of the work and there is a portion of the project that requires work to be completed on a night shift. I am trying to set up what you referred to above as a "swing shift". I have multiple custom resource calendars (potato, patato) each with different work hours and non-working days. I will change the date format and may just change the hours on all the custom calendars to be an 8 hour day for simplicity. Can you have 2 different work day durations (8 hours and 10 hours if they are for different custom calendars?).

Trevor, this project requires various work shifts for different activities throughout the project. I have created multiple resource calendars to use primarily for day work, night work and concrete curing, but there are other resource calendars throughout. Based on what I understand you mentioned above, are you saying the default work day start time should be 1900 hours for each resource calendar and to make the duration of the tasks in hours rather than days? If the second part is correct, not sure I have done that, so where do I go to set the default start time (under file and options?) and where do I go to change the durations to display in hours rather than days? Second, do all tasks need to be in hours or can I apply the tasks durations in hours just to the tasks that are assigned to the resource calendar where work is taking place over night? To answer the last part of your reply, I need to show that a duration of 1 day of work will start on "02/01/22" at 7pm and be completed at the end of the shift on "02/02/22" at 5am. I currently have the overnight work shift resourced to the 24 Hours calendar.

Curt C,

Sorry but you can't have multiple project calendars. Do you perhaps mean you created multiple custom calendars?

Why are you trying to use a 24 hour calendar? It might make sense to make the Project calendar a 24 hour calendar if for example, you have custom task calendars that cover multiple work shifts. But you only describe what might be referred to as a "swing shift" (i.e 7pm to 5:30 the next morning).

You say the duration is not working out correctly. In the custom calendar you describe you have a 10 hour workday. Did you set the definition of a "day" to 10 hours (File > Options > Schedule group)?

This is how I set up the work shift your describe:

Custom calendar (named Curt C)

Then set the Project calendar and the start date AND time

Along with setting the definition for a day to 10 hours, I also suggest you set the date format to also show the time (File > Options > General group). Doing all that, your one day task will look like this:

Hope this helps.

John