It is possible to model cure time in Microsoft Project using an elapsed time lag. But to better document the reason for the delay model the cure time as a task with a unique cure time calendar.
There is more than one way to model cure time in Microsoft Project. As mentioned, you could model your cure time using elapsed time lag. A more descriptive way to model the cure time is as a task with a unique calendar.
The question then becomes how do we define the cure time calendar? You could use a 24-hour a day 7-day per week calendar. A simpler approach is to use a standard hours per day calendar that has been adjusted for a 7-day workweek.
This article discusses how to model cure time in Microsoft Project as a separate task using standard hours and a 7-day work week.
Our demonstration project is displayed in Figure 1.
This schedule has a six day lag between pour concrete and strike forms. This works well! But we want to better describe the schedule situation, so we replace the lag with a concrete cure task.
We begin by inserting a task named concrete cure between pour concrete and strike forms. Select Task | Insert ribbon group | Task drop down menu and Task, Figure 2.
Make the predecessor of concrete cure pour concrete and the successor strike forms, Figure 3.
Set the duration of concrete cure to 6-days, Figure 4.
Note that concrete cure spans a total duration of 9-days, because weekend cure is not accounted for.
The default calendar, as per our project information dialog, Figure 5, is a 4×10 work week calendar that consists of 4 10-hour days, and a 3-day weekend.
We want our cure time calendar to include weekend cure time, so we define a 10-hour per day 7-day per week calendar. Select Project | Properties ribbon group and Change Working Time, Figure 6.
In the calendar dialog select create new calendar, Figure 7.
In the create new base calendar dialog, select the 4×10 work week calendar, Figure 8.
Select the work weeks tab and click the details button, Figure 9.
In Details, Figure 10, set every day to a 7:00am to 5:00pm work day.
Great! The 7-day week cure time calendar is done. Set the task calendar of concrete cure to the 7 Day Cure Time calendar, Figure 11, and your done.
Yes, Microsoft Project has a nice feature for a 24-hour elapsed time lag. But for a more descriptive and better documented schedule model the cure time as a task using standard hours and a 7-day work week calendar. It is not necessary for your calendar to be 24-hours, in fact this makes the scheduling process more nuanced and tedious.
The important point is to count weekends, including Fridays for 4×10 workweeks, as whole workdays. One parting thought is to note that the cure process has no associated costs so no resources should be assigned to this activity. This may become an issue when inspecting the schedule using the Defense Contract Management Agencies (DCMA) 14-Point Assessment. The resources criteria in this assessment flags any cost loaded schedule that has non-resourced activities.