Primavera P6 Duration types with Examples

The behavior of Units, Duration, and Units/Time are all elements to consider when selecting a duration type. Do you want them to be locked? Or do you want them to be flexible?

The duration type Primavera P6 is best understood via the angle of three terms:

• UNITS – “we have 100 Bricks of works” – so if we treat 1 Bricks as a unit, we have total fixed units of 100
• DURATION – “a limited duration to complete the works” – so need a fixed duration
• UNITS/TIME – “We don’t know how many bricks to be installed” – so the units/time (effort) needs to be flexible

As a summary, the below values will change according to each duration type in Primavera. For example with Fixed Units/Time selected, when you change the activity duration – the units change.

Which Duration Type should be used

With the Activity types, you can quickly recognize the Activity Duration type:

1) Fixed duration & Units:

This type is used if the schedule is more essential. When you change or update activities, the duration does not vary regardless of the quantity of resources assigned. Among these four categories, fixed duration & units is the default. Because it is mostly reliant on the activity calendar, it is classified as a task-based activity. The duration and units are fixed in this kind.

Example:

It takes ten days to construct 100 units. In this case, P6 would conclude that you must create 10 units every day even if the activity has not yet begun. Let’s imagine the activity started a day ago and only 1 unit was constructed. This implies the 9 units that were not built are now spread out over the next 9 days, requiring you to generate 11 units per day for the next 9 days. To allow for the missing 9 to be created, P6 will not prolong the time by a day.

2) Fixed duration &units/time:

It’s a task-dependent activity, too. The duration and units/time are predetermined in this kind. The activity calendar is used for this specified duration and unit/time.

Example:

A manufacturing line understands that it can generate a certain number of units each day for a certain number of days, and this determines the overall number of units produced. When the entire production required is uncertain, this method is used to determine how much can be generated in a day and over how many days.

3) Fixed Units:

When the entire work effort or fixed costs are the most significant factors, this kind is chosen. It suggests that the budget (unit/cost) is the limiting element, implying that the entire quantity of work is predetermined. Even if the length or resource rate of activity changes when you edit it, the labor effort necessary to finish it remains constant. It is a resource-reliant activity that follows the resource calendar.

Example:

A site must demolish 100 units by a certain date, but there is no set limit. As a result, P6 will determine the number of units to destroy every day based on duration, and vice versa. This is essentially a manufacturing line with an infinite total unit count and the expectation of fixed unit production limitations. So, while the length and units/time may alter, the total unit goal is defined, and the activity is done once the goal is met.

4) Fixed Units /Time :

Even when activity duration or budgeted units change, the units/time for the resources remains constant. When the productivity output each time period is fixed, this method is used. When the activity type is Resource Dependent, this is the most common usage. This option is chosen if your company is worried about resource leveling and you designate particular hours each day to tasks. This kind is used if resource availability is the most critical factor. Even if the activity’s length or labor effort varies, the resource’s unit/time or rate remains constant in this kind. It’s also a resource-intensive activity that operates according to a resource calendar.

Example:

A factory line that produces ten units per day will continue to do so until it is shut down. They will generate 100 units if the length is 10 days; if the period is 20 days, they will produce 200 units. When you change the budget units back to 100, the length is reduced to ten days.

Conclusion

In Conclusion, Duration Type is a parameter that allows the user to determine how the duration, resource units, and resource units/time for activities are synchronized, ensuring that the following equation is true at all times:

Duration x Units/Time = Units

If the activity is not started, the names of the values are: Original Duration x Budgeted Units/Time = Budgeted Units

If the activity has started, the names of the values are: Remaining Duration x Remaining Units/Time = Remaining Units