Convert between gross and target programs with ease in P6!

One of the key factors which can influence the finish date of construction projects is weather. It is common practice to develop calendars which are based on historical weather patterns that take into account estimated additional non-working days due to rain, heat or wind speed.

These calendars are then assigned to activities which are influenced by those weather patterns. For example Earthworks, Structure and Pavement works are influenced by weather in different ways.

We recently completed a tender program for a client who, as part of the requirements, wanted to create earthworks and structures calendars which were inclusive of weather allowances. This would give them a good feel for production rates as they would occur in real circumstances.

The tender program was developed and submitted however during the evaluation process, the client was requested to resubmit the tender schedule and remove weather allowances altogether. To do this quickly on a 5,000 activity schedule is a pretty laborious task.

There are of course those who believe weather allowances should be at "the end" of a schedule and those who dont. Putting this difference of opinion aside we had to come up with a simple, yet effective method by which we can quickly convert between the Gross (inclusive of weather) and target (exclusive of weather) versions of the program. 

The steps in our solution were pretty simple:

  1. Define the project calendars including the base calendars to be used which do not include weather allowances
  2. Develop an activity coding system that outlines the 'type' of work being undertaken (eg, earthworks, pavement, crane lifts)
  3. Assign the base calendars and activity codes to activities as required.
  4. Take a snapshot (baseline) of the project for comparison later
  5. Run a global change to switch the assigned calendar based on the activity code defined

From here the project team can quickly switch between gross and target programs and compare the results in a Gantt format. 

For more detail on this approach Download our Notes.

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