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More than one calender??

13 replies [Last post]
Sun, 2010-04-04 12:55
David Blades
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Groups: Petro-Chem / Oil & Gas
Can someone explain the correct way to use 2 calenders on one project please? I want to use 24/7 amd 37.5.

Obviously there are several options... one being to use the 24/7 calender for the project and then use a resouce that has a 37.5 hour calender?

Just want to know your thoughts on the most reliable way to set it up??

Thanks in advance
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Replies

Mon, 2010-04-05 06:31
#1
Rafael Davila
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David,

In Primavera SureTrak, which I no longer use, you could display in your resource histograms quantity instead of hours, you could set it to display maximum quantity. This would give you the maximum quantity of resources used on any time span. If you use hours it would give you the total hours on a given period, with this you can get averages only.

Also try reducing the time period of your histograms to get a better view on resource usage changes.

Maybe in P6 you can work it out if similar to P3 and SureTrak.

Best regards,
Rafael
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Mon, 2010-04-05 05:28
#2
David Blades
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Thank you guys.... I’m grateful for your input.
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Mon, 2010-04-05 04:20
#3
Mike Testro
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Hi David

Again I am assuming that the 24/7 crew are actually doing the work and driving the task duration and the Engineers on 37.5 are in some sort of supervision role.

In fact you have two 12hr 7 day crews not one on 24/7 so my instinct would be to set up two 12 hour shift calendars and allocate them to the rotating crews.

The 37.5 hr shifts can then be allocated to a summary bar covering a series of tasks.

Best regards

Mike Testro.
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Mon, 2010-04-05 03:26
#4
Anoon Iimos
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yes David, for me, that makes sense

I believe Mike is suggesting to use only one calendar?

David,

I may suggest that you use Crew (one), so that you’ll assign only one unit (whole number).

You can work out the details of your crew using excel.
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Mon, 2010-04-05 03:19
#5
David Blades
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Hi Mike

In the oil and gas offshore industry we have 24 hour operations with guys working a 12 hour (back to back) shift system.

On the particular activities that I have been working on I have guys working both the 12 hour shifts (24 hours back to back) and engineers working a 37.5 hour day shift.

Again I hope this makes sense.

Thanks for your assistance
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Mon, 2010-04-05 03:08
#6
Mike Testro
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Hi David

Why are you setting workers to a 24/7 calendar?

This calendar should be used for tasks such as drying out or curing - not work related.

You will get conflicts when you mix task and resource calendars on the same task.

Leave your resources as calendar neutral and the problem will disapear.

Best regards

Mike Testro.
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Mon, 2010-04-05 03:00
#7
David Blades
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Hi Mike

Problem is on this project I have been trying to show the number of people required in the neatest way.
The split between 24 and 37.5 hour workers seems to be what is giving me the discrepancies in my results.

I hope this makes more sense?

Thanks
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Mon, 2010-04-05 02:53
#8
Mike Testro
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Hi David

I am not sure what your problem is.

If you are running a histogramme of planned resources then the allocated number should be displayed for the selected timescale - Hour - day - week - month etc

There should be no need to divide by the calendar hours.

Best regards

Mike Testro
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Mon, 2010-04-05 02:50
#9
Mike Testro
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Hi Rafael

I put the predicted weather in the calendar as non work days.

Part of the weekly progress update is to change the predicted weather to actual work stoppages.

It is not a perfect system but it works well enough - particularly when establishing weather delays.

Best regards

Mike Testro.
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Mon, 2010-04-05 01:30
#10
David Blades
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Groups: Petro-Chem / Oil & Gas
Thank you guys, I’m grateful for your thoughts.

Moving on from this but still connected, how do you manage the difference in the results that you get when you run a histogram. To get how many people you require you cannot simply divide by 37.5 or 24 as the histogram data is mixed?

I currently manage by pulling the 37.5 and 24 hour data separately but again wasn’t sure if this was the best method / only method?

Again, thanks in advance
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Sun, 2010-04-04 23:27
#11
Rodel Marasigan
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David,
The correct way of using multiple calendars will depends on the activity types you used when you set your project.
There are only 2 main activity type which is Task Dependent and Resource Dependent. The rest are milestone, level of effort (hammock) and WBS summary which used as indicator or summary.
Activity type = task driven or Task Dependent then calendar should assigned to activity. Activity type = resource driven or Resource Dependent then calendar should assigned to resource.
Note: Primavera calculate calendar as per activity type settings. Meaning if an activity type is set to Task dependent and no calendar set on task it will use the default even resource calendar are set or vice versa.
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Sun, 2010-04-04 17:11
#12
Rafael Davila
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Mike,

About weather disruption:

I have seen the following approaches for the scheduling of weather impact in some of our specs, with some minor modifications.

1-Set allowance assuming some periodic distribution (a predicted weather calendar). But what happens if it does not rains even if expected rain is one day per week, are you going to plan with all Fridays as a holiday. What if on paper this delays the Early Start of a successor, it does not rains but because of this you planned for some delivery is going to be late and know you have to delay the activity because the rain assumption was poor planning? It did not rained, you should have known.

2-Include allowance as part of the activity duration. Seems not bad, but what if activity is delayed beyond rainy season? Yes I know here is rainy season year-round, but we had in the 80’s two consecutive drought years. Maybe we should have known.

3-Set weather allowance at the end of the job and as progress happens deduct available allowance.

In order to calculate true earliest dates, those that might occur if no rain happens, perhaps it is better to set the allowance at the end of the job, and if questioned about a certain milestone just add the allowance from data date to milestone finish. You delay your prediction of finish date but not early dates before finish date. Do not fool the computations for early dates it reminds me of these constraints that fool backward computation of Late Dates. Keep both unobstructed.

Best regards,
Rafael
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Sun, 2010-04-04 14:18
#13
Mike Testro
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Hi David

The simple method is to use a suitable calendar for each task.

24/7 for curing / drying out periods and 37.5 hrs for active work.

The worst scenario is if you mix 2 calendars on one task by assigning resources with different calendars to that of the base task - it is best to keep resources calendar neutral.

Work out what your calendars are going to achieve and then assign them accordingly to the appropriate task.

If you have tasks that are liable to weather disruption then they need to have a predicted weather calendar assigned.

Best regards

Mike Testro
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