Website Upgrade Incoming - we're working on a new look (and speed!) standby while we finalise the project

Tips on using this forum..

(1) Explain your problem, don't simply post "This isn't working". What were you doing when you faced the problem? What have you tried to resolve - did you look for a solution using "Search" ? Has it happened just once or several times?

(2) It's also good to get feedback when a solution is found, return to the original post to explain how it was resolved so that more people can also use the results.

I need drawings 6 weeks before starting a Phase

13 replies [Last post]
Mon, 2007-04-09 15:18
Terry White
User offline. Last seen 12 years 23 weeks ago. Offline
Joined: 8 Feb 2004
Posts: 39
Groups: None
The Phases all start on a specific date, and the contract states that we should have the drawings 6 weeks before that date. How do I link that in with the start date of the phase and what type of task is it ? Do I have it set up as a Start to Start with a 30 day lag ?

Thanks for your help.
Top

Replies

Wed, 2007-05-23 02:28
#1
Hannes de Bruyne
User offline. Last seen 2 years 7 weeks ago. Offline
Joined: 25 Jul 2005
Posts: 154
Groups: None
Hello Andrew

nothing against a negativ lag ... as long as the link is FS and the lag is less than half of the duration of the predecessor.
Top
Tue, 2007-05-22 13:56
#2
Andrew Sherwood
User offline. Last seen 17 years 11 weeks ago. Offline
Joined: 26 Mar 2007
Posts: 12
Groups: Petro-Chem / Oil & Gas
What is more important, the schedule, or the techniques used to get to the proper dates??

In my opinion, the use of negative lag is appropriate in some situations, but using it may throw off a Monte Carlo analysis...

I feel that P3 was created to support the use of negative lag, therefore it can be used...Some project controls people are against the use of it, but I am not...

Hope your schedule works out okay...
Top
Tue, 2007-05-08 13:31
#3
Terry White
User offline. Last seen 12 years 23 weeks ago. Offline
Joined: 8 Feb 2004
Posts: 39
Groups: None
Fair comment if you’re in complete control of the planning.

In this situation though, I’m not and I need the 6 week negative lag in the plan so that its picked up by the searchlight as I check through my several Projects that I have on the go at any one time.

Thanks for your comment though, its much appreciated.
Top
Tue, 2007-05-08 08:02
#4
Hannes de Bruyne
User offline. Last seen 2 years 7 weeks ago. Offline
Joined: 25 Jul 2005
Posts: 154
Groups: None
I think making a predecessor out of a successor by using a negative lag is nice drawing but very bad planning.
How can can you do proper follow-up of your progress? You can only find out that yr drawings are late at the moment construction works start.
Top
Fri, 2007-05-04 06:08
#5
Terry White
User offline. Last seen 12 years 23 weeks ago. Offline
Joined: 8 Feb 2004
Posts: 39
Groups: None
Thanks Bijaya,

In truth, what happened, I wrote the post and sent it. While I was waiting, I re-read all the posts again and picked up your reverse SS suggestion. Tried that and it worked.

Then Rodel came along and confirmed what I’d just tried and got working. My thanks should have gone to you as well for the original tip.

You’ve both been a great help as with others on the forum. I’m now getting more and more confident with using P3. Its a shame its been stuck in a box for so long not being used because I found it so hard to not only get into, but use on a daily basis to produce meaningful information.
Top
Fri, 2007-05-04 05:48
#6
Bijaya Bajracharya
User offline. Last seen 8 years 28 weeks ago. Offline
Joined: 25 Feb 2005
Posts: 175
Groups: None
Good to know it worked. If you read them carefully you will find that I had given you the same solution in my earlier reply back on 10 April.
Top
Fri, 2007-05-04 01:31
#7
Terry White
User offline. Last seen 12 years 23 weeks ago. Offline
Joined: 8 Feb 2004
Posts: 39
Groups: None
Thanks Rodel, to the rescue again. It now works a treat.

I also noticed that it still wasn’t quite working properly, showing only 4 weeks instead of 6. I hunted high and low for an explanation. I discovered that in my fragnet, I had one line which was using the 7 day calendar that I had created for weekend working, which I was now using for drawing issues. I fixed that :)

Top
Thu, 2007-05-03 17:45
#8
Rodel Marasigan
User offline. Last seen 22 weeks 1 day ago. Offline
Joined: 25 Oct 2006
Posts: 1699
Groups: Petro-Chem / Oil & Gas
Terry,

Use SS with negative (-6week) lag and a successor of fixed starting date. If the data date is greater than the negative lag then it will sit on data date unless you put actual date.
Top
Thu, 2007-05-03 10:40
#9
Terry White
User offline. Last seen 12 years 23 weeks ago. Offline
Joined: 8 Feb 2004
Posts: 39
Groups: None
I’m still having problems getting this to work. They all appear on the Data date rather than 6 weeks before the start date of each phase.

To try and answer your questions about what I’m trying to do. I’m working for a Contractor who has stipulated dates for starting a phase. He is required to give us drawings 6 weeks before each phase, but these are not drivers of the phase. I.e. if he’s late with the drawings, we still have to start on the fixed dates no matter how late the drawings arrive.

To be fair he is quite good, but I want to get the items in the right places so that I don’t miss the drawing issues and can chase them if they’re due.

Top
Wed, 2007-04-11 04:40
#10
Bijaya Bajracharya
User offline. Last seen 8 years 28 weeks ago. Offline
Joined: 25 Feb 2005
Posts: 175
Groups: None
Drawings are always predecessor (or are important) before the Phases start. My point was that when you put zero float constraint on Drawing milestone, these milestones will appear as critical activities. And in reality, there is nothing that prevents the Drawings being ready more than 6 weeks before Phases start.

The reason Drawings are shown as milestone is that it is done by another firm or another department. (Or else drawing is an acviity in itself with its own dependincies and resources (within Design team).

By introducing a Drawing milestone in construction programme, one is trying to shown the end date of drawing activity (which in reality) is not dependent on any of the activities in the programme. But the activity in the programme (Phase) depends on having the drawing 6 weeks in advance.

In this context, it may be worth calling drawing milestone as "Deadline to get drawings completed Flag" and it can remain 6 weeks ahead of Phase.
Top
Tue, 2007-04-10 09:14
#11
Rodel Marasigan
User offline. Last seen 22 weeks 1 day ago. Offline
Joined: 25 Oct 2006
Posts: 1699
Groups: Petro-Chem / Oil & Gas
Bijaya,

I tend to agree with you but it’s all depends on the situation. We don’t know the whole scenario and we can’t say it’s wrong to show that way.

“Terry said: The Phases all start on a specific date, and the contract state that we should have the drawings 6 weeks before that date.”

We can interpret that the drawings is the driver to start the Phases and it means it is critical. Why? How can we start phases or construction without any drawings to base on? (one scenario) We can constrain the milestone from 6 weeks before the phases start if this is not the start milestone so it won’t move on the data date when it was not yet due.

We can also interpret that the drawings is not that important for phases need to start and does not requiring any drawing to start with. (I haven’t encounter one but it might be the case) So you can consider that is not critical and we can used your solution.

For a construction contract only and not an EPCM it may vary on their scope whether they have IFC drawing before moving to site or they may have a preliminary drawing for quotation or bidding purposes only. In this case IFC drawing is the driver for them to proceed the construction phase otherwise they don’t have any basis of correct layout, details and constructability of their scope.

Either way is a correct approach depends on correct picture of the problems.

Regards,
Rodel
Top
Tue, 2007-04-10 08:25
#12
Bijaya Bajracharya
User offline. Last seen 8 years 28 weeks ago. Offline
Joined: 25 Feb 2005
Posts: 175
Groups: None
Rodel,

If you just have Drawing milestone as FS predecessor to phase, when you reschedule it, all the milestones will appear along the data date. For the presentations purpose, you may put zero float constraint to those milestones 0 then they will appear 6 weeks or whatever lead is specified before phases.

In doing so, the milestones will appear in your crtical path filter and there are many instances, you would not like to show them as critical activities because they are not. In such situation, some times I tend to give a reverse SS link - from phase to milestone with required negative lag. The direction of arrow in relationship appear wrong but otherwise, everything is correct in this way. it will be telling you when the drawings are required for each phase.
Top
Mon, 2007-04-09 18:54
#13
Rodel Marasigan
User offline. Last seen 22 weeks 1 day ago. Offline
Joined: 25 Oct 2006
Posts: 1699
Groups: Petro-Chem / Oil & Gas
Hi Terry,

You can create a milestone (Drawings) as a predecessor with FS relationship on all phases and put log if necessary before all the phases can start. This milestone will trigger if the phases are ready to start.

Regards,
Rodel
Top