Hi Mike,

"When I come across a programme with more than 1 critical path it means that it has been rigged to suit and I would reject it."

I have not seen any contract requirement that programme should have only 1 critical path and on what ground you will reject the programme, say the contractor complied all the contract requirements.

Cheers,
Nestor

Hi Rafael

1. How much?
Whatever is needed to fill in the float gap.
2. Where to allocate it?
Either at the end of every cascade to fill in the gap between construction levels or at one time only to fill in the gap between planned and contract completion - or a combination of the two.
( I would not suggess a buffer at the end of every activity)
3. How to comply with contractual requirements within the limits of our software?
The contractor is entitled to insert a time risk buffer to take account of whatever risks he contemplates. Only one set of software allows this to be reproduced in a stand alone task.
4. How buffers affect the interpretation of delay?
See Below.

The whole point about buffers is that they are absorbed as and when delay events use them up.

Therefore the Contractor’s buffers are to be used as and when culpable delays are impacted.

Therefore they are flexible and consumable.

In delay analysis the original buffers remain until they are absorbed by Contractors delays - although I have to admit that I have not yet seen a contractors programme that uses buffers - unless it is one of mine.

If there is an employers delay that impacts on a buffer then the remaining buffer duration has to be fixed before reschedule.

In Powerproject this is a simple procedure to change a buffer to a normal task for the time being - it can be switched back after the impact analysis.

I hope this helps

Best regards

Mike Testro

Hi Rafael

A true critical path will span the whole contract duration.

I would not advocate any form of "fiddling" to make non critical tasks longer just to remove float.

I would advocate the use of "Time Risk Buffer" tasks to retain float in the Contractors ownership.

In powerproject a time risk buffer will turn everything upstream visually critical.

Powerproject is the only software that has this buffer task facility.

With other systems you have to use a combination of linked milestones and a summary bar which does not automatically show critical.

I hope this helps.

Best regards

Mike Testro

Hi Edniel

When I come across a programme with more than 1 critical path it means that it has been rigged to suit and I would reject it.

I have never yet come across a programme where EVERY task is critical mainly because I don’t think it can be done - unless every task is set to an ALAP position so that any float is left to the front of the task.

A fully ALAP programme would be un-manageable because every delay would cause a delay on the critical path.

Tell your employers that what they are asking is a waste of time because:

1. It will be rejected and they will have to submit again with float in the right place.

2. Every delay on progress - including the Contractor’s delay - will cause a delay to the contract.

Best regards

Mike Testro

Dear Edniel,

You need to show float in your submitted schedules. This is essential to take care of uncertainties.

In most cases, it will not be approved by Consultants without a float.

With kind regards,

Samer

10-4

Schedule Analyzer is a suite of Programs designed to
assist the Scheduler and Delay Claims Expert using
Primavera’s P3, P5/P6 Software.

http://scheduleanalyzer.com/index.htm

It is not limited to Baseline Schedule Analysis, but a suite that among others includes a file comparison application that might be better than Digger within P6, worth to explore.

Hi planners,

Hi Rafael, back to your post that quote "if you submit an initial baseline schedule with negative float......."

Rafael, in our industry (oil and gas) sometimes we need to highlight the critical activity in order to express them (client) that we gonna to expedite something that very urgent.So both parties will look forward on this matter. Is a common for me that client will ask planner what is a critical path.

Hi Gary,

Your recent post quote that "are they any negative lag relationship used"

Just wanna to ask you is it that negative lag is not recommended for schedulling wise?

Mike

This is usually required on some CPM Specifications, this only for the baseline schedule.

If you submit an initial baseline schedule with negative float at the start you are behind. He won’t accept it as his acceptance might be interpreted as accepting you will be late and unable to deliver as per contract duration.

If you submit an initial baseline schedule with positive float as if projecting early finish this would create some response from the Owner, he will argue that this means a reduction in Contract Time and a few other arguments.

I have no objection to this requirement, seems fair. If for some reason you cannot schedule your job as per required contract time you should say so prior to Bid Opening.

I know you know it, but could not resist your request for a why?

I might be the dissenting voice in favor of the Contractor, a few have taken the other side, the Owner/Engineer/Architect/Supervision/Inspection and I believe it is good for the debate a few of us take the Contractors’ side.

Cordially,
Rafael

Dear Edniel,

Now you have plenty of information from many people. Time to use this information to fit your case.

If you give us more information about the type of construction and the size of project, maybe we can help some more.

With kind regards,

Samer

Edniel,

To answer the 2nd part of your question, i.e what comments to expect from a client review. Some of the areas I check when doing this are:

a) Is the programme submitted as per contract? (some contracts will specify electronic or paper version, specific planning software, wbs, resource-loaded, etc)

b) Are all scope elements clearly indicated?

c) Are Key milestones (Contract award, Design freeze, Sectional Completions, Commissioning, payment milestones, etc) displyed?

d) Are all contractual constraints accurately reflected? (No vegetation work during nesting season, UXB survey before site clearance, etc)

e) Are all activitites linked by predecessor(s) & successor(s)?

f) Are there any scheduling constraints imposed, and can they be justified?

g) Are there any negative lag relationships used?

h) Are all client approval activities included?

i) Do the durations seem reasonable?

j) Are the calendars used appropriate?

k) Detailed analysis of all critical & near-critical activitites to ensure the CP is "genuine"

Cheers,

G

Yes Anoon, you must first discuss the adjustments, especially this type of adjustments, I even have a client who one of the principals would go with plain truth while the other would go with adjusting the schedule in its favor, the Contractor.

It is good for a scheduler to know how to manipulate the schedule and if on the other side, how to detect schedule manipulation.

Schedules can be double edged; it is good to have some cushion on your side. The same way a Contractor would try to manipulate the schedule in its favor the Owner will try to do so as early as he writes the Contract and CPM specifications, in addition at times will include exculpatory clauses that usually will hold in court even when the judge would not like these, or will even include other conditions with the knowledge that in court will not hold. Government agencies are good at this.

The Owner writes the specifications; here the Contractor is at a disadvantage, believe me they are no saints, on the contrary many times abusive.

I have no doubt Samer knows by experience.

Nestor approach I believe should be the theoretical way to go, the correct way. But seems like Samer is a street guy and knows some Owners will try to steal the schedule away from you by limiting the way you can use the software it no longer represents your planning methods, they might also want to steal some float away from you, yes free float that you need as a resource buffer in case you start falling behind and even if you are ahead this might interfere with your right to finish early.

If at the beginning after your first update you show an updated schedule behind schedule they will jump over you. A way to get them out of your shoulder is to allocate some extra time at the activities that occur first. In this way after your first update you will show you are ahead of schedule.

It is not unusual to reduce retainage on payments after some point but this will not happens if you show an update behind schedule. That is another reason to unbalance your schedule in your favor, don’t be naïve, never into their favor.

I believe, once before, I commented the opposite to Samer but after perceiving the attitude of some Owners and their Schedulers to use the tool against the Contractor I am changing my position. Don’t overdo it, do it in an elegant way, in my neighborhood we would say use some Vaseline, so it won’t hurt.

If you are comfortable with the 18 days float and front load it, then after the first or second schedule updates it will show your true schedule anyway.

You can always keep a true schedule for your own, you got to know true schedule. Keeping two schedules updated with Post Office is an option; never let them know otherwise they will jump so high they will kill themselves when hitting the ceiling, after the shock if they survive they will argue your submitted schedule is not valid. Be careful.

Under a Fixed Price Contract I believe it is morally right to keep two schedules to keep control of your means and methods when the Owner tries to control you planning methods. And he calls you a cheater when he is, if he is to interfere he should use other contract type.

Yes Samer, I am 100% in agreement with you. How to keep the float to yourself hidden? seems like a good topic, I got a few ideas, like coordination and mobilization activities prior to construction activities. If the owner delays start of your construction activity by one week you can claim up to 1 month for coordiantion and mobilization plus a week.

Hope to see a few Owners’ reps jumping with my comments, some deserve it.

Dear Edniel,

I would recommend that you keep the float to yourself hidden and increase the duration of activities as you see reasonable in order to submit a total float =0 as your manager asked.

Best Regards,

Samer

Dear All,

To my understanding, a Contract is necessary to protect the interests of both the Contractor and the Client. If something that is to be implemented is to the advantage of one party there must be a specific cluause in the Contract to draw a line.

Cheers,
Nestor