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maximum duration

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Sayed Ibrahim
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dear all
throw our work i recieve some comments from client regarding maximum duration for any site activity some time they said max. duration should be 14 days , another time they said 21 days ....etc
but from may openion this duration based quanitity and production rate in every stage of work .
pls if there any roles in this subject send to me.

Replies

ashraf alawady
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Dear Engineer Sayed

i’m so happy to recieve the opinion of a proffisional planner like you and i would like to invite you to continue your profitable sharing in Plannet Planet Forum.

i wish for you all the best wishs.

Regads
Sayed Ibrahim
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Hi Ashraf
from my opinion assumption from Oliver Melling is excellent Because based on the required detailed from the client / Engineer and available resources with the correct logic we can decide the original duration
the problem is:
1- The Engineer/Client decide the maximum original duration without doing the detailed program frist after that not before they can decide the maximum duration , not to make a relation between reporting period and maximum duration
2- The maximum duration mainly should depend on work breakdown structure (level of detailed required ) and resources also in last level of details we should have unique activity.
3- I advice Engineer / Client to do the driving and correct action related to the maximum duration as
a- to decide the priorty of work and work breakdown structure this to action will lead to the maximum duration which is different from one contractor to Other contractor based on his avilable resources on the same activity
Example: Contractor (1)has many resources in earth work the assume after finishing time schedule he found max. duration =10 days
Contractor(2) has 50% resources on earth work compared with contractor(1) then he will found his max.duration =20 days
the versus will happen on another activity
finally I need to say that There is no any thing = maximum duration but we havethe following
1- WBS work breakdown structure based on technical assumption not planning assumption
2- Priority of works
3- Productivity of complete group of resources (idel group ) Based on our estimation , I cann’t accepte duration = 2days for Q=300 ton/day asphalt where the productivity of asphalt group = 600 ton/day and I argue with the Engineer that Ihave 20 days maximum duration in the contract
Regards
Elsayed Ibrahim
Planning Manager
NDIA - Qatar
ashraf alawady
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Are these factors are same and fixed for all types of projects.

Can we apply the same factors for a project with total duration three years and other project with total duration three months and what are the differeneces in both projects to assume the maximum duration.
Oliver Melling
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Surely the detail in a programme is determined by 3 things.

The level of detailed knowledge available.

The level of detailed knowledge requested.

And the amount planning resource of hours available.
Tomasz Wiatr
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Hi - in the aspect of starting post of Brenan - this great sentence cited by Brenan is very brainy. Additional sentence "My point is that there is a limit to the amount of detail you should go to in your schedule. More detail does not necessarily mean a better schedule" is short and great too AND I have own oppinion in this aspect! Yes, I have :-)

Schedule level of detail must be fitted to risk analysis purposes (what we want to analyse). In some cases we must/we want to go down for "processess" but it is not lowest level, not yet! We can go down for lower level... of events! But this is job only for fanatics of exact "modelling", because it is like a atomisation of project for smallest portion of action. In some cases it is "highly not practical", f.e. in big project.

So level of detail is related to situation, too. In my oppinion exists some suboptimal levels of details for different purposes - it is true in the aspect of Shakespeare answer/thesis of Brenan :-) but we can go down below these levels and all is correct too :] - If our software is able to work with it.

congratulations!
Tomasz
Charleston-Joseph...
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Hello Rey,

Generally, the shorter the duration will make it easy to control. I got the same comments from client that the duration shall be not more than 30 calendar days.

In the event that an activity, for example selected fill for road embankment of more than 780,000 cu m, will span more than 30 calendar, then we have to chop the activities in such a way that the maximum duration will be 30 calendar days.

It was really a pain to repeat and repeat the same activity description.

but this scenario depends on the client representative since other CA will not comment if a particular activity will run for two years.

so the maximum duration will depend on the client representative and how the contractor representative will present contractor’s idea of maximum duration.

This is more of project related specifics.

cheers,

charlie
Rey Basadre
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"The shorter the maximum duration... the more questions arise such as..."

This is exactly the very essence of planning, for those questions to come up so that risks are identified and actioned before it will be a little too late.

Cheers
Stephen Taylor
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Hi,
I think there is always a compromise. If you are doing a routine task there is no point in planning it to the nth degree. But if it hasn’t been done before, breaking the work into small activities can really help. But the bigger the schedule, the harder it is to change, and if you have lots of detail you can also run into logic problems and out-of-sequence activities.

As planners, I think we don’t need to tell people how to do their day job, but we do need to monitor the overall progress of the project.

I think planning experience helps - I have in the past created schedules with too little detail and also ones with far too much detail!

Regards
Ioannis Leontiou
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Both Vladimir Liberzon and Rey Basadre have set it right

"Planning is detailing. The shorter the duration of each activity the better"

In the old days, when planning applications could not handle more than 100 activities, we were frustrated waiting for the next improved version to overcome this.

YES planning in as much detail as possible, will give much more advantages during tracking and updating, and will help produce any report, These reports could be overall and high level or in detail at your will.

This assumes that we have to do a lot of work and a lot of input. This should be the practice, unless we want to hide something, but planning is "Revealing everything", at least for in "house" purposes

Thanks

Ioannis Leontiou
Brennan Westworth
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My point is that there is a limit to the amount of detail you should go to in your schedule. More detail does not necessarily mean a better schedule.
The schedule shall be able to simulate project execution and give the answer to potential questions like:
what resources are needed and when? what materials are needed, in what quantities and when? what project cost distribution is expected? what contingency resources shall be created? etc.
Management shall get necessary reports for decision making and shall require details if necessary.
Detailed schedule does not mean that management will get too involved in the detail. But if the schedule is not detailed you will not be able properly simulate resource work.
Regards,
Vladimir
Rey Basadre
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Planning is detailing. The shorter the duration of each activity the better.

As to presenting or giving management an overview? Ah, that’s where the WBS, the activities roll-up, etc comes to play... as long as the schedule code structure is sound.
Brennan Westworth
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"If planning can be defined as modeling the project by decomposing the project into its constituent tasks, then it follows that more decomposition, ie more and more detail, is better modeling." (Trev)

I would disagree with this statement, I have seen many schedules where the level of detail is too great. This results in management getting too involved in the detail instead of taking an overview.
Ioannis Leontiou
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Let me agree with some of the replies.

But what is planning and scheduling for?

As Trevor mentioned, decomposing a project into its various activities, is a rigorous and time consuming job and has to be done ASAP.

For my point of view this activities should be so unique and clearly defined, so the planning team could identify the exact duration and resources needed, (always have in mind that the production rates are not so constant even for the same "type" of tasks), based of course on the amount of workload and quantities.

Leontiou
Trevor Rabey
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When the task is easily measurable, eg lay 10km of track or pour 100m3 of concrete or lay 10000 bricks, it can have a longer duration, but when harder to measure must be shorter.
It’s still better not to see 120 day tasks in a construction project.
Brennan Westworth
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I usually use the rule of thumb that the maximum duration should be equal to twice the update frequency.

weekly schedule updates = max duration of two weeks

This way an activity should be either started, in progress or completed in any sucessive update.

Exceptions to this are linear activities, the simplest exapmle of this is construction of a 10km stretch of rail. These activities can be longer and their progress is best monitored by production curves.


Trevor Rabey
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If planning can be defined as modeling the project by decomposing the project into its constituent tasks, then it follows that more decomposition, ie more and more detail, is better modeling.

When contracts stipulate a particular max duration, this obviously done on someone’s advice that it is just good practice. They choose a particular number which seems reasonable and because the lawyers who write the contract are hung up on certainty.

So many modeling problems can be fixed just by chopping up the project into more tasks.
Problems with complicated predecessor links and negative lag, date constraints and all other kinds of bad modeling just go away.

Good modeling in the planning phase really pays off in the execution and tracking.

It is important to try to make the duration of the task at least shorter than the reporting period, usually monthly.

Very long durations just say "I can’t define this task".
If a task has a max duration of about 1 week and is something that is done by one person or a small team, in Australia this costs about $1000. This leads to a possibility to estimate how many tasks will describe the project, according to the overall cost/value of the project, eg 1000 tasks per $1M.
Rey Basadre
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Guys,

I agree entirely to have 20 short-termed 100% completed activities than a 10% long-period single bar when presenting progress of a project.

It may take several months of planning and thousands more short-termed activities to link, resource, and what-else (that is exactly the reason planners/schedulers exists) but during the course of project execution the analyzing, forecasting and re-scheduling will be more realistic.

The benefit is glaring when generating/re-scheduling 3-weeks look-ahead taking into consideration a shortage of resources at-hand for example, expected availability/delivery of resources, the current site condition, and other factors affecting progress as originally planned.

The term “maximum duration” is open to argument. Until the precise definition is specified in the contract or agreed by all parties involve, the practice of building a schedule with a 15 to 21-days duration activities is worth it.

Cheers,

Rey
Tahir

It depends entirely upon what the activity is as to whether it can be split.

"Design Software" 120 days. Can for example usually be split into design (several) modules, test modules, integrate, retest etc. "Build Tunnel" 300 days. Split it by rings, chainage, location.

Remember for whom you are ultimately working. The Client. If they want short activities, let them have short activities. They are paying your salary.

If you have a fully resourced activity 120 days duration, including manpower, materials, overheads etc, then you can probably leave it like that and show progress against the resources used. But if it is not fully resourced? Or if it is a summary of a sub-contractor then what?

There is no right and wrong here. Some cases; long durations are fine, others definitely not. Again from the clients side, it often ’looks better’ to have 20 activities being completed and that little progress bar being filled in all the way down a sequence of activities than a couple of millimetres further along a single long bar. Presentation can be important to some clients.

As I said no right answers, no wrong answers. Every case is different.

Cheers

Nige
Tahir Naseem PMP,...
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Dear Nigel
I am totally agreed with Mr. Ashraf point of view and explanation. Would you like to explain if one activities is 120 days how you will break it. Then why we feel the need of computerised monitoring system. Then why we need the percentage weightages in the planing field. As per your way the planner lfe become so easy but we cant say it a logical and systematic planning in the construction field.
Sorry if you feel some word.
regards
Tahir
Hi All

The reason for the maximum duration is to make monitoring easier. The only exception is procurement lead time.

Had to do this on numerous contracts. Look at it from the client’s point of view, it is a lot easier to monitor a short duration than a long. And now that I work for the client...

"Are we going to finish in time" on a 2 week activity is an easier question to answer than the same question on a 120 day activity. Similarly progress percentages, remaining durations etc.

Some activities must be longer than 2-3 weeks - concrete curing time for one - but most need not.

Cheers

Nige

ashraf alawady
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*I believe that the max. duration can not be fixed in general to be as a role for any project.
*max. duration can only discussed and mutually agreed betwwen all te parties(client, engineer and the contractor) in the beging of the project.
*max. duration is depending on the following:-
condition of contract(if it was specifed clearly).
type of the project.
Quantities for the major activities of the project.
Original total duration of the project.
Reasonable period for monitoring and reporting of the progess.
Benefit of the project.
approval from the client &acceptance from the contractor.

If we have a project with a total duration 2 or 3 months only or we have a project with a total duration 4 or 5 years, how can planners saying that the max. duration should be 14 to 21 days(it does not make sence).

REGADS

Aurelio Eugenio D...
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That would depend on the conditions of the contract. Sometimes they specify the maximum durations on activities for the client and his rep to monitor progress.

Leo