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Turnaround schedule levels

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floris gering
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In various literature I see two different kind of schedule levels. Level 0-4 or Level 1-5.

Which definition is commonly used ?

What would be the appropriate levels for a turnaround schedule and could someone give me some specific examples for a turnaround of each level ? (duration 2,5 weeks, 2500 mechanical hours)


Anoon Iimos
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You may not need to level resources for offshore works, but you must be always precise. It is always a safety issue, so even if your schedule says what you have to do, and the safety officer will not allow it, then of course you have to cancel it and make another precise schedule. And I guess there are no schedule levels (levels 1,2..5) for precise works, but yes WBS is always there, regardless of the weather conditions.
Rafael Davila
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As I said it is easy if using software capable of modeling spatial resources as well as other advanced resource models.

I suggest you download Spider Project Demo.

Then download sample schedule limited to less than 40 activities where you can explore how beds are leveled by the resource leveling engine.  Because of the activity number limitation on demo software instead of adding activities I suggest to increase number of beds to see how everything is automatic, no need to mess with artificial constraints. We can also explore other advanced resource modeling scenarios such as those shown in the above presentation.


Steven Auld
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It may seem insane to resource level beds manually, however due to the number of variables I find it hard to do any other way.

All personnel are mobilised by helicopter to the platform.

16 seats available on the outbound flight, up to 19 available on the return from the platform.

An individuals trip offshore cannot exceed 3 weeks.

Majority of shutdown scope is executed by external contract companies, not core crew.

Platform POB Limit for number of beds - need to make sure this number is not exceeded between flights if there is more than 1 flight on a day.

Number of flights available to the platform is limited, up to 3 per week, availability of additional flights is not guaranteed.

Shutdown plan only accounts for Shutdown Personnel - catering & other non shutdown personnel are considered for the POB Allocation but not for any other reason & not included within the plans.

Platform team competencies needs to be taken into account - i.e. are they authorised to perform Isolations of plant or not.

Number of platform competent Performing Authorities that can take permits out needs to be taken into account

Dayshift / nightshift split needs to be considered.

Work Location for SIMOPS needs to be considered - working at height means work cannot progress below it.

Fall back work needs to be identified for the usual Weather Constrained activities.

Material delivery planning needs to be taken into account due to limited deck space & only usualy 2 sailings per week to get material out. Nitrogen purging spread takes up quite a bit of deck space for the pumps & tanks of liquid nitrogen - the nitrogen tanks also flash off when sitting, so need to be mobilised as close to the shutdown start as possible, as otherwise you are loosing nitrogen all the time & would need to mobilise more offshore.

Type of Work being performed also needs to be considered - cannot break containment on Hydrocarbon systems if Hot Work / Spark Potential activities is taking place in the same area.

If breaking containment (e.g. removing a valve for replacement), I cannot release the valve flanges then wait for a rigger to be available to remove it next day - needs to happen as soon as possible after containment broken - Primavera is a pain for this as if I try to use Resource Levelling it usually ends up splitting these tasks which then needs to be resolved manually.

Currently planning shutdowns for 3 different plaforms all with different POB restrictions & flights per week - all due to happen in the same 25 day period. Currently have 35000 Man Hours in the plan & a fair bit to add yet. 

The 3 platform shutdowns are all separate scopes of work, but 2 of the platforms tie into the 3rd, so the flushing of the plant needs to be completed before the 3rd platform can start flushing. All need to be resourced separately.

Export Pipeline route is being shutdown by a 3rd party on a fixed date - all platforms need to be flushed by this date or no route available for process fluids.

Not sure how I would model the number of variables that need to be considered to rely on the software doing it for me!

Once I get the fully resourced activity details into the plan I then work out the POB Requirements - the POB Mobilisations / Demobilisations are worked into the flights lists to make sure I can get the required numbers of each trade onboard, then I work the plan up to suit the mobilisations then review & repeat until it works out. In some cases I need to remove scope from a shutdown as we cannot get sufficient competent personnel to allow us to complete the work in the required timeframe.

A single day of delay to a single platform restart can cost the company over 1 million from additional costs & lost production, so time constaints are the biggest factor. 

If you are suggesting that I could add all my activities to a planning tool & provide the seat & bed availability & it would work it all out for me automatically then I would be pushing the company to get that software.



Rafael Davila
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Leveling number of beds is an issue of resource modeling easy if considered as spatial resources.

It would be insane to resource level beds manually. 

WBS Structures are just a way to organize your schedules WBS do not interfere with resource leveling. 


In large and long projects different schedules of the same project may be used for contract management, for project management team, for project resource management. These schedules may be of different "levels" and have different time for the same events (contingency and management reserves may be added or not). If TAR project is executed by internal resources (usual way) there is not need for many different schedules and schedule levels are just the levels of WBS. TAR projects require detailed resource constrained scheduling in any case.

Bed space is one of the project constraints that shall be taken into account when resource constrained schedule is calculated.

Steven Auld
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How Peter describes it makes sense to me & is pretty much how I build my shutdown / TAR Plans.

The Level 1 Summary basically indicates overall shutdown duration - this is the one that Senior Management are interested in.

I use the Level 2 to split out the shutdown into the major Phases required to complete the shutdown (e.g. Drain-Flush-Purge-Vent-Isolate / Mechanical Window / Leak Testing / Line Walking / Start Up).

The Level 3 is split into Systems, as this relates to the Leak Testing & Line Walking - some systems are required to be available before other systems can be brought back into service (e.g. Flare & Drains systems so that Leak Testing can take place on the remaining plant systems).

Level 4 is split into Major Work Groups for each system - e.g. Vessel Inspections / Valve Replacements / Relief Valve Replacements / Discipline Routine Maintenance etc.).

Level 5 is each package of work that is to be completed within that system / Work Group.

When you say "The schedule can be collapsed up to certain level of WBS and that's all" - the same could be said for pretty much any WBS structure for any project.

The personnel requirements for each of the Level 2 items is usually quite different from the next & may require additional flights arranged to account for the change in Personnel - We require Nitrogen Pumps & Operators to purge the plant, however the requirement for these technicians once the plant has been purged is reduced & we do not have sufficient bed space to accommodate these tech's whilst executing the main body of work so we usually change out the N2 tech's for additional Pipe fitters / riggers at the end of the DFPVI phase.

Once the Majority of the Main shutdown scope has been executed, we reduce the Pipefitters / Riggers to allow the N2 Tech's to come back out to complete the leak testing.

This may not be as much of an issue on an onshore plant, however offshore is very restrictive as to how many beds we have to execute work, so having this split out helps in identifying when the main crew changes are for additional flight requirements.



I don't see any sense in the levels of TAR schedules.

The schedule can be collapsed up to certain level of WBS and that's all.

Peter Bailey
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Level 1 - Total project or TAR summary.  One single bar showing the start and end dates

Level 2 - Shows the Major Milestones of the project or TAR usually in Gantt chart style

Level 3 - Shows the Major components of the project or TAR such as systems, plant units and areas

Level 4 - Shows the main equipment types such as Exchangers, Towers, RV's etc and should align with the cost WBS

Level 5 - Shows the details of the job or activities needed to do the work on the equipment.  

Anoon Iimos
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From a layman (or even not), when you say level 1 or level 5 schedule, I guess there is no specific meaning. How do you define or structure the level(s) of the schedule for simple projects like say: Replacement of pressure relief valve? Or Cleaning of Storage Tank? What are the disciplines necessary? For me, referring to schedule levels doesn't have any meaning unless you have specific definitions.