link between eng. and procurement

Suggest that you provide some allowance for submittal rejection, not uncommon and many times a possibility not considered.  In long duration jobs it might be advisable to delay some deliveries keeping a minimum buffer.  In other jobs where storage space is limited deliveries shall be coordinated to be just in time or ALAP.  

As a general rule try to get the approvals ASAP and deliveries some shall be scheduled ASAP others DELAYED depending on the need and storage facilities, there are no universal rules, but common sense that never is precise, so in both cases some buffer must be considered. 

As the job progress if expected delivery does not change progress the activity as planned if not then adjust remaining duration so that the end of delivery activity matches with expected delivery date.  Some software provides a special constraint that will adjust remaining duration to an expected finish date, is not a real constraint but a remaining duration calculator. 

In summary the following might be a list of activities in tandem for each procurement set.

1. Prepare Submittal 
2. Engineer Approval/Rejection   usually 2 weeks unless otherwise stated under contract conditions
3. Additional activities if rejected to consume an approval buffer.
   1. Prepare Submittal
   2. Engineer Approval/Rejection
4. Go to step 3 if rejected if approved proceed with delivery.
5. Delivery   usually an estimated time of arrival is supplied but is optimistic and you must add additional transit time if time is defined at the gate of the supplier. 
6. Delivery buffer.  We usually provide for the buffers (approval + delivery) by planning the procurement sequence with enough float and do not use buffer activities functionality that creates confusion.  In some occasions we use a hammock between the end of the delivery and start of the installation activities. 

Never say never to negative lag, in some cases it will provide for just in time with some float as ALAP will create 0 float condition, the trick is on the delay milestone. 

Best Regards

Rafael

Procurement is usually driven by leadtime of the material. Long leadtime material can become critical resulting in delay of construction work. So don't delay the ordering of long lead items. The material which is easily available can be scheduled ALAP keeping some delay margin but not long lead items.

Piping material can be ordered when detailed bill of material/quantity is available. BOQ can be calculated when isometrics are finalized and approved for construction. Sometimes isometrics are prepared very late and waiting for isometrics can lead to delay in piping material procurement. In this case, quantity is estimated using piping plans. These estimated quantities should be verified after isometrics and any difference should be ordered immediately.

So sequence will be as follows

Piping Plans---Piping isometrics---BOQ---Ordering of piping material---material leadtime---Shipment---Custom Clearance---Inland Shipment---Delivery

I hope this will help.

Thanks.

Syed Hussain

Moutaz,

I would not recommend to use lag that sets too hard constraint on the procurement date.

Procurement is planned backward from the required delivery Delivery precedes to the usage of procured items. Procurement is usually modelled as a set of activities (like contracting, production, transportation, custom clearance, delivery). If you need to track the procurement add these (or similar) activities to your schedule. If it is not necessary add just planned delivery.

To store procured items costs money and besides the guarantee time is expiring. So it makes sense to minimize storage time.

But still there are some uncertainties with timely delivery, so it makes sense to add some contingency reserve.

So I suggest following: Eng documents precede Procurement and Procurement precedes to installation with time lag (reasonable contingency reserve), but set Procurement activities as ALAP. In this case P6 automatically moves procurement dates forward as following activity(installation) and dependency lag permits. In this case if eng documents delivery will be late procurement will not move if time reserve is sufficient (with lag it will move and this is wrong if time reserve is large enough).

But if procurement contract is signed procurement activity properties shall be changed to ASAP - now delivery dates depend on contract only and installation delay will not affect pipes delivery.

Hope this may help.

Best Regards,

Vladimir

Mike,

I don't remember if Tilos includes resources constrained scheduling. Do you suggest to forget that resources are constrained, that machines may broke and welders may be on leave for some reasons?

If pipeline construction is planned for Contractor it is necessary to optimize resource crews, simulate risks, create and manage contingency reserves. Drawing time-location chart is like drawing Gantt Chart, no difference at all and it is not planning.

But it could be acceptable for the Client who thinks that resource planning is Contractor responsibility and just sets targets.

Regards,

Vladimir

Hi Moutaz

In pipelines you have to consider a linear programme.

P6 is totally inadequate for the task.

So abandon that software to start with - switch to Tilos or Vico.

Now it is unlikely that there will be one pipe specification along the line - so your programme will have to be aligned with the different types of pipe and the location.

Now select how many crews will be working and whether they are using Auto welding / semi auto / manual welding.

Once you have determined how many metres of the different pipes have to be laid and the number of welding crews to determine the completion then it is a simple process to allocate the procurement of the pipes to the installation - using ALAP links.

This allows the Engineering to precede the Procurement.

To Simplify - Installation programme first - Porcurement - Engineering - working backwards.

Easy really - when you know how.

Best regards

Mike Testro