Greetings,
I am currently preparing a shceule for the installtion of 3 new Chillers and their auxillaries in a Plant Utilities Expansion Project.
I introduced lags in my schedule based on the lead time commitments for procurments by the shortlisted vendors during our preliminary meetings.
If I have Feeder Bucket Procurment with a lead time of 60 days from the date of purchase order, I have assinged a lag of 60 days between the activities "Release PO for Feeder" and " Receive Feeder at Site'.
Both these actvities are on a 5 day per week calender. But the Lag in between these activities also spans the 60 days on a 5 day / week basis.
I want the lag to be on a 7 days/week set up so that by schedule does not refelect 16 extra days over the 2 months of lead time.
What should i do ?
Lags should have their independent calendars when needed, sometimes equal to predecessor, sometimes equal to successor, sometimes equal to global and sometimes different with his own exceptions or non-work periods. Lag calendar shall be transparent, hidden rules shall be avoided, all software shall provide for independent lag calendar.
But in this case even if your software provides for individual lag calendars and in addition provides to make annotation for what the individual lag means it can be better if you model the waiting period as an activity.
Not all lag shall be modeled as an individual activity as this might create many unnecessary activities you will have to update.
Lag shall be used when the lag value is not expected to change, but in the case of procurement it will change frequently. If not modeled as an activity and you do not make the required adjustments the model will be wrong.
Best regards,
Rafael