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Total Float not equal in same relationship

2 replies [Last post]
Zhenguo dai
User offline. Last seen 5 years 35 weeks ago. Offline
Joined: 24 Nov 2014
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All,

I am trying to understand in what way oracle primavera calculate toatal float in same logic relationship. Thereby, I made a sample testing projest with only 3 activities A B and C

A--(FS)-->B--(FS)-->C

The duration for A B and C are all 5 days.

Now comes two results for total float with different calenders

Situation-1

When I use the same calendar(7days and 10hours) for A B and C the total float are all "0", which seems to be reseanable.

Situation-2

However, after I change calendar for B into "5 days 8 hours" then F9, I got 2.6 days for A and 0 day for B C.

The defult setting is 8 hours per day in primavera( Just for information I am not sure whether it is in relation with total float calculation)

Could anybody explain how does primavera calculate total float? why I got 2.6 day total float in situation-2?

Thank you guys.

Dennis

Replies

Gary Whitehead
User offline. Last seen 1 year 39 weeks ago. Offline

  

Task A is forecast to complete by end of Friday (for example).

But task B cannot start until Monday (becuase Saturday & Sunday are non work days on your 5 day calendar), so Task A could actually be delayed until end of Sunday without delaying Task B. That’s 2 days of float which on a 10hr calendar = 20hrs

Also Task A can start an hour earlier on Monday than Task B could (because it’s a 10hr calendar vs an 8hr calendar –starts 1hr earlier, and finishes 1hr later), so actually Task A could even be delayed an extra hour on Monday morning without delaying Task B. So that’s a total of 20+1 = 21hrs.

 

Your default settings (which is used to convert total float from hours into days) is 1day = 8hrs, hence 21hrs float = 21/8 = 2.6days float for Task A.

Zoltan Palffy
User offline. Last seen 1 day 21 hours ago. Offline
Joined: 13 Jul 2009
Posts: 2882
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that is because activity C can begin on work hour 8 of the same day that activity B finishes. There are still 2 hours of available work time in that day for activity C to begin. 

if activity B finishes at 5 pm (8 hour day) then activity C can begin on 5 pm and work 2 hours (8+2=10) on that same day and finish the other 8 hours on the next day.

go to edit users preferences and turn your times on and you will see exactly what I am talking about.

it all has to do with HOURS (TIME) in the calendar.