## Network Diagram question

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Venkat
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### Network Diagram question

Hi Saket,

in the attached there are network diagrams to calculate the relationships using precedence diagramming.

I'm getting ES = '8' for activity E, but it seems to be wrong.

Thanks a lot,
Venkat
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1.08-06-2014 22-57-37.png (50.36 KiB) Viewed 5074 times
namita
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### Re: Network Diagram question

I think ES 8 is fine for E. Is there any other dependency?
Venkat
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### Re: Network Diagram question

thanks, i recalulated today morning and got the answer as '8' and learnt never calulate critical path at midnight.
indusharma
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### Re: Network Diagram question

Venkat ,

We will look into this quampus question

Regards
Indu Sharma
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saket
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### Re: Network Diagram question

Yes friends, you are doing great in calculating it

Critical Path with FF
CPM3.jpg (27.97 KiB) Viewed 5047 times

one more question, which activity has free float and what is the duration of that float ?
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namita
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### Re: Network Diagram question

I shall wait for sometime for some answers... before I do
harin4627
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### Re: Network Diagram question

Activity "c" has one day free float
indusharma
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### Re: Network Diagram question

Activity C is the only activity which is not on Critical path.
EF for C is 6, and LF is 7 (as if E need to start on 8th day, C can start as late as 7th day).

C has 1 day as free float
Indu Sharma
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namita
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### Re: Network Diagram question

Answer is correct. Just to elaborate on things we need to consider when we are talking about Free Float. Before anything else what is Free Float once again

The amount of time that a schedule activity can be delayed without delaying the early start date of any successor or violating a schedule constraint

So the important points when we think about Free Float are:

1. Is there more than one successor for the activity we are calculating the free float? If so, all successors ES should not be impacted. In current example this situation is not a problem as C has only one successor

2. Formula should be considering Start of successor activity/ies and finish of current activity

3. Free float can only come into existence if successor is having more than one activities converging on it or the successor activity is having constraint applied on it e.g. can not start before a defined date etc.... In our example E is having C and F so this condition is satisfying

So this is all about Free Float I have.. Anyone has anything more..please share
Last edited by namita on Tue Jun 10, 2014 6:11 am, edited 2 times in total.
indusharma
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### Re: Network Diagram question

Well explained Namita
Indu Sharma
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kripakrish
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### Re: Network Diagram question

In this diagram isnt cp =27 ?ABFEG=3+4+6+4=10=27? doesnt LF of G should be 27?or not necessary always.
For back ward pass would we start with LF of G as 21 or 27?
namita
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### Re: Network Diagram question

As we have dependencies, CP length will be 21 in this case. Also LF will be 21 only
Housam Bassal
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### Re: Network Diagram question

saket wrote:Yes friends, you are doing great in calculating it

CPM3.jpg

one more question, which activity has free float and what is the duration of that float ?

Saket,

I have question regarding the ES of activity E

If I calculate ES of activity E depending on EF of activity C it will be 6+1=7, however If I go by the calculation ES= EF-duration+1 = 11-4+1=8

What did you choose 8 and not 7 , is there any rule for that (for example as its ES , so we need to choose the Biggest number(forward method), and in case of EF we need to choose the smallest number(backward method)?)

Housam Bassal
manishpn
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### Re: Network Diagram question

Housam Bassal wrote:
saket wrote:Yes friends, you are doing great in calculating it

CPM3.jpg

one more question, which activity has free float and what is the duration of that float ?

Saket,

I have question regarding the ES of activity E

If I calculate ES of activity E depending on EF of activity C it will be 6+1=7, however If I go by the calculation ES= EF-duration+1 = 11-4+1=8

What did you choose 8 and not 7 , is there any rule for that (for example as its ES , so we need to choose the Biggest number(forward method), and in case of EF we need to choose the smallest number(backward method)?)
[b][i]Calculations are shown by Saket, you need to consider FF relationship and not relation between C and E[/i][/b]

harin4627 wrote:Activity "c" has one day free float

Br,
Manish P
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