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NETWORK PATH ANALYSIS
Table 24.1
B
A
C
D
G
I
E
F
Float Time
There are two types of float times for non – critical activities:
1.
Total Float:
is the amount of time an activity can be delayed without delaying the duration fo
the whole project. The formula to calculate the total float is
T F = LFT – Duration – EST
2.
Free Float:
it is the amount of time an activity can be delayed without delaying the start of the
following activities. The formula is:
Free Float = EST (next activity) – duration – EST (this activity)
ACTIVITY
0
1
3
2
0
3
5
4
16
7
16
6
10
5
10
2
3
10
14
6
14
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Critical path: ADGH
Total Floats = LFT – Duration – EST
TFB = 6 – 2 – 9 = 4 wks
TFE = 14 – 8 – 2 = 4 wks
TFC = 10 – 2 – 3 = 5 wks
TFF = 14 – 4 – 5 = 5 wks
B
Free Floats = EST 9next activity – Duration – EST (this activity)
FFB = 2 – 2 – 0 = 0 wks
FFE = 14 – 8 – 2 = 4 wks
FFC = 5 – 2 – 3 = 0 wks
FFF = 14 – 4 – 5 – 5 wks
B
4.
D is a critical activity and its delay usually leads to delays in the whole project.
However, the project could still be completed on time by speeding up the prelaunch advertising i.e. instead of conducting it for four weeks, it may be
conducted for just 2 weeks. This depends on duration of delay in activity D. also,
the additional resources for speeding up production of adverts could come from
non-critical ones. E.g. instead of focusing on buklding upstikcs, labour from this
activity could be proved to activity D as this activity E can be afforded to be
delayed for sometime.
0
1
10
2
52
0
20
4
7
59
82
10
82
48
34
5
62
20
59
20
3
22
6
64
42
8
70
74
9
74
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b.
Critical path: EHKL
Duration:
20 = 39 = 15 = 8 = 82 days
Total Floats: LFT – Duration – EST
TFA = 48 – 20 – 0 = 28 days
TFB = 52 – 10 – 0 = 42 day
TFC = 62 – 26 – 0 = 36 days
TFD = 62 – 14 – 20 = 28 days
TFF = 64 – 12 – 10 = 42 days
TFG = 70 – 8 – 34 = 28 days
TFI = 70 – 6 – 22 = 42 days
TFJ = 74 – 4 – 42 = 28 days
B
It goods were to arrive on day 25, then the starting of cash would be 5 days after
the EST and thus there would be idle resources for these days causing
unnecessary delays. These resources after quick completion of task D could
have been utilized in the critical tasks in case of unexpected delays in critical
activities.
If goods were to arrive on day 15, then this would just be pointless and may
causes problems in working capital management or shortage of cash. Activity D
could only be started on day 20 which is EST and by having goods arrive before,
there would be no speeding up of the project completion.
C
A
E
C
6 days
G
16 days
D
6 days
F
H
3 days