3. • It is the earliest time in which an activity can
start in the project.
• An activity starts when its tail event occurs
hence if the tail event of the activity occurs at
its earliest time then the activity will also start
at its earliest.
5. • It is the earliest time in which an activity can
finished in the project.
• If an activity starts at its earliest time then it
also finished at its earliest finish time.
• While analysing EFT of an activity, event time
of head event is not considered as and it also
depends upon other activities.
7. • It is the latest time in which an activity can be
finished in the project without afecting the
scheduled completion time of the project.
• When an activity finished its head event
occurs hence if the head event of an activity
occurs at its latest time then it also finishes at
its latest time.
9. Types of float
• Total float FT
• Free float FF
• independent float (FIN )
• Interfering float (FIT )
10. Total float
• The total float is the time by which the starting
and finishing of an activity can be delayed
without affecting the scheduled completion time
of the project .
• It is also defined as excess of maximum time
available over the activity duration.
• While analysing the total float of an activity
finishing of preceding activity and starting of
succeeding activity is constrained and hence it
affects preceding and succeeding activity both.
11.
12. Free float
• Free float is THE +VE portion of total float that can be used by an
activity without delaying any succeeding activity( or without
affecting the total float of the succeeding activity).
• While analysing the free float of an activity finishing of preceding
activity is constrained but stating of succeeding activity is not the
constrained.
• Free float = total float – head event slack
• Ff= FT- SJ
• WHERE Ft= (TL
j - TE
i ) –t ij
• SJ = TL
j - TE
j
• F f = TE
j - TE
i – t ij
13.
14. Independent float ( FID )
• It is the time by which starting or finishing of an
activity can be delayed without affecting total
float of preceding or succeeding activity.
• While analysing the independent float of
concerned activity neither finishing of preceding
activity is the constraint nor starting of
succeeding activity is the constraint.
• Independent float = total float – head event slack
– tail event slack
– FID = FT – SJ – Si = FF – Si
– Where Si = Tl
i – TE
i
15.
16.
17. Interfering float ( FIT )
• Interfering float is just another name given to
head event slack.
• FIT = SJ = HEAD EVENT SLACK
• FIT = FT - FF
18. Find out the values of the activity times, total
float, free float , independent float .
19. Critical activities and critical path
• Out of the various types of floats, total float is the
most useful. Since the total float is the difference
between maximum available time and the activity
duration, there are 3 possibilities:
• It may have a –ve value, if the time availability is
less than activity duration .
• It may have a zero value of the time availability is
equal to the activity duration.
• It may have a positive value if time availability
exceeds the activity duration.