0-1-2-3-10-11-12-13
0-1-2-3-12-13
- Compute the early event time TE of each event
The early event time is the earliest possible date at which the event may occur. Compute
the early event time from TE(n^ = TE(n^ + D, where TE(ri) = early event time of a given
event; = TE(n^ = early event time of preceding event; D = duration of intervening activi-
ty. Where an event has multiple immediate predecessors, this equation yields multiple
values of TE\ the correct value is the maximum value.
Table 18 shows the calculations for the early event times. In the calculations, the start-
ing date of the project was used as the datum. Record the early event times on the network
by entering the time (usually in days) in a square above each event. From Table 18, the
minimum duration of this project is 37 days.
- Compute the late event time TL of each event
The late event time of each event is the latest date at which the event may occur without
extending the duration of the project beyond the minimum time. Use the relation = TL^ —
= TL(ril} - D, where = TL(n) = late event time of a given event; TL(n^ = late event time of
succeeding event; D = duration of intervening activity. Both early and late event times are
usually measured in days, but on unusually long projects they may be measured in
months. Where an event has multiple immediate successors, the equation above yields
multiple values of TL\ the correct result is the minimum value.
Table 19 shows the calculations of the late event times. Enter the late event time on
the network in a circle above each event.
- Compute the float of each activity
Float is the time, usually in days, that the completion of each activity may be delayed
without extending the duration of the project, with the understanding that no other delays
TABLE 18. Calculation of Early Event Times
Event TE, days
0 O
1 4
2 4+3 = 7
3 7 + 3 =10
4 10+14 = 24
5 24 + 2 =26
6 10 + 3 =13
7 13 + 8 =21
8 26 + 9 =35
or 21 + 12 = 33 (disregard)
9 10 + 8 =18
10 10+1 =11
11 18 + 4 =22
or 11+6=17 (disregard)
12 22 + 4 =26
or 10 + 6 = 16 (disregard)
13 35 + 2 =37
or 26 + 5 =31 (disregard)
