TABLE 19. Calculation of Late Event Times
Event T 1 , days
13 37
12 37-5 = 32
11 3237-4 = 28
10 2837-6 = 22
9 2837-4 = 24
8 3737-2 = 35
7 3537-12 = 23
6 2337-8 = 15
5 3537-9 = 26
4 2637-2 = 24
3 2437-14=10
or 15 37-3 = 12 (disregard)
or 24 37-8 =16 (disregard)
or 2237-1=21 (disregard)
or 3237 - 6 = 26 (disregard)
2 1037-3 = 7
1 737-3=4
O 437 -4 = Owill occur. Compute the float from F = rL(7)) - (TE(i) + D), where F = float, usually in
days; TL^ = late event time of completion in the same time as F; TE^ = early event start-
ing time, in the same time units as F. The expression in parentheses represents the earliest
possible date at which the activity may be completed. Table 20 shows the float calcula-
tions.
- Identify the critical path
An activity is critical if any delay in its completion will extend the duration of the project.
The path on which the critical activities are located is termed the critical path. (There may
be several critical paths associated with a project.) In the terminology of CPM, a critical
activity is one having zero float. The critical path for this project is therefore 0-1-2-3-4-5-
8-13.
7. Verify the results of step 6
Plot the project activities on a time scale, Fig. 16. This diagram was constructed under the
assumption that each activity commences at the earliest possible date.
Note in Fig. 16 that the float of a given activity equals the total gap in the chain ex-
tending from the completion of that activity to the completion of the project. For instance,
6-7 has a float of 2 days, and 10-11 has a float of 5 + 6 = 11 days.
8. Indicate where the actual schedule departed from the forecast
List the data as follows:
New Delay in completion,
Old mark mark days
D 3-9 *
H 3-12
I 11-12 1