Eskom Procurement Book 2015

PURCHASING ANALYSIS TOOLS AND TECHNIQUES

if help can be enlisted then parallel paths are possible. The suggested rule is to schedule as if it were possible to get help. This is especially important to remember in a work setting, or it will be difficult to complete the development of the schedule.

Figure 8.5: Arrow diagram for a room cleaning project.

Parts of the work may have to be done in a certain order, but often there is flexibility. For example, milk cannot be loaded for delivery until it has been bottled. There is no single ‘right’ solution, but a diagram can be said to be wrong if it violates logic. The next step is to determine how long it will take to do the job. To do this one can use historical data for how long each activity has typically taken in the past, to estimate times for a current or future project’s tasks [4]. Once a suitable network has been drawn, with durations, it is necessary to determine the longest path in the network and whether it will meet the target completion date. The longest path through the project determines the minimum project length of time and if any activity on that path takes longer than planned, the end date will be affected accordingly. Because of its importance, this path is called the critical path.

8.6.6 SCHEDULING COMPUTATIONS

188 CHAPTER 8