DuPont
developed a Critical Path Method (CPM) designed to address the challenge of
shutting down chemical plants for maintenance and then restarting the plants
once the maintenance had been completed.
Complex
project, like the above example, require a series of activities, some of which
must be performed sequentially and others that can be performed in parallel
with other activities. This collection of series and parallel tasks can be
modeled as a network.
CPM
models the activities and events of a project as a network. Activities are
shown as nodes on the network and events that signify the beginning or ending
of activities are shown as arcs or lines between the nodes. The Figure 7.3
shows an example of a CPM network diagram:
The
critical path is the longest-duration path through the network. The
significance of the critical path is that the activities that lie on it cannot
be delayed without delaying the project. Because of its impact on the entire
project, critical path analysis is an important aspect of project planning.