Dangling event and Dummy activity in network diagram

Dangling event and Dummy activity in network diagram.  (Apr 2004)

Dangling event – It means an event which is not connected to another event by an activity. An activity is merging into the event, but no activity is starting or emerging from that event (Except the last event of the network.) Hence, the event becomes detached from the network.

Dummy activity – A Dummy activity is an imaginary activity. It does not exist in the Project activities. It is used in the network diagram to show dependency relationship or connectivity between two or more activities. It is represented by a dotted arrow.

Say in a network following is the dependency relationship-

Activity           Preceding Activity

D                                 B

E                                  B, C

Activity D follows activity B. Activity E follows both the activities B & C. Hence, for drawing E, we need to show a connection between B & C. Hence, from B we will draw a Dummy activity on C.