and manpower are required. There are four basic types
of schedules: progress, material, equipment, and
Progress schedules coordinate all the projects of a
Seabee deployment or all the activities of a single
project. They show the sequence, the starting time, the
performance time required, and the time required for
completion. Material schedules show when the
material is needed on the job. They may also show the
sequence in which materials should be delivered.
Equipment schedules coordinate all the equipment to
be used on a project. They also show when it is to be
used and the amount of time each piece of equipment
is required to perform the work. Labor schedules
coordinate the manpower requirements of a project
and show the number of personnel required for each
activity. In addition, the number of personnel of each
rating (Builder, Construction Electrician, Equipment
Operator, Steelworker, and Utilitiesman) required for
each activity for each period of time may be shown.
The time unit shown in a schedule should be some
convenient interval, such as a day, a week, or a month.
A network represents any sequencing of priorities
among the activities that form a project. This
sequencing is determined by hard or soft
dependencies. Hard dependencies are based upon the
physical characteristics of the job, such as the
necessity for placing a foundation before building the
walls. A hard dependency is normally inflexible. Soft
dependencies are based upon practical considerations
of policy and may be changed if circumstances
demand. The decision to start at the north end of a
building, rather than at the south end, is an example.
Network procedures are based upon a system that
identifies and schedules key events into
precedence-related patterns. Since the events are
interdependent, proper arrangement helps in
monitoring the independent activities and in
evaluating project progress. The basic concept is
known as the critical path method (CPM). Because the
C P M p l a c e s g r e a t e m p h a s i s U p o n t a s k
accomplishment, a means of activity identification
must be established to track the progress of an activity.
The method currently in use is the activity-on-node
precedence diagraming method (PDM) where a
node is simply the graphic representation of an
activity. An example of this is shown in figure 2-24.
To build a flexible CPM network, the manager
needs a reliable means of obtaining project data to be
represented by a node. An activity in a precedence
diagram is represented by a rectangular box and
identified by an activity number.
The left side of the activity block represents the
start of the activity. The right side represents the
completion. Lines linking the boxes are called
connectors. The general direction of flow is evident in
the connectors themselves. Figure 2-25 shows a
typical activity block used by the NCF.
Activities may be divided into the following two
1. Working Activities Activities that relate to
2. Critical activities Activities that together,
comprise the longest path through the network. This is
represented by two slashes drawn through an activity
The activities are sequenced logically to show the
activity flow for the project. The activity flow can be
determined by answering the following questions:
Figure 2-24.Precedence diagram.
Figure 2-25.Typical activity block.
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