prepare government construction specifications. The 16 major divisions of work are as follows:

1. General;

2. Site work;

3. Concrete;

4. Masonry;

5. Metal;

6. Carpentry;

7. Moisture protection;

8. Doors, windows, glass;

9. Finishes;

10. Specialties;

11. Architectural equipment;

12. Furnishings;

13. Special construction;

14. Conveying systems;

15. Mechanical; and

16. Electrical.

The activities in the various labor estimating tables are divided into units of measurement commonly associated with each craft and material takeoff quantities. There is only one amount of man-hour effort per unit of work. This number represents normal Seabee production under average conditions. As used herein, 1 man-day equals 8 man-hours of direct labor. Man-day figures do not include overhead items, such as dental or personnel visits, transportation to and from the jobsite, or inclement weather.

No two jobs are exactly alike, nor do they have exactly the same conditions. Therefore, you, as the estimator, must exercise some judgment about the project that is being planned. The production efficiency guide chart and graph (table 9-2 and figure 9-7) are provided to assist you in weighing the many factors that contribute to varying production conditions and the eventual completion of a project. You can then translate what is known about a particular project and produce a more accurate quantity from the average figures given on the labor estimating tables.

SCHEDULING

LEARNING OBJECTIVE: Upon completing this section, you should be able to explain the scheduling requirements for a construction project.

After World War II, the construction industry experienced the same critical examination that the manufacturing industry had experienced 50 years before. Large construction projects came under the same pressures of time, resources, and cost that prompted studies in scientific management in the factories.

The emphasis, however, was not on actual building methods, but upon the management techniques of programming and scheduling. The only planning methods being used at that time were those developed for use in factories. Management tried to use these methods to control large construction projects. These techniques suffered from serious limitations in project work. The need to overcome these limitations led to the development of network analysis techniques.

BASIC CONCEPTS

In the late 1950s, this new system of project planning, scheduling, and control came into widespread use in the construction industry. The critical path analysis (CPA), critical path method (CPM), and project evaluation and review technique (PERT) are samples of about 50 different approaches. The basis of each of these approaches is the analysis of a network of events and activities. For this reason, the generic title covering the various networks is "network analysis."

Network analysis techniques are now the accepted method of construction planning in many organizations. They form the core of project planning and control systems.

Advantages and Disadvantages

There are many advantages of network analysis. As a management tool, it readily separates planning from scheduling of time. The analysis diagram, a pictorial representation of the project, enables you to see the interdependencies between events and the overall project to prevent unrealistic or superficial planning. Resource and time restraints are easily